U.S.S. FINBACK (SS-230) — war patrol report SS-230_FINBACK_Part1.pdf

— page 5 —
19 April 1943
To: 12 May for her fifth war patrol, through most of which she patrolled off Taiwan, and along the shipping lanes from the Japanese home islands to the Marshalls. On 27 May, she sank a cargo ship, and sent another to the bottom on 7 June. Yet another of Japan's dwindling merchant fleet was sunk by _Finback_ 4 days later. After refitting at Fremantle, Australia, 26 June to 18 July, the submarine sailed for her sixth war patrol along the Java coast. Her first contact was made 20 July, and although the freighter defended herself with gunfire, she was sunk, as was a larger cargo ship on 3 August. On 10 August, she outwitted both a surface escort and a patrol plane to inflict damage on another merchantman. _Finback_ encountered two small minefields, a tug, and an interisland steamer on 19 August, and engaged all but the tug with surface gunfire, leaving three badly damaged ships behind when her dwindling supply of ammunition forced her to break off the action.

After a major overhaul at Pearl Harbor between 12 September 1943 and 15 December, _Finback_ sailed for the South China Sea on her seventh war patrol, characterized by heavy weather, few contacts, and continued sighting of patrol planes. She sank a large tanker in a surface attack on New Year's Day 1944, sent a fishing trawler to the bottom after a surface gunfire action on 30 January, and left another badly damaged after a similar action the next day.

The submarine refitted at Pearl Harbor once more between 11 February 1944 and 6 March, then sailed for her eighth war patrol, off Turk in the Caroline Islands. Prevented from launching attacks through most of this patrol because of her assignment as life-guard for carrier air strikes on targets in the Car- lines, _Finback_ contacted a six-ship convoy on 12 April, noting three escorts. She attacked four of the ships before heavy counter-attack sent her deep. On 16 April, while making a reconnaissance of Oroluk Atoll, she fired on a partially submerged steamer and a lookout tower on the atoll. Three days later, she sank one of a group of sampans, then sank a freighter off Pearl Harbor from 1 May to 30 May.

During her ninth war patrol, off the Palaus and west of the Marianas, _Finback_ again had as her primary mission lifeguard duty during plane strikes covering the opening of the Marianas operation. She returned to May 21 July 1944 for refit, then sailed 16 August on her tenth war patrol, assigned to life-guard duty in the Bonaire. Guided by friendly aircraft, she rescued a total of five downed pilots, one very close inshore off Iwo Jima. On 10 and 11 September, she tracked a convoy, and although twice her attacks were broken off by an alert escort, she sank two small freighters. On her eleventh war patrol, for which she prepared at Pearl Harbor from 4 October to 1 November, _Finback_ was again detailed to lifeguard duty in the Bonaire. She sank a freighter on 16 December, and returned to Midway 24 December.

The submarine's third war patrol, made between 20 January 1945 and 25 March in the East China Sea, was frustrated by lack of worthwhile targets, and _Finback_ returned to Pearl Harbor for thorough overhaul. Still at Pearl Harbor at the close of the war, she sailed for New London 29 August 1945.

Homeported at New London for the remaining 5 years of her active career, _Finback_ was engaged in training student submariners. Twice, in 1947 and in 1948, she sailed to the Caribbean to take part in 2d Fleet exercises. She was decommissioned and placed in reserve at New London 21 April 1950.

All save the third, ninth, and twelfth of _Finback's_ war patrols were designated "Successful." She received 13 battle stars for World War II service, and is credited with having sunk 59,383 tons of enemy shipping.

---

**Finch**

A family of small or moderate-sized singing birds. (AM-9 was named for the bird.)

Joseph Warren Finch, Jr., born 8 March 1920 in Chicago, Ill., was appointed ensign in the Naval Reserve 28 May 1941. He was killed in action in the naval Battle of Guadalcanal, 13 November 1942, when his ship _Laffey_ (DD-459) was sunk. Lieutenant Junior grade _Finch_ shared posthumously in the Presidential Unit Citation awarded his ship for its outstanding performance in action against the Japanese in the southwest Pacific from 15 September until his loss. (DD-328 is named in his honor.)

---

(A) - 9.50 ft. (9.50 m); 1.87'10"; b. 35'6"; dr. 10'4"; s. 14 k.; cpl. 78; a. 2 3")

The first _Finch_ (AM-9) was launched 30 March 1918 by Standard Shipbuilding Co., New York, N.Y.; sponsored by Mrs. F. G. Peabody; and commissioned 10 September 1918, Lieutenant J. C. Lindberg in command. After training and operations with a submarine kill, Orkney Islands, Scotland. Here she based for months of duty removing the vast number of mines laid in the North Sea during World War I. _Finch_ returned to Carrier 29 November 1920, and on 3 January 1920 sailed for San Pedro, Calif., where mission. Modernized, she sailed from San Francisco 20 August 1921 for duty with the Asiatic Fleet, and for the next 20 years, served in the Philippines in the summer and out of the China base at Chefoo in the Philippines. Her duties were varied, and included towing and salvage work, as well as participation in the Tangtze River Patrol. She joined in fleet exercises, and as war tension heightened, played a part in protecting American citizens and interests in the Far East. In 1941, she began work in intensive development facilities with submarine and mine groups in the Pacific, and as war came closer, spent December without more at the eastern point of Corregidor, _Finch_ was damaged by the near miss of a Japanese bomb, her seas opening and fragments of the bomb piercing her hull. The entire crew landed safely, and _Finch_ was abandoned to sink the next day, 10 April 1942.

_Finch_ received one battle star for World War II service.

---

II

(DE-328: dp. 1,200; l. 306"; b. 36'7"; dr. 8'7"; s. 21 k.; cpl. 186; a. 3 3"; 3 21" tt., 8 dcp., 1 dcp. (hh.). 2 dct.; cl. Edstaff)

The second _Finch_ (DE-328) was launched 28 August 1943 by Consolidated Steel Corp., Orange, Tex.; sponsored by Miss Grace Cushing, fiancee of Lieutenant (junior grade) Finch; and commissioned 13 December 1943, Lieutenant Commander A. H. Nienau, USNR, in command.

_Finch_ arrived at Curacao, Netherland's West Indies, 7 March 1944, and from that time until 31 May, twice escorted convoys of tankers laden with vital petroleum ing in the Caribbean and in Casco Bay, Maine, prepared for her departure from Norfolk 28 July 1944. She was assigned to the assault on Southern France. The escort ship returned from this voyage to New York 31 August.

Between 29 September 1944 and 8 May 1945, _Finch_ sailed as escort to five convoys from New York and Boston to ports in Great Britain. Upon the end of the European phase of the war, the escort ship prepared

— page 6 —
15 14 15
FF12-10/A16-3(5)
Serial 0977
DECLASSIFIED
COMMANDER IN CHIEF
U.S. FLEET
GENERAL
UNITED STATES PACIFIC FLEET
SUBMARINES, PACIFIC FLEET
Care of Fleet Post Office
San Francisco, California.
August 26, 1942.

From: The Commander Submarines, Pacific Fleet.
To: Submarines, Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - First War Patrol.

Enclosure:
(A) Copy of subject war patrol.
(B) Copy of Contestgroup 8.5 Conf. 1tr. TG8.5/A16-3 Serial 08 of August 14, 1942(1st endorsement to enclosure (A)).
(C) Copy of Comsubron 10 Conf. 1tr. FC5-10/A16-3(FB5-101) Serial 09 of August 24, 1942.

1. The first war patrol of the FINBACK appears to have been efficiently conducted in spite of the difficulties connected with a noisy shaft.

2. The Commander Task Group Eight Point Five h-s given FINBACK credit for sinking a destroyer on July 5, 1942, apparently based on the following evidence:
   (a) Six torpedoes were fired in direction of two destroyers. Sound followed last torpedo to direction of target and heard one explosion after which propeller noises of that target ceased.
   (b) Although two destroyers were present, only one engaged in anti-submarine measures.
   (c) Plane observed oil on surface of Vega Bay which is general position of destroyer when hit.

In view of the circumstantial nature of this evidence, the Commander Submarines, Pacific Fleet, cannot consider this sinking positively confirmed. However FINBACK is credited with 1 hit and damage to 1 destroyer.

DECLASSIFIED

— page 7 —
1. U.S.S. FINBACK - FIRST WAR PATROL.
2. U.S.S. FINBACK - FIRST WAR PATROL.
3. The FINBACK has the Bureau's approval type shield-
   ing. The radar technicians in this area are not prepared to
   make any changes at this time. However, a new type of diplexer
   is about to be issued which may remedy the unsatisfactory con-
   dition.
4. The FINBACK is credited with the following dam-
   age to the enemy:
   DAMAGED
   1. Anashio Type Detroioyer - 1500 ton.
   R. H. ENGLISH.
DISTRIBUTION
(210C-42)
List I, Case 2:
Pl(5), SSs.
Special:
EN3(5); Comsublnnt(2);
ComsubS.Fnc (2); Cominch (5).

E. R. SWINBURNE,
Flag Secretary.

— page 9 —
100° port. Lost depth control for about two minutes and on next periscope exposure found transhorst had zigged away giving 150° angle on bow at over 5000 yards. Did not consider small chance of getting hit under these circumstances with disclosing presence. Failure to develop attack can be directly attributed to low visibility which prevented earlier detection which would have permitted an opportunity to close range and get in favorable firing position. It is believed enemy ships were bound for "Isik Harbor via Anchitika Pass or possibly Oglala Pass. Enemy not trailed because ship's position not considered accurate within ten miles, high speed of enemy ships (18 to 20 knots) and visibility reduced to from zero to 500 yards. Attempt to send contact report for three hours on 8270 kcs.

7/5/42
0815-Y
Picked up southwestern ship of "Isik Island. First time since on station that land has been sighted or visibility permitted reconnaissance of island. Inspected all of southern coast and sighted no ships in Vega Bay or coves along south coast.

1154-Y
Completed examination of southern coast of Isik. Headed away on course 210° T. to patrol across most probable approach to south of island from Attu.

1454-Y
Sighted two enemy destroyers one of Anagiri class and one of Asashio class (originally reported as "Hinakaze class but better scud of silhouettes indicate it was probably an Asashio class destroyer) bearing 275° T. range 6500 yards; angle on bow 25° starboard. At 1507 fired tubes-7/1, 1/2 and 1/3. at first destroyer and 1/4, 1/5 and 1/6 at second destroyer. Destroyers were overlapping one-half of a ship's length and near destroyer searching with supersonic echo ranging on 17 kcs. First destroyer a narrowly had a doubtful contact on us at this time. firing and maneuvered to avoid as the first depth charge came at 1510 and was accurately placed. Sent to 180 feet at 1509. "Fallow-ing first depth charge attack with 300 feet. Took evasive action. Received total of eighteen depth charges and heard one explosion. Time of explosion indicates one hit on second destroyer. Sound ran followed last torpedo to target. Explosion occurred fifty-two seconds after last torpedo was fired. Propeller noises ceased.

- 2 -

INCLOSURE (A)

— page 10 —
21-15-Y
Surfaced and withdrawn to southward. Attracted to get off message reporting action to 37-6, 5. Unable to get off message after two hours.

7/6/42
Patrolling off Oglala Pass. No enemy forces found. At 1233 heard sound resounding death charges at great distances. At 2400 got off message reporting action and contact. After three hours transmitting. Received message from 37-6, 5 saying reconnaissance plane had seen oil on surface of Vega Bay.

7/7/42
Got second navigational fix since reaching area when visibility lifted for about one hour. Holding sighted on southwest coast of Alaska. Visibility reduced to 500 yards before Vega Bay could be completely examined.

7/8/42
Commenced submerged approach on South Pass looking for anchored targets. Visibility closed into 500 yards. Patrolling along 100 fathom curve south of South Pass.

7/9/42
At daylight was about ten miles south of southeast end of Northwest as directed by dispatch from 37-6, 5 to observe demolition party. Visibility closed in to about 500 yards and did not lift all day. Heavy rain tides and currents were experienced. Taken not observed after about 0500.

7/11/42
Conducted reconnaissance of Vega Bay, south coast of Kiska and Little Kiska Island, South Pass and at Island. This is first day of good visibility since arrival in area. Holding sighted. Tried numerous underwater explosions in attack area. (Low order detonations similar to blasting).

7/14/42
Set course for southern part of area to get off message requesting permission to take route anywhere east to Dutch Harbor.

- 3 -

— page 11 —
7/15/42 Patrol led southern part of area and across line between Pararusihiru and kiska. Visibility very good.

: 1900-Y Left area heading for Dutch Harbor on receipt of CTG 8.5 dispatch 160545.

: 7/17/42 Arrived Dutch Harbor, transferred patient and commenced taking on fuel and stores.

: 7/19/42 Underway for station assigned in Combat Task Force Eight Operation Order No. 8-42, off kiska Island.

: 7/22/42 Arrived on station and commenced patrolling on surface.

: 7/24/42 Received C.T.G. 6.5 dispatch 250745 ordering FINBACK to observe bays on south coast of attu on 25th and 26th. Sct course for attu.

: 7/25/42 Radar ranges showed ship about ten miles off attu. Visibility 500 yards. Dov to conduct submerged observation as visibility permitted.

: 7/26/42 Departed vicinity of attu for patrol station off kiska.

: 7/27/42 Arrived patrol area, conducting surface patrol except when visibility was reduced to less than 1000 yards.

: 7/31/42 Sighted object, distance about 1500 yards, later determined to be a submarine, bearing about 1200 relative on parallel course, turned left to a 900 track for stern tube shot. Further examination revealed sub was probably Scil class but distinguishing features could not be made out positively due to low visibility. Submerged when other sub either drove or was lost in low visibility. No contact on sound. Did not attack submarine in accordance with C.T.G. 8.5 dispatch 181040.

: 0745-Y Visibility improved. Surfaced to send report, finally after 40 minutes broadcast message on 6470 keys. No receipt obtained. Retransmitted at 2355-Y

: 8/2/42 Received C.T.G. 6.5 dispatch 302359 directing FINBACK to proceed to kiska areas 7 and 8.

- 4 -

ENCLOSURE (A)

— page 12 —
8/3/42
2200-Y
Received C.T.G. 8.5 dispatch 021958 directing FINB.CK to stay northeast of arc.

8/4/42
0330-Y
Received C.T.G. 8.5 dispatch directing FINB.CK to transmit during darkness on 450 kcs. asking her position.

2200-Y
Broadcast message to GRUNION. Received no answer. Sent results to C.T.G. 8.5 and proceeded to west at 18 knots.

8/5/42
0445-Y
Heard eight explosions several miles astern. Believe them to be aircraft bombs dropped by enemy patrol plane making dawn patrol of arc where FINB.CK was located by DP while transmitting on 450 kcs. The plane probably saw wake of ship and followed track to point of dive as the sea was very smooth. No other explanation seems plausible for dropping of bombs ninety seven miles from nearest land. The last bomb sounded like a 300 pound depth charge about 200 yards away. The noise had a "swish". Nothing could be sighted through periscope.

8/6/42
1250-Y
Heard eight heavy explosions to the eastward.

8/7/42
2330-Y
Received C.T.G. 8.5 dispatch 081043 directing FINB.CK to leave station at darkness on 8 August 1942.

8/8/42
2030-Y
Deported station for Dutch Harbor.

8/9/42
0100-Y
Received C.T.G. 8.5 dispatch 090537 directing FINB.CK to proceed to Nazan Bay and carry out special mission assigned by C.T.F. 8. Narrative of this mission covered in enclosure (b).

8/11/42
2220-Y
Mission completed. Deported for Dutch Harbor.

8/12/42
Arrived at Dutch Harbor.

- 5 -

— page 13 —
2. "Weather:-
North of latitude 370 N the sea was force 2 and the sky continually overcast. No star sights could be obtained before the morning. The weather on the morning of the 2nd was fair. The visibility was good, but the sky was overcast. The visibility was good

— page 14 —
5. Description of enemy vessels sighted:

CONTACT: DATE: POSITION :COURSE: SPEED: TIME : DESCRIPTION OF VESSEL
NO :

— page 15 —
7. See printed form (Enclosure (C)) for "Summary of Submarine Attacks".

8. Enemy A/S Measures:
   - (a) Enemy used supersonic echo ranging on 17.0 kcs.
   - (b) On depth charge attack on 5 July, the first pair of depth charges exploded exactly three minutes after the first torpedo was fired, one forward and one aft of Conning Tower and to Port. Subsequent attacks were accurately placed and all charges exploded above the ship. Destroyer used short scale pinings and apparently did not stop to listen. His screws could not be heard continually, and bearings were obtained on his sound projector. He ran at constant speed due to the fact that the port shaft howled below 85 turns or when starting or stopping.

   (c) All explosives dropped for FINBACK's benefit by planes are believed to have been aircraft bombs. The attack on 9 August, from a low flying plane was very accurate.

9. Major defects experienced:
   - (a) On the third day out, during training dive, the port shaft developed a squeal and terrific vibration below 130 RPM. Upon speeding up the squeal and vibration disappeared. At first the noise was traced to the reduction gear of starboard coupling. Then it was traced to the strut bearings for the noise appeared first in the after torpedo room. The next morning the shaft could be run as low as 100 turns without vibration or noise. Prior to arrival in the area the shaft ceased vibrating above 65 RPM, but could be heard in the sound gear up to 85 RPM. It has remained at this speed of 85 RPM and consequently has not been used during submerged petrol except in an emergency. This condition must be corrected prior to next patrol. It is believed that the enemy destroyer attacked on 5 July, picked up ship prior to firing because of the squeal of this shaft. The noise has not decreased and now (August 12th) the noise seems much more pronounced and is a definite handicap to submerged operations. Below 100 feet at 65 RPM the noise in the Torpedo Room is almost unbearable.

- 8- - ENCLOSURE (A)

— page 16 —
10. Radio Reception:
(a) Radio reception from Commander Task Group Eight Point Five and this task unit were very satisfactory through NPL Fox. On one occasion a dispatch was not repeated on the submarine Fox schedule which required movement to a new area until the following night.

(b) When patrolling the area to the south of Kiska considerably difficulty was experienced clearing traffic on 8270 kcs. On one occasion 4135, 8270, 4235, 8470 and 12,705 kcs were all tried during the space of one day without success. The message was finally delivered at night on 2716 kcs to TR, Dutch Harbor.

(c) The Radar causes considerable interference but does not completely prohibit copying of NPL on low frequency. It is impossible to copy high frequency with the Radar operating.

(d) Submerged reception on the loop was last accomplished while at 57 feet when about 1000 miles from Pearl Harbor.

(e) On several occasions 4235 kcs was jammed by the Japanese for short periods, 8270 kcs was continually jammed by the Japanese. Occasional transmissions by the Japanese were heard on 450 kcs, but no traffic was received on this frequency from our own units on the area.

(f) Except for difficulty in transmission south of Kiska, radio transmission on 4235 kcs at night was very successful to both NPL and TR.

(g) All cables were received from C.T.G. 6.5 and the last sent was C.T.G. 8.5 13 May Serial ______.

(h) Radar proved very useful in navigating in this area with the prevailing fog. "Good" "Pips" were obtained on peaks as far as 35 miles, the limit of the screen.

(i) Spare Radar tubes, as many as 5000 in some cases, are considered necessary, as the radar transmitter was used almost continually on the surface.

- 9 -

ENCLOSURE (A)

— page 17 —
U.S.S. FINBACK - REPORT OF FIRST WAR PATROL.

11. Sound Conditions and Density Layers:
   - (a) Sound conditions on the area are very poor. On the occasion of the sighting on July 3, no propeller noise was heard, and the enemy would not have been heard unless they had been pinging.
   - (b) In the attack on the 5th of July, the propellers of the destroyers were not heard until about 2500 yards distant.
   - (c) Several unidentified noises were heard in the vicinity of Kiska. These were a "tapping" sound which accelerated and decelerated in speed and was noted in Vega Bay, south of Anchitka and north of Sirius Point when within 12 to 25 miles of the Island and south of Attu.
   - (d) The fathometer was useful and practically indispensable to navigation in this area, and excellent results were obtained.

12. Health and Habitability:
   - Health and habitability in general was very good in spite of heavy sweating of boat. One case of acute appendicitis successfully delivered to the dispensary at Dutch Harbor.

13. Miles Steamed:
   - Enroute to Station: 2550
   - From Station: 1246
   - On Station: 6038

14. Fuel oil expended:
   - 90,675 gallons.

15. Factors of Endurance Remaining:
   - Torpedoes: 18
   - Fuel: 48,710
   - Provisions (Days): 35
   - Fresh Water: Unlimited
   - Personnel: 10

- 10 - ENCLOSURE (..)

— page 18 —
16. Factor causing end of patrol:-
    Orders from Com.Task Group Eight Point Five.

17. Remarks:-
    (a) Twilight in this latitude lasts all night until July 24th. If it were not for the fog submarine operations in the area would become untenable.
    (b) It is considered essential for morale that news be available. Provision of short wave radio sets that are not regenerative would help this situation.

- 11- ENCLOSURE (A)

— page 19 —
1. Narrative of Tanaga Surveying Party.
Subject: U.S.S. TRINIDAD - Report of First Tar Patrol.

1. Narrative of Tanaga Surveying Party.
C/9/42 Set course for Hazan Bay, Atka Island at best speed.
0530-Y Div'd on sighting plane coming out of fog on starboard quarter, distance about 1000 yards, headed directly for ship. Bomb exploded as ship reached 100 feet. Plane appeared to be very similar to our PBY Type, and Lookout identified it as type 97 Two engines Patrol Plane: 3c-cause of distance of ship north of Aleutian Chain, it is believed the ship's transmission acknowledging receipt of message ordering TRINIDAD to Hazan Bay was DF by the Navy, and the plane located us accurately by Radar. The bomb was accurately placed. Paint was taken from the overhead and a nifty cone of sighting plane carried away. The submarine shiver of water grounded out the Trinidad, and the plane was not sighted. The Trinidad was not sighted. Trinidad

— page 20 —
1st Endorsement to USS FUBACK Serial (C-023) of August 13, 1942.
August 14, 1942.

TGB.5/A16-3
Serial (08)

COI/PIDNTIAL

From: Commander Task Group Eight Point Fiye.
To: The Commander Submarines, Pacific Fleet.

Subject: Var Patrol - U.S.S. FINBACK.

1. Forwarded.

2. This, the first "Var Patrol of the FINBACK, extended for a period of forty-eight days, of which thirty-one days were spent in various patrol areas along the Aleutian Chain. The Patrol was interrupted for a period of six days while the FINBACK proceeded to Dutch Harbor to deliver a man suffering from acute appendicitis.

3. The FINBACK carried out all assigned tasks in a highly efficient manner, including a most difficult assignment in connection with a survey of Tanaga Island and Bay.

4. On 3 July contacts were made with a plane tender of the CHIYODA class and a large transport, in each case too late for attack. Low visibility prevented the FINBACK from having a "field day."

5. The FINBACK is credited with destruction of one enemy destroyer. This is based upon the attack report and upon plane report that the water where the attack occurred was covered shortly thereafter with a heavy scum of fuel oil. In view of the firing data it appears that the running depth of Lark XIV torpedoes may have been the cause of failure to obtain more than one hit. Based upon the latest information on depth performance of the Lark XIV it is believed that a depth setting of ten feet for firing at destroyers is proper.

6. The vibration and noise which developed in the port shaft soon after departure Pearl increased steadily and is believed to be due to insufficient clearance. Several of the new submarines have experienced this difficulty and it is suggested that wood bearing material is not being properly prepared by soaking for a sufficient length of time. Another defect, to which attention is invited, is the interference between Radar and

— page 21 —
1st Endorsement to
USS FINBACK Serial (C-023)
of August 13, 1942.

TGS.5/A16-3
Serial (08)

CONFIDENTIAL

Subject: 1st Patrol - U.S.S. FINBACK

high frequency radio reception. It is believed this can be eliminated by proper screening.

7. The Commanding Officer, officers, and crew of the FINBACK are congratulated upon a well conducted patrol and for the damage inflicted upon the enemy. The subject of award has been taken up by the Task Force Commander.

Copies (complete) to:
Comstockforce 8
Consubron 10

- 2 -

EDITOR'S NOTE: (B)

— page 23 —
1. NARRATIVE:
September 23, 1942.

0900(VV) Underway in company with TIKIGER and CACHALOT escorted by LITCHFIELD in accordance with Commander Task Force Seven Operation Order No. 87-42.

1335(VV) Fired 3" gun, 20 MM, and 50 and 30 cal. machine guns at target towed by LITCHFIELD.

1350(VV) Made trim dive.

1611(VV) LITCHFIELD dropped three depth charges for indoctrination at ranges of 2000, 1000 and 300 yards. Keel depth 50', depth setting 100'.

1645(VV) Calibrated R.D.F. and magnetic compass.

2000(VV) Parted company with escort. Set course for Midway.

September 24-27, 1942

Enroute Midway conducting daily training dives, fire control drills and ship's drills.

September 27, 1942

0933(Y) Cent alongside U.S.S. FULTON in Midway lagoon and commenced fueling. Made minor repairs and tuned SD and SJ Radars.

-1- ENCLOSURE (B)

— page 24 —
1600(Y) Underway for patrol area under Air and PT boat escort.
September 28 - October 9, 1942.

Proceeding to patrol area, conducting daily training dives, fire control drills, and ship's drills.

October 9, 1942.

0930(I) Entered area. Set course for point five miles south of Okinawa Shima to investigate possibility of enemy routing traffic outside of Nansai Shoto and between Miyako Shima and Okinawa Shima to Kirun. This position will also cover route between Basni channel and Yokohama.

October 10, 1942.

1622(I) Conducted submerged patrol. On surfacing sighted lights of about five sampans. Set course for Hoko Sho (Agincourt Is.). One lighted sampan ran on slightly covering course. Did not attack sampan as it was not desired to disclose presence in area. (Contact no. 1).

October 11, 1942.

Conducting surface patrol along 100 fathom curve enroute to Hoka Sho.

October 12, 1942.

0215(H) Sighted Hoka Sho Light, showing flashing white light every fourteen seconds instead of fifteen seconds. It appeared to be turned on full power.

0945(H) Dived on radar contact on planes. Radar jamming as identified from Radar Bulletin #1, page 12, top left sketch, was observed at this time. As we were 51 miles from Formosa, this seems to indicate that the Japanese Flanges were equipped with Radar operating on same frequency as our SD Radar. Lookout reported three planes, which were not seen by COD. Patrolling submerged along 100 fathom curve, twenty miles east of Hoka Sho. (See paragraph 12

- 2 -

ENCLOSURE (B)

— page 25 —
U.S.S. FINBACK - Report of Second War Patrol.

for density layer data). On surfacing, patrolled north of Hoka Sho and set course for Fuki Kaku to conduct submerged patrol.

October 13, 1942.

0230(H) Sighted lights of patrol vessel patrolling on an east-west line, ten miles north of Fuki Kaku Light. Cleared this vessel to westward. His activities prevented closing the Formosa Coast as near as desired prior to diving. (Contact no. 2).

1015(H) Sighted steamer of about 4500 tons, about one mile off Formosa coast, hull down with 900 port angle on bow. Commenced approach. Steamer apparently headed for Kirun on course of 070°. Unable to close range to less than 10,000 yards. Discontinued approach and continued to try and close coast against adverse current. (Contact no. 3).

1155(H) Sighted freighter-passenger of about 7000 tons, on course 260° T, distance 12,000 yards, angle on bow 100° starboard. Unable to close. (Contact no. 4).

1230(H) Sighted "Catcher" type patrol boat, range 7,000 yards, angle on bow 70° starboard. Considered too small to attack. (Contact no. 5). After closing coast, it was found at

1439(H) that the ship was being set to eastward at rate of about two knots with the change of tide, so changed course to northward to keep clear. Rip tidos made depth control very difficult. At one time prior to clearing Fuki Kaku ship was making good at course of 063° T, while headed 345° T, at speed of five knots. Were almost too successful in closing the beach at distance from the shore of 750 yards was reached before clearing Fuki Kaku. The current experienced at that point was estimated at about six knots setting to the eastward.

October 14, 1942.

0445(H) At 0445 while closing coast of Formosa, south of Fuki Kaku, sighted lights of patrol vessel at distance of

- 3 -

ENCLOSURE (B)

— page 26 —
U.S.S. FINBACK - Report of Second War Patrol.

five miles. At

0450(H) patrol vessel challenged by searchlight and headed toward FINBACK. (Contact no. 6). Divad and continued approach to coast assuming patrol vessel had not made definite contact. This was apparently the same patrol vessel contacted on previous morning. (Contact no. 2).

1123(H) Then unable to see patrol vessel any longer, surfaced to open distance on patrol vessel and improve position. On surfacing sighted patrol vessel headed in our general direction so dived immediately. The patrol vessel apparently did not sight us on surfacing.

1410(H) Sighted convoy consisting of a patrol vessel (Trawler-type) followed in column by four steamers, distance 10,000 yards, angle on bow 80° starboard, and speed of nine knots. (Contact no. 7). Although change of closing range seemed poor, took up normal approach course at six knots. Convoy then changed course to right reducing angle on bow sufficiently to allow us to hold bearing steady and slowly close range. The last and largest vessel in column apparently was a converted naval auxiliary carrying the convoy Commodore. She was painted war color and carried numerous boats and liferafts. This vessel flew flag signals and continually changed position, attempting to herd the next to last ship into close column. She was similar to the Kitano Haru 7951 tons, #224 of "Recognition of Japanese Merchantmen". When range was closed to about 2,000 yards and started to open, it was decided to fire. Shortly prior to firing, the auxiliary ranged ahead and to starboard of the next ship in column presenting an overlapping target. With the targets on a 115° starboard track, at

1507(H) fired two torpedoes at the auxiliary, followed by two at (Attacks the next ship. The other vessel was similar to Koyada #1&2). Muru, 5,339 tons, #105 of "Recognition of Japanese Merchantmen". Two explosions followed at times which indicated that the 1st and 4th torpedoes had hit. On raising periscope to observe the results, depth control was lost due to swallowing the "Bubbles" and only the masks could be observed, with those of the patrol boat very prominent apparently headed directly for us. Went to 180 feet in what was believed to be 200 feet of water.

- 4 -

ENCLOSURE (B)

— page 27 —
1518 (H) patrol vessel dropped a pattern of seven 'depth charges and then retired. At

1530(H) heard distant explosion believed to be on one of ships hit. At

1546(H) came to periscope depth. Observed two steamers and patrol boat continuing to southward, range 7,000 yards. The smaller vessel fired at was missing. The auxiliary was sighted at a range of 3,000 yards, well-down by the bow, with about four feet clear of water. There were liferafts in the water, she was lowering her lifeboats, and the crew was abandoning ship. Commenced turning to close auxiliary, and discovered small destroyer circling auxiliary and searching. (Contact no. 8). At

1558(H) had just started approach on destroyer when it was discovered that another destroyer, range 1,000 yards, was headed for our periscope. Ordered depth of 150 feet.

1600(H) One depth charge was dropped at range of about 500 yards while ship was at 80 feet. At

1635(H) assuming destroyer had abandoned attack, ordered periscope depth. On passing 90 feet received a pattern of four depth charges at range estimated to be 500 yards. Ordered ship to 160 feet. This seemed to indicate that a density layer existed at about 120 feet which had prevented the destroyer from picking us up at 150 feet.

1725(H) Went to periscope depth, nothing in sight. Reloaded tubes forward and surfaced. Decided not to chase remaining ships in convoy as SQR radar was out of commission, overcast sky and no moon offered small chance of a successful night attack, and further the convoy would be in the foreseeable Straits at dawn. Set course for China coast.

2042(H) Sighted Tungchuan Light. Closed light and commenced patrolling along coast on line parallel to line between Tungchuan Light and Tungyuan Taolight.

October 15, 1942

No contacts made along China coast. Set course for Hokon Sho.

- 5 -

ENCLOSURE (B)

— page 28 —
U.S.S. FINBACK - Report of Second War Patrol.

October 16, 1942.

Patrolling on 100 fathom curve 13 miles northeast of Menka Sho. At

0636(H) sighted freighter masts and stack of freighter, hull down, bearing 243° T, distant eight miles, course 150° T. (Contact no. 9). Started approach. At

0658(H) target changed course to about 170° T. Decided to conduct surface chase. Surface with stern to target and opened range with Hoka Sho Light at a distance of thirteen miles. At

0944(H) unable to see anything of target except black smoke, changed course to close target, though it appeared now that target was headed for Kirun. At

1020(H) sighted patrol vessel bearing 210° T, distant six miles. (Contact no. 10). At same time heard loud transmissions on 500 kcs distress frequency and noted "Railing" effect (Radar Bulletin #1, page 12) on SD Radar. Dived. Sighted second patrol vessel bearing 195° T. Did not see steamer again. He would have passed within five miles had he continued on course 170° T. Closed nearest patrol vessel to about 3,000 yards when he headed for Kirun.

October 17, 1942.

Patrolling between Menka Sho and Peitan Kaku.

October 18, 1942.

1008(H) Sighted steamer bearing 0950 T, course 150°, distant 12,000 yards. (Contact no. 11). Target similar to Seattle Maru. Started approach. At

1030(H) target changed course to right and began zig-zagging on base course of 270° T, heading for Kirun. Decided to use stern tubes when target zigged at ship at range of 3,000 yards. At

1110(H) fired tubes #9 and #10 at target, at estimated range of 1,100 yards (should have been 2,000 yards) and track of 110° starboard. Both torpedoes missed astern. Increased speed on

- 6 -

EXCLUSIVE (B)

— page 30 —
1145(H) sighted. steamer of about 6000 tons bearing 170°, distant 10 miles, course 300° T. (Contact no. 16). The ships leaving and approaching KIRUN' seem to follow no definite route. Some hug the coast, while others keep well clear.

: 1400(H) Sighted smoke of three ships leaving KIRUN' bearing 170° T, course 270° T. speed 10 knots and distant 7 miles. (Contact no. 17). The approach on contact no. 15 pulled us out of position for these ships. Surfaced as soon as dark obscured us from shore batteries and gave chase. All freighters identified as aindlar to Ivons' Nuru. During the chase down the west coast of FORNOSA, lighted patrol or fishing trawlers were sighted at intervals of about ten miles. At

: 2315(H) sighted the three freighter at range of 8,000 yards, bearing 035° T, and angle on bow 00°. 'As we were between the moon and the target, dived to conduct submerged approach at.

: 2340(H) Forcd '5 tube at leading ship with track of 100° port, range 500 yards and depth setting of 15 feet. Got an influence hit aft. As it was desired to get a hit on two ships as soon as possible, shifted set-up on TMO to second ship and fired #6 tube on track of 80° port (steamer was changing course) range 1,400 yards, and depth setting of 15 feet. The torpedo ran in the tube for about five seconds and then missed astern. (See "remarks" for details). As the second ship was maneuvering to avoid, shifted back to finish off leading ship who did not seem to be sinking. Fired '3 tube on 110° track and range of 1,400 yards and depth setting of 15 feet. Watched track of torpedo dis-appeared under target and fell to explode. Fired '4 tube on 160° track, range 1,800 yards and depth setting of 15 feet. 'Attched track of torpedo dis-appeared under target and fell to explode. At this time saw that the third ship was clearing out to the northward under a cloud of smoke, but the second ship was apparently thoroughly confused. He was on course 270°, angle on the port bow 900 and range of 2,500 yards. At

: 2359(H) swung ship for straight bow shot and fired '1 and '2 on 110° port track, range 2,500 yards, and a reduced depth setting of 10 feet. Result - two hits. This last torpedo was fired on 20 October and hit on 21 October. This ship

— page 32 —
U.S.S. FINBACK - Report of Second War Patrol.

The target apparently did not see the torpedoes until after they crossed his track, when he turned stern toward us and pulled away. Heard three distant explosions which were first thought to be gunfire and later identified as our own torpedoes exploding in water of about 35 fathoms at the end of their run. The interval between explosions was identical with the firing intervals.

The target was observed to fire his stern gun wildly with a 300 error in deflection. Because of target's high speed, did not give chase.

1750(H) Set course to patrol down China coast in hope of picking up some traffic from South China ports.

October 22, 1942.

Patrolling along route between Hongkong and Takao.

October 23-24, 1942.

Riding out northeast Cole along Hongkong - Takao trade route and off Takao. Experienced seas of condition eight and kind of force ten. At

2030(H) Fixed position six one-half miles southwest of Takao with SD radar and Pathfinder. To navigational lights burning.

October 25, 1942.

At

0650(H) sighted camouflaged passenger-freighter of 3,400 tons (Contact no. 19), bearing 2500 T., headed for Tankan. At

0715(H) fired tubes 7", 8", and 9", at range of 1500 yards and 1070 port track

— page 33 —
1210(H) sighted patrol boat similar to our FC-450, bearing 000° T, at range of 4,000 yards, angle on bow 100° port. (Contact no. 20). Took evasive action at periscope depth. At

: 1315(H) sighted destroyer of Momo class, bearing 000° T, range 10,000 yards, and angle on bow zero. (Contact no. 21). Started approach. At

: 1350(H) abandoned approach, went to 200 feet, ran silent and retired to west to evade one more destroyer (Contact no. 22), and three patrol boats who had joined the first destroyer. At

: 1600(H) lost searching patrols. These vessels used the usual procedure of stopping, listening, going ahead slowly and then going ahead at high speed.

October 26, 1942.

Patrolling south of Formosa off Goarap Pii.

October 27, 1942.

Patrolling along east coast of Formosa.

October 28, 1942.

Patrolling between Samucho Kaku Light and Menka Sho. Experienced extreme difficulties with depth control. Large temperature differentials (ten degrees) exist between periscope depth and 120 feet. At

: 1128(H) sighted patrol vessel ssaidiar to Contact no. 20, bearing 0550° T, distant two miles. (Contact no. 23).

: 1200(H) Patrol vessel disappeared on course 050° T.

- 11 - ENCLOSURE (B)

— page 34 —
0125(H)    At
    During poor visibility (about 3000 yards), sighted
    darkened ship bearing 2750 T. Turned toward ship and
    prepared tubes #3 and #4 for firing. Raid out ship
    to be a destroyer at about 1,000 yards, angle on bow
    300 starboard, and both decreasing rapidly. Since it
    appeared destroyed was trying to run, swung toward
    him, and dived. Did not fire due to short range and
    rough seas. Sound heard high-speed screws which
    drew rapidly down starboard side and stopped. Did
    not regain contact on conning to geriscope depth. No
    depth charges were dropped. Sound conditions were
    poor and the sea was condition six.

0351(H)    Surfaced. Patrol located northwest of Tuki Kaku.

October 31 - November 2, 1942.

Patrolling on surface off Hoka Sho and on 100 fathom
curve Icnka Sho to Jento Shosho as traffic seems to
be temporarily diverted from Kikuu. Patrol was in
position to observe traffic from Kikuu three out of
four proceeding days.

November 3, 1942.

Patrolling on surface in channel between Hiyako
Shima and Okinawa Shima. It

1435(H)    sighted ocean-going steamer off 100 ton. He attempted
    to escape. Closed to point blank range and opened
    fire with 3" gun, 20 ft, 50 cal. 17, two 30 cal. 17,
    Drowning Automatic rifle and four torpedo guns. Obtained
    nine hits with 3" out of fourteen rounds fired. Three
    shells exploded and the remainder holed the hull. All
    personal, about twelve men, were killed and the san-
    pan left squatting and low in the water. Has able to
    fire only three rounds with 20" gun. (Joe Renner's)
    As the saman was well broken up and casualties decided
    further expenditure of 3" ammunition would be un-
    necessary.

-12-    J. CLOSURE (D)

— page 35 —
1942

Patrolling on surface in channel between Hiyako China and Okinawa Shima. Tested 20:11 gun which operated satisfactorily.

November 6, 1942

Patrolling eastern part of areas on surface.

November 7, 1942

Departed area for Iidaya in accordance with operation order.

November 15, 1942

1000(Y) Arrived Iidaya. Received 19,442 gallons of fuel. Conducted dock trail and inspection of bow buoyance tank. Repair personnel unable to board ship at rendezvous due to rough weather.

November 16, 1942

1300(Y) Departed Iidaya for Pearl in accordance with Commander Task Force Seven dispatch, 160000.

November 20, 1942

Arrived Pearl.

-13-

— page 37 —
4. NAVIGATIONAL AID. (Continued).

Hoka Sho, Menka Sho and Yahei Sho are most useful in fixing your position off the northern coast of Formosa. The island of Formosa seems to be blanketed by rain and haze this time of the year.

- 15 -

NICLOSURE (B)

— page 39 —
5
Description of a convoy vs. patrol vs. patrols (continued)

| Date | Time | Location | Type of Vessel | Type of Activity | Notes |
|------|------||||-------|
| 10/9/42 | 12:00 | 12-25N, 35E | Sub | Patrol | 10/9/42, 12:00, 10 tons, 3 ships, 1 torpedo, 1 depth charge, 1 periscope, 1

— page 42 —
8. ENEMY A/S MEASURES.

(c) At present the enemy seems to be very short of escort vessels in the Kirin area. Patrol vessels were usually encountered about twenty miles of Hoka Sho as we were approaching the position at which we intended to dive. They seemed to patrol on the visibility circles of the lights of Hoka Sho, Samucho Kaku, and Puki Kaku. On the west coast of Formosa, it was noted during the chase on the night of 20 October, that lighted sampans seemed to be stationed about every ten miles on a line ten miles off shore. Due to the strong currents prevailing near the coast, it is necessary to dive at the point you intend to patrol as the current seldom runs at less than your submerged patrolling speed. Surface daylight running under the reported radar and gun emplacements on the beach was considered inadvisable.

(b) While running down the China coast, three different patrol vessels were sighted at a distance of about five miles near the various light houses. On each occasion, the DQ receiver picked up a message on the distress frequency which gave AAA followed by numerals which matched our course and gave their call number. (See paragraph 11). These messages came in on the bearing of the patrol vessels.

(c) This AAA signal was first heard on the 500 kcs distress frequency on the DQ receiver on 16 October, while conducting a surface chase of a steamer. At the same time "Railing" effect was noted on the SD Radar. The distress signal was not definitely identified as such until the night of 20-21 October following the sinking of the two freighters. The AAA message was picked up at that time containing numerals exactly corresponding with the Latitude and Longitude of the attack.

9. MINES/WEEPING OPERATIONS:

None observed.

10. MAJOR DEFECTS EXPERIENCED:

(a) Noisy Tail Shafts:

During a training dive on 5 October, while enroute area, the port shaft started squealing at about twenty RPM, and was continuous until the shaft stopped. This was the first squealing noted since the shaft was realigned at the Navy Yard, Pearl Harbor, during the last refit period. The port shaft has been

— page 43 —
U.S.S. TRIDENT - TRIPLE OPS D'AN PAROL.

carefully observed during every daily dive. To date there has been no improvement and the noise has become progressively worse. In addition the port reduction gear has become progressively noisier. The squallings noise is evident in the port strut as well as the stern tube bearings. On 25 October while running silent at 200 feet, the port shaft started to squeal at 60 RPM, and caused a roaring noise and vibration that was evident throughout the boat. This noise persisted until return to periscope depth and is now evident at any depth while running at 40 RPM or above. The starboard stern tube bearings is quiet. The starboard strut bearings starts to squeal at 20 RPM and the noise increases as the speed is increased. This noise is similar to the squeal in the port strut bearings. It is considered that this noise is due to military hazard.

(b) LENGTH OF DUTY TIME TRACK:

The flood valve on the negative tank started leaking while running silent on 25 October. This casualty made the use of negative tank impossible in close water. It is believed that the flood valve gasket is partially blown out. The forecast gasket was ruined in by the U.S. Navy during 1942.

(c) HOURS IN PORT DURING TRACK:

There is a heavy pounding noise in the vicinity of bow buoyancy tank. This noise seems to be the beginning of some heavy structural noise. The noise first appeared during the radio on 22-24 October and is heard when the ship is pitching. This bang-ing has been heard submerged and while on the surface, during rough weather. It seems to shake the whole forward part of the ship.

(d) JACK-UP DUTY:

The shaft for the TR-30 sound head emits a groaning noise which can be heard in the Control Room when trained at normal speed. Reaching of the upper bearing is not eliminated this noise. It is believed that this trouble is due to a bent shaft or tightness of machinery in the lower bearings. The electrical lead for the TR side of the head is grounded.

-21-

— page 44 —
11. RADIO RECEPTION:

(a) Last consecutive serial received: 7/7/1942
Last consecutive serial received: 7/7/1942

(b) Radio reception is general was good. Interference by a Japanese radio station was noted on the 7/15 and 6/30 series, which were very short in duration. Returning from a station, reception was strength one and strength two in the Donian area, and complete copying was very difficult.

(c) A log was kept of the signals received on the 20-21 October. A typical message was as follows:

| Date | Message |
|------||
| 7/15  | 7/15 7/

— page 45 —
12: SOUND CONDITION AND DEPLOYMENT (CONT)
(b) Sound density layer at 120 feet: twenty miles west of Puki Iaku light.

(c) Sound conditions off Radio were excellent. Targets were picked up at 14000 yards. A temperature increase of 15°F was noted at 100 feet.

(d) Sound conditions north and west of Formosa are in general very poor.

13. EXPLAIN AND IDENTIFY:

(a) The health of the crew in general was very good. Various skin fungi were contracted by numerous members of the crew. Sun-shine received at the return trip proved to be the best cure. It is believed that a sun lamp would have helped eliminate this skin ailment more rapidly.

(b) Reliability was very good except when it was necessary to secure the air condition during silent running.

(c) A washing machine was sorely missed and it is strongly recommended that one be provided prior to the next patrol.

14. ITEMS REPORT:

Enroute to station: 4541
Enroute from station (Friday): 2030

-23-

— page 47 —
18. REMARKS (Cont'd.)

(b) The ship's I.C. electrician and fire controlman also assisted in this repair work. Although much good practical knowledge of the build-up of the equipment was gained, "Cut-and-Try" methods did not seem to bring results. This vessel warmly seconds the recommendation of the HADDOCK that at least one man having technical ability to repair this Radar be placed aboard until personnel can be trained sufficiently to keep the equipment operating.

(c) It is believed that the majority of the southbound traffic is routed along the westcoast of FORMOSA. All traffic seems to arrive and depart Kirun at the slack water. Ships not in convoy, headed south, hug the coast. Patrolling close to the beach off Puki Kaku was found to be quite dangerous because of ground swells, rip tides and very strong currents. The low lying west coast makes determination of position very difficult.

(d) Depth control gave continual trouble because of currents, tide rips, and long ground swells caused by the N.E. monsoon. A depth of 60 feet was used for running and the ship was brought up to 56 feet for searching. Numerous whitecaps and absence of air patrol made longer periscope exposures possible.

(e) The majority of the ships sighted were coal burners who laid down a nice trail of smoke which was most helpful in picking them up.

(f) An impulse pressure of 315 pounds was used throughout the patrol. It is believed that a small impulse bubble contributed to enemy's weak A/S measures. This reduced pressure failed to get the torpedo out of #6 tube on the night of October 20, 1942. This could partly be attributed to the speed of six knots on the ship at that time. The poppet valve vented the tube before the torpedo left. The torpedo did not leave until the poppet was closed and the torpedo built up enough pressure to force itself free.

(g) The 20 MM gun was mounted every night when in the area and the sea was smooth enough to allow using it. The pressure proof tank on the bridge flooded with the gun several times because of poor gasket on door. This usage required continual upkeep and it is evident the

— page 48 —
10. RANGES (COIN)

QUI WAST NOT designed to be used this way. "Iron the sampan" was attached on 1 Nov 1943, 3/9/2, only three rounds were fired. This failure was due to personnel. The gun captain did not know how to clear stowage in magazine catch and feed mechanism. Personnel have been instructed.

(h) It is recommended that a topside sound inod be installed. During this patrol it was considered necessary to keep one sound head raised when operating in the shallow water along the west coast of Formosa and along the China coast due to the over present danger of grounding while submerged.

(i) It is recommended that a quiet type of trim pump be installed. Because of the noisy operation which is inherent in its design, it was never used when running silent. This is a distinct handicap as it necessitated the blowing of variable tanks to maintain depth control with the crew present during air bubbles.

(j) It is considered that the main hydraulic system should have a quiet type of automatic by-pass valve installed. It is understood that a quiet type of automatic by-pass valve has been developed by the Portsmouth Heavy Yard.

(k) The Commanding Officer desires to commend the Officers and crew for their efficiency and devotion to duty during this patrol. It is especially desirable to commend Lieutenant Commander T.A. Scott; LT, for his excellent work as investigator in tracking the convoy on 20 October, which contributed to the success of the night attack; Lieutenant J.T. Turner, Jr., USN, for his outstanding performance as Assistant Inspector of Officer; and Lieutenant P.C. Collins, USN, as Diving Officer, for his fine control of the ship during patrols when enemy tactics were necessary.

-26-

— page 49 —
5-42/A4-3  SUBMARINE DIVISION FORTY TWO
Serial (070)  Care of Fleet Post Office,
San Francisco, California,
November 24, 1942.

CONFIDENTIAL

From:  The Commander Submarine Division FORTY-TWO.
To:  The Commander Submarine Force, Pacific Fleet.
Via:  The Commander Submarine Squadron FOUK.

Subject:  U.S.S. FINBACK - Report of Second War Patrol.

1. In spite of the fact that the staffs were relieved and the bearings recorded by the Navy Yard, Pearl Harbor, during the vessel's last refit, trouble was again experienced on this patrol with squealing gantries and noisy bearings and reduction gears. The vessel was scheduled to be refitted at Midway, but in view of this serious noise which constitutes a military hazard, it was brought back to Pearl and will be sent to the yard for determination of the refit requirements and cause of noises and proper remedial action. Headlines date to depart on next patrol depends somewhat on the time required by the yard.

2. The Commanding Officer will be directed to submit more detailed recommendations covering the recommendations mentioned in paragraph 18(k).

3. It is expected that a radio technician will be available to be assigned to the FINBACK before next patrol.

4. Steps will be taken to provide sun lamps and a washing machine. It is expected that the latter can be obtained before the next patrol. It was previously understood that all Squadron TEN submarines had washing machines.

5. The FINBACK submitted a separate Radar report which was very complete and informative. It is considered that the performance of its SIT set is not representative of such equipment and unless some seriously basic defect exists, it is expected that the set will be in a satisfactory operating condition at the end of current refit. Confidence in the equipment and belief in its performance are two essential ingredients for a worthwhile radar installation.

6. Lack of material is an item that will prevent any corrective measures from being taken to improve the noisy operation of the trim pump or automatic by-pass valve for the hydraulic plant, but docking will enable investigation to be made of the groaning noise emitted by the JIC-QC sound head shaft.

- 1 -  ENCLOSURE (A)

— page 50 —
7. The reconnaissance for a torpedo head is significant. This is a feature of the submarine design conference and the heads have been installed in the hull because of superior performance but the need for it in the experience of the submarine is outlined in paragraph 15(1) as the "very accurate and well run, turns in the right."

8. Include all comments and notes in the margin. Do not remove or alter the original text.

(a) Write a description of the submarine and use or same to describe the design of the submarine.

(b) Use of the standard symbols.

(c) Accuracy of the specifications in ______ area.

(d) Radar parameters.

(e) Ship characteristics and submarine's position and course in natural groups.

(f) Frontal and cross-butt ship's ships.

(g) Failure of torpedo to clear tube.

(h) Ranges of 20 mm gun.

-2- ENCLOSURE "A"

— page 51 —
1/4/23 11:00 AM
FF12-10/A16-3(5)/ SUBMARINE FORCE, PACIFIC FLEET
Serial 01371
COCLASSIFIED
Care of Fleet Post Office,
San Francisco, California,
December 2, 1942.

CONSUMBAC PATROL REPORT NO. 100.
U.S.S. FINBACK - SECOND WAR FLEET.
From: The Commander Submarine Force, Pacific Fleet.
To: Submarine Force, Pacific Fleet.
Subject: U.S.S. FINBACK (SS230) - Report of Second War Patrol.
Enclosure: (A) Copy of Consubidv 42 Conf 1tr FB5-42/44-3, Serial 070 of November 24, 1942.
(B) Copy of subject war patrol.

1. The FINBACK, on her second war patrol, covered the assigned area with judgment and thoroughness and all contacts were aggressively exploited.

2. The percentage of torpedo hits - 35% - is slightly below the average for the months of September and October, and should improve with more training and war time experience of officers and men. Experience combined with aggressiveness, initiative, judgment and skill is the formula that sights them and sinks them.

3. There is insufficient evidence to support the claim of sinking of the 5,339 ton freighter on the 14th of October. A more likely possibility is that the 7,951 ton passenger-freighter was hit twice, and the smaller ship was able to escape beyond the range of visibility in the 39 minutes between firing and first observation. It is probable that the 7,951 ton passenger sank but because of a lack of positive evidence damage only is credited.

4. The Commanding Officer, Officers and Crew are congratulated on a job well done, in having inflicted the following damage on the enemy:

SUNK
1 Freighter - 7,000 tons
1 Freighter - 7,000 tons
1 Samoan - 100 tons
Total - 14,100 tons

DECLASSIFIED
DECLASSIFIED-ANT. 0445, OPNAVINST 5510.10
BY S/P-02/22/22 DATE 5/20/22

/24.305 -1-

— page 52 —
1/2-10/A16-3(5)/ SUBMARINE FORCE, PACIFIC FLEET (11)
Serial 01371
CONFIDENTIAL
OCCUPIED PATROL REPORT NO. 100.
U.S.S. FINBACK - SECOND AIR PATROL.
Subject: U.S.S. FINBACK (SS230) - Report of Second Air Patrol.
DAMAGED
1. Freighter - 7,951 tons
1. Freighter - 5,800 tons
Total - 13,751 tons

R. H. ENGLISH.

DISTRIBUTION:
(35CM-42)
List III: SS
Special:
Pl(5), EN3(5), Z1(5),
Consubstant (2), X3(1),
Consubowsespac (2).

E.R. S. INBURNE,
Flag Secretary.

— page 55 —
U.S.S. FINBACK (SS230)  :  Jk
SS230(A16-3)

CONFIDENTIAL

U.S.S. FINBACK - Report of Third War Patrol - Period from December 16, 1942 to February 6, 1943.

PROLOGUE:

Arrived Pearl Harbor on November 20, 1942, from Second War Patrol. Coronated refit on November 21, 1942, by Submarine Base, Pearl Harbor. Dry docked at New York, Pearl Harbor, to renew gasket on Negative tank flood valve, straighten sound head shafting, and check alignment of teal shafts. Completed on December 10, 1942. Sound test conducted, deperming not required. Training period of three days allowed.

1. NARRATIVE:

December 16, 1942.

0908(V1) Underway escorted by LITCHFIELD in accordance with Commander Task Force Seven Operation Order 112-42. Upper conning tower hatch gasket, which had been renewed and tested for tightness during refit period, leaked. Adjusted by shimning up low sectors.

1826(V1) LITCHFIELD dropped two depth charges for indoctrination at ranges of 500 and 300 yards, with depth settings of 100 and 50 feet. Depth to keel, 56 feet.

1840(V1) Fired 4" gun, and 20 Mi and .50 cal. machine guns. LITCHFIELD departed. Set course for Midway.

December 16-20, 1942.

Enroute Midway. Heavy weather encountered on December 18 and 19, preventing our arrival Midway on nineteenth. Remained outside Midway thirty mile circle until daylight.

December 20, 1942.

0927(Y) Moored to Pier at Midway. Received 21,800 gals. of fuel oil. Repaired minor damages caused by heavy weather of December 18 and 19.

1230(Y) Underway to take station for operations with Task Force 17, as directed by Cincapa.

December 23, 1942.

1805(L) Took station for operations with Task Force 17.

- 1 - ENCLOSURE (A)

— page 56 —
U.S.S. PINBACK - Report of Third War Patrol.

December 24, 1942.

1625(I) Released by Commander Task Force 17. Set course for area assigned by Commander Task Force 7 Operation Order 112-42.

December 27, 1942.

0550(K) Sighted small petrol vessel (Contact No. 1), similar to our 20450 class, bearing 310° rel., distance about 6 miles, Avoided by changes of course and speed, as vessel was too small for torpedo attack, and weather did not permit use of deck gun. Vessel flashed white light and appeared to open fire. No splash observed.

December 30, 1942.

1443(I) Sighted small patrol vessel (Contact No. 2) bearing 900° rel., distance about 9 miles, speed 2 kts. Submerged and began approach. Avoided.

1744(I) Surfaced.

2132(I) In accordance with orders, reversed course to 0900T. until.

December 31, 1942.

0645(I) when, at daylight, reached assigned position. Patrol led submerged until.

0917(I) (Started to surface at 0815 but plane was sighted close aboard).

1732(I) Abandoned search. Set course for assigned area.

January 1, 1943.

1129(I) Sighted small patrol boat (Contact No. 3), same vessel as Contact No. 2, bearing 322° rel., distance about 8 miles. Submerged and commenced approach. Closed to 2500 yards. Vessel, a small converted yacht, had 4" or 5" gun aft, and a gun forward. Avoided.

1418(I) Surfaced. Sighted small motor sampan (Contact No. 4). Submerged to avoid. Too rough for the gun.

1439(I) Surfaced.

January 3, 1943.

1830(I) Entered area. Proceeded to vicinity of TANEGA SHIMA.

- 2 -

ENCLOSURE (A)

— page 57 —
1943. Conducted submerged patrol in VAN DIEMEN STRAITS, to northcoastward of northern tip of TANEGA SHIMA. At

1819(I) Surfaced. Sighted Navy type 95 reconnaissance plane bearing 090°T, distance 2000 yards, altitude 200 feet, on opposite course.

1820(I) Divested. Apparently not sighted.

1900(I) Surfaced.

2105(I) Radar contact at 7000 yards. Submerged. Commenced approach. Target (Contact No. 5), identified as sampan. Weather too rough for dock gun.

January 4, 1943.

Conducted submerged patrol off ARIATE VAN during hours of daylight. No activity noted.

0910(I) Sighted yacht type patrol boat (Contact No. 6), bearing 081° rel., distance 4000 yards. Too small to torpedo.

1532(I) Observed formation of six planes.

2300(I) SJ Radar contact, bearing 000° rel., distance 17,000 yards. Conducted surface approach. Rader indicated large target on course 320°T. at slow speed. At

2347(I) Identified target (Contact No. 7) as patrol boat sighted earlier in day (Contact No. 6). Broke off approach at 3000 yards. Ship has large high stack, with cleverly constructed false sampan bow, and gun forward and aft. False stack and high waves aided in maintaining radar contact when coached on the bearing. Contact would fade out completely and return. Exercised radar tracking party.

January 5, 1943.

Conducted submerged patrol off entrance to ARIATE VAN, with VAN DIEMEN STRAIT, between northern TANEGA SHIMA and southern KYUSHU, under observation. No activity noted.

January 6, 1943.

Conducted submerged patrol to eastward of northern part

— page 58 —
U.S.S. FINBACK - Report of Third War Patrol.

of TANEGA SHIMA. At

1108(I) Sighted four fishing boats off east shore of TANEGA SHIMA.

January 7, 1943.

Conducted submerged patrol. At

1022(I) Sighted six planes.

January 8, 1943.

Conducted submerged patrol.

January 9, 1943.

Conducted submerged patrol along ARIANE VAN - KII SUIDO route.

0738(I) Sighted single plane.

January 10, 1943.

Proceeding in accordance with orders.

0122(I) Sighted searchlight glow beyond horizon and in direction of ARIANE VAN, bearing 260°T. Believed to be from the shore, estimated distance thirty miles.

January 11, 1943.

0510(I) Reached position. At

0607(I) Commenced submerged patrol.

1435(I) Surfaced and conducted surface patrol at estimated 1600 position. Heavy weather encountered.

January 12, 1943.

0000(I) Abandoned search. Proceeding to assigned area. One broken arm when man thrown out of high bunk due to heavy seas. At

2200(I) Entered area.

- h -

ENCLOSURE (A)

— page 59 —
2007/1/13/1943
U.S.S. FINBACK - Report of Third War Patrol.

January 13, 1943.

Patrolling southwestern sector of area, off TANEGA SHIYA, until dark. At

1241(I) Sighted small motor sampan (Contact No. 8). Minimum range about 8000 yards. At

1845(I) Surfaced. Proceeding in accordance with orders.

January 14, 1943.

Proceeding in accordance with orders. At

2150(I) Sighted two planes, bearing 0350T., distance about three miles, showing lights. Submerged and at

2220(I) Surfaced.

January 15, 1943.

Proceeding in accordance with orders. At

0645(I) Arrived at assigned position. Commenced surface patrol, changing course at two hour intervals. Expected set of 2 knots to northeast did not materialize. Experienced 1 knot set to south.

January 16, 1943.

Conducting surface patrol. At

0600(I) Abandoned search. Set course for area. At

0610(I) Following quick dive, took water through upper conning tower hatch into control room and pump room. Casualty caused by QD dogging the hatch before it was closed. After hatch was secured, surfaced. Attained maximum depth of 43 feet. At

0612(I) Commenced freeing pump room bilges of water by bailing. The below listed casualties resulted from flooding:

1. 200# Air Compressor and Motor - flooded.
2. Gyro Compass - Binnacle flooded. Follow-up system grounded. Azimuth motor burned out.

-5- ENCLOSURE (A)

— page 60 —
3. Pump room power distribution panel - flooded.
4. Both air conditioning motors and motor control panels - flooded.
5. #1 Periscope lower limit switch - grounded.
6. Drain pump control panel - flooded.
7. #1 H.P. Air Compressor motor - flooded.
8. #2 H.P. Air Compressor motor controller - flooded.
9. General announcing system - grounded.
10. JK-QC training motor generator - flooded.
11. TBL motor generator and power supply panels - flooded.
12. Commissary storeroom under control room - flooded, with loss of 750 pounds of sugar, 200 pounds of dried beans, prunes and dried peaches.

0717(I) Submerged. Commenced repairing and cleaning flooded machinery. At

1903(I) Surfaced.

January 17, 1943.

Patrolling on surface, closing land at western edge of area. At

0555(I) Submerged. Continued repairing damage caused by flooding. Rested crew. At

1835(I) Surfaced. At

2130(I) Sighted light bearing 0450T. and rel. Changed course to close, and at

2134(I) Identified vessel as patrol boat with familiar box structure aft. SJ Radar picked up vessel at a range of 3400 yards. At

2136(I) Submerged. Closed target and continued ranging with SJ Radar. At

2143(I) With vessel about 1000 yards distant, bearing 3300 rel., made battle surface. Opened fire with 4" gun and 20 MM machine gun. The weather was clear, with no moon. The 4" gun pointer reported that the light of the 20 MM tracers and explosions were blinding. Smoke frequently obscured the target after 4" shell hits. No fire was observed. At

ENCLOSURE 4

— page 61 —
2210(I) Went close aboard. No personnel observed. Target settling at. Large deck house eastern broken up. Because of proximity of land, did not set target afire. Expended 15 rounds, including 3 misfires, of 4" and 480 rounds of 20 M. Target was estimated to be 150-200 tons patrol boat. First ran of 20 M riddled the deck house and cleared the deck of personnel. The explosions of the 4" shells were devastating. At

2230(I) Continued to close coast.

January 18, 1943.

Continued to close coast. At

0551(I) Submerged to eastward of TOI MISAKI light. Numerous fishing sampans in immediate vicinity. At

1750(I) Sighted plane bearing 1600T., distance about 4 miles, on northeasterly heading. Damage incident to flooding, with exception of grounded field coils in JK-QC motor generator set, repaired.

January 19, 1943.

Continued submerged patrol off coast in northern part of area. Numerous fishing sampans observed. At

1704(I) Observed destroyer, hull down, (Contact No. 10), bearing 0090 rel., 1490T., distances about 12,000 yards, speed checked at 30 knots, on westerly course, angle on bow, 90° starboard. At

1711(I) Destroyer passed out of sight in vicinity of O SHIMA. At

1901(I) Commenced surface patrol. Proceeded east to 160° line from BUNGO SUIDO because of low visibility.

January 20, 1943.

Proceeding to eastern sector of area. At

0600(I) Commenced surface and submerged patrol along 160° line from BUNGO SUIDO. Continued low visibility and rain until, at

1000(I) Weather began to clear.

- 7 - ENCLOSURE (A)

— page 62 —
1943. Conducted surface and submerged patrol in center of area.
At: 2140(I) Noted interference on SD Radar. At: 2205(I) Interference on SD Radar died out, until: 2230(I) When it was again noted. This interference occurred during a line squall when heavy rainfall and numerous flashes of lightning were observed. Radio room receivers, R&L, RAK and DQ were blocked completely during this time.

January 22, 1943.
Conducted surface and submerged patrol in northwestern part of area. At: 0833(I) Sighted 9000 ton merchantman, range 14,000 yards end angle on bow 80° port (Contact No. 11). Commenced approach. Target zigging at 3 minute intervals. At: 0859(I) Broke off approach, with angle on the bow 120° port, and range 9000 yards. Speed checked at 17.5 knots. Too close to the beach to surface and due to high speed of target, chase would have been fruitless. This ship came through the southern side of VIN DIENEN STRAITS, avoiding TOI MISAKI. At: 1605(I) Sighted small patrol boat (Contact No. 12). At: 1817(I) Sighted similar small patrol boat (Contact No. 13). At: 1946(I) Shortly after surfacing, plane came down a bright, full and low noon at an altitude of about 200 feet. Dived. At: 2002(I) Surfaced. At: 2230(I) Sighted vessel (Contact No. 14), distance 7 miles. Commenced approach on surface. At: 2240(I) Submerged. At: 2250(I) Target identified as patrol boat. At:

— page 63 —
2358(I) Surfaced.
January 24, and 25, 1943.
Continuing surface and submerged patrol in northwestern sector of area.

January 26, 1943.
Conducting surface and submerged patrol off VAN DIEMEN STRI.ITS. At
0938(I) and
1344(I) Sighted small motor sampen.

January 27, 1943.
Conducted surface patrol proceeding to northern limits of area in vicinity of TOI MISAKI light. At
0129(I) Sighted plane on converging course. Submerged. At
0156(I) Surfaced. At
0323(I) Sighted plane. Submerged. At
0353(I) Surfaced. At
0530(I) Submerged. Patrolled area five miles to eastward of TOI MISAKI light. Numerous fishing sampans observed. Identified mast on the hill behind TOI MISAKI light house as a Radar tower. Rectangular shape on top appeared to be similar to our "Bed spring" type antennae.

January 28, 1943.
Conducted surface and submerged patrol in central sector of area near southern limit.

January 29, 1943.
Conducted surface and submerged patrol in central sector of area.

- 9 -

ENCLOSURE (A)

— page 64 —
1943
Conducting surface patrol. Cleared area. Set course for
Midway, in accordance with provisions of operation order.

February 1 and 2, 1943.
Noted interference on SD Radar and radio receivers
identical to that encountered on January 21, 1943, during
similar atmospheric conditions.

February 5, 1943.
Made six hour battery discharge with one cell jumped out
in each battery. Capacity - 114% (See paragraph 10(a)).

February 6, 1943.
0949(Y) Arrived Midway.

— page 65 —
U.S.S. FINBACK - Report of Third War Patrol.

2. WEATHER.

The weather encountered on the patrol was the worst experienced on any patrol to date. Head seas were battled for the entire trip to the area except for two days. The crew was practically worn out from "hanging on" prior to arrival on station.

After leaving the area, a northwest storm of marked intensity was encountered East of the BONINS, minimum barometer 29.48. We were blown and set 55 miles south of our intended track in twenty-four hours. This storm was accompanied by rain, sleet, snow and hail, and reentered the control and engine rooms. The barometer remained below 29.60 for twenty-six hours.

3. TIDAL INFORMATION.

Currents encountered in the area usually set between North and East Northeast with a drift varying between a half and three and a half knots. As they were unpredictable, the position of the ship after a night's run was often in doubt until after a morning fix had been obtained.

A reversal of the KUPOSHIO, was experienced on several occasions. The reversed currents were particularly strong close to the coast between OSHIMA light and TOI MISAKI light, and in the eastern entrance to OSUMI KAIKYO (VAN DIEMEN STRAITS).

During the night of January 31-February 1, a seven and a half knot current, setting East Northeast, was experienced close aboard and to the south of SUJISU SHIMA (SMITH) ISLAND. A speed of twenty-one knots, over the ground, was made good for a period of five hours, while making turns for thirteen and a half knots.

4. NAVIGATIONAL AIDS.

O SHIMA LIGHT - operating with listed characteristics. Light structure painted white.

TOI MISAKI LIGHT - showing single white flashes with period varying between 45 seconds and 1 minute and 55 seconds. Usually dimmed, and visible about 14 miles. On two occasions was observed to be burning steady with visibility estimated to be that listed, 38 miles. The light structure is camouflaged to blend with the background.

A Radar mast, with a "Bedspring" type antenna, was observed on the high peak directly to the north of TOI MISAKI light.

-11-

— page 69 —
U.S.S. FINBACK - Report of Third War Patrol.

8. ENEMY A/S MEASURES.

Patrol boats, small converted yachts and boats very similar to our P.450 class were encountered in the area. They patrolled at slow speeds; 3-6 knots and their screws could just be heard (6 kts - 200 RPM) at 1500 yards. Patrols were not numerous but were persistent. The yacht type patrols appear to be heavily armed. A four or five inch gun aft, a three inch gun forward and what appears to be depth charge throwers around a large false stack amidships. These patrols were avoided at periscope depth, only machinery silenced were the bow and stern planes and steer- ing.

Air patrols were frequent in the daytime and at night during periods of bright moonlight. They conveniently displayed running lights at night.

9. MINES DEFLING OPERATIONS.

None observed.

10. MAJOR DEFECTS EXPERIENCED.

(a) The ship has been bothered by high voltage grounds during the entire patrol. Battery grounds constitute the major part. Prior to this patrol, maximum battery grounds never exceeded 15 volts. Ground readings now average 70-80 volts. On January 20, each battery was isolated in turn and checked for grounds. Four cells forward and three aft were found to have zero internal (element to steel insert) grounds.

In addition three low cells, readings from 10,000 to 500,000 cms, were found forward and one low cell reading 50,000 cms aft. Specific gravity readings and height of electrolyte were normal in the above cells.

On 4 February, a four hour equalizing charge was put in, prior to a contemplated six hour discharge. Specific gravity and voltage readings were taken and the specific gravity of Cell #27 forward was too low to be read on the hydrometer. Voltage was 0.4 volt lower than the rest of the cells. Temperature was below the average of other cells. Batteries had been watered prior to the equalizing charge. There was no evidence of gassing in Cell #27. Each battery was isolated in turn and ground readings taken. Four cells forward (including #27) were found to have zero internal grounds and five were

— page 70 —
U.S.S. FINBACK - Report of Third War Patrol.

Subject: found with readings of 500,000 cbmms to 1.5 megohms. Four cells were found aft with zero internal grounds. No other low cells were found aft. Temperature, specific gravity, voltage and height of electrolyte were normal in all low cells except #27. Cells #27 forward and #15 aft were jumped out of the circuit.

On 15 November, 1942, ground readings were taken on both batteries and no low readings were found. This would indicate that a progressive deterioration of the steel clad jars is taking place. It is doubtful if another patrol can be completed prior to their replacement.

(b) The shaft for QC-JK sound head emits a groaning noise which can be heard throughout the ship when it is trained at normal speed. The Navy Yard attempted to correct this condition during the last refit period. No improvement was noted. Leakage of hydraulic oil around the JK-QC shaft is excessive.

(c) Torpedoes. Mk. 14, Mod. 3 torpedo #19916 received from Submarine Base, Pearl Harbor, was found to leak about 150 lbs. per square inch per day. This torpedo was removed from #7 tube and another substituted. The afterbody was removed and several attempts were made at locating the leak, with negative results. This torpedo was carried in the racks fully charged with the stop valve closed and could have been reloaded and fired if necessary.

(d) The upper conning tower hatch gasket, installed after the training period, was found to be bulged just prior to trim dive while enroute Midway. The gasket was shimmed in the low spots after much trial and error, to give it a fair seat. It could be made tight on a dive by the efforts of two men swinging on the hatch handwheel. Insufficient time existed to install a new gasket while in Midway.

(e) The JK-QC training motor generator field coil was grounded in the flood. A spare field coil was not available so the QB training motor generator set was connected so that it could be used on either the JK or QB. A permanent arrangement will be made during this refit period to allow for this contingency.

(f) The baffles installed forward of the engine induction were carried away by the heavy seas encountered.

(g) #2 periscope continues to fog in high power as reported in report of Second War Patrol. #1 periscope is still extremely difficult to train and three previous efforts at correction of this difficulty have been unsuccessful.

- 16 - ENCLOSURE (A)

— page 71 —
11. RADIO RECEPTION:
    (a) Last serial sent: Subpace Ser 15. Last serial received: FINBACK INGRAM.

(b) Radio reception was complete and no trouble was experienced in copying the NPM submarine Fox schedules. Low frequency reception was reliable up to Longitude 155 degrees E. When it became necessary to constantly shift frequencies in order to solidly copy the schedules. This was due to both atmospheric noise and jamming; the noise on low frequency, and the jamming on 4.115 kc and 8330 kc. while on station. NPM goes out on all frequencies for a period of about two hours between 1900 and 2100 GCT. The signals were excellent on 8230 kc, at that time and it is believed that if that frequency were to be left on until 12345 kc had time to come in, better communication could be maintained. The numerous squalls experienced during the latter part of the patrol caused interference on both the radio receivers and the SD Radar. The jamming consisted mainly of another transmitter operated close to the operating frequency with the key down at long intervals, and could be eliminated by use of receivers with crystal filters and of higher selectivity than the RAK and RAL series.

(c) The SJ and SD Radars operated satisfactorily. Interference was noted on the SD (see Radar Report) when severe electrical storms were encountered.

12. SOUND CONDITIONS AND DENSITY LAYERS.

Sound conditions were in general very poor in Van Bicmen Straits and the noise level was high. The noise level decreased when out of the Straits and in the Kurishu proper. A destroyer making thirty knots was not picked up at 12,000 yards.

No density layers were found.

13. HEALTH AND HABITABILITY.

The health of the crew in general was very good. The sun lamp was a very popular addition and was used by practically all the crew.

Rations of quick frozen strawberries, peaches and peas were retained until the last three days prior to arrival at Midway and were well received. Vitamin pills were issued daily after the first week underway.

- 17 -

ENCLOSURE (i.)

— page 72 —
14. METERS STEAMED:
Enroute to Station - 5198
Enroute from Station (Midway) - 2857

15. FUEL EXFENDED:
Fuel Received from Midway - 21,769 gals.
Fuel to Station (from Pearl) - 57,290 gals.
Fuel on station - 15,710 gals.
Fuel from station (Midway) - 23,900 gals.

Total expended - 97,900 gals.

16. FACTORS OF ENDURANCE REMAINING:
Torpedoes | Fuel | Provisions(Days) | Fresh Water | Personnel on Station
24 | 14,700 gals. | 5 (Balanced Ration) | Unlimited | 2 days

17. FACTORS OF ENDURANCE ENDING PATROL:
Provisions of operation order.

18. REMARKS:
(a) Due to high fuel consumption from the 20th to the 23rd, and head seas encountered enroute to the area, speed was reduced to 80-90 on one engine for the last 1200 miles. Fuel consumption was maintained at an average of 570 gals. per day while on station by using the generator engine for surface patrol at night.
(b) The dilution of the crew with additional inexperienced personnel was quite evident this patrol.
(c) A quiet operating trim pump and silent type of bypass valve on the hydraulic system are still desired as requested in the report of Second Patrol.

(d) There was no noticeable shaft squeal during this patrol below 80 RPM, except for the usual noise when changing speed.

- 18 -

ENCLOSURE (A)

— page 73 —
U.S.S. FINBACK - Report of Third War Patrol.

The shafts are still quite noisy above 80 RPM.

(e) The 4"-50 Cal. gun mount sets up a loud rumbling noise when submerged at speeds above three knots, apparently due to vibration of supporting members, or athwartship bulkhead. An attempt will be made to eliminate this noise during the refit period.

(f) The 4" gun, mounted forward, is in a very effective position. However the mount is considered to be too low and should be raised about 18 inches. The sights flooded during a normal all day dive. The open sight was used. For the type of shooting usually done by a submarine, and considering the rate of fire, a 3"-50 gun mounted forward, and using sensitive ammunition, would be far more effective than the present 4"-50.

(g) Radar detector, made by LIVELY, D.E., RTL, V-6, USNR, covered a frequency range of from 90 to 140 megacycles was used upon surfacing at night and prior to diving in the mornings with negative results.

(h) Fuel received in Midway on the way to the area contained a tar residue which colored the fuel black. The sludge from this fuel made it necessary to clean purifiers four to six times as often as normal, and the cotton yarn filters were plugged with the residue. The engines smoked heavily while using this fuel. Two quart. samples have been retained.

(i) The performance of duty of all officers and men during this patrol was excellent. The electricians, especially, working without relief for many hours, did an excellent job of drying out and repairing electrical equipment flooded on the 16th of January.

- 19 -

ENCLOSURE (A)

— page 74 —
1. FINBACK Third War Patrol extended from December 16, 1942, to February 6, 1943. Of the total time of fifty-two days, four were employed working with another Task Force and twenty-eight days were spent in the patrol areas.

2. The patrol was well conducted in the face of much heavy weather and strong unpredictable currents.

3. The failure to properly close the conning tower hatch on January 16. is a type of casualty that has occurred on many submarines. The primary cause is a latch requiring lubrication, together with an over-eagerness to slam the hatch. Then the hatch is slammed shut a sluggish latch will not operate fast enough to "hook" before the hatch rebounds. Simultaneous operation of the closing handle will move the dogs to prevent reseating of the hatch. The Division Commander has recently noticed several latches in which verdigris prevented the spring from closing the latch when it was forced open by hand. Occasional oiling is necessary while on patrol.

4. It is regretted that only two ships were encountered and that these were beyond torpedo range. The night battle surface, gun attack on the sanpan patrol boat was very well conducted.

5. The probable existence of radar near Tci Misaki Light is noted.

6. FINBACK is refitting at Midway. The noisy JK - QC shaft will be remedied during current refit, and battery jars will be replaced after next patrol.

— page 75 —
10/10/1943
(FCB-101)
Serial 018
CONFIDENTIAL

From: The Commander Submarine Squadron Ten.
To: The Commander Submarine Force, Pacific Fleet.

Subject: U.S.S. FINBACK (SS230), Third War Patrol - Comments on.

Reference: (a) CO FINBACK Conf 1tr SS230/A16-3 Serial (C-01) of February 4, 1943.

1. Forwarded. The small number of contacts made by FINBACK on the Third War Patrol is disappointing.

2. It is anticipated that the steel battery jars on the FINBACK will be replaced by laminated jars on the completion of the next patrol.

3. The FINBACK is credited with the sinking of one patrol boat approximately 150 to 200 tons.

ENCLOSURE {C}

— page 76 —
1/2 copy

SUBJECT: SUBMARINE FORCE, PACIFIC FLEET

Serial: 0-33

CERTIFICATE OF
DECLASSIFIED
CONSUMPTION PATROL REPORT NO. 141
U.S.S. PHILIPPE - THIRD WAR PATROL.

From: The Commander Submarine Force, Pacific Fleet.
To: Submarine Force, Pacific Fleet.

Subject: U.S.S. PHILIPPE (SS230) - Report of Third War Patrol.

Enclosure: (4) Copy of Subject War Patrol.
(2) Copy of Consubron 10 conft. 1tr Serial 016 of 14 February, 1943.
(4) Copy of Consubdiv 101 Conft. 1tr. Serial 05 of 16 February, 1943.

1. The absence of traffic is normally well used area suggests the possibility of the enemy making use of Shore Radar to "DF" the position of submarines, and re-routing traffic. Information as to the distances "SDI" and "SU" radars might be intercepted, has already been promulgated by separate dispatch.

2. This command does not agree that the installation of a 3" 50 caliber gun would be more efficient than the present 4" 50 caliber.

3. The ideal information submitted for this area is interesting, and should benefit other submarines patrolling this area.

4. The FINALIS is credited with inflicting the following damage on the enemy:

SUNK
1 Patrol boat (approximately) --- 150-200 tons.

C. A. LOCKWOOD, Jr.

DISTRIBUTION:
(1-43)
List III: SS
Special
FlG(5), EN3(5), Z1(5),
Consubstant (2), X3
Consubowsespec (2)
Subschool NL (2)
Contaskfor 42 (2)
Consubron 50 (2)

E. R. SWITZER,
Flag Secretary.

44612

— page 77 —
1943, U.S.S. FINBACK - Report of Fourth War Patrol.

Period from, February 27, 1943, to April 13, 1943.
Across: # and #.
Operation Order No. 29-43.

PROLOGUE:

Arrived Midway on February 6, 1943, from Third War Patrol.
Commenc'd refit by Submarine Base personnel assisted by the Relief
Crew of Submarine Division FORT-FOUR. Completed refit February 20,
1943. I.M.O. Hydraulic Pump installed. Readiness for sea on Feb-
27, 1943. Conducted independent training one day. Scrap
day's training with minesweeper prevented by casualty to #10 Torpedo
Tube. Not depermed or wiped.

NARRATIVE:

February 27, 1943.

1600 (Y) Underway for area.

February 27 to March 7, 1943.

Enroute to station conducting daily training drives, fire-control problems, and ship's drills.

March 5, 1943.

1639 (K) Sighted heats of ship on horizon. Started closing
(Contact #1) ship at full speed and inspecting through #1 Portescope.
Ship appeared to be large sea going tug or small inter-
Island steamer. The masts whore high and close together.
She had a bridge, but no discernible stack. Tracked ship
on course 330°, speed 8 knots, at range of 16,000 yards
while running around for position ahead. When darkness
set in, changed course to gain position 8,000 yards ahead
of target on his track, and try to pick up target on
SJ Radar while reaching attack position. It
stopped on supposed track and waited. Target was never
contacted again. The target must have seen us and waited
until dark to make radical change of course. It was
felt that target was worth one torpedo.

1940 (K)

March 8-9, 1943.

Patrolling Truk - Enjoy traffic line in passage between
Nauruitu Island and Hall Island.

- 1 -

ENCLOSURE (A)

— page 78 —
1517 (K)
Sinoo no contacts had been made in the passage between Nanmonuito Island and Hall Island, left this seemingly good spot to make submerged patrol off of North Pass commencing at dawn this date. It sighted smoke inside Truk lagoon. No ship left North Pass today.

March 11, 1943.
It sighted smoke of vessel later identified as patrol vessel leaving North Pass.

March 12, 1943.
The FINELOCK this date was a victim of one of the most recent tricks (planned or unplanned) of the war. It sighted smoke in North Pass while conducting submerged patrol. It identified smoke as coming from patrol vessel and steamer proceeding to Empire on course 320°(T). Commenced approach. Angle on bow 70° Starboard. Closest range 15,000 yards. Hull or upper works of ship were not sighted. Masts and stack were painted black. Stack second to have housing marking. Decided to trail and chase target after opening range on Truk. It sighted seaplane at about two miles headed in our direction. Went to 140 feet. It went to periscope depth, no plane in sight. Smoke of steamer in sight and escort vessel apparently returning to Truk. It just prior to planned time of surfacing, sighted plane on target's bearing so assured air escort had relieved surface escort. It surfaced 16 miles off North Pass and commenced chase at full power. Sighted smoke of escort vessel on port beam. No more plane sighted. It sighted smoke of target. Commenced rounding target, who was zig-zagging, for position ahead, keeping masts in sight with #1 periscope. It while closing track to time was 18:04. Further closing of on red light. Sunset time was 18:04. Further closing of target showed a properly lighted hospital ship with Red Cross near stack, lighted green band along Hull, and range lights. Target not identified as URAL HIRU, Page 31 of O.N.I. 208-J. Decided to close target to at least check our SJ Radar after our futile chase of 139 miles. SJ Radar unable to place up target at 8-10,000 yards. As we turned away, heard SSS and call sign on DQ received.

- 2 -

INCLOSURE (A)

— page 79 —
1500 (K) Patrolling area East of Truk north of Marshall Islands to patrol on plane at 6 miles. No bombs or surface and continued patrol on surface.

March 13, 1943.

1350 (K) Patrolling submerged off North Pass. At sighted trawler type patrol boat at 8,000 yards while about seven (7) miles off North Pass. Headed in his direction in case he had a LNRU with him. Patrol boat drew to eastward and disappeared. At on surfacing sighted patrol boat on port beam. SJ Radar gave range of 10,000 yards. Evaded on surface. Decided to patrol off Northeast Pass tomorrow as our presence is known.

March 15, 1943.

1510 (K) sighted patrol boat at 5,000 yards which had apparently passed close aboard during the passing rain squall.

March 16, 1943.

0714 (K) Patrolling submarine off North Pass. At sighted large FO boat or small DD zig-zagging and headed for North Pass. Took normal approach course. Closest range 6,000 yards. At sighted observation plane. At heard supersonic pinning on 18 kcs. Nothing in sight. At sighted same plane apparently circling us and once noted to start a dive in our direction. Picked up same PC boat seen earlier. At as PC boat seemed to be patrolling and not escorting, went deep to lose plane and avoid his ex-lieutenant with PC boat. PC boat closed to estimated range of 3,000 yards and then opened out. No ucd usual Jap tactic of running, then stopping and listening. On losing scores anf pinning, returned to periscope depth. At clear. Experienced camouflaged difficulty maintaining depth control due to smoke.

1030 (K) ENCLOSURE (A)

— page 80 —
1000 (K) Patrolling submerged off North Pass. At
: 1245 (K) commenced to clear vicinity of Truk submerged. At
: 1250 (K) sound picked up propellers. At
: 1410 (K) discovered same PC boat seen yesterday coming out of
: 2300 (K) rain squall, range 6,000 yards, and angle on bow 90°
: 2310 (K) starboard. PC boat was zig-zagging at 15 knots heading
: 2315 (K) toward North Pass. At
: 2320 (K) surfaced and commenced surface patrol along Truk-Empire
: 2325 (K) route. At
: 2330 (K) left area for Palau.

March 18-20, 1943.

: 0930 (I) Emroute to Palau conducting daily training dives, ship's
: 1040 (I) drills, and fire-control problems.

March 21, 1943.

: 1122 (I) At
: 1040 (I) conducting surface patrol along Palau to Empire lane. At
: 1122 (I) sighted large steamer on #2 periscope at 17,000 yards
: 1122 (I) coming out of rain squall. Dived and commenced approach.
: 1122 (I) Target was making radical zigs at high speed. At 2,000
: 1122 (I) yards, target gave us a zero angle on bow, forcing the
: 1122 (I) use of our stern tubes which contained l'ark XV torpedoes
: 1122 (I) with small heads. At
: 1122 (I) fired three torpedo spread, first torpedo 300 right gyro,
: 1122 (I) 1200 starboard track. Range 700 yards. Spread used 70,
: 1122 (I) depth setting 6 feet. Result - two hits. Target tentatively
: 1122 (I) identified as KINNA NAVI, 9,310 tons, Page 44 of O.N.I.
: 1122 (I) 2008-J. First torpedo observed to hit about 20 feet
: 1122 (I) inside of stern. Second hit definitively identified as
: 1122 (I) torpedo explosion but not observed due to periscope being
: 1122 (I) awash. Sound traced third torpedo astern of target.
: 1122 (I) Swing left and made two tubes ready forward. Target pull-
: 1122 (I) ed away turning stern toward us. Decided not to waste
: 1122 (I) any torpedoes on 180° track with a fast target. At range
: 1122 (I) of 3,500 yards target had slowed perceptibly. Went ahead
: 1122 (I) 6 knots for six minutes hoping to close for another shot.
: 1122 (I) Range began to open slowly as target repaired damage and
: 1122 (I) built up speed. Target appeared to be used as Naval
: 1122 (I) Auxiliary. Numerous personnel topside in whites. Be-
: 1122 (I) lived to be flying a Jap Ensign. At
: 1122 (I) reloaded aft and checked two torpedoes forward preparatory
: 1122 (I) to starting surface chase in hope we had slowed him down.
: 1122 (I) At

EINCLUSIVE (A)

— page 81 —
1247 (I) 1801 (I) 2000 (I)

Surfaced and started surface chase. Target appeared to be 'down by the storm and slowed down.' At with target on our starboard beam and barely visible, the target commenced challenging us with a large searchlight sending KING and four dashes. He had apparently picked up our fairwater against the horizon provided by the setting sun. At abandoned chase after crossing his track line at expected intersection point and proceeding for one-half hour. Our speed differential of about four knots would have been reduced to two on his discovering us if he stopped zigzagging. He could have made Yep Island which was now 37 miles distant. Set course to get on Saipan - Palau Lane.

March 22, 1943.

Patrolling on surface along Saipan - Palau lane approaching Palau.

March 23, 1943.

Patrolling submerged about five miles off entrances to Malakal Harbor. Saw one small fishing sampan during day. On surfacing proceeded to round Babelthau Island to northward via Ngaruungl Passage to patrol off Toagel Mlungui (West Channel) tomorrow.

March 24, 1943.

Patrolling submerged off Toagel Mlungui. At daylight discovered we were five miles south of our expected line of patrol which was the approach line to Toagel Mlungui. At sighted two funnel steamer similar to Taizan Maru, 3,930 tons, page 20 of O.N.I. 208-J, at range of 16,000 yards, angle on bow 90° starboard. Started approach. Closest range 12,000 yards. Ship had air escort. At sighted traveler torpedo boat coming out of channel as target entered channel. At heard pinging and sighted two more small patrol vessels to northward searching along entrance approach line. Closed approach line as patrol vessels drew aft. This was a new type of patrol vessel which seemed about the size of our old subchasers. The traveler was pinging on 18 kcs and the patrol boats on 19 1/2 kcs. The traveler circled us at about 8-10,000 yards for remainder of day. At sighted smoke inside reef to right of channel entrance. At came to normal approach course on leading vessel of five

ENCLOSURE (A)

— page 82 —
1921 (I)
2023 (I)
2150 (I)
2313 (I)
March 25, 1943.

| Date | Time | Location | Description |
|------|-------|||
| 1921 | I     | S. S. FINBACK | Report of Fourth War Patrol |
| 2023 | I     | S. S. FINBACK | Ship convoy as his mates gave us angle on bow of 60° starboard, range 18,000 yards. Closed last ship in column to 12,000 yards as they all turned south to course 1850(T). No escorts except air sighted but supersonic pinging was heard on the bearing of the last steamer. Commenced trailing submerged. At surface and commenced chase. At picked up convoy on S. Radar at 17,000 yards. Decided to trail to determine enemy track on rounding Anguar Island. At |
| 2313 | I     | S. S. FINBACK | surfaced after giving convoy time to be well out of visibility range. At |
| March 25, 1943. | 0023 (I) | S. S. FINBACK | Regained sight contact on smoke of convoy at estimated range of 28,000 yards. No ships sighted off Anguar Island which was passed at 6 miles in bright moonlight. At |
| 0126 (I) | S. S. FINBACK | discovered convoy was rounding Anguar Island and taking easterly course. Continued to trail to determine convoy's course and speed after rounding Anguar Island. Hoped to get targets in open sea and emulate the WAHOO. At |
| 0511 (I) | S. S. FINBACK | made trim dive and allowed convoy to open out to daytime visibility range. At |
| 0730 (I) | S. S. FINBACK | started rounding convoy for attack position at four engine speed. Convoy's course was 1000(T) and speed of advance 8.5 knots. Convoy was zig-zagging. At |
| 1313 (I) | S. S. FINBACK | in position ahead of convoy. At |
| 1330 (I) | S. S. FINBACK | reestablished contact and started closing in for attack. At |
| 1426 (I) | S. S. FINBACK | dived and commenced submerged approach which netted the FINBACK good experience, but no hits. The convoy formation (See attack diagram) consisted of three columns in a line with an escort in outboard bow of leading ship in the outer columns. The outer columns consisted of two ships each, while the center column consisted of one lagging the convoy. Three different sets of supersonic ranging equipment were heard, but no escorts were sighted until the range had closed to 5,000 yards. In view of this, it was decided to attack from the starboard flank as the convoy was maintaining a constant helm zig-zag plan. These two ships were the largest in the convoy. The leading ship was tentatively identified as the TOTORI MARU, 5,973 tons, and the second as the TAIBUN MARU, 6,581 tons, pages 205 and 206 respectively of O.N.I. 208 -J. About two minutes before reaching the firing point, sound reported that the starboard escort was close and |

ENCLOSURE (A)

— page 83 —
1910 (I)
At daylight the sea had become oily smooth making an undetected periscope approach on this convoy impossible. Decided to track from ahead until more favorable conditions existed. Snake was kept in sight during morning. At sent message to Comsubpace reporting our position and situation. At
1215 (I)
ran into a rain squall with strong wind and good seas. Decided to close convoy in rain squall and attack. At
1316 (I)
dived at an estimated range of eight miles in order to prevent convoy suddenly catching us on coming out of rain squall. At
1347 (I)
picked up smoke of convoy which had apparently slowed down some during day. In view of yesterday's experience placed ship on convoy and headed down the middle. We were able to check the convoy's zig-zag plan exactly. The convoy was zigging 40o either side of the base course with 4 minute legs. At 3,000 yards the escorts were abaft our beam. The set up locked perfect. We swung left to fire bow tubes at the left hand column. At exactly this time (1700) the convoy changed course to 150°(T) and the closest range seen on any target afterwards was 3,000 yards. It was not realized at first why the targets had failed to zig back as previously tracked. Again we had been done out of a good shot, but due to an unusual coincidence. At

EICLOSURE (A)

— page 84 —
1849 (I) surfaced and resumed chase. Planned to conduct surface radar approach before moonrise. It would be nip and tuck as to whether we could get to a firing position ahead of moonrise. Moonrise expected at 2157. At slaved to convoy speed at distance of 10,000 yards on their starboard beam to check convoy disposition and locate escorts. At 2101 (I) spooked up to get in attack position on bow. At 2130 (I) commenced closing convoy on battery at ten knots with forward group flooded down. Approached on a constant bearing from 8,000 yards with target engine on the bow of 560' starboard. This made us pass in a 45' port angle on bow. We were forced into presenting other than bow on appearance in order to attack before moonrise. Visual contact with the targets was maintained at all times. The locking escort was sighted at 6,500 yards. The exact formation was hard to determine but the two nearest and largest ships were in column and ahead of the others in bearing. Picked those for our attack. A flashing light was soon momentarily on the second ship. At 2141 (I) when 4,400 yards from the track the moon came over the horizon much to the Commanding Officer's surprise and the Navigator's chagrin. Continued in with a nice red bell rising. Here luck favored us and the moon ducked under a cloud. Escort still held course though quarter-master on watch believed she was exchanging signals with convoy with shielded lights whose loom was seen. At 2145 (I) when distance to track was 1,900 yards, escort commenced challenging with white light and turning toward us. He then turned on in rapid succession one red light, two vertical red lights, and one red light. On first light, we swung left to fire. At 2146 (I) commenced firing. Fired spread of three torpedoes at (attack #28#3 first and three torpedoes at second slip. Blow forward group after firing first three and ordered flank speed. The target ships' bearing firing their guns while we were still firing the torpedoes. A red flash followed by a black puff of smoke rising 100 feet in the air was seen on the second ship. At this time while the Commanding Officer was concentrating on the Pelorus bearings, the Executive Officer reported a shell splash 100 yards ahead and the Quartermaster remarked, "They have the deflection, but not the range". Dived as gunfire became more accurate. The soundman heard three torpedo explosions as did people below decks. The TDC and radar setup checked perfectly prior to and during firing. From the times of the explosions and watching the tracks of the torpedoes, it is believed that the first torpedo hit the leading target and two torpedoes in the second spread hit the second target.

ENCLOSURE (A)

— page 85 —
1700 (I) cleared message to Comsubpac reporting lost contact. At 1800 (I) turned back and began search to northward because of low fuel on hand and doubtful chance of regaining contact. Sufficient fuel remaining over our reserve to allow one engine speed to Midway. Inspection of topside revealed little damage from the depth charge attack. A 1 inch lead ball had gouged the deck on the port side of the conning tower and split the decking underneath for about one foot. Two unidentified metal brackets were found on the dog house step.

March 28-29, 1943.

: 0830 (I) sped up and set course to northeastward to patrol across trade lanes from Empire to Rabaul and Mandates.

March 30, 1943.

: 1312 (K) patrolling along lane from Empire to Puluwat. At 1333 (K) dived on plane radar contact which moved in to ten miles. At 1444 (K) surfaced and continued patrol. At sighted submarine bearing 3350(T). Submarine fired red smoke bomb. Submarine was U.S.S. HADDOCK. Closed to hailing distance and exchanged information. Continued patrolling to east of above line. At dusk set course to pick up return routing to Pearl via Johnston Island.

March 31, 1943.

: Enroute Pearl via Johnston Island.

April 1, 1943.

: At 0104 (K) changed course to head for Midway via Wake Island. At 1100 (K) informed Comsubpac by dispatch of action taken.

April 2-4, 1943.

: Enroute to Wake Island.

April 5, 1943.

: Dived before sunrise to make submerged approach on Wake Island, distance 15 miles. When Wake was not picked up as expected, decided we had received a set to westward during the night and changed course to 0900(T). At 1200 (L) sighted Wilkes Island bearing 1180(T). Sighted a steamer (Contact #17) of BRISBANE MARU class, 5,425 tons, beached with bow on reef south of Wake Island. The steamer was well down by the stern. Changed course to southward to clear reef and approach ship from the south. At 1218 (L) sighted trawler type patrol boat at 4,000 yards; angle on

- 10 -

ENCLOSURE (A)

— page 86 —
2154 (I) These are believed to be the same two ships reported
:    seen in the right hand column, "sounds of ships breaking
:    up were heard prior to depth charge attacks. At
:    following picking up a superstitious-pinching and screws in
:    sound gear received first depth charge attacks consisting
:    of pattern of five fairly close, At
:    received pattern of three closer, Continued to hear
:    pinging and faint screws. Believed escorts had lost us.
:    Looked like we could come up. This was the normal depth
:    charging we had expected. At
:    received pattern of three depth charges. Closer this
:    time. After torpedo room reported water coming in. The
:    torpedo tubes outboard went had carried open and inboard
:    vents were open. This attack had been made by one of the
:    vessels who ran silent and was directed on by the pinging
:    vessel. From now on the attacking vessels stayed right
:    on us and proceeded with best sound school doctrine. At
:    received five charges which really jarred us. Charges
:    seemed to be set deeper. Coming tower hatch was lifted
:    off seat port lighting small tackle go. After torpedo room
:    reported hot run in #7 tube which proved to be the jarring open of the water filling valve on the firing valve.
:    This allowed about 50 pounds of impulse air to escape
:    before the filling valve was secured. Quick action in
:    closing this valve prevented lifting of the firing valve
:    which would have actually given us a "Hot Fun". Valve
:    wheels and transches flew in all directions. Gyro Azimuth
:    motor commenced snaking forcing securing of follow-up
:    system. At
:    received four depth charges. Not as close as fourth
:    attack, but still too close for comfort. Continued to
:    hear pinging and screws. At

March 27, 1943.

0030 (I) Last sound contact indicating that escorts must have rejoined convoy which we assumed had completed picking up survivors and clearing area. After our experience of losing the escorts following the second depth charge attack, decided to take our time in going to shallower depths with such efficient opponents. At
0135 (I) came to periscope depth and situated nothing. Reloaded torpedo tubes forward, pumped bilges and checked trim, drained down after torpedo tubes, and repaired St Radar. SJ Radar slip rings were salted by: SEEPAGE during attacks. At
0200 (I) surfaced and resumed chase at full speed. Noticed strong smell of gun powder. At
0930 (I) when we estimated we had passed convoys position by one hour, commenced a retiring search on each flank. Visibility was excellent. At

- 9 -

ENCLOSURE (A)

— page 88 —
1515 (L) bow zero. At same time sighted observation plane circling ship. Decided to run at 140 feet between looks to avoid detection by plane while getting into position for attack. Patrol boat circled us and headed south. At sighted patrol boat heading into boat landing and two engine bomber patrolling along reef. The beached MARU was on heading 060°(T). Decided to work to eastward and fire with target on about 130° track. When 1100 yards off reef and 1,400 yards from target turned so as to fire stern tubes. As target seemed to be well up on coral reef, aimed torpedoes to hit just abaft stack so as to avoid hitting reef. At fired tubes #7 and #8. Result one hit. Both torpedoes were set to the left of the point of aim indicating a current from the eastward for which we had not allowed. The first torpedo hit inside the stern with excellent effect jarring us considerably. The second torpedo just missed, the stern and exploded on hitting the reef. The torpedo explosion was not heard in the boat but was heard in the sound gear and seen thru the periscope. This probably was a low cruiser explosion. No patrol boats or planes in sight. Retired to southeast at high speed and rigged for retaliation by planes. At heard explosion of three aircraft bombs about one minute apart. With sunset at 1806 and a moonless night ahead, this wouldn't keep up long. At two more bombs. At two bombs heard only in conning tower. At two bombs closer this time. At two more bombs. At one last bomb which was a surprise considering time since sunset. None of the bombs were very close. At surfaced and set course for Midway.

April 6-8, 1943.

Enroute to Midway.

April 8, 1943.

At arrived Midway, T.H. Received 18,810 gallons of fuel.

April 9, 1943.

Transferred eleven torpedoes to the Submarine Base, Midway. At departed Midway for Pearl under air escort.

April 13, 1943.

Arrived Pearl.

- 11 -

ENGLISH (A)

— page 89 —
2. WEATHER:
Northeast trade winds with condition two to four seas were experienced between Midway and Wake. South of Wake the wind was from the same direction, but seas were condition one to two.

3. TIDAL INFORMATION:
Between Midway and Truk experienced sets to the northwest of 0.5 to 0.9 of a knot.
North of Truk the currents were unpredictable.
East of Atoll Harbor, Palau, experienced a one knot current setting to the eastward.

4. NAVIGATIONAL AIDS:
Difficulty in cutting in position off Palau by use of mountain tops was experienced at first. It was found that the 790 foot peak shown on H.O. chart #5418 was not very prominent. The 641 foot peak near Toagel Mungui passage shown on H.O. chart #5423 is a sharp pointed peak and very prominent.

- 12 -

ENCLOSURE (A)

— page 93 —
7. SUMMARY OF SUBMARINE ATTACKS

| Attack | (1) | (2) | (3) | (4) |
|-------|-----|-----|-----|-----|
| Date  | 3-21-43 | 3-26-43 | 4-5-43 |
| (Lat.) | 7° 30' 11" | 5° 02' 1" | 50° 02' 1" |
| Location (Lat.) | 13° 42' 1" | 12° 10' 1" | 139° 10' 1" |
| Torpedoes Fixed on each Attack | 3 | 3 | 2 |
| Hits | 2 | 1 | 2 | 1 |
| Number Sunk (Tonnage) | 0 | 0 | 0 | 0 |
| Number Damaged or probably sunk | 1 | 1 | 1 | 1 |
| Type of Target | Fr. Pass. | Freighter | Freighter | Freight |
| | 9310 tons | 5973 tons | 6581 tons | 5425 tons |
| Range | 700 | 1,900 | 1,900 | 1,700 |
| Periscope Depth | Yes | - | - | Yes |
| Surface Night | - | Yes | Yes | - |
| Deep Submergence Estimated | - | - | - | - |
| Draft Target Depth Setting | 12 ft | 14 ft | 14 ft | 20 ft |
| Bow or Stern Shot | Stern | Eow | Bow | Stern |
| | 120(S) | 75(S) | 80(S) | 130(S) |
| Track Angle | - | - | - | - |
| Gyro Angle | 30(F) | 20(T) | 10(R) | 0 |
| Estimate Speed | - | 16 kts | 8 3/4 kts | 0 |
| Target: Speed | 15 secs. | 9 secs. | 13 secs. | 0 |
| Firing Interval | 70 | 20' | 20' | - |
| Spread - Amount and Kind | divergent | divergent | divergent | None |
| Remarks: | 1st hit seen 20 ft inside of stern. | 1st torpedo hit. | two torpedo es hit. | 1st torpedo hit. |

- 16 -

ENCLOSURE (A)

— page 94 —
8. ENEMY A/S MEASURES:
(a) Off North Pass of Truk, patrol vessels consisting of either converted trawlers or a new type similar to our PC-451 sighted daily. PC-boat used supersonic pinging on 18 kcs. Observation planes were seen twice.

(b) Off Toagel Mungui, Palau, a trawler equipped with supersonic equipment covered area very thoroughly. This area would be included in a sector made using the passage as a center and fifteen miles as a radius.

The subchers sighted entering Palau were probably the escorts for the convoy leaving later that date.

A plane covered the entrance of the freighter and the exit of the convoy on March 24, 1943.

(c) The escorts of the convoy were a new type of patrol boat similar to our PC-450 class in size. They had a very stream lined appearance. Their sound gear appeared to be excellent and they knew how to use it when presence of submarines was known. They caught us under excellent sound conditions and made five attacks which old Desdiv was unable to do. Both ships pinged until we were located. Then one pinged and the other attacked. All attacks were very deliberate with patterns of three to five depth charges. Turning the stern toward the attacking ship to present a narrow target did not seem to bother these vessels. Their best attack was delivered from our stern right along our axis. Our attempts at evasion did not seem to make the enemy more inaccurate.

The smallest ship in the convoy had supersonic ranging equipment. This ship had a large box aft. She could have been a "Q" ship, though it is believed unlikely.

9. DESCRIPTION OF MINESWEEING OPERATIONS:
None observed.

10. MAJOR DEFECTS EXPERIENCED:
(a) The I.M.O. Hydraulic Pump on the main hydraulic plant was found to operate much more quietly, but it could not be operated continuously because of overheating of the hydraulic oil. The excessive temperatures of the oil are believed to be caused by faulty operation of the By-Pass valve. This valve does not seat properly allowing leakage. Overhauling by Ship's Force has not remedied this condition. This trouble made necessary the practice of securing the hydraulic plant, except when actually in use, with a subsequent increase in diving time for surprise dives.

(b) The Trim Pump continues to be useless piece of equipment in close enemy waters because of excessive noise.

- 17 -

ENCLOSURE (A)

— page 95 —
(c) The port propeller shaft has become progressively more noisy during this patrol. There is a heavy grinding noise transmitted to the reduction gear on stopping the shaft from a speed above 5 knots when submerged. The port-strut bearing squeals at speeds above 70 K.P.M. This noise has increased since the depth charging on March 26, 1943.

(d) The casualty to #10 torpedo tube was the subject of separate correspondence prior to leaving on patrol. It is believed that renewal of the inboard section of this tube will be required.

(e) Some part of the operating gear to #2-B M.B.T. after flood valve inside the tank carried, carrying a heavy banging of the valve. This banging could only be stopped by jamming the gear and valve in a partially closed condition. This slowed down the diving time. It is believed that the flood valves should be removed during the coming overhaul.

(f) The steel inserted jars of the main storage battery require replacement by laminated rubber jars. Ten cells now have a zero ground. This condition is gradually getting worse as indicated by increasing number of cells with low readings. One cell has failed because of low capacity caused by iron in the electrolyte treatment and change of electrolyte during last refit failed to return this cell to normal health. A six hour discharge conducted prior to arrival in Midway showed the main storage battery to have an ampere-hour capacity of 117%.

11. RADIO RECEPTION:

(a) No difficulty was experienced in copying NPM schedules. Subpac serial #98 was not received and it was assumed that it was sent in a channel not held by the FINBACK.

(b) No outgoing messages could be cleared through NPM. The Island stations on 4265 series were just about as difficult to use. We were quite successful in clearing contact messages through Tulagi, Guadalcanal, and Noumea on the 4205 series and VHM (Melbourne) on the 4235 series when near Palau.

For results on reception of NPM on submerged loop see Enclosure B.

12. SOUND CONDITIONS AND DENSITY LAYERS:

(a) Sound conditions around Truk were only fair. A slight density layer seemed to exist at 275 feet.

(b) Sound conditions around Palau seemed to be good. Off Malakal Harbor discovered a definite density layer at 150 feet through which it necessary to force the boat. At 300 feet the boat was lighter than at Periscope Depth. A temperature gradient existed as follows:

60 feet - 85°F. 200 feet - 80°F.
100 feet - 83°F. 250 feet - 78°F.
150 feet - 80°F. 300 feet - 76°F.

- 18. ENCLOSURE (A)

— page 96 —
13. HEALTH AND HABITABILITY:
Health and habitability were excellent due to the large percentage of time spent on the surface. One case of catarrhal fever took one man off the watch list for four days.

: 14. HITLES STEAMED:
Enroute to area #: 2250
In area #: 1640
Enroute area # to area #: 1605
(including one contact and chase)
In area #: 1050
Enroute to Pearl: 4538
Total: 11,083

: 15. FUEL EXPENDED:
Enroute to area #: 22290
In area #: 10410
Enroute area # to area #: 15465
(including one contact and chase)
In area # and chasing: 14025
Enroute to Midway: 27910
Total: 90,100

: 16. FACTORS OF ENDURANCE REMAINING:
Torpedoes | Fuel | Provisions (days) | Fresh water | Personnel (days)
13 | 2,150 | 20 | Unlimited | 20

: 17. FACTOR OF ENDURANCE ENDING PATROL:
Lack of sufficient fuel to continue caused termination of patrol. This was caused by required 13 knot speed to and between areas, and four high speed chases.

: 18. REMARKS:
(a) It is strongly recommended that #4 Main Ballast Tank be converted to a fuel tank. On this type of patrol, in which much high speed running is required, the radius of action would be greatly increased.

(b) The ship received an excellent material refit, to the extent of their capabilities, from the Submarine Base, Midway. The personal interest and care taken in all work done by Midway was greatly appreciated by the officers and crew of the FINBACK.

(c) The depth charging received on March 26-27 was the most severe received by this ship to date. The damage suffered was minor.

- 19 -

ENCLOSURE (A)

— page 99 —
22 - ENCLOSURE (A)

Subject: U.S.S. FINBACK - Report of Fourth War Patrol.

JAPANESE FIVE SHOT CONVOY FORMATION

CONVOY TRAILED AND ATTACKED BY USS FINBACK
March 26-28 1943.

DAY FORMATION

Small Steamer - Pinging
500 yds
500 yds
1000 yds
1000 yds
Patrol boats patrolling station.
Pinging or listening.
500 yds
500 yds

NIGHT FORMATION

The night formation was similar to day except formation closed up and positions of the ships were irregular. The small steamer ranged in the middle and one patrol boat patrolled ahead while other patrolled astern.

— page 101 —
1. The Commander Submarine Division One Hundred One.
To: The Commander Submarine Force, Pacific Fleet.
Subject: U.S.S. FINBACK - Fourth War Patrol - Comments on.
Reference: (a) CO FINBACK conf. 1tr. SS230/416-3 serial 08 of 4-13-43.
1. FINBACK Fourth War Patrol lasted for 45 days, from February 27 to April 13, 1943. After 21 days in patrol areas and across trade routes adjacent to such areas it was terminated due to shortage of fuel according by surface chases.
2. Comment on the five contacts (other than small vessels):
   (a) March 12: The Commanding Officer identified this hospital ship as URAL MARU (listed as hospital ship in ONI 208-J). This ship is 38-5-

— page 102 —
1. March 24 - 26: Two attempted daylight attacks on the convoy, one on March 25 and one on March 26 were frustrated because of various reasons, one of them being the luck factor. Constant helm can be very disconcerting when seven ships have you surrounded and are using it. The convoy shifted on March 26 to a 4-minute zig plan, using 400 and 800 zigs. They were not zigzagging during the nights. The surface attack on the third night should have netted two hits in each salvo. The fact that only 1 hit resulted from the first attack was probably caused by the fast gyro changes while firing. FINBACK was swinging hard left through a 20° course change while firing, but steadied down for the second salvo at the other target.

In connection with the Commanding Officer's remark concerning the use of the periscope at night, a useful thumb rule is believed to be: The Target can be seen through the periscope when the range is about one-third the range at which the target can be first picked up through 7 x 50 binoculars. This applies to treated periscopes. For 34' periscopes (2'0.5) the figure is about one-half instead of one-third.

(d) April 5: This attack should have resulted in two hits or two misses. It nearly did. There two torpedoes are fired in salvo, a spread is desirable against a beached or anchored target.

3. Torpex was not used. It is of note that there were no erratic torpedoes or periscopes, and that, with moderate white caps, nine torpedoes, all set to 8' depth, ran well.

4. FINBACK is undergoing normal refit at Pearl. The Main Storage Battery will not require installation of laminated jars at the present time. The shaft squeal will be corrected.

5. This is the Commanding Officer's first patrol in command. His patrol is a fine beginning marked by aggressive determination, dogged hanging on to his contacts, six hits out of eleven torpedoes, and each of his four targets hit. Well Done!

ENCLOSURE (B)

— page 103 —
FC5-10/A16-3
(FB5-101)
Serial 056

CONFIDENTIAL

From: The Commander Submarine Squadron Ten.
To: The Commander Submarine Force, Pacific Fleet.

Subject: U.S.S. FINBACK (SS230), Fourth War Patrol - Comments on.

1. The fourth war patrol of the FINBACK was of 45 days duration. 32 days were spent in the assigned area or in the vicinity of the assigned area. Numerous contacts were made, but only a few were worthwhile targets.

2. It is noted that the FINBACK encountered an escorted and zig-zagging hospital ship. While the presence of air and surface escorts and the maneuvers of the vessel tend to create suspicion of unnuclar service, there is nothing in the provisions of Hague Convention III or Hague Convention X which could be construed as justifying an attack. Present existing orders to our submarines are quite specific respecting and exempting from attack all ships marked as hospital ships. However, the frequency with which hospital ships are encountered by our submarines leaves little doubt that the Japanese are using these ships for purposes other than designated.

3. The tenaciousness shown by the Commanding Officer in chasing a convoy is commendable. The chase lasted for a period of three days and was concluded then only because of shortage of fuel. It is unfortunate that circumstances did not permit further chase and ultimate destruction of the entire convoy.

4. Eleven torpedoes were fired and six hits scored for an excellent percentage of 54.5%.

5. It is noted that submerged reception of NPM Fox Scheduled was successful at a distance of 1640 miles from Pearl Harbor at signal strength and readability of 3.

6. The FINBACK returned from patrol in excellent material condition. As a result, overhaul of this vessel has been deferred and it will be ready for sea again after a normal refit period.

-1- ENCLOSURE (C)

— page 104 —
FC5-10/A16-3
:  (FB5-101)
:  Serial 056
:  CONFIDENTIAL
:  Subject:
:  U.S.S. FINBACK (SS230), Fourth War Patrol -
:  Comments on.

7. The Commander Submarine Squadron Ten congratulates
the Commanding Officer and personnel of the FINBACK on a well-
conducted and highly-aggressive patrol. The following damage to
the enemy is credited:

| Damage | Description |
|||
| AP (KINKA MARU) | 9310 tons |
| AK (TOTTORI MARU) | 5970 tons |
| AK (TAIBUN MARU) | 6580 tons |
| AK (BRISBANE MARU) | 5425 tons |
| TOTAL | 27285 tons |

- 2 -
- ENCLOSURE (C)

— page 105 —
1/2-10/AL6-3(5)/(16) SUBMARINE FORCE, PACIFIC FLIGHT
Serial 0517
Care of Fleet Post Office,
San Francisco, California,
April 21, 1943.

CONSUMBAC PATROL REPORT NO. 168
U.S.S. FINBACK - FOURTH WAR PATROL.

From: The Commander Submarine Force, Pacific Fleet.
To: Submarine Force, Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Report of Fourth War Patrol.

Enclosure: (A) Copy of Subject War Patrol Report.
(B) Consubid 101 Conf. 1tr. F55-101/16-3
Serial 030 of April 14, 1943.
(C) Consubron 10 Conf. 1tr. F05-10/16-3
(FB5-101) Serial 056 of April 14, 1943.

1. The fourth war patrol of the U.S.S. FINBACK was made with a new commanding officer. The FINBACK covered her areas extremely well and carried out attacks in a most aggressive manner.

2. It is noted that much of the time spent in the area was utilized in surface patrolling. This, of course, is highly commendable, but must always be weighed against the possibility of discovery by the enemy, thus, causing him to reroute all shipping.

3. The three day tenacious chase of an important convoy against the difficult odds of bright moonlight nights and expert enemy escorts was executed with the highest degree of military efficiency. The culmination of this long chase in firing six torpedoes at two ships of the convoy after being detected, is considered extremely aggressive. Further enemy anti-submarine action prevented the FINBACK from observing the results of her attacks although hits were observed on the second ship and three explosions were heard by personnel below.

4. The disappointing all-day chase of what turned out to be a hospital ship, which had been using military defensive tactics all day, has been made the subject of an official letter to the Commander-in-Chief, U.S. Pacific Fleet.

5. FINBACK's torpedo attack on the beached target previously badly damaged by the TUNNY resulted in the destruction of the stern of the vessel which, therefore, can be considered a total loss. Credit for the destruction of this vessel will, therefore, be assessed half to the FINBACK and half to the TUNNY.

DECLASSIFIED ART. 0445, OPENWINST 5510.1C

BY: 00-0922 - DATE: 1/2 -1- DECLASSIFIED

— page 106 —
1. SUBMARINE FORCE, PACIFIC FLEET
Serial 0517
CONFIDENTIAL
CONSUMPTION PATROL REPORT NO. 168.
U.S.S. FINBACK - FOURTH U.S. PATROL.
Subject: U.S.S. FINBACK (SS230) - Report of Fourth War Patrol.

6. The Commander Submarine Force, Pacific Fleet, congratulates the Commanding Officer, Officers, and Crew of the FINBACK for this successful and aggressive patrol, carried out in extremely hazardous areas. The FINBACK is credited with having inflicted the following damage to the enemy:

SUNK
$ - 1 Passenger Freighter (SUNAHU) - 5,236 tons

NOTE: Although this vessel was identified at the time by the Commanding Officer as of "the BRISBANE UHU class, careful study of the photographs obtained prove that it was of the old type passenger freighter SUNAHU class. The tonnage listed for this vessel is 10,672, half of which is credited to the FINBACK.

DAMAGED
1 Transport (KIIKA MUU) - 9,310 tons
1 Freighter (TOTTORI MUU) - 5,970 tons
1 Freighter (T.IBUN MUU) - 6,580 tons
TOTAL: 21,360 tons

C. A. LOCKCOD, Jr.

DISTRIBUTION:
(1N-43)
List III, SS
Special:
PL(5), ENS(5), ZL(5),
Consubmarine (2),
Subschool, IL (2),
Cometiskor.72 (2),
Consubron 50 (2)
Comscope (2),
Cincinet (2),
Comtaskor 15 (1).

E. R. SWINBURNE,
Flag Secretary.

— page 107 —
58230/A16-3
Serial (11)
DECLASSIFIED:
From: The Commanding Officer,
To: The Commander Submarine Force, Pacific Fleet,
Via: Official Channels,
Subject: Patrol Report,
Inclosure: (A) Patrol Report, Period 1st, 1943 to June 26, 1943.

1. Reclosure (A) is forwarded herewith.

DECLASSIFIED
J. A. TAYLOR, JR.
DECLASSIFIED
BY: [Signature]
DATE: [Date]
[Signature]

— page 108 —
0-0-N-F-I-D-E-I-T-I-A-L
U.S.S. FINBACK (SS230) - Report of Fifth War Patrol.
Period from May 12, 1943 to June 26, 1943.
Area - 10 - Operation Order # 80-43.

PROLOGUE:
Arrived Pearl Harbor, T.H. on April 13, 1943, from Fourth War Patrol. Commenced refit on April 14, 1943, by tender repair force and navy yard. Navy yard realigned propeller shafts and replaced bent plating on starboard side of safety tank. Completed refit May 3, 1943. Sound test conducted. Training period ended. Not departed or wiped. Readiness for sea on May 12, 1943.

1. Narrative.

May 12, 1943.
1000 (VX) Deported Pearl for Area Ten via Midway under escort of U.S.C.G. HUNY. Commander Submarines, Pacific Fleet in FIJI-BOK.

May 15, 1943.
0703 (Y) Moored to dock at Midway. Commander Submarines, Pacific Fleet left ship. Received 19,300 gallons of fuel.

1330 (Y) Deported Midway for area. Encountered numerous Army bombers (B-24s) returning from Wake Island raid. Also encountered PT-Boats and Patrol planes (PEYS) searching for a downed B-24 after dark.

May 16, 1943.
0550 (Y) Crossed 180th Meridian.

May 17-26, 1943.
Conducting daily dives and drills for control personnel and crew enroute to area.

May 19, 1943.
1941 (L) Div'd on sighting running lights of plane by Quartermaster and O.O.D. Although we had a full moon and clear night, the commanding officer is at liberty to explain the presence of a plane so far at sea (230 miles north of Wake) No bombs dropped.

2000 (L) Surfaced and proceeded.

May 20, 1943.
0554 (L) Div'd on radar contact on plane at 6 miles. No bombs

— page 109 —
0721 (L) Surfaced.
: 2300 (K) Passed between Ragan Island and Alamagan Island.
: 1700 (I) Entered area. Set course across northern end of area to take up patrol across traffic lanes from Empire at Formosa ports.
: 0002 (I) Picked up contact on radar at 10,250 yards. Put target on starboard quarter and commenced tracking. Unable to get good check on enemy course and speed due to unreliable bearings. As noon rose at 0026 opened range into moon streak at full speed on four engines. Moon was ducking in and out of the clouds. After moonrise was able to take bearings on strike. On ascertaining our position as being on targets beam, headed for position ahead at four engine speed.
: 0138 (I) While getting ahead of target to check his course by change of bearing, radar picked up three pips bearing 315° relative at 13,500 yards. Rough estimate sight these ships to be on course 300°(T) to 315°(T). As had determined our first target's course and speed, decided to attack and then chase convoy. "A bird in the hand seemed 'crutch' two in the bush." In order to reach an attack position ahead of the convoy we would have to pass close to our first target and would probably be sighted in the improved light conditions.
: 0157 (I) With range of about 8,000 yards, dived to 40 feet.
: 0212 (I) With range of about 3,300 yards, went to 60 feet.
: 0217 (I) With target track of 90° port, speed 10, and range of about 1,800 yards, fired a three torpedo spread. Fire torpedo, premature at 20 seconds, second torpedo - h. On bow, third torpedo - hit on stern. Sound unable to hear screws after two hits. Definitely heard break up noises on sound gear. The premature momentarily blinded the periscope. Only one torpedo, the third, was seen to hit, but all hands heard two hits following the premature. The target was surrounded by black smoke. Sighted target with decks awash.
: 0230 (I) When unable to see the target any longer, came to 40 feet to search with radar for target and possible

— page 110 —
0240 (I)
: 0243 (I)
: 0256 (I)
: 0700 (I)
: 1000 (I)
: 1605 (I)
: 1956 (I)

May 28, 1943.

Conducted submerged patrol along trade routes to Elba from Empire and Formosa.
SURFACED and continued surface patrol.
At
Sighted masts of same patrol vessel seen yesterday.
He was headed toward us and apparently sighted us
Tent ahead four engine speed. 'Has able to pull
head very slowly.
LT

- 3 -

— page 111 —
1105, (I) heard signals on D' receiver on 175 kcs. similar to craft honing signals from the direction of the patrol vessel. Later heard what sounded like transmissions from a plane on 35k ccs.
: 1132 (I) as we were losing the patrol vessel and just about to run into a rain squall, sighted float type observatic plane in direction of patrol vessel. Dived and went to 200 feet as sea was very smooth. Plane apparently had not seen us as no bombs were dropped. Realized that this area. Escorted patrol as we seem most unpopular not seen again. It looks as if we have just been optimistic about these patrol vessels leading us to target. Decided to try a new spot the next day.
: Day 29, 1943.
: Conducted submerged patrol 5 miles south of Anquar Island. The sea was glassy smooth.
: Day 30, 1943.
: Conducted submerged patrol southeast of entrances to Malakal harbor. The sea was glassy smooth. On surfacing, patrolled across trafic lane from Anquar Island to Truk.
: Day 31, 1943.
: Patrolled 5 miles south of entrances to Malakal harbor. Just as we were coming to periscope depth following rise for observatlon, sound reported screws bearing 130° relative. Shortly afterwards heard underwater explosion which was distant, but very heavy; lost per-peller noise. On arriving at periscope depth ten minutes after fighting up thru density layers at one third speed, could see nothing.
: 1000 (I) heard two noises resembling low order detonations. Nothing in sight.
: 1900 (I) surfaced and commenced patrolling along Truk - Palau route on surface.
: June 1, 1943.
: At 1022 (I) sighted smoke bearing 087° (T).
: At 1034 (I) dived when it was thought that tops of the ship were visible and we knew his base course. Found we had A similar to the ATUMBI LARU, 7,065 tons, page 7. C. I-208-T and an escort similar to our PC-boats. A-touch our first attack had proved to be an easy "A-l practice",

— page 112 —
1346 (I)
1357 (I)
2010 (I)
2055 (I)
June 2, 1943.
0010 (I)
0032 (I)
0110 (I)
0443 (I)
0512 (I)
(Attack #2)

U.S.S. FINBACK
this time the Japs were putting their minds to evoking us. Diagnosed the zig plan as a constant helm, it finally, as we later discovered, the target was doing a constant helm sur- rimposed on a regular zig plan which kept him off of this base course most of the time. The total of our efforts to reach a firing position a spot 2,500 yards from his track with a good sized gyro angle. Decided not to fire with such a poor ship we could easily get him tonight (no moon) when he still had zigging. At
surfaced and commenced trailing.
At
went ahead four engine speed to close target to range.
At
contacted target on radar at 15,300 yards. Tracking showed that target had fooled us and was still zig zagging. At
commenced rounding target for position ahead. Although there was no moon, the sky was bright with stars and the were very few clouds around the horizon. Light conditions were poor for a surface attack and poorer for a submarine attack.
At
put ship in position believed to be 4,000 yards off targets track, flooded down forward and after groups and started in for surface attack which would have been successful on a target steering a straight course.
At
we were 100 on starboard bow of target at range of 5,000 yards and since we had seen escort for about 2,000 yards, dived to avoid detection. Continued approach radar at forty feet. Could make out target shape visible, but not escort at this depth. At 3,000 range went to 60 feet and were unable to see target thru periscope. Decided not to fire on sound as no damage on the bow could be obtained.
At
surfaced and ran ahead to get in attack position at dawn. At
picked up land about entrance to Malakal Harbor, at seventeen miles. Gradually let target close. At
picked up shape which looked like a petrol boat ahead. While our target was at the stern of us, so dived and started approach. At
fired three torpedo spread with 1000 port track, speed of 1 1/4 knots, and actual range of 1,150 yards. All torpedoes were set on 15 feet. The first torpedo hit a schip with a terrific explosion, but the second e-

— page 113 —
0514 (I)
The secret headed for us to start retaliatory measures.
Next deep. Received depth charge attacks as follows:
0517 (I) one charge, at a comfortable distance,
0520 (I) two charges, close aboard. Jarred open valves. Start small leak in all air bank bottle opening.
0524 (I) four charges, farther away.
0528 (I) two charges.
0548 (I) four charges which sounded a lot like aerial bombs at considerable distance. Escort continued supersonic pinging and maintained some kind of contact until 0800 (I). A temperature gradient of 16°F. was probably helping us.
At
0845 (I) lost supersonic pinging. There is also a possibility that the escort stayed around the target picking up a
vivors and just kept pinging. His bearing indicated this.
At
0945 (I) started up to periscope depth. Had considerable diffi
cultly in forcing ship thru density layers at slow speed and silent running. Nothing in sight. Continued
periscope patrol. On surfacing headed for north to
patrol in northwest part of area the next day.
Received dispatch on June 1, 1943 schedule from Commander
Submarines, Pacific Fleet changing our operation order.
The FINBACK is to spend the rest of her patrol in the
present area and then proceed to Fremantle, West
Australia for refit.
At
2000 (K) received rest of information from Commander Submarines
Pacific Fleet giving routing to Fremantle.

Tune 3, 1943.
Conducting submerged patrol on Empire - Palau trade lane.

Tune 4-5, 1943.
Conducting surface patrol across trade lanes from Empi.

June 5, 1943.
During afternoon passed through area in which the fleet
ing debris was seen; two overturned lifeboats, spars, j

— page 114 —
U.S.S. FINKLOCK
Oil drums and furniture. One boat was taken close aboard. The English letters had were noted on the bow. This boat had a propeller, e.s.s.pan bow, and boat falls, which he parted, dragging astern. If this debris had drifted 15N. May 27, 1943.

June 6, 1943.
Conducting submerged approach of Toggel Mlungui Passage at sighted passenger-freighter of about 4,000 tons coming from signal, range 7,000 yards, and angle on bow 45 per cent. Target zigged right and continued out on course: about 3000(T). Closed range 5,500 yards. Picked up 5 of our smoking trawler friend of last patrol. Pinging our target. He did not seem to be keeping up with us.

1010 (I) secured from approach as range increased to 10,000 yards.

June 7, 1943.
Patrolling submerged off Toggel Mlungui Passage.

1013 (I) sighted smoke and heard pingling bearing 3500(T). As this smoke drew around to the southward, assumed it was our smoking trawler friend making his usual sweep. At sighted mast of freighter in some smoke bearing 2400(T). Started approach. Closest range reached was 8,000 yards. This freighter of about 5,000 tons was escorted by a patrol vessel and a plane. Only the masts of the patrol vessel were visible. At

1430 (I) when escorting plane headed in our direction, went to 14 feet. Target was already opening range.

1515 (I) came to periscope depth on hearing a new supersonic tone. Contact #11) Discovered a convoy of four ships headed out from clean net on course 3200(T) led by one escort and covered by one seagull. This time we were too far to the south after having tried to close freighter earlier and closest range obtained was 8,000 yards. Commenced trailing submarine preparatory to chasing on surface after dark. These vessels took a formation of two columns in line, with escort ahead. The ships were tentatively identified as being similar to the following ships: Near column Yuki Iaru - 5,704 tons, Page 213, ONI-203-J and Heian class - 5,400 tons, Page 215, ONI-208-J. Far column Lima Iaru class - 7,000 tons, Page 227, ONI-208-J and Maru class - 5,400 tons, Page 215, ONI-208-J. At

1827 (I) lost visual contact with smoke of convoy.

1358 (I) surfaced and started closing convoy at full speed.

— page 115 —
2021 (I) At when no contact was established, stopped to listen for supersonic pinging of escort. It became apparent that the convoy had changed course radically at dark.
: 2038 (I) At started retiring search to northward to cover all enemy changes of course around to 0300(T).
: 2211 (I) At shortly before we intended to start covering convoy course to the westward, picked up smoke just as convoy entered rain squall.
: 2213 (I) At contacted convoy on radar at 13,700 yards. Commenced tracking convoy to determine his approximate course and to obtain an idea of his zig plan.
: 2325 (I) At started rounding convoy at about 12,000 yards range.

une 8, 1943.
: 0012 (I) Steamed on port bow of convoy at his course and speed. As there had been numerous rain squalls during night decided to wait for a good black background and make a surface attack.
: 0131.(I) At crossed over to starboard bow for good background.
: 0204 (I) At turned toward convoy, shifted to battery, and stopped. Found the escort was conveniently 2,000 yards ahead of convoy. He was long, low, and strongly resembled one of our old destroyers in the dark. Believe he was a torpedo boat. Our background of cloud was so black, they couldn't possibly see us. The adjacent ships of each column were keeping good line abreast.
: 0227 (I) At fired a three torpedo spread at each of two leading ships which almost presented an overlapping target. Range to nearest target - 1,500 yards; track - 1000 starboard; gyro angle - 0.10; and range to far target 2,300 yards. Swooping hard left at flank speed to clear two after ships, who had a smaller angle on bow, and to try a stern tube shot. Cleared nearest ship 600 yards (by radar) when we were seen to beam. Already had two stern tubes ready and set on 10 feet in case our escort got too friendly.
: 0232 (I) At fired two torpedoes while still swinging at overlapping after ships. Total results - one hit on nearest leading target (Lima Maru Class); two hits on farthest leading target (Yuki Maru); and one hit on farthest after target (Heian Maru class). These hits were seen, heard, and checked by tire of torpedo run. The last ship hit was seen taking a down angle as we retired to southwest at

— page 117 —
1847 (I) with escort passing ahead at 400 yards, right hand ship (attack #6) with zero angle on bow, range 2,000 yards, center ship with 200 port angle on bow, range 3,000 yards, and leight hand ship 800 port angle on bow, 1,200 yards, fired three torpedoes (TNT heads) at left hand ship. 1st torpedo jumped clear of the water twice at about 400 yards, just astern of the escort and later prematured, the 2nd torpedo hit, and the 3rd torpedo missed. The escort started turning toward us after 1st torpedo prematured. Went deep to avoid ramming and to evade depth charge attack. Our going under one ship and astern of another seemed to confuse the escort. He dropped for depth charges, but none were very close. The escort then commenced searching with supersonic. He seemed to be sircitly amateur. At escort dropped one depth charge at about 4,000 yards. Escort stayed in. our vicinity echo-ranging. At 2036 (I) lost echo-ranging and came up to periscope depth. Searc thoroughly with periscope and SJ radar. At 2044 (I) surfaced in bright moonlight with not a cloud visible. Went ahead on four engines trying to reestablish contact When unable to reestablish contact, began patrolling P-15. - Fire trade lane and returning to area. We were about 160 miles north of area. We now had a very poor torpedo distribution with six torpedoes (two torpedoes) aft and one torpedo forward. This meant our future surface approaches had to be made backing down if we wanted more accuracy.

June 9-10, 1943.

Patrolled on surface along Empire-Palau routes. Our recent activity had apparently caused a re-routing of traffic.

June 11, 1943.

Patrolled submerged off Taogal ilungui on channel range of 1050(T). At 0817 (I) sighted smoke bearing 2850(T). Commenced approach. Found (Contact #13) we had three ships in line abreast with a small destroyer, 1,000 class, escorting ahead. Sea was glassy smooth so all observations were very short.Tentative identification of these ships was made as similar to the following ships in 0-20-J: left hand ship: Nagoya Maru, 6,072 tce Page 35; middle ship(annoufleged): Sirogane Maru, 3,130 tce Page 108; right hand ship: Hiltro Maru, 6,534 tons, Page 75. At about 5,000 yards fortunately for us, it began

— page 118 —
0954(I)
rain and let up just before we fired. It is doubted if an undetected approach would have been possible otherwise.
: 1000 (I)
with the ship definitely sinking and the destroyer had in our direction, went deep. Heard cracking up noises for about forty minutes.
: 1011 (I)
destroyer dropped two depth charges.
: 1022 (I)
he dropped two more. None close.
The Palau temperature gradient and density layers appear to have been established at once. A temperature gradient of 17°F. existed between surface and 300 feet. Supersonic pinging and screws were heard until 1103 (I). Decided to take our time coming up to periscope depth due to expected plane search and proximity to channel entrance.
: 1157 (I)
picked up pinging again.
: 1310 (I)
finally lost pinging.
: 1327 (I)
started up to periscope depth. Again the need of a slit train pump was sorely felt. It was necessary to blow out 15,000 pounds of water in bringing ship up from 300 feet. This was done by blowing water to negative tank from #2 and #3 auxiliary tanks and then blowing negative with 2 pound air. Found all clear at periscope depth. Relocated torpedo tubes aft and pumped bilges. Decided to patrol off Anguar Island the next day in hope of getting a phosphate ship and in order to allow the area off the periscope to cool down.

June 12, 1943.
Petrolled submerged off Anguar Island. Sea was glassy smooth.

June 13, 1943.
Petrolled submerged about 20 miles off Anguel Milungui was closing Island when.

— page 120 —
2300 (I) cleared message to Commander Submarinos, Pacific Fleet reporting we were heading for Australia. Received Roger on following Fox schedule.

June 16-17, 1943:
Enroute Western Australia on surface via Djailolo Passage conducting daily drills.

June 18, 1943:
Enroute Western Australia via Cerem Sea and Namipa Pass Held "crossing the line" ceremonies during the forerunner.

1320 (I) :dived on sighting two fighter planes. It is believed that these were probably high flying, soaring birds of a type not previously encountered by this ship. Conducted a drill control problem while submerged.

June 19, 1943:
Passing through Banda Sea and Ombai Strait.

June 20, 1943:
Completing transit of Ombai Strait and entering Indian Ocean east of Swu Island.

1127 (H) :dived on radar contact at 7 miles.

1204 (H) :surfaced, following launch and proceeded.

June 21, 1943:
Enroute Western Australia on surface.

0710 (H) :sighted two engineed bomber at about 7 miles. Dived. No bombs. Conducted trim dive.

0740 (H) :Surfaced.

June 22, 1943:
Enroute from area on surface.

June 23, 1943:
: 0800 (H) made 1 rendezvous with U.S.S. ISABEL five miles north of Vlei Light. Proceeded under escort to oil barge in South Gulf (approximate location - Lat - 22°-11' N. Long. - 114°-09' (E)) for fuel.

— page 121 —
1210 (H) after parting both mooring lines and carrying away
    pelican hook on towing pendant due to heavy seas,
    abandon attempts to fuel from oil barge. Received
    permission of S.O.P.A. to fuel from CHAUTOCL'HER when
    THRESHER completed her fueling or from Dutch tanker
    S.S. ONDINA.
    At
1301 (H) moored along side tanker.
    At
1533 (H) cleared tanker and anchored to await completion of
    ISAB L's fueling.
    At
1645 (H) under-way under escort of ISABEL for Fremantle.

UNE 26, 1943.
Arrived Fremantle.

- 14 -

— page 126 —
1) 1 2) 3) 4)
: 1717 2012 1727 472:
: 5-26-43 6-1-43 6-7-43 6-7-43
: 80-41(N) 70-11(N) 90-07(N) 90-07(N)
: 13L-02(E) 13L-03(E) 13L-03(E) 13L-03(E)
: 3 Mk XIV 3 Mk XIV 3 Mk XIV 3 Mk XIV
: Torpex Torpex Torpex Torpex
: 2 1 1 2
: 6,000 5,704
: 7,065 7,000
: Fr.Fr.-Pass. Fr.Fr.-Pass. Fr.Fr.-Pass. Fr.Fr.-Pass.
: 1,800 1,150 1,500 2,300
: (P) (P) (S) (S)
: (N) (N) (N) (N)
: (R) (R) (R) (R)
: 13 13 13 13
: 15 15 15 15
: Bow Bow Bow Bow
: 90(P) 100(P) 100(S) 100(S)
: 1-356 1-349 1/2 1-024.5 1-023 1/7
: 2-352 2-344 1/2 2-033 2-024
: 3-354 3-347 3-033 3-022
: 10 11 3/4 8 8
: 8 secs. 8 secs. 8 secs. 8 secs.
: 20 30 3 1/40 2 1/2
: Divergent Divergent Divergent Divergent
: No-SEE Yes Yes Yes
: NOTES:
   - Attack #1 - First torpedo was premature at 20 secs.
   - All spruces fired with last torpedo set with most accurate information.
   - Det N. Attacks #3 and 4 was the best obtainable but not necessarily exactly correct.

- 19 -

— page 127 —
5 6 7 8
: 1732 0947 0054 1128
: 6-7-43 6-7-43 6-11-43 6-15-43
: 90-07 (M) 11-36 (N) 70-36 (N) 100-00
: 1340-31 (E) 1320-10 (E) 1340-17 (E) 1310-10 (E)
: 2 Mk XIV 3 Mk XIV 3 Mk XIV 3 Mk XIV
: Torpax 1 1 1 2 0
: 1 1 2 0
: 5,100 6,072
: 6,370
: Freighter 1,200 1,200 800 3,500
: (S) (P) (P) (P)
: (R) (N) (S) (R)
: (R) (N) (S) (

— page 129 —
1. RADIO RECEPTION:
(a) The following results were obtained on the submerged loop while copying IWM enroute to area:

| Depth | Distance | Relative | Signal | Readability |
|-------|||||
| 50    | 1840     | 3        | 3      | 3         |
| 51    | 1890     | 3        | 3      | 3         |
| 53    | 1890     | 3        | 3      | 3         |
| 54    | 0540     | 1        | 1      | 1         |
| 50    | 0020     | 3        | 3      | 3         |
| 53    | 0120     | 2        | 2      | 2         |
| 54    | 0120     | 2        | 2      | 2         |
| 50    | 1350     | 1        | 1      | 1         |
| 51    | 1350     | 1        | 1      | 1         |
| 52    | 1350     | 1        | 1      | 1         |
| 50    | 2930     | 2        | 2      | 3         |
| 52    | 2930     | 0        | 0      | 0         |

* Symbols in accordance with U.S. Navy Procedure Signal Book.

# Height of top of D/F loop above keel - 39 feet.

(b) Commander submarines, Pacific Fleet serials 72 (May) and 23 (June) were missed. These were not requested as they did not concern us. The readability and signal strength of transmissions on all frequencies from IWM while in this area were considerably lessened during the two or three hours proceeding dawn. The DC receiver when operated with sense antenna radiates a signal. The RAK receiver, when tuned to this second harmonic of the beat frequency oscillator of the DC, picked up a strong signal from the DQ. The range of this emission is not known.

— page 130 —
5. SOUND CONDITIONS and DENSITY LAYERS:

(a) Sound conditions in this area can be called fairly good. We picked up supersonic ranging at 10,000 to 12,000 yards and slow speed scores at 5,000 yards.

(b) Close to this island of Babelthump very pronounced density lay and temperature gradients exist. In general, the bathymetric recorded an isothermal layer to a depth of 100 feet and a negative gradient of about eight degrees per hundred feet from 100 feet to 300 feet. These observations were made east and west of this islet at distances of about twelve miles. It was necessary to flood 1,000 feet of water to hold the boat at a depth of 300 feet. Density layers were noted at 220 feet and 150 feet as we surfaced and the boat was 14,000 pounds heavy. The negative gradient decreased as the distance from this island increased.

3. HEALTH and HABITABILITY:

Health and habitability were excellent during this patrol.

4. MILES STEADY ENOUGH TO AIM FROM STATION:

Miles enroute to area 4,543
Miles steamed in area 3,538
Miles enroute to Fremantle 3,505

Total 11,586

5. FUEL EXPENDITURE:

Fuel enroute to area (from Pearl) - - - - 50,940
Fuel used in area 26,810
Fuel enroute to Australia 37,110
Fuel received at Xenouth 8,425

6. FACTORS OF INFLUENCE: REMAINING:

| Factor | Fuel | Provisions | Fresh water | Personnel |
||------||||
| 1      | 3,500| 20 days    | unlimited   | 15       |

7. FACTOR OF INFLUENCE: ENDING RATE:

Area was left early as only one torpedo remained on board.

Scheduled departure date - - - - - - - June 24, 1943.
Actual departure date - - - - - - - June 16, 1943.

- 23 -

— page 131 —
3. REMARKS:
(a) The performance of duty of this officer and men attached to this vessel during this patrol was excellent. Results obtained can be attributed to good work by all members of the team. Owing to lots of contacts, good luck, and limited enemy A/S measures, morale is at a high pitch.

(b) Many of the members of the crew completing their fifth war patrol definitely showed strain during enemy A/S measures. This should be possible to correct in most cases during the ships overhaul period with a little leave.

(c) This is the first patrol that this vessel has experienced any trouble with torpedoes. The last attack made on June 15, 1943, was definitely poorly done and not up to our standards. Poor torpedo performance was not the main cause of failure.

(d) The Commander's Officer believes that our successful attacks with a new T.I.C. operator can be attributed in a large measure to the training and instruction given to the operator by Lieutenant Commander R. E. Dennis, U.S. Navy prior to our departure on patrol. This school is particularly beneficial for a ship losing it's experienced T.D.C. operator.

— page 132 —
25-6/416-3
Serial No. 0279

SUBJECT: TIDES ENDORSEMENT TO
U.S. SUBMARINE CONFIRM
1tr. SS230/416-3 serial
(1) of June 26, 1943.

From: The Commander Submarine Squadron SIX.
To: The Commander-in-Chief, United States Fleet.
Via: (1) The Commander Task Force SEVENTY-ONE.
(2) The Commander SEVENTY-FLIET.

Subject: U.S.S. FINBACK - Fifth War Patrol - Comments on.

1. The FINBACK is fifth war patrol covered a period of 4 days of which 24 were spent in the patrol area or north of the Nome Barrier. The patrol was terminated on 15 June, 1943 when only one torpedo remained. The FINBACK then proceeded to fire ten rounds of 1" TNT.

2. The FINBACK arrived in French Polynesia following the fifth war patrol in excellent material condition excepting for those items situated by the Commander's office in basic report. Refit of FINBACK in preparation for the next patrol is being currently carried out by FINLTS and will be completed within the normal two week period. No cost, but will be made to replace main battery jars on those cells showing zero grounds between element and jar inserts but electrolytic from each will be analyzed and changed in those showing high iron content.

3. Health and habitability were excellent during the patrol. Three men will probably require relief due to physical condition. The ship was clean and well kept.

4. On the nine contacts made with torpedo targets six were developed into attacks. While making the approach for the first attack a three ship convoy was picked up on the radar. The Commander's office chose to continue his attack instead of shifting targets. It was good judgment to take the third in hand. Its scouting course indicates that it probably had the most valuable cargo. It is considered that the evidence on attacks #3, 4 and 5 is ample to justify the assumption that two ships were sunk and one damaged out of the four ship convoy. The area was well covered as indicated by the number of contacts, and the patrol was aggressive and conducted.

5. The Commander Submarine Squadron SIX is pleased to heartily congratulate the Commanding Officer, officers and crew of the FINBACK on an aggressive and successful patrol. It is con-

— page 133 —
5-6/16-3
: 1st No. 0279
: U.S. Submarine Squadron Six
: (c/o)
: Care of Fleet Post Office,
: San Francisco, California,
: July 4, 1943.

FIRST PHOTOGRAPHED:
: U.S. SUBMARINE
: TR. SS230/AL6-3 Serial
: 11 of June 26, 1943.

OBJECT:
: U.S.S. PT-6A-1
: U.S.S.

— page 134 —
1. 1/24-71/A16-3
Serial 0608
C-O-N-T-I-D-E-N-T-A-L
7 July 1943.
SECOND INDORSEMENT to
CO, USS FIREBACK Contr.
1tr, SS230/A16-3 serial
(11) dated 25 June 1943.

From: The Commander Task Force SEVENTY-ONE.
To: The Commander in Chief, U.S. FLEET.
Via: The Commander TWENTY FLIGHT.

Subject: U.S.S. FIREBACK - Fifth War Patrol - Comment on.

1. The remarks of Commander Submarine Squadron SIX are concurred in.

2. The Force Commander considers this patrol to be a fine example of the use of sound judgement and excellent submarine practices. It again demonstrated what can be accomplished with an S3 Radar in good operating condition. The results obtained with this instrument reflect great credit upon the state of training of the operators and the thoroughness of the maintenance personnel. It is further noted that intelligent use was made of the bathythermograph.

3. The Commander Task Force SEVENTY-ONE takes great pleasure in congratulating the Commanding Officer, Officers and crew of the FIREBACK on an aggressive well conducted patrol. As all damage to the enemy was inflicted prior to coming under the operational control of this command, Commander Submarines, FIRST FLEET, is requested to credit the tonnage in his records, and to make suitable recommendations for awards.

4. It is considered that the following damage was inflicted on the enemy:

| Damage | Tonnage |
|||
| 1 AK  | (Unidentified) | 6,000 tons |
| 1 AK  | (YUKI MARU class) | 5,704 tons |
| 1 AK  | (TIBIAI MARU class) | 5,400 tons |
| 1 AP  | (TAGOYA MARU class) | 6,072 tons |

TOTAL ... 23,176 tons

- 1 -

— page 135 —
24-71/A16-3
Serial 0608
C-O-N-P-T-I-D-E-M-T-I-A-L
SECOND ENDORSEMENT to
CO, U.S.S. FINBACK Conf.
1tr SS230/A16-3 serial
(11) dated 26 June 1943.

Subject: U.S.S. FINBACK - Fifth War Patrol
Comment on:

(4 Cont'd) -

DAMAGED

1 AX (TANUCAITI MARU class) 7,064 tons
1 AX (LIMA MARU class) 5,989 tons
1 AF (USSUIT 1ARU class) 5,386 tons

TOTAL ..... 20,439 tons

R. W. CHRISTMAS.

DISTRIBUTION
CONTROL:
VICE ORNAV (1) (2) Via COI? TIN FILET
COM 1ST FILET (1) (1)
COM 2ND FILET (1)
COM 3RD FILET (1)
COM 7TH FILET (1)
CONSUBS 1ST FILET (2)
CONSUBS 2ND FILET (2)
CONTRACTION-72 (2)
DIVCOLS, RON-5 (1)
CONSURC-3 (1)
S/Ms H.A. (1) (1) Each - NOT TO BE TAKEN TO SEA - BURN)

Lieutenant Commander, U.S.N., Flag secretary.

— page 136 —
19 JUL 1943
A16-3
Serial: (01491)
CONFIDENTIAL
THIRD INDICEMENT to
CO U.S.S. FINBACK confr.
1tr. SS230/A16-3 serial
(11) dated 26 June 1943.
From: The Commander Seventh Fleet.
To: The Commander in Chief, U.S. Fleet.
Subject: U.S.S. FINBACK - Fifth War Patrol - Report of.

Copy to:
Vice OPMV

FILMED

— page 137 —
1943, U.S.S. FINBACK (SS230)
U.S.S. FINBACK - Report of Sixth War Patrol.
Period from: July 18, 1943 to September 12, 1943.
Areas: CTG - 71.1 Areas 404; 403; 501; 502; 504.
Operation Order: 20-43.

PROLOGUE:
Arrived Fremantle, West Australia on June 26, 1943, from Fifth War Patrol. Commenced refit on June 26, 1943, by U.S.S. PELIAS Assisted by Submarine Division SLETY-TWO Relief Crew. Completed refit on July 11, 1943. Readiness for sea July 18, 1943. Conducted sound tests and checked degaussing readings. Training period held.

NARRATIVE:
July 18, 1943.
1400 (H) Underway for day and night training with H.H.H.S.
2100 (H) Departed operating area for Exmouth Gulf, Conducted daily fire control, ship, and gun drills enroute.
July 21, 1943.
0700 (H) Conducted special assigned tests for shore installations north of Flaming Head Light.
1329 (H) I.0ored alongside Dutch Tanker, S.S. ODINA, in Exmouth Gulf to fuel. Received 10,221 gallons.
1853 (H) Underway for area after waiting for Officer Iessenger Mail.

July 22-24, 1943.
Enroute to area on surface, conducted daily fire control, ship, and diving drills.

July 24, 1943.
1410 (H) Dived when lookout reported two planes dead ahead with 450 port angle on bow. O.O.D. did not sight planes. No bombs. Hydraulic line to hull induction valve in crews mess carried away on diving. Some oil got into storeroom and magazines, but was quickly wiped up with no damage resulting. Remained submerged to repair hydraulic line. At surfaced upon completing repairs.
1543 (H) started passage of Lombok Strait.

July 25, 1943.
Conducted submerged patrol south of Kanggan Islands

-1-
MCLOSURE (A)

— page 140 —
2355 (H)
July 31, 1943.

: 0005 (H)
0335 (H)
0559 (H)
2140 (H)
2247 (H)

At the top of the page:
U.S.S. FINBACK (SS230)

page 83 of ONI-208-J.
After the hit, the pip on the radar seemed to decrease about 15% and then stay the same size. We opened range to 7,500 yards and then rounded target to attack again from northward should he fail to sink. Target continued to fire gu.s to southward for about twenty minutes. Then numerous lights were seen about the decks.

At
when north of target at range of 8,000 yards, headed toward target for another attack. At this time radar officer reported that pip on radar was getting weak-er although we were closing the range.

At
lost pip on radar at 5,000 yards. Continued to close the spot where target had been. Picked up two life-boats on radar at ranges of 1,500 and 1,800 yards. Closed range to 900 yards and as target had definitely sunk, set course to northward. Darkness of night prevented recovery of any material of intelligence value.

At
picked up pip on radar at 10,000 yards. Started tracking and working for position ahead.

At
turned toward target and dived for a dawn attack. It soon became evident from the target's small silhouette that he was not a freighter, but probably a patrol boat up to no good. Discovered target was a torpedo boat similar to the Chidori class which draws six feet. The sea was condition two or three. Abandoned attack and evaded at periscope depth. It is felt that this decision was proved to be sound during our second attack because the same torpedoes which would have been fired, permeatued at that time. Conducted submerged patrol along trade lane from Singapore to Fook Point off Bawan Island.

At
made radar contact on target at range of 12,600 yards. Commenced tracking target. When we had determined target course and speed, closed range to about 6,000 yards to locate possible escorts. None found.

At
a bright light flashed on starboard beam at a height indicating it was probably in a fishing boat. At this time the target, which had maintained a straight course along a normal trade route, turned away and

- 4 - EXPLOSIVES (..)

— page 141 —
0547 (H)  DIVED AND COMMENCED APPROACH.  AS IT BECAME LIGHT, IT WAS FOUND THAT WE HAD AN UNCORRECTED, ZIG-ZAGGING JI SIMILAR TO THE TAIGEN IARU, 5,660 TONS, PAGE 207 OF OII-208-J.  THE TARGET WAS NOT LOADED.  IT HAD THE NUMBER 934 PAINTED ON THE SIDE OF THE BRIDGE.  AT

0634 (H)  FIRED THREE TORPEDO-SPREADS AT RANGE OF 1,300 YARDS, 370 STARBOARD TRACK, 09 GYRO ANGLE, AND DEATH SETTING OF 15 FEET.  RESULTS - LOSS. 1 AND 2 PRECEDED AT 23 SECONDS; 3 HIT TARGET IN BOW.  IT IS BELIEVED THAT TARGET SLOWED DOWN ON SEEING PRETENDERS AS 3 SHOULD HAVE HIT AT.  WHEN FIRST TWO TORPEDOES PRETENDERS, MADE THREE MORE TUBES READY FOR FIRING.  AT

0637 (H)  FIRED 4 TORPEDO AT RANGE OF 1,700 YARDS WITH A TRACK OF 1610 STARBOARD, AND 001 GYRO ANGLE.  TORPEDO MISSED AS TARGET EVADED.  TARGET TOOK A 30-DOWN ANGLE, RAISED HIS SCREW PARTLY OUT OF THE WATER, GAVE US A 1300 ANGLE ON BOW, AND PULLED AWAY AT ABOUT 8 KNOTS.  THE TARGET FIRED ABOUT 30 ROUNDS FROM HIS STERN GUN AT THE PERISCOPE.  AT

0820 (H)  WITH RANGE OF ABOUT 16,000 YARDS, SURFACED AND COMMENCED SURFACE CHASE.  THE APPARENTLY FOUND HE HAD MORE SPEED AS WE HAD FIGURED WE COULD REACH A SPOT AHEAD IN 75 FEET OF WATER AND FINISH HIM OFF.  WE DID NOT GAIN HEARING ON TARGET AS FAST AS WE EXPECTED.  AT

1025 (H)  ABANDONED CHASE WHEN WE REACHED 72 FEET OF WATER AND HE WAS STILL BEARING 2450(T).  IT WAS HEART BREAKING TO LOSE AN UNESCORTED TARGET WITH SUCH A PERFECT SET UP.  THIS RETIREMENT PROVED TO BE NONE TO SOON.  AT

1037  DIVED ON RADAR CONTACT ON SD RADAR AT 7 MILES.  DEPTH OF WATER WAS 62 FEET.

— page 142 —
1038 (H) plane dropped two aerial bombs. Credit Japs with two "near misses". No damage done. Ran at 75 feet at two thirds speed to clear diving position.
: 1050 (H) looked with periscope and found plane circling astern. White caps and clouds were on our side. Remained submerged and cleared area to south.

August 2, 1943.
Conducted submerged patrol at junction of two trade lanes east of Baven Island.

August 3, 1943.
Conducted submerged patrol northwest of Surabaya.
: 0756 (H) sighted three ships, which developed into escort vessels; headed into Surabaya. They were a mine sweeper, a torpedo boat, and a converted trawler.
: 0830 (H) sighted a small PC boat following above ships. Apparently the Japs had decided their ships need escorts in this area. It looked like "old home vock"
: 0844 (E) sighted plane above these ships, "lant to 100 feet as sea was very smooth.
: 0351 (H) plane not in sight.
: 1305 (H) sighted smoke which drew to east. Started approach. Discovered we had a peculiar type craft which is apparently used as an interisland trading vessel. This vessel had one mast forward, a stack amidships, and a canopy covered after deck. He was not close enough to obtain a picture.
: 1422 (H) sighted AC similar to Ioya Maru, 5,471 tons, page 211 of Oil-208-0-1 heading from direction of Surabaya. Commenced approach. Target had a small escort which resembled a converted cabin cruiser that patrolled on his quarters. When unable to close target to favorable range with a good set up, decided to trail and attack on surface after dark.

- 6 - INCLOSURE (A)

— page 143 —
1610 (H) while trailing target, sighted small oiler heading toward Surabaya. This vessel was light and resembled our coastal oilers.
: 1555 (H) surfaced.
: 2023 (H) contacted target on radar at range of 14,000 yards.
: 2241 (H) reached attack position on starboard bow. We had put two main engines on the battery charge after contacting target on radar. At 3,500 yards range, quartermaster sighted white signal light on escort.
: 2319 (H) with escort at 2,300 yards, fired three torpedo spreads from bow tubes with following setup: track angle - 950 (S); range 1,700 yards; gyro angle 40 right; and depth setting of 12 feet. All torpedoes seemed to run normally and looked good. Results - no hits. With the spreads used, the consistency of our data, and actual torpedo tracks observed, the commanding officer believes it was impossible to get three misses unless the torpedoes ran too deep. A subsequent careful check-up of all personnel and data has not revealed any explanation for three misses.

When the third torpedo left the tube, swung ship hard right at flank speed and placed target astern.
: 2322 (H) fired two torpedoes from after tubes by applying load angle on after T.D.T. and using zero gyro angles. Results - two hits. The first torpedo hit amidships giving off a large amount of flame. The second torpedo hit well aft. The target was covered with black smoke, but seemed to start down aft at once. All hands on bridge watched bow rise out of water and then the target took its final plunge. At the same time the radar officer watched his ply line and then disappeared. The target sank in two and one-half minutes. Approximately neither the target, who was closed to 1,300 yards, nor the escort who closed us to 2,400 yards, with a broadside view, ever saw us. The escort charged off astern of target dropping depth charges to a total of nine. They sound fine when you are on the surface. Cleared area to north, got off message to CTF 71.1, and headed east so as to be able to clear area the next night.

- 7 - ENCLOSURE (..)

— page 144 —
1943
Patrolled submerged east of Baven Island along trade route from Singapore to Makassar. On surfacing after sunset, took up patrol station north of Baven Island on Bornoo to Surabaya Route.

: 1943
Patrolled on surface along Singapore - Makassar Route leaving area.
At
sighted smoke. Headed toward some to investigate. Found tops of two ships which could have varied in size from escort vessels to good sized ships. Ex-1-

— page 145 —
U.S.S. PTB-1ACK (SS230)
CONFIDENTIAL

This sound had was put out of commission for the remainder of the patrol.

August 9, 1943.

Conducted submerged patrol off of Inkang Bay, Celebes, N.E.I..

August 10, 1943.

Conducted submerged patrol off Liankang Bay, Celebes.
At
1627 (H) surfaced and set course for Salier Strait.
At
1300 (H) entered area 501. After clearing Salier Strait, commenced patrolling along route from Salier Strait to Tioro Strait (both off southern end of Celebes).
At
2215 (H) sighted shape of ship at 14,000 yards and put SJ radar on it. The moon was directly overhead and the night was quite bright. Tracked target with radar and took position ahead for submerged attack before ship could reach Salier Strait or moon could set.
At
2341 (H) dived and continued approach at 40 feet.
At

August 11, 1943.

0003 (H) with target at 5,600 yards and radar unable to discover an escort, went to 60 feet and continued approach. Discovered small escort trailing target about 1,000 yards just prior to firing.
At
0021 (H) fired a three torpedo spread from stern tubes with 90° port track, 2,000 yard range, 180° gyro angle, and 12 foot depth setting. Results - first torpedo hit under attack, second and third torpedoes missed ahead and stern as they should have, since a spread of 125° coverage was used. The target was very lightly loaded and riding high. It was identified as the Tatumiya Iaru, 6,344 tons, page 77 of OIC-20-3.
Changed course 90° to left after watching torpedo hit, to clear torpedo track. Although escort was hard to make out, sound heard him speed up immediately following the torpedo explosion. Ran at full speed for ten minutes and went deep.

- 9 - ENCLOSURE (A)

— page 146 —
0026 (H) At
: 0035 (H) Escort dropped two depth charges at fairly good range, but they seemed to be large and set deep. Escort did not have echo ranging gear. Continued to hear screws above us for sometime. We had about a 60 F. negative temperature gradient.
: 0212 (H) surfaced and headed for attack position.
: 0222 (H) Contacted target at 12,900 yards. Target seemed to have stopped and to have settled some. Commenced closing target on surface, very slowly, while trying to locate the escort. Since the moon had set, a surface attack looked feasible if the escort was not to alert. When we discovered the escort 1,200 yards this side of the target, slowed and waited for him to circle target. When the escort commenced a circuit around the target, we began closing range.
: 0333 (H) fired two bow tubes at about 3,800 yards 90° port track, 0° gyro angle, and depth setting of 12 feet. Results - two promontures at about 17 seconds. Neither target nor escort fired at us as we retired southward. Dedicated to circle target at full speed and got in an attack from the north before dawn.
: 0447 (H) fired two bow tubes at 3,900 yard range, 0° gyro angle, 90° starboard track, and spread torpedoes by using masts as points of aim. Results - two misses astern. The target seemed to kick ahead very slowly just as we fired. We had used a target speed of zero. This time the target opened up with his gun. No splashless vice seen. This failure meant that our next attack would have to be a submerged one in daylight as dawn had begun breaking at the east.
: 0515 (H) dived and ran west to head off target from Salier Strait.

- 10 - ENCLOSURE (A)

— page 148 —
2145 (H)
Conducted submerged patrol in western entrance to Tioro Strait. On surfacing patrold route to Salier Strait.
At
2145 (H)
just as ship was turning northward to patrol the following day off Pomalaa, Celebes, picked up target on radar at 3,750 yards, 034° relative. . . . that time we sighted a patrol vessel visually for the first time and turned away. When the commanding officer arrived on the bridge, he found a patrol vessel with a big bow wave bearing down with zero angle on the bow and range of 2,700 yards. The range opened fairly rapidly as four Fairbanks-Morse engines warmed up. At a range of about 3,500 yards, the patrol vessel presented a 10° angle on the bow and opened fired with a gun of about 3" caliber. At this point the FINBACK joined the group that strongly believes in the 5" gun aft. Decided to stay on surface as long as we opened range and firing was not too accurate. The only close shot dropped 75 yards to starboard of forward engine room hatch. This shot did not explode. He continued to fire until range opened to 6,000 yards. As he was in our path to Pomalaa, decided to retire to southeast and patrol southwest of Buton Island the following day. This patrol vessel was only soon heard on. At first he appeared to be a small destroyer, but as he only made about 10-11 knots it is believed that he was a PC type patrol boat.

August 13, 1943.
Conducted submerged patrol at west entrance of Buton Passage.

August 14, 1943.
Conducted submerged patrol off Pomalaa, Celebes. At
2011 (H)
sighted patrol boat similar to that soon on August 12, 1943. We ran around him and continued southward to conduct patrol in Buton Passage.

August 15 - 16, 1943.
Conducted submerged patrol in Buton Passage. Sighted a bonched tanker just southwest of

- 12 - ENCLOSURE (A)

— page 149 —
1228 (H)
Conducted submerg'd patrol off eastern end of
Tioro Strait.

: 1328 (H)
Conducted high periscope, submerged patrol along
trade route from Tioro Strait to focal point off
Boeroe Island.

: 1328 (H)
Conducted submerged patrol off northwest corner
of Boeroe Island.

: 1328 (H)
at
sighted two ships similar to our Army mine
planter type, one small tug; and an inter-island
steamer or barge of about 1,500 tons in column
passing inshore of us. ...s our'cuts had shown us
only 5,000 yards off the beach, these ships seem-
ed very small as they passed inshore. Since.no
sizable gun was apparent decided to attack with
the 4" gun. ...armed up SJ radar.
At
surfaced and started in pursuit. The range to
the steamer by SJ radar was 9,000 yards. This
showed we had been farther off the beach. Closed
targets at full speed on the surface. They paid
no attention until we opened fired on the steamer
at 5,000 yards range. The steamer was light and
very high out of the water. Hit steamer about
five times. Leading mine planter turned toward
us and opened fire with a gun which seemed to be
about a one pounder. Directed 4" fire at this
ship. He continued to close range in spite of
numerous hits until we opened fire with our three
20 mm guns and two 50 caliber machine guns. This
barrage combined with a fire breaking out on
board, discouraged him and he opened range rapidly.
This vessel had settled about three feet. Shifted
fire back to the steamer and the second mine plan-
ter began closing us. His machine gun fire was
falling about 100 yards short. Began to hit him
repeatedly with 4" gun. Soon put him on fire from
stem to stern. He finally headed for the beach
blazing furiously. At this point the first mine

- 13 - ENCLOSURE (A)

— page 150 —
1943

Patrolled submerged west of Ceram and northeast of Ininiya Strait.

1458 (H) sighted 'masts of small inter-island steamer of about 1,000 tons or a small mine sweeper. Unable to positively identify target because of poor visibility and fogging up of periscope. Decided he was to small for a torpedo. On surfacing set course for Dampier Strait.

2030 (H) received message from CTF 71.1 requesting number of torpedoes aboard. Decided to stay close to Ceram until message was cleared in order not to disclose future movements.

August 21, 1943.

Conducted 'high' periscope, submerged patrol in Ceram Sea, on route from Ininiya Strait to Dampier Strait.

1615 (I) surfaced and set course for Sagavin Strait.

August 22, 1943.

Conducted submerged patrol off western entrance to Sagavin Strait.

- 14 - INCLUSION (A)

— page 152 —
U.S.S. TINBACH (SS230)
CONFIDENTIAL

trying to keep a small silhouette to both target and escort, a 280 right gyro was accepted. Target and escort headed south as we opened to north, Escort dropped two depth charges aimlessly. Abandoned chase as we could not get ahead of target undetected before he began to hug coast of Ceram. At daylight, he could be in either Kelang or Imanipa Strait. This set-up had checked so accurately that we had already credited ourselves with 5,000 tons.

August 25, 1943.

Conducted high periscope, submerged patrol along route from Imanipa Strait to Dampier Strait.

August 26, 1943.

Conducted submerged patrol off west tip of Bantam Island so as to cover both Dampier and Sagoevin Straits.
At
1055 (I) sighted smoke boring 0990 (T) indicating a ship leaving Sagoevin Strait. Started approach. Discovered we had a patrol boat of the torpedo boat or PC-class. This vessel was using supersonic ranging on 19 kcs. Abandoned approach at range of about 9,000 yards.

August 27, 1943.

Conducted surfano patrol from Dampier Strait through Dijalolo Passage.

August 28, 1943.

Enroute from area to Midway.
At
0000 (I) left area 502.

August 29 - 31, 1943.

At
0901 (I) passed to Command of Submarines Pacific. Enroute from area to Midway. Conducted daily training dives.

September 1, 1943.

Enroute from area to Midway.
At
1222 (K) dived on SD radar contact at 5 miles. No bombs.

- 16 - ENCLOSURE (A)

— page 153 —
1257 (K) surfaced.
At: 1420 (K) dived when lookout sighted reconnaissance plane.
No bombs.
At: 1517 (K) surfaced.
At: 1810 (K) passed between Pagan and Agrinan Islands, Mariana Islands.

September 2, 1943.
Enroute from area to Midway.
At: 1225 (K) had SD radar contact at 26 miles. Plane closed to 24 miles and was sighted by lookout on course 160° (T). Ship than 240 miles from Pagan Island and 345 miles from Marcus Island.

September 3-6, 1943.
Enroute from area to Midway. Conducted daily ship's drills and fire control problems.

September 7, 1943.
While enroute to Midway.
At: 0200 (H) made radar contact on object at 5,400 yards bearing 037° relative. Unable to sight object. Commenced tracking and found object which we suspected was a submarine on some course we were making 9 knots. At this time decoded message stating we would probably pass GAR. Decided to exchange identification signals. Found ship was TAMOR. First sighted TAMOR from astern at 1,900 yards. She fell in astern and took up our speed.

September 7, 1943.
1638 (Y) Arrived Midway. Moored to U.S.S. SPERRY. Received 20,640 gallons of Diesel Oil.

September 8, 1943.
1500 (Y) Departed Midway for Pearl in company with TAMOR.

September 9-12, 1943.
Enroute Midway to Pearl.

September 12, 1943.
Arrived Pearl.

- 17 - ENCLOSURE (A)

— page 158 —
7. SUITABLE FOR SUBMARINE ATTACKS
U.S.S. PETRAS

| Attack | (1) | (2) | (3) | (4) |
||-----|-----|-----|-----|
| Time  | 1   | 2   | 3   | 4   |
| Date  | 7-30-43 | 8-1-43 | 8-3-43 | 8-3-43 |
| (Lat.) | 60-31' (S) | 150-19' (S) | 50-18' (S) | 50-18' (S) |
| Location (Long.) | 1110-26' (E) | 1120-09' (E) | 1110-52' (E) | 1110-52' (E) |
| Number & type Torpedoes on each attack. | 3-1k XIV | 4-1k XIV | 3-1k XIV | 2-1k XIV |
| | Tpx - heads: Tpx - heads

— page 159 —
5: 6: 7: 8:
Attack: 1621 1933 2047 1507
Date Use G.C.T. 8-10-43 8-10-43 8-10-43 8-24-43
(Lat.) : 50-31' (S) 50-31' (S) 50-31' (S) 20-22' (S)
Location (Long.) : 120°-46' (E) 120°-46' (E) 120°-46' (E) 128°-27' (E)
Number & type of Tor: 3-1K ZIV: 2-1K ZIV: 2-1K ZIV: 2-1K ZIV
Pedoes on each Attack: Tpx - head Tpx - head Tpx - head Tpx - head
Hits 1 0 0 0
Number sunk (Tonnage): 0 0 0 0
Number Damaged or
probably sunk 6,344 0 0 0
Type of Target AK AK AK
Range 2,000 3,800 3,900 1,450
Type of Attack:
Periscope (P) Radar
(R) Surface (S) (P) (R) (S) (R) (S) (R) (S) (R)
Light (I)
Estimated draft target: 10 10 9 9
Torpedo Depth Setting: 9 9 9 9
Bov or Stern Shot: Stern BOV BOV BOV
Track Angle : 1 - 382 P: 90 P: 90 S: 116° S
: 2 - 92 P:
: 3 - 37 P:
: 1 - 1013 0° 0° 026
Gyro angle : 2 - 173 0° 0° 11.5
Estimated Target Speed: 3.25 0 0 11.5
Firing Interval : 3 secs 10 secs 10 secs 5 secs
Spread - Amount : 3 1/4" Point of Point of 30
and Kind Divergent: aim aim Divergent
Was Torpedo Performance Satisfactory: Yes No Yes Yes
Notes:
Attack #3 - The reason for three misses cannot be explained.
Attack #4 - This was a smart firing so data is rough.
Attack #5 - 1st torpedo hit under stack.
Attack #6 - Two pronatures at 17 seconds.
Attack #7 - Two misses astern.

-23- ENCLOSURE (A)

— page 160 —
8. ENEMY ARTI SUBMARINE PASSURES:

Escorts encountered in this area were converted craft not especially designed for the job. Only one escort had supersonic ranging equipment. All escorts trailed the target and did not seem particularly alert. 'e were faster than any escorts encountered actually escorting. Depth charges dropped seemed to be heavier than those previously experienced.

Planes covered all ships entering or leaving Surabaya. Planes were readily available in the Gulf of Boni.

No patrol vessels were contacted in any of the narrow straits or passages.

9. DESCRIPTION OF ENEMY LINE SURPRISE OPERATIONS:

None observed.

— page 161 —
10. MAJOR DEFECTS EXPERIENCED:

(a) The J/K-QC sound head was scraped on the bottom damaging the head and probably bending the shaft. The hydraulic shaft is sprung slightly and the lower drift stops are bent. The head cannot be raised.

(b) Six cables running between the Control Room and Conning Tower and passing outside the hull and three cables to the Bridge are grounded due to leaky insulation. The insulation on cables exposed to action of the seas has deteriorated and all cables between Conning Tower and Control Room and Bridge should be renewed during the navy yard overhaul.

(c) There is an air leak in number two main ballast tank. Cause of leak has not been determined but it is in number two air bank or the blow manifold.

(d) The steel inserted jars of the main storage battery will need replacement during the coming navy yard overhaul. There are a total of fourteen cells with zero grounds between the plates and the steel inserts of the jars. A four hour discharge conducted on June 25, 1943 gave an ampere hour capacity of 91.37J. On the three hour discharge conducted on September 10, 1943 an ampere hour capacity of 102J.

- 25 - INCLOSURE (A)

— page 162 —
11. RADIO RECEPTION:
(a) The serials originated by CTF 71.1 were all received. All messages sent to VIXO were cleared immediately. Radio communications are excellent in this area.

(b) All NPM serials were received. The message sent from west of the Marianas was cleared immediately.

(c) Submerged reception tests were not made every day due to securing of the NPM signal during the daily dive. Dives could not be made on two days because of the necessity of maintaining surface speed in order to arrive at rendezvous on time. The following results were obtained:

| Date | Depth | Distance | Relative | Signal |
|------|-------|||-------|

— page 163 —
12. SOUND CONDITIONS and DENSITY LAYERS:

Sound conditions, in general, were fair with a high background noise level. Only one density layer was experienced. This was in the gulf of L'oni, east of Salcier Strait. It had a negative temperature gradient of 20 F/100 feet.

13. HEALTH and HABITABILITY:

Health and habitability were excellent.

14. TILES STEAMED ENROUTE TO AND FROM STATION:

To Area 1, 1976 miles
In Area 5, 5391 miles
From Area 3, 1734 miles
(Iddnavy) Total 11,101 miles
(Pearl) Total 12,251 miles

15. FUEL EXPENDED:

To Area 19,855 gals.
In Area 40,220 gals.
From Area 40,040 gals.
Total Expended (Midway) 100,115 gals.

16. FACTORS OF ENDURANCE RELATING:

Torpedoes Fuel Provisions Fresh Water Personnel
3 2,400 10 Unlimited 5

17. FACTOR OF ENDURANCE CAUSED ENDING THIS PATROL:

Operation order ended patrol.

18. ENEMY:

1. The refit given the ship by the U.S.S. YELLS was excellent. The system of relieving all ships personnel during the refit gave the officers of the P.I.B.C. the first real period of relaxation obtained during a refit since the war started. A good liberty port greatly raised the morale of the crew.

2. The performance of duty by all hands was up to its usual high standard. It was noted that those people who were pretty well shaken up by the death charging received on the fourth patrol seemed to have recovered their confidence and cockiness.

3. Although no strenuous A/S measures were experienced during this patrol, the urgent need of a silent trim pump is still felt.

- 27 - ENCLOSURE (A)

— page 164 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-E-N-T-I-A-L
18. REMARKS: continued

4. The commanding officer feels that this patrol would have
been more successful if the five torpedoes which premarched, had
run hot, straight, and normal.

- 28 - ENCLOSURE (A)

— page 165 —
1/2/1943
Serial 01285
CONFIDENTIAL

FIRST ENDORSEMENT to
FINBACK Report of Sixth
War Patrol dated 9-12-43.

CONSPUSCAPAC PATROL REPORT NO. 249
U.S.S. FINBACK - SIXTH WAR PATROL.

From: The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, U. S. Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Report of Sixth War Patrol,
(18 July to 12 September 1943).

1. The sixth war patrol of the FINBACK was conducted under the
operational control of the Commander Submarines, Southwest Pacific Force, while
enroute to Pearl Harbor from Australia.

2. This patrol was an extremely active one, with attendant great
success. The Commander Submarine Force, Pacific Fleet, considers this one of
the most aggressive patrols thus far performed. The gun battles against a
1,500 ton inter-island steamer and two 750 ton mine planters were exceptionally
well conducted and resulted in considerable damage to all three. All torpedo
attacks were tenaciously and aggressively executed, resulting in severe damage
to the enemy.

3. Because the FINBACK's results of the fifth war patrol were
delayed in arriving, she was not credited for Combat Insignia. Therefore, both
the fifth and sixth war patrols of the FINBACK are considered successful for
Combat Insignia award.

4. The Commander Submarine Force, Pacific Fleet, congratulates the
Commanding Officer, officers, and crew for this very successful war patrol.
The FINBACK is credited with having inflicted the following damage to the enemy:

S U N K

1 - Passenger-Cargo Vessel (HUSIMI
MARU class) - 10,800 tons
1 - Freighter (KOYA MARU class) - 5,471 tons
1 - Mine Planter* - 750 tons

TOTAL: 17,021 tons

RINISHED-NEWTON: 17,021 tons

2 OCT 1943
12 tkm 056
A/6-3(23)/SS230
95678
-1-

— page 166 —
12-10/416-3(5)/(16) SUBMARINE FORCE, PACIFIC FLEET 1d

Serial 01285
Care of Fleet Post Office,
San Francisco, California,
16 December, 1943.

FIRST ENDORSEMENT to
FINBACK Report of Sixth
War Patrol dated 9-12-43.

COMSUBSPAC PATROL REPORT NO. 249
U.S.S. FINBACK - SIXTH WAR PATROL.

Subject: U.S.S. FINBACK (SS230) - Report of Sixth War Patrol,
(18 July to 12 September 1943).

DAMAGED

1 - Freighter (TAIGEN MARU class) - 5,660 tons
1 - Freighter (TATUMITA MARU class) - 6,344 tons
1 - Small Steamer* - 1,500 tons
1 - Mine Planter* - 750 tons

* By gunfire TOTAL: 14,254 tons

5. All of the above damage inflicted was performed in the operational areas of Commander Task Force Seventy-One who is requested to credit this damage on his records.

C. A. LOCKWOOD, Jr.

DISTRIBUTION:
(Complete Reports)
Cominch (5)
VCNO (5)
Cinepac (6)
Intel. Cen. Pac.
Ocean Areas (1)
Serforpac (1)
(Adv. Base Plan.Unit (1)
Cincelant (2)
Comsubsblant (8)
S/M School, NL (2)
Comsepac (2)
Comsewsepace (1)
Comsubsewsepace (2)
CTF 72 (2)
CTF 16 (1)
Comsubspace (18)
SUBAD, MI (2)
ComsubspaceSubordeam (2)
All Squadron and Div.
Commanders, Subspace (2)
U.S.S. FINBACK (1)
(Endorsements only)
All Submarine, Subspace (1)

R. C. LAWVER,
Flag Secretary.

— page 167 —
15-142/A16-3/FB101
Serial 09
DECLASSIFIED

From: The Commander Submarine Division 142.
To: The Commander Submarine Force, Pacific Fleet.
Via: The Commander Submarine Squadron Fourteen.

Subject: U.S.S. FINBACK (SS230) - Report of Sixth War Patrol - Comments on.

1. The sixth war patrol of the FINBACK covered a period of fifty seven days of which thirty three were spent either in assigned areas or patrolling enemy controlled waters. There were 19 contacts with the enemy of which 9 were worthy of torpedo fire and 4 were successfully attacked. One contact with four small miscellaneous ships was successfully attacked by gunfire.

2. Attacks

Approaches were well conducted and attacks aggressively executed. Twenty one torpedoes were fired and five hits obtained for a percentage of 23.8. Five torpedoes were premature. Four misses are attributed to control errors, four as the result of spread used, one as a result of evasive action by target and two may have been deep runners or duds. Ranges and track angles were favorable except in attacks Number 2, 6 and 7. The last torpedo in attack Number 2 was fired on a track of 161°. Ranges on attacks Number 6 and 7 were 3800 and 3900 yards. Zero or small gyro angles were used in all attacks except Number 8. Except for attack Number 5 spreads used were on the conservative side. The SJ Radar contributed much to the results achieved. It was used in every attack either to gain a favorable position for submerged approach or for pressing home night attacks on the surface.

3. Material

The FINBACK has made six consecutive patrols and requires a Navy Yard overhaul which will be undertaken at the Navy Yard, Pearl Harbor. It is estimated that the overhaul will be completed in about seven weeks. The major item to be accomplished is the replacement of

DECLASSIFIED (B)

DECLASSIFIED. 0445, OPPAVINST 5510.10
BY: 0P-0782C DATE 3726/2

55595

— page 168 —
15 September 1943.

FIRST ENDORSEMENT:
Comsubdiv 142 Conf. 1tr.
FBS-142/A16-3/FB101 Serial
09 of 14 September 1943.

From: The Commander Submarine Squadron Fourteen.
To: The Commander Submarine Force, Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Report of Sixth War Patrol - Comments on.

1. Forwarded concurring in the remarks of Commander Submarine Division One Hundred Forty-Two.

2. The sixth patrol of FINBACK was characterized by careful planning, and by such planning the initiative was retained even in the shallower waters where a great part of the patrol was conducted.

3. The ship was extremely clean and tidy upon return from patrol, reflecting the pride of the crew in their ship and the leadership which has made FINBACK an outstanding submarine.

4. The commanding officer, officers and crew of FINBACK are to be congratulated on an excellent patrol.

J. B. LONGSTAFF.

Copy to:
Comsubdiv 142.
CO FINBACK.

— page 169 —
1/2
FBS-142/A16-3/FB142
Serial 09
SUB: RINE DIVISION 142
CONFIDENTIAL
Subject: U.S.S. FINBACK (SSE30) - Report of Sixth War Patrol
Comments on:
the steel insert battery jars with the soft laminated rubber type.
4. The state of cleanliness and preservation throughout the officers and crew. During the Navy Yard period those officers and men who have made four or more consecutive patrols will be sent to the main- land for leave and recuperation.
5. The Commanding Officer, officers and crew are congratulated on an aggressive and successful patrol.
W. D. WILKIN.
Copy to:
CO FINBACK
Consubdiv 101
-2-
ENCLOSURE (B)

— page 170 —
4. The state of cleanliness and preservation throughout the ship was exceptional and is a reflection of the excellent morale of officers and crew. During the Navy Yard period those officers and men who have made four or more consecutive patrols will be sent to the main-land for leave and recuperation.

5. The Commanding Officer, officers and crew are congratulated on an aggressive and successful patrol.

W. D. WILKIN.

Copy to:
CO FINBACK
Comsubdiv 101

- 2 -

ENCLOSURE (B)

— page 171 —
SS230/A16-3
Serial ( 017 )
CONFIDENTIAL

From:  The Commanding Officer.
To:  The Commander Submarine Force, Pacific Fleet.

Subject:  Sixth "ar Patrol - Report of

Reference:  (a) Subacft Conf. Ltr. 8-42.

Enclosure:  (A) Subject Report.
    (B) Track Chart.

1. In accordance with reference (a), subject enclosures are forwarded herewith.

cc:  CSS-14
CSD-141

— page 172 —
5/24/1944
Serial (05)
DECLASSIFIED: T-I-a-I

Pro: The Containing Officer:
To: The Commander in Chief, U.S. Fleet.
Via: (1) The Commander in Chief, U.S. Pacific Fleet.
(2) The Commander in Chief, U.S. Pacific Fleet.

Subject: U.S. FLEET - Report of Seventh War Patrol.

Enclosure: (A) Subject Report.
(3) Track Chart.

1. Enclosure (A) covering the Seventh War Patrol conducted in Japanese Emirare's waters during the period from 15 December, 1942 to 6 February, 1944, is forwarded herewith.

J. A. TREE, Jr.

DECLASSIFIED: 0445, OPM/AVINST 5510.10C
BY 02-0829C DATE 5/24/42

DECLASSIFIED

2 (2359)

46905

— page 174 —
0944 (K) Dived on SD Radar contact at 6 miles with Tori Shima bearing 1650T, distance 24 miles.
: 1125 (K) Sighted very slack biplane at 3,000 feet at about 12 miles head sea course. Strayed on surface and headed toward plane until when we dived as plane started to head in our direction. At surfaced, Picked up plane at about 25 miles heading away on northeast course.
: 2015 (K) Picked up 10 on interference on SJ Radar which we assumed was from BAPISH whose area we were crossing. Removed blanks from vents on 4.4

— page 175 —
2320 (I)
At
when about dead ahead of target, she changed base course to 215°, commenced a small constant helm zig, and increased speed to 15 knots. Decided to attack on surface. Placed ship 3,500 yards off target's track on her port bow in order to obtain best background.

January 2, 1944.
At
saturated in to attack.
At
plotting party reported we were dead ahead of target at range of 4,600 yards. Turned right for stern tube shot. Target zigged away so turned right for bow tube shot. We ended up with a 115°(T) track, 15° gyro, and 3,000 yard range. Decided to shoot with this poor set-up, as target was too fast to catch again.

0152 (I)
At
fired tubes #4, #5, and #6. Result - two observed hits. Ratched on surface. Target did not have an escort. These hits stopped the target.

0204 (I)
At
target commenced firing his deck guns. He fired intermittently until our second attack. Heard minor explosions and saw numerous flashes aboard. "We opened range to 10,000 yards and circled him to the north. He opened up on his radio and talked to Taraskai. We were listening on the DQ loop. The radar was remained strong so it looked like the tanker's driver officer needed further help in order to get her down. Decided to close target on surface as close as possible, submerge to 40 feet, and conduct a submerged attack.

0319 (I)
At
divided to 40 feet at range of 3,000 yards.

0334 (I)
At
with range of 1,430 yards, went to 50 feet when a shell exploded close aboard. As we definitely wanted to sink this ship before hull arrived, at.

0336 (I)
At
fired tubes #1, #2, and #3 at range of 1,300 yards. Results - three observed hits. Heard cracking up noises in sound gear.

0341 (I)
At
a terrific explosion took place which shook us considerably. Target was lost at that moment. Obtained a sound range just prior to the explosion of 2,180 yards and set it into D.C. at 2,500 yards came to 4.0 feet and screwed with 50 yards. To contacts except on land at 58,000 yards.

0358 (I)
At
surfaced with range of about 3,000 yards. No target in sight and no further radar contact. Clustered area of attack to northwest feeling good about our first day in the area.

Conducted submerged patrol at focal point of

— page 176 —
1944

Conducted submerged patrol at tactical point on Nagasaki - Transcribed from the original text:
"Conducted submerged patrol at tactical point on

— page 178 —
1057 (I) dived to 140 feet on sighting plane. SD radar not in use.
: 1112 (I) returned to periscope depth and found plane circling us. Went to 140 feet
: 1150 (I) unable to find plane. Surface watertight did not seem too smart in this area.

January 25, 1944.

Conducting submerged patrol alone Negasaki - Forosa trade lane.

0832 (I) sighted smoke. Started tracking with T.D.C.
: 0945 when we found smoke must be opening, surfaced and headed toward smoke at full speed on four main engines. Further tracking showed source of smoke to be making about 12 knots. A check on the chart showed an end around was not possible because of the proximity of the convoy to port. Made out two ships and three smoke.
: 1038 (I) dived when forced down by air escort which caused us to lose contact. Closed this trace lane submerged.

January 26 - 27, 1944.

Conducting submerged patrol along Negasaki - Forosa trade lane.

January 28, 1944.

Conducted submerged patrol off Colnett Strait and on traffic lane along Nensei Shoto. Avoided patrol boat prior to diving.

January 29, 1944.

Conducted patrol as on 23th.
: 2050 (I) departed area. Decided to use only two engine speed while crossing traffic lanes from emir.

January 30, 1944.

Enroute from area.
: 1110 (I) sighted trawler with #1 periscope. Closed trawler on surface and destroyed with gunfire.

January 31, 1944.

Enroute from area.
: 6 -

— page 179 —
1345 (I) sighted trawler with 1l' periscope. Decided to expend remainder of 4th ammunition. Sea too rough to be sure of many hits. Expended 4th ammunition, damaged trawler, killed majority of personnel, and resumed course to eastward.
: 1636 (I) sighted another trawler similar to one just fired on. Avoided.

'February 1 - 6, 1944.
Enroute from area. Encountered rough quartering sea which tore loose plates of metal decking aft. Conducting daily fire control and ship drills.

'February 6, 1944.
0900 (Y) Arrived 'l'dway for refit. Ordered to continue to Pearl. Transferred 16 I.K. XIV-34 torpedoes to Submarine Base, Midway. Received 21 Mk XVIII torpedoes to transport to Pearl. Received 14,000 gallons of fuel oil.

'February 7, 1944.
0700 (Y) Departed 'l'dway.

'February 8 - 10, 1944.
Enroute 'l'dway to Pearl. Conducting daily training dives, fire control drills, and ship's drills.

'February 11, 1944.
Arrived Pearl.

2 (2359)

— page 181 —
1) WEATHER:
Rough weather delayed the ship's arrival on station and caused
unusual rattles to the crew. On many days in the area rough seas not only
dealt with the ship but also made torpedo firing impossible. Enroute to area seas varied from one to five.
It was found to be much warmer in the southern part of the area
nearer Kyushu where the Japan current was of some effect. Average
temperature at night in this area for month of January was 45°F.

2) TIDAL INFORMATION:
None obtained.

3) NAVIGATIONAL AID:
Cairo Shima Lt. No.1658 - PL'c.v. 14 secs normal intensity
Nara To Lt. No.2784 - PL'c.v. 10 secs reduced intensity
Cyr To Lt. No.2764 - PL'c.v. 6 secs normal intensity
Kusaraki Shima Lt. No.1650 - PL'c.v. 28 secs normal intensity
Yokohama Shima Lt. No.1656 - PL'c.v. 60 secs reduced intensity
Kano Misaki Lt. No.1484 - PL'c.v. 30 secs normal intensity
Yasukawa Sakai Lt. No.1486 - PL'c.v. 30 secs normal intensity
Ise Shima Lt. No.1648 - PL'c.v. 45 secs normal intensity
Ge Haku To Lt. No.2758 - PL'c.v. 10 secs normal intensity
Kyobun To Lt. No.2756 - PL'c.v. 15 secs normal intensity
every other flash intensified.

2 2 2 3 3 9

— page 185 —
ATTACK DATA: (continued)
read Div 1 1/4° - - -
a Condition Two - -
erhaul Activity SPERRY S/II Base S/II Base
P.H.,T.H. P.H.,T.H.

S.S. FINBACK TORPEDO ATTACK NO. 2 PATROL NO. 7
No 0336 (I) Date 1-2-44 Lat. 29° 30' (N) Long. 128° 50' (Z)
TARGET DATA - DANGER INFLICTED
scriotion: Same target hit with two torpedoes on attack #1.

:pts / Sunk: 1 - tanker of about 10,000 tons.
:pts / Damaged
probably sunk:
:age Determined Seeing three torpedoes hit. Target exploded with a
terrific explosion. Unable to pick up target on Radar
at range of 2,500 yards and depth of 40 feet. Sur-
faced at 3,000 yards range and could not pick up
target by sight or on radar.

:get Draft 32 Course 210 Speed 1 1/2 Range 1,300
CDN SHIP DATA
eed 4 Course 173 Depth 52' angle 20° dive (at firing)

FIRST OPTIONAL TORPEDO DATA
ne Attack: Radar approach. Submerged to depth of 40 feet. Then
unable to see target continually thru #1 periscope,
fired on SJ Radar bearings.

|    |    |    |    |    |
|------|------|------|------|------|
| 1    | 2    | 3    | 4    | 5    |
| 148(S) | 150(S) | 143(S) | 145(S) | 146(S) |
| 005 1/2 | 007   | 005    | 006    | 007    |
| 8 ft   | 8 ft   | 8 ft   | 8 ft   | 8 ft   |
| High  | High | High | High | High |
| Hit   | Hit  | Hit  | Hit  | Hit  |
| No    | No   | No   | No   | No   |
| XIV-3A | XIV-3A | XIV-3A | XIV-3A | XIV-3A |
| 25652 | 23780 | 39283 | 39283 | 39283 |
| V-4   | V-4   | V-4   | V-4   | V-4   |
| 1331  | 2376  | 1614  | 1614  | 1614  |
| Contact | Contact | Contact | Contact | Contact |
| Contact | Contact | Contact | Contact | Contact |
| XVI   | XVI  | XVI  | XVI  | XVI  |
| 10336 | 10127 | 2156  | 2156  | 2156  |
| TPX   | TPX  | TPX  | TPX  | TPX  |
| 10 sec | -    | -    | -    | -    |
| 1 1/4° | -    | -    | -    | -    |

- 13 -

— page 186 —
1. ATTACK DATA: (continued)
Sea Condition: Two
Overhaul Activity: S/1 Base
P.H., T.T.
S/1 Base
P.H., T.T.
S/1 Base
P.H., T.T.

U.S.S. FINBACK
GUN ATTACK NO. 1
PATROL NO. 7
Time 1110 (I) Date 1-30-44 Lat. 30° 19' (H) Long. 134° 00' (E)

TARGET DATE: DETACHMENT

PUNK: Trawler - (sampan bow) of about 120 tons. Target speeded up from 7 to 10 knots. Diesel propelled.

Damaged or
Specify Cunk
Type Deternined: Coing alongside and examining visually. Left with
S: stern submerged, on fire, and sinking.

DETAILS OF ACTION

Sea was condition four which made the ship an unstable platform. Target bounced around in sea. Sighted target with #1 riscose and closed at on the surface. Opened fire at 2,100 yards with 4" gun using sensitive nose ammunition. Gradually closed range to 400 yards. Over 4" fire with three 20 mm guns and two air cooled 50 cal. machine guns. 5,000 yards target fired at us with small arms until we silenced them with several hits which cleaned off the superstructure. Used SJ Radar for ranges. Fire was not too accurate in this sea. The loss of our foot firing device, due to the linkage carrying away in touch seas enroute to the area, undoubtedly caused a lot of near misses. Sensitive nose ammunition was very effective against this wooden target.

Amunition Extended: 4" - - - 99 rounds
20 mm - - - 550 rounds
50 cal. - - - 320 rounds

J.S.S. FINBACK
GUN ATTACK NO. 2
PATROL NO. 7
Time 1431 (I) Date 1-31-44 Lat. 30° 42' (H) Long. 139° 49' (E)

TARGET DATE: DETACHMENT

PUNK: Trawler of about 100 tons. Target speed of 7 knots. Probably Sunk: Diesel propelled. Damaged. Range Determined: Sceing 4 inch shells hit and explode. Superstructure
S: and hull holed.

DETAILS OF ACTION

Sea was condition four. Too rough for good shooting. Sighted target with #1 periscope and closed it on the surface. Opened fire

— page 187 —
2,200 yards with 4" gun using 4" common ammunition. Closed range 900 yards. Opened fire with three 20 mm guns and two air cooled 0 cal. machine guns at 1,300 yards when target opened fire with a machine gun. Obtained aout eight hits with 4" gun, three of which exploded. Numerous hits were obtained with the small arms and the enemy machine gun was silenced. The small arms eliminated all non-ornel topside. Broke off action when all 4" ammunition was extended, and we had a smooth sea, more would have been obtained, and the aircraft completely wrecked. The lack of a 4" gun in the armament is contributed to our inaccuracy of fire. Sensitivity of ammunition is much more effective than common ammunition against a number of targets.

Annunition expended 4"

— page 190 —
1. USS STANFORD - FULL USED:
   - Pearl to Area: 4,269 miles
   - In Area: 3,983 miles
   - Area to: Midway to Pearl: 2,911 miles
   - Total: 12,429 miles

   - 52,500 gallons
   - 23,680 gallons
   - 39,915 gallons
   - 14,400 gallons

   - 130,495 gallons

2) DURATION:
   - Days enroute to Area: 16
   - Days in Area: 29
   - Days enroute to Base: 14
   - Days submerged: 29

3) FACTORS OF DURATION REMAINING:
   - Torpedoes (No.): 18
   - Fuel (gals): 12,915
   - Provisions (days): 10
   - Personnel Factor (days): 10

4) LITTLE FACTOR THIS P.TROL - OPERATION ORDER

5) REMARKS:
   - (1) During the first half of the patrol, the weather was our worst enemy. We would have rattled badly during silent running.
   - (2) Carrying fuel in 14 Main Ballast Tank definitely makes these rats poorer sea boats. It is very satisfying however to have no oil worries. Following rough figures obtained on difference in speeds.

- 18 -

— page 191 —
1. Main storage battery:
   - The cell tops of all main storage battery jars require resealing.
   - Sealing compound has been used to allow the electrolyte to
   - This was caused by the working of the ship in the rough
   - The new laminar rubber jars work
   - In more easily due to their reliability.
   - In order from station hatch battery grounds, which could not be
   - When below 90 volts at sea, were experienced. In route to area,
   - Venty jars were resealed with all the sealing compound available.
   - The rubber-sprayed steel strong-
   - The rubber-sprayed steel

— page 193 —
7. Relative to the Commanding Officer's Comments:

(a) It is not believed that docking will be necessary each refit to give satisfactory speed.

(b) The Division Commander agrees one hundred percent with the comment that submarine personnel must be rated on the submarines and not in the Relief Crews. This is a cardinal principle.

8. FINBACK will require docking. Repairs to the battery jars will require four days longer than normal refit period.

9. Commander Submarine Division 101 congratulates FINBACK on another fighting patrol. The scarcity of contacts is the only thing that kept the Japs from losing more ships.

Copy to:
CO FINBACK

— page 194 —
10/16-3 SUBMARINE S. U. DRON T. TN
Serial 034
Confidential
SECOND ADDRESS TO
CO FINE. OK Conf. 1tr.
SS230/16-3 serial 05
of 6 February 1944.

From: The Commander Submarine Squadron Ten.
To: The Commander-in-Chief, U.S. Fleet.
Via: (1) The Commander Submarine Force, Pacific Fleet.
    (2) The Commander-in-Chief, U.S. Pacific Fleet.

Subject: U.S.S. FINE. OK - Seventh War Patrol - Comment on.

1. Forwarded concurring in the remarks of Commander Submarine Division One Hundred One.

2. The scarcity of contacts plus the heavy weather encountered must have made this patrol very trying to FINE. OK personnel.

3. The FINE. OK is to be congratulated upon the workman-like manner in which she stayed and then sank the one large ship contact which could be closed and attacked. It is recommended that FINE. OK be credited with infiltrating the following damage to the enemy:

| SINK | TYPE UNKNOWN | TON | TOTAL |
|------||-----|-------|
| 1.0  | TRAWLER     |     | 10,000 |
|      |             |     | 120 tons|
|      |             |     | 10,000 tons|
|      |             |     | 100 tons|

*By gunfire.

Copy to: CO FINE. OK.

By direction.

2 (239)

— page 195 —
12-10/416-3(15)/(16) SUBMARINE FORCE, PACIFIC FLEET
Serial 0328
CONFIDENTIAL
THIRD ENDORSEMENT to
FINAOK Report of
Seventh War Patrol.
COMSUBPAC PATROL REPORT NO. 366
U.S.S. FINBACK - SEVENTH WAR PATROL.
From: The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, U. S. Pacific Fleet.
Subject: U.S.S. FINBACK (SS230) - Report of Seventh War Patrol.
(15 December 1943 to 11 February 1944).

1. The seventh war patrol of the FINBACK was conducted in the East China Sea areas.

2. All traffic routes in the area were thoroughly patrolled. Recent heavy losses by the enemy in this area undoubtedly caused the re-routing of traffic by him while the FINBACK was present.

3. Of the two contacts worthy of torpedoes, only one could be closed for attack. This contact was aggressively attacked and eventually sunk, in spite of enemy gunfire. In addition to sinking tanks valuable target, the FINBACK destroyed two trawlers by gunfire.

4. This patrol is designated as successful for Combat insignia award.

5. The Commander Submarine Force, Pacific Fleet, congratulates the Commanding Officer, officers, and crew for inflicting the following damage upon the enemy:

S U I K
1 - Tinker (class unknown) - 10,000 tons (attack Nos. 1 & 2)
1 - Trawler - 100 tons (Gun attack No. 1)
1 - Trawler - 100 tons (Gun attack No. 2)
TOTAL 10,200 tons

J. H. BROWN, Jr.,
acting.

Distribution and authentication on following page.

-1-

— page 198 —
35230/A16-3
Serial (011)
U.S.S. FINBACK (SS230)
Care of Fleet Post Office;
San Francisco, California,
1 May, 1944.

Subject: U.S.S. FINBACK, Report of "Air Patrol Number Eight."

Enclosure: (1) Subject Report.
(2) Track Chart.

1. Enclosure (1), covering the Eighth Air Patrol of this vessel conducted in Caroline Islands during the period 6 March, to 1 May, 1944, is forwarded herewith.

J. A. TURN, Jr.

Copies to:
CSS 10
CSS 4
CSD 12

DECLASSIFIED

75926 FILMED

— page 199 —
1. PROLOGUE
Arrived Pearl Harbor from Seventh War Patrol February 11, 1944. Normal refit was accomplished by SPERY in two weeks. A new deep well trim was installed; ship was sound tested. Conducted three day training period. Readiness for sea on March 6, 1944.

(B) MARRITIME:
March 6, 1944.
1300 (VT) Denared Pearl for Eighth War Patrol in corr. with WH-1 and C-580. (S)
1915 (VT) Escort departed.

March 7-10
Arrive to Midway conducting daily ship, fire control, and diving drills. Arrival delayed by rough weather.

March 11 - 12
Circ. off Midway waiting for channel to be opened.

March 13:
Entered lagoon at Midway, received 23,000 gallons of fuel an effected minor repairs.

March 14:
0700 (Y) Departed Midway. Departure date from area extended four days by CTR-17.5.
2230 (Y) Crossed 130th Meridian

March 16 - 20.
Arrive to area conducting daily dives, ship drills, fire control problems, gun firing, and controller drills for new men.

March 21.
0725 (Y) Dived when after lookout sighted plane which was probably a friendly B-24 out of Hiwetok.
0745 (Y) Surfaced and continued to area.
2300 (Y) Entered area. Decided to patrol east of Hall Island as we could not reach passage between Hall and Manouquito before follow in dawn.

March 22.
Conducted submerged patrol. Believed this would be most productive in view of SPROUT sinking of enemy submarine and a lot of knowledge of air coverage at present.

— page 200 —
23. Conducted submerged patrol between Hall Island and Nanumut to Island. On surfacing, set course to patrol across route from Palau to Truk.

: 2348 (K) made radar contact on object at 13,000 yards.

: 23. (Contact #1)

: March 24.

: Closed radar contact to range of 10,000 yards and commenced surfacing. The net was very dark. The radar showed two targets and from three to four escorts bobbing in and out. Found that targets were following a constant helm zig-zag plan. By the time each base course for a leg was solved and a position ahead of the convoy reached, the convoy started a new leg. Our best time for solving a new course was five minutes.

: 2308 (K) Decided to head in for an attack anyhow and let the chieftain know where they might be. The control party reported only one target and two escorts then. The other one had been allowed to open out and leave the convoy without seeing that the word got to the bridge. Called off attack when we found ourselves dead ahead of target. The escorts were doing a good job of being where we wanted to be unless we shot at 3000 to 3500 yards. O'ened out dead, reported this performance three times and closed to 4000 yards on one occasion. The last attempt was. O'ened by an alert escort who apparently discovered or suspected our presence at 5000 yards. Visibility made sighting impossible. The escort turned toward us and closed at speed of 13 knots. He shifted to short scale echo ranging, as we opened out, he stayed between us and he target, but would not be drawn out more than 3000 yards. The other escort also shifted to our side of the target. The target then zigged away 400 putting us 550 feet the boat.

: 0430 (K) When it came evident on the morning board that we could not reach a position ahead of either a dawn submerged or a dark or another night surface attack prior to daylight or abandoned the chase. The target was making an early morning arrival at Truk. The C.O. now considered as he made a mistake in trying this last surface attack instead of utilizing ahead and making a dawn submerged attack. The maneuver of these boys on the first team clearly showed our control party's inability to analyze this particular problem rapidly enough. Immediate steps as described in Paragraph (Q) were taken to forestall such a sad performance again. Unfortunately a "U" factor was missing on all attempts.

The target was never identified as to shaper size. Although the radar seemed normal, it was difficult to track the target at ranges exceeding 10,000 yards and the escorts at 8000 yards.

— page 202 —
0839 (K)
1121 (K)
1751 (K)
1754 (K)
1829 (K)
1846 (K)

: 1943 (K)

: 2110 (K)
2130 (K)
1732 (K)

: 0550 (K)
0735 (K)
0739 (K)
1047 (K)
1113 (K)
1138 (K)
1144 (K)

: 11144 (K)

:

— page 203 —
1155 (K) Dived. Decided we could get this news a little later. Looked like a rather poor idea to provide target service for Japs needing a landing field. Conducted patrol at 56 feet with high periscope. At while taking a final search before surfacing sighted two engine bomber at 35 miles. This bomber stayed in our general area for at least one half hour. As we were apparently being watched, decided to stay down until sunset. To date the planes we had life guarded for had struck after dark. No bombs observed at night.

April 3.
Conducted surface plane life guard patrol. No planes seen. Observer start of bombing. Saw numerous flashes and one very brilliant flare-up. Also observed two rapidly falling flares, which could have been burning planes at a distance. Obtained clear contact with 3J on plane at 8 miles. At decided bombing was over and set course to westward to resume patrol in accordance with ConSubPac Dispatch 260750 or 26 March, 1944.

April 5.
Conducted surface patrol on Truk-Saipan route. At received message saying two planes were down. Set course eastward at four engine speed. Subsequent message reported lack of knowledge as to probable position of downed planes. In position where we had been for raid on previous night. Coincided search to southward. With noon out the majority of the night, we were able to conduct search within five miles of reef.

April 6.
Searched for downed B-24's. In absence of any information as to planes location, decided to search along line on Truk to anvlecock. Knew no planes had gone down nor our assigned position for raid. White caps and a tree sea did not help our chances. Searched continually with two periscopes. The after-lockout reported a periscope. He saw two (Contact #2)exposures, reported the periscope did not bob with the

— page 204 —
2000 (K)
: April 7.
: 0559 (K)
: 0631 (K)
: 2200 (K)
: April 8.
: 1952 (K)
: 2140 (K)
: April 9.
: April 10.
: 0645 (K)
: 0930 (K)
: 1132 (K)
: 1335 (K)
: 1240 (K)
: 1250 (K)

Searched for planes north and northeast of Truk awaiting answer to our message.
Dived on 5D radar contact at 7 miles. While submerged
trimmed ship and took it deep.
Surfaced. A three sea with whitecaps again reduced
efficiency of search.
At
on receiving message from ComSubPac, headed west to
patrol San Juan-Truk route south of Nanumuito Islands.

Transcribe to and patrolled south of Nanumuito Islands.
Dived on sighting a "Betty" bomber at about 4 miles
coincident of a cloud.
Received message ordering us to return to plane guard
duty. He had had about twelve hours in a possibly
fruitful spot.

Conducted plane life guard patrol. No planes sighted.

Conducted plane life guard patrol. No information
received relative to last strike. Decided to stay in
this position and take position for that night's strike
after 4 o'clock.
Dived on reported a plane. Believe it was a bird.
Surfaced.
Sighted boat reconnaissance plane at 10 miles.
Dived on sighting another float reconnaissance plane at
5 miles.
At
when it seemed these planes were not covering ships,
surfaced. Sighted same plane thru periscope. Returned
to 60 feet and watched plane over out. Picked up second
plane near or us and circling. Attached this plane until
when he turned toward us and started dive. Went to 140
feet. Nice white caps and clouds helping us. Saw no
bombs on plane and he dropped none.

(6)

— page 205 —
1310 (K) Returned to periscope depth. Looked like we had better stay submerged awhile. Our next strike was scheduled for that night.

April 11.

: 0300 (K) Conducted life guard patrol.
: 0350 (K) Observed large flare-up in the direction of Truk.
: 0355 (K) Heard plane motors.
: 0554 (K) Observed what appeared to be a plane falling in flames. The diance to this flare was hard to estimate, but it was definitely over the horizon. At daybreak commenced search along this bearing in absence of further information. A man in a life jacket alone would be hard to find in the existing sea.
: 0521 (K) Received Jomsubpac dispatch releasing us to patrol area. Headed to western part of area at 15 knots.
: 0554 (K) Divded when all sighted two fighters crossing and almost overhead.
: 057 (K) Surfaced.

: 0911 12.

: 0210 (K) Decoded Combat Message telling us two of our planes were missing. Sent PIB-OK's serial two to ComSubPac reporting it was had seen and action taken. Requested permission to continue patrol.
: 0407 (K) Received a radio message.
: 0417 (K) Divded to 140 feet on sighting a Kawanishi 97 flying boat headed in our direction.
: 0427 (K) Assumed he hadn't sighted us, came to 60 feet to find this one 3 miles away headed toward us. Went deep. Still, no bombs, but he had us spotted.
: 0430 (K) Found a thing in sight, but sky was full of cumulus clouds.
: 0440 (K) Surfaced. Honored we hadn't scrolled our chances in this part of sea.
: 0450 (K) Sighted smoke of convoy. Launched to make a surface attack before no. rise at 2110 and then make subsequent attacks submerged in the bright moonlight. Closed convoy as rapidly as sighted.
: 0855 (K) Commenced tracing convoy with radar at ranges between 8000 and 10,000 yards. Radar showed six targets and three escorts. The convoy had changed course to right 90° at dusk and was doing a constant helm zig. The escorts were ranging ahead and on the flanks at distances

— page 206 —
2043 (K) when ready to start an attack, since the escort on our side had ranged in close to the convoy, we sighted a white signal light on our port quarter. 'Then we could not pick up anything on the radar decided to make our attack because, if the light was a ranging escort, he was too far out to bother us.
2050. (K) Secured the engines and started in to attack. At a range of about 5000 yards, escort on our side gave us a zero angle on the bow. The escort worked out to 3000 yards on the beam of the convoy and then came to the convoy's course. This meant we had to fire at a 4000 yard range or dive with a strong chance of discovery. He would shut us if we gave him a broadside view. The escort was a two stack destroyer. The convoy seemed to be in two columns of three with the largest ship (8-10,000 tons) leading the far column. The rest of the ships lost like medium sized AK's or AP's. The range to the far was 4800 yards. This formation gave us over a target. None of the ships were in exact position to the type of zig plan.
2115 (K) with destroyer bearing 005 relative, range 1100 yards, fired three torpedo spread at leading ship of the near column using a 3270 gyro angle, 1120(P) track, and 3750 yard range. With destroyer dead ahead, fired a three torpedo spread at three overlapping ships which were next after using a 3500 gyro angle, 900(P) track, and 3500 yard range. These torpedoes passed under the bow of the destroyer who was frantically signaling and had stowed. Due to the proximity of the escort, his movements were followed more closely than those of the targets after we fired. The following facts were definitely noted: (1) Explosions were seen from the bridge on two targets; (2) Five torpedo explosions were heard topside and below; (3) The soundman reported five torpedo explosions; (4) The time of the explosions checked well with expected torpedo runs; (5) One of the ships in the second target group was stopped and completely covered with greyish smoke similar to shavs sunk on other patrols by this ship; (6) Neither of the observed explosions was on the smoking ship; and (7) No depth charges were seen or heard until after the last torpedo explosion. Entering the field of deduction, the torpedo runs indicated a hit on the first ship, a hit on a ship in the far column, two hits on a near ship in the overalwing group of three, and a hit on a ship in the far column. It is

— page 208 —
1623 (K)
: 1703 (K)
: 2200 (K)

: April 14.
: 0048 (K)
: 0145 (K)
: 0545 (K)
: 0945 (K)
: 0931 (K)
: 0933 (K)
: 1100 (K)

: April 15.
: 0845 (K)

— page 209 —
1442 (K) Sighted 4 planes at 10 miles on course 070° (T); turned stern toward planes.
: 1445 (K) Div'd when planes headed toward us.
: 1555 (K) Surfaced.
: 1625 (K) Sighted a patrol boat coming out of the sun. This was a' (Contact #4) mutual sighting as he turned toward us as we turned away. Evaded on the surface.

April 17.

: 0207 (K) Heard motors of planes headed west.
: 0225 (K) Heard motors of planes headed west.
: 0923 (K) Div'd as bomber, looking something like a B-24, came out of range and started to circle us.
: 1012 (K) Surfaced.
: 1950 (K) Heard west to attempt interception of ship sighted by our search planes.

April 18.

: 1222(K) Enroute to and patrolling off Truk-Tempire route south of Namonuito Islands, covering routes to all Truk pass.
Set course for life guard station as we had failed to intercept the ship. We would still intercept any ship going by.

April 19.

: 0720 (K) Sighted W-4 anchored to be five samans and a patrol boat. After running ashore, decided to end around, dive ahead and look this over.
Found we had six samans or trawlers carrying supplies to the Hall Islands. We were four miles southwest of Nomwin Island.
: 1127 (K) Surfaced, closed range from 4000 to 2100 yards on last saman and opened fire. The five leading samans continued with best speed toward the pass, and the last saman, in spite of 4" hits and small arms fire, tried to close range to us to make his machine gun more effective. He forced us to continually turn away to stay out of effective range. We straddled him on a tinny, but obtained only about ten 4" hits with 72 rounds. These hits left the target's hull holed, splintered, and all personnel killed that didn't jump overboard. The target was left floating. Clear area before Truk should send a plane after us since other samans had reached pass in Hall Atoll. As we had lost Nomwin Island to with 25 miles and not received any gunfire, it is assumed no sizable guns are located there.

(11)

— page 210 —
1837 (K) SJ ran picked up plane at 3700 yards.
: 1838 (K) Dived as plane closed to 3700 yards on same bearing.
: 1855 (K) Surfaced.
: 2010 (K) Observe I bomb flashes in direction of Truk.
: 2036 (K) Heard plane motors.

April 20.
: 0020 (K) Observed start of bombing runs.
: 0054 (K) Saw last of bomb flashes.
: 0113 (K) Heard plane motors.
: 0140 (K) Heard plane motors.

April 21.
: 1700 (K) Headed for northeast corner of area.
: 0222 (K) Departed area.

April 22.
: 0654 (K) Enroute Pearl.
: 0717 (K) Div'd when B-24 search plane wheeled and headed toward us.
: 1030 (K) Surfaced.
: 1030 (K) Conducted training dive for battle problem.

April 23 - 28.
: 0747 (Z) Arrived Johnston Island. Received 17,000 gallons of fuel oil.
: 1549 (Z) Departed Johnston for Pearl.

April 29 - 30.
: 0747 (Z) Arrived Johnston Island. Received 17,000 gallons of fuel oil.
: 1549 (Z) Departed Johnston for Pearl.

May 1.
: Arrived Pearl for refit.

— page 220 —
21.15 (K) Date: 4-12-44 Lat. 09° 39' (N) Long. 147° 50' (E)

Target Data - Damage Inflicted

Description: The convoy consisted of one large AK or AP, five medium AK's or AP's, and three escorts (one a two'stack destroyer, one SC or PC, and the other not seen). The contact was made by sighting smoke and later seeing shots of the targets. After dark six shapes were counted at about 7000 yards. The escorts could not be seen until about 5000 yards. The large AK or AP was definitely seen as a modern ship of 3-10,000 tons. The only other target definitely sighted by an explosion was an old H-T-1 freighter of about 5000 tons. The near escort was long, low and had two stacks. He was seen at 900 yards. The PC was identified as such by his smaller relative size.

| Ship / Sunk: | One |
|:---|:---|
| Ship / D. | C a medium AK or AP (possibly another AK or AP) |
| D. | Sinking a dual orange-colored explosion, hearing two torpedo hits on bridge, in the boat, and over the sound of, and checking the torpedo runs against the times of the explosions. |

Target Draft: 20 Course: 2450(T) Speed: 3.5 Range: 3750

CRITICAL DATA:

Swept: 10 Course: 24.4 Depth: -- Angle: --(at firing) (in in. slowly left)

FIRE CONTROL and TORPEDO D.T.

Type attack: Junkers radar attack, using T.B.T. bearings for firing. 1st torpedo and generated bearings for 2nd and 3rd torpedoes. Range was excessive due to position of escort. Over lapping targets presented unusually good target. Escort not fired on as did not want to take time to set torpedoes to shallow depth. Assured target length of 400 set and used 100% spread coverage.

(19)

— page 221 —
1. TUBES FIRED
2. Track angle 112(P) 113(P) 114(P)
3. Gyro angle 3270 3300 3310
4. Depth set 81 81 81
5. Power High High High
6. Hit or Miss Hit Miss Hit
7. Erratic No No No
8. Mark Torpedo XIV-3A XXIII XIV-3A
9. Serial 26269 25870 26767
10. Mk. Exploder VI-4 VI-4 VI-1A
11. Serial No. 70 8598 3231
12. Actuation Set Contact Contact Contact
13. Actuation Actual Contact Contact Contact
14. Mk. 'harched' XVI-1 XVI-1 XVI
15. Serial No. 12539 12204 11160
16. Explosive TPA TPA TPA
17. Firing Interval 8 sec --
18. Spread 3/4 o --
19. Sea Condition One S/M/B se S/M/B base
20. Overhaul P.H.T.H. P.H.T.H. P.H.T.H.

U.S.S. FUBACK
TARGET NO. 2
FACTOR 1 NO. 8

Time 2116 (K) Data 4-12-44 Lat. 090 39' (N) Long. 1470 50' (E)

Target Data - Damage Inflicted

Description: Sane convoy described under attack #1. Torpedoes fired at three overlapping medium AK's or AP's astern of first target. (Attack #1)

Ships / Sunk: None
Ships / Damaged:
or probably sunk: Two medium AK's or AP's.
Damage Determined: Seeing one right explosion; hearing three torpedoes exploding on either, below, and over sound gear, each time of torpedo runs against the mines and covered by dense smoke not the color of coal smoke. The explosion seen was on a ship beyond the one heavily smoking.

Target Draft: 20 Course: 2450 Speed: 8.5 Range: 3500

C.H. KIPP D.T.
Speed: 10 Course: 3400 Depth: -- Angle: -- (at firing

— page 222 —
4-12-44 1st 090 39' (N) 1470 50' (E)

Transcript Data - Damage Inflicted

Discretion: Destroyer - two stacks (large stack aft). Believed to be Pukuk type destroyer.

Shins / Sunk: None
Shins / Damaged: None
Or prob. blc sunk: None
Damage Determined: -

(21)

— page 223 —
6 Course 130° Speed: 12 Range: 1100

CUN SHIP DATA

Speed: 15 Course 130° Depth - - Angle - - (at firing)

TYPE CONTROL and TORPEDO DATA

Type Attack: Surface radar attack, "Down-the-throat" shot fired in effort to discourage the escort. Range too great to contact a sure hit. Target evaded by jogging to the left.

Tubes Fired 7 8 9
Track Angle 0 0 0
Gyro -angle 1320 1340 1370
Depth 3ft 4' 4'
Power High High High
Hit or Miss Miss Miss
Erratic No No No
Mark Torpedo AIV-3A XXIII XIV-3A
Serial 23035 41020 26780
Mk.Exploder VI-14 VI-4 VI-14
Serial No. 3646 3240 2352
Actuation Set Contact Contact Contact
Actuation Contact Contact Contact
Actual VI-XVI-1 XVI
Mk.1.4.

— page 224 —
4" ATTACK DATA: (continued)
holes in hull, oil streaming astern, demolition of deck house, exploding of engine, and seeing crew in water.

Details of Action
Conducted battle surface, closed range on surface from 4000 to 2100yards, and opened fire on last sampan in column of six headed for Noonbin Island, with 4" gun, three 20 MM machine guns, and 2 air coolers. The 4" gun fire was not as effective as usual due to smallness of target; the targets moved, and the stiffness of the foot firing device, The gun captain fired the gun on pointers "Fire". Stiffness of foot firing device was due to bending of linkage in rear seas. The target was straddled continually. The range varied between 2000 yards and 900 yards. Some shells of common ammunition seemed to pass thru the target without exploding. About ten 4" hits were served in addition to those hits not exploding. Brick of action with only 18 rounds of 4" ammunition left, and after wrecking sampan, a reinforced jam with all three 20 MM guns. These jams were as follow: #1 20 MM - broken firing pin; #2 20 MM-defective ammunition; and #3 20 MM - broken firing pin.

Fired Following Ammunition:
42 rounds - 4" H.C. (sensitive nose)
30 rounds - 4" Common
1025 rounds - 20 MM
1110 rounds - 50 Caliber

*Note:
Fired 4" gun on April 16th at small ship on rear and at lookout tower on Oroluk Island. No separate report made as no positive results were obtained and pertinent data is contained in narrative.

(I) MISS
None observed.

(J) ATTACK DATA: (continued)
Both convoys contacted were using a constant helm zig-zag plan. The first convoy had a constant helm plan superimposed on a regular zig plan. The escorts seemed to range farther out on the beams than usual at distance between 1000 and 3500 yards. This ship was at two-thirtiespeed (80 RTI) with good sound conditions existing and no temperature gradient. The radar officer definitely identified 10 cm radar interference on the escort after a attack, but not before. The enemy gave no evidence of discovery, as with radar, but it probably means he is still in the poor operator and faulty equipment stage of his development on his smaller ships.

(23)

— page 225 —
1. JETOR DEFENSE S and D. L. GEE
Nong

(1) JETOR DEFENSE S and RADIO RECEPTION

Reception from JETOR was very good during this patrol, although the readability and signal strength of transmission lessened during the two hours proceeding dawn. All messages sent were cleared immediately. Commander Submarines, Pacific Fleet, serials 39 'T', March, an 90 D, April, were missed. These were not requested at that date, but came on us. The signal on the life guard frequency (6210 kcs) was difficult to understand at any great distance. This frequency had considerable Japanese interference.

(2) RADAR

The performance of the SJ-2 radar was good. Initial contacts on enemy were light, and twenty two thousand yards; low flying planes were picked up at sixteen thousand yards. The radar was out of commission for twenty four hours on 17 March due to failure of condenser C 22 A in the transmitter modulation generator bias circuit. Trouble was encountered during the first week of patrol in tuning the transmitter to peak performance. This trouble was remedied by changing the 721A gas tube.

During the attacks on the convoys the P.T.I. scope proved almost useless since the conditions necessitated tracking at ranges greater than eight thousand yards. If a larger scope cannot be had, it is suggested that it be lighted and varied sweep be increased to about twelve thousand yards.

The performance of the SD-A radar was unsatisfactory. Although tuning was checked by R.O.A. engineer at Midway and by our O.A.C. frequency meter, its radar failed in most instances to pick up close high-flying planes. The trouble is thought to lie with the new type antenna (ONV-66AFE).

(3) SOUND GAR and UND CODEPHONES

No major defects or damage is experienced with any of the sound equipment. Sound conditions in general were from fair to good. Scopes could be heard up to 4000 yards submerged on the night of the attack on April 12th.

The JET sound equipment proved to be a great disappointment. Results obtained this patrol seemed far inferior to results obtained by other boats with the same equipment. JETROWS or RECF noises could not be picked up at ranges greater than 3000 yards.

(24)

— page 227 —
21,860 Gals.
In Area 6880 Mi. 61,920 Gals.
Area to Pearl 3179 Mi. 31,528 Gals.

(S) DURATION:
Days Enroute to area 15
Days in area 31
Days Enroute to base 10
Days Submerged 5
Days of Offensive Patrol 71/2
Days of Life Guarding 23 1/2

(T) FLOTORS OF INDUCTS RETAINING:
Torpedoes (no.) Fuel (cals) Provisions (days) Personnel Factor (days)
15 5,100 10 15

Limiting Factor for this patrol Operation Order.

(U) MARKINGS:
1. Plane Life Guarding - Communications presented the greatest difficulty on this assignment. None of the planes which were downed were heard using their voice to attempt communication with us. "We frequently heard the test equipment. Unfortunately all information relative to downed planes was received very late. If submarines are going to be worthwhile plane guards, information must be gotten to the submarines in a much shorter time. On two occasions we pulled clear of our last plane guard station to resume offensive patrol in accordance with previous instructions, only to be recalled after we were over 100 miles away. This meant we neither did a good job as plane guard nor as a submarine.
2. This vessel spent 23 days of the 31 days in the area on life guard duty.
3. The night I. hitting on the T.D.C. is a vast improvement and very helpful for night approaches. Some difficulty is experienced in

(26)

— page 229 —
1. The Commander Submarine Division FORTY TWO.
To: The Commander-in-Chief, United States Fleet.
Via: (1) The Commander Submarine Force, Pacific Fleet.
      (2) The Commander-in-Chief, U.S. Pacific Fleet.

Subject: U.S. FUBLOCK (532530) - Report of Night War Patrol.
Pat. 1 - Corroants on.

1. The HEACK's eighth war patrol covered a period of 56 days. This "one day's" were spent in the assigned areas of which twenty-three were devoted to life-guard duty.

2. Torpedoes Attacks.
Attack No. 1: This was a night surface attack on a convoy of six ships disposed in two columns of three ships each with three escorts, one ahead and one on each flank, ranging from 500 to 3,000 yards from the convoy. The convoy was torpedoed twice at the 3,750 yards. The other three were torpedoes were fired at the next three ships, which were over-lapping at 3,500 yards range. All of this firing was accomplished while pointing at a destroyer escort only 1,100 yards away which was observed to have stopped and under which some of the torpedoes fired must have passed. Explosions were seen on two targets and a total of five explosions heard. The submarine then swung 100 and three stern torpedoes set at four feet were fired "down-the-throat" at the destroyer escort which had turned toward the submarine at a range of 1,100 yards. No hits were observed or heard.

Damage Assigned:

2.2

— page 231 —
1/6/44
FPE-4/416-8
Serial 0168
S.C.F. DENTAL
SIC AND INDIRECT TO
T.F. FINANCY Report of
Fifth War Patrol.

From: The Commander Submarine Squadron FOUR.
To: The Commander-in-Chief, United States Fleet.
Via: (1) The Commander Submarine Force, Pacific Fleet.
    (2) The Commander-in-Chief, U. S. Pacific Fleet.

Subject: U.S.C.F. FINANCY (SS230) - Report of Eighth War Patrol - Comments on.

1. Forwarded, concurring in the remarks of Commander Submarine Division FC.TY-TWO.

2. The missed opportunity in the development of Contact #1 was somewhat alleviated by the excellent tracking and results obtained in the succeeding attacks. A firing range of between 3500 and 4000 yards gave excellent results for the surface firing. This is recommended when the range is obtained from SJ and the bearings visually for a continuous plot.

3. The Commander Officer, officers, and crew are congratulated for this near fifth consecutive successful patrol.

C. E. MOMSEN.

— page 232 —
6 0878. 4-253
FILMED FORCE, PACIFIC FLEET
Serial 0869
CONFIDENTIAL
THIRD ENDORSEMENT to
FILMECK Report of
Eighth War Patrol.
CO.1. SUBSPAC PATROL REPORT NO. 414
U.S.S. FILMECK - EIGHTH WAR PATROL.
From: The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, U. S. Pacific Fleet.
Subject: U.S.S. FILMECK (SS230) - Report of Eighth War Patrol.
(6 March to 1 May 1944).

1. The eighth war patrol of the FILMECK was conducted in the Caroline Islands in the vicinity of Truk.

2. Of the 31 days spent in area, 23% were devoted to life-guard duty. Of the two convoys contacted, only one could be closed for attack. The FILMECK carried out an aggressive night attack against this convoy and succeeded in inflicting damage upon the enemy. In addition to the three torpedo attacks, 25% made on the above convoy, the FILMECK carried out two gun attacks, one against a 50 ton German ship and one of six undoubtedly carrying supplies to Monwim Island in the Caroline Group; and the other in attack was made against a small ship around on a reef and at a lookout tower on Oroluk Island.

3. The comments made by the Commander's Officer regarding recommendations for life-guard duty are appreciated and will be given careful consideration.

4. This patrol is designated as such a full for Combat insignia Award.

5. The Commander Submarine Force, Pacific Fleet, congratulates the Commanding Officer, officers, and crew, and only for inflicting damage upon the enemy, but for the excellent manner in which the life-guard mission was conducted. The FILMECK is credited with having inflicted the following damage upon the enemy:

| DAMAGE | DESCRIPTION |
|||
| 1 - Freighter (class unknown) | 4,000 tons (Attack No. 1) |
| 1 - Freighter (class unknown) | 4,000 tons (Attack No. 2) |
| 1 - Freighter (class unknown) | 4,000 tons (Attack No. 2) |

TOTAL 12,000 tons

FILMED -1-

— page 233 —
1- Supply Sampan
: 50 tons (Gun Attack No. 1)
: GRAND TOTAL 12,050 tons

J. H. IOWN, Jr.

DISTRIBUTION:
(Complete Reports)
Cainich (5)
CINO (5)
Cincpac (6)
Intel.Cen.Pac.Ocean Areas (1)
Conservpac (1)
(Adv.Base Plan.Unit) (1)
Cinclant (2)
Consubslant (8)
S/M School, NL (2)
Consopac (2)
Consowespac (1)
Consuboswespac (2)
CTF 72 (2)
Comnorpac (1)
Corsubspac (40)
SUE.D, MI (2)
ConsubspacSubordcom (3)
All Squadron and Div. Commanders, Subspac (2)
Consubstrainpac (2)
All Submarines, Subspac (1)

E. L. HYNES, 2nd, Flag Secretary.

— page 235 —
30 May 1944.

1330 (V.I) Departed Submarine Base, Pearl Harbor, T.H.

31 May - 2 June 1944.

Narrative: [Narrative text here]

Narrative:

— page 236 —
3 June 1944.
0800 (X) Arrived Midway. Received 15,000 gallons fuel. Repaired radio antenna, leaky main inquisition, and master gyro compass.
1530 (Y) Departed Midway for Patrol area.
1500 (Y) Fired all guns at previously prepared canvas target.
2400 (Y) Set clocks ahead 24 hours to (-) 12 time.

5 June - 10 June 1944.
Anroute area. Approach problems and training dives daily.

11 June 1944.
1210 (K) Dove for contact on S.D. radar, range 12 miles.
1240 (K) Surfaced.

12 June - 14 June 1944.
Anroute area on surface. Seas building up. Speed cut down to 9 knots.

15 June 1944.
0230 (I) On station. Latitude 15° 30' N, Longitude 136° 57' E. Unless otherwise stated, all times will be ITEM.

16 June 1944.
Patrolling on surface.

17 June 1944.
0724 S.D. radar contact at 22 miles. Dove. Surfaced. Immediately dove on S.D. contact at 10 miles.
0810 Sighted low wing monoplane, possibly a carrier plane through periscope.
0820 Started high periscope watch at 53 feet believing enemy task force would be sighted.
1030 Nothing sighted yet, so surfaced and reported planes to Consubpaco.

- 2 -

MCLOSURE (A)

— page 237 —
18 June 1944.

0630
Dove, S.D. contact at 6 miles closing to 6, Dore.
0700
Surfaced. Headed south 2 engines speed to new patrol section.
1015
Dove for S.D. contact at 16 miles.
1100
Surfaced.
1210
Dove for S.D. contact at 12 miles.
1240
Surfaced.
1430
Dove for S.D. contact at 30 miles.
1425
At periscope depth sighted 2 planes on course 2900(T), distance 10 miles. Appeared to be friendly 3320's searching.
1510
Planes out of sight. Surfaced.
1910
Sighted two searchlights over horizon bearing 2700(T). Latitude 140 19' T, Longitude 1370 05' E. Went to full speed on 4 engines on course 2700(T).
2030
No contact by sight or radar. Picked up searchlight signalling, bearing 2350(T) over horizon. Headed for searchlight.
2145
No contact, so carried course to 2050 believing that true bearing was crawling left.
2245
Changed course to 1000 for same reason.
2300
No contact established, so slowed to 10 knots and headed back to patrol station. Reported sighting searchlights to Consulbar.

19 June 1944.

0030
1010
S.D. radar contact at 16 miles not closing.
1016
Sighted plane bearing 3250(T) distance 8 miles.
1046
Dove.
2055
Surfaced.
2110
Sighted searchlight bearing 1300(T). Headed for 10 4 engines.
2121
Sighted another searchlight bearing 1700(T). These lights were very strong and were sweeping both vertically and horizontally at intervals of about two minutes.
2121
SJ radar contact 15,000 yards bearing 1300(T).
Latitude 140 20' N, Longitude 1370 04' E.
2125
Tent to battle stations and commenced tracking.

- 3 -

[END OF TRANSCRIPT]

[END OF REPORT]

— page 238 —
2150
Radar indicated two groups of ships, the nearest body of ships seemed to be small ones, and the farthest group contained one very large ship.
Radar ships were very weak.
Could not pull away from leading ships and range closed rapidly to 14,000 yards. Main body was on course 320°(T), speed 25 knots. Four destroyers apparently broke off and closed us rapidly with zero angle on bow, playing searchlights in our direction. Believed they had us on radar. There being no way to identify them in the dark and this being a class "B" area, we were not justified in making a sub-surge radar attack.
Dove. Went to 300 feet. Screws remained in our vicinity until
2331
Surfaced. Tried to send contact message but radio transmitter was out of commission. Decided to trail at 4 engines speed on course 320°(T).

20 June 1944.

0500
Dove on S.D. radar contact at 6 miles.
0530
Surfaced.
0600
Sighted light bomber bearing 230°(T) distant 6 miles. Dove. Radio transmitter still out of commission, can't get off contact report. Radios working continuously.
0545
Periscope depth. Sighted plane close aboard coming in fast. Went to 140 feet.
0730
Periscope depth, all clear.
0745
Surtaced. Went ahead on 4 engines.
0910
Sighted plane bearing 080°(T) distant 3 miles coming in low and fast. Dove.
0950
Surfaced.
1010
S.D. radar contact 14 miles. Dove.
1040
Periscope depth. Sighted plane circling about 5 miles. Decided to stay down long enough for hit to go away this time.
1230
Surfaced.
1410
S.D. radar contact 10 miles. Dove.
1510
Surfaced.
1530
Dove for S.D. contact at 8 miles. Decided to stay down until dark since our air banks were getting dangerously low and the planes seemed to have us too well located.
1830
Surfaced after sunset.
1850
Dove for S.D. radar contact, 12 miles, closing fast.

- 4 -

ENCLOSURE (A)

— page 239 —
1920
Decided to tempt them with S.D. radar at 50 feet.
Almost immediately got a contact at 3 miles. Went
back down.
Surfaced without using S.D., hoping to lose them
that way.
Picked up plane on S.J.T., dead ahead, range 6,000
yards closing to 3,000 yards. Dove. Decided to
stay down four hours.

21 June 1944.
0050
Surfaced. Managed to get in a small air and battery
charge.
0457
S.D. radar contact 7 miles. Dove.
0510
Heard one distant explosion.
0513
Sighted two planes about 7 miles away dropping depth
charges or bombs. Decided to remain submerged today
because air activity forced us to dive several times
an hour and air banks were low.
1706
Surfaced.
2205
Headed at 2 engine speed for area containing downed
aviators.

22 June 1944.
1147
Sighted plane distant 7 miles. Dove.
1220
Surfaced.
1843
S.D. contact 30 miles.
2030
S.D. contact 30 miles.
2105
Sighted aircraft flares bearing 130°(T) distant
about 20 miles. Went to 4 engine speed on course
130°(T). Ran about 20 miles and slowed to 7 knots.
Fired green flare every 10 minutes while searching
area.
2300
Gave up search because the plane was not necessarily
friendly, and no answering signal or flares were
ever seen.
2335
S.D. contact 14 miles, closing to 8 miles. Listened
carefully on all aircraft search frequencies but
heard nothing.

23 June 1944.
0945
Sighted plane distant 6 miles. Dove.
1046
Surfaced.

INCLUSIVE (4)

— page 240 —
24 June 1944.
Sighted large oil slicks, more belly tanks, two Jap wooden barrels and one table. Hoved search area to westward allowing for wind and current. Sighted searchlight over horizon bearing 145°(T). Raided for it on 4 engines. Gave up search, having run about 50 miles with no further visual or radar contact. Resumed search for aviators, firing flares every half hour.

25 June 1944.
0630 Sighted belly tank.

26 June - 27 June 1944.
Sighted few bits of debris. Sea choppy, making search difficult.

28 June 1944.
1830 Discontinued search and headed for regular patrol area.

29 June 1944.
Enroute patrol area.

30 June 1944.
On station submerged. Resorted to submerged patrol because of limited fuel remaining.

1 July 1944.
Submerged patrol.

2 July 1944.
Submerged patrol.
1045 Sighted 4 engine flying boat bearing 000°(T) distant 5 miles heading for Palau.
1900 surfaced.
1930 Dove on sighting running lights of a plane close aboard.
2000 surfaced.

- 6 -

ENCLOSURE (A)

— page 241 —
0-0-N-T-I-D-E-N-T-I-A-L
2 July 1944. Submerged Patrol.
0946 Signed bomber bearing 3450(T) distant 6 miles.
0952 Signed large flying boat bearing 3400(T) distant 8 miles. These two planes sealed to be taking measures to avoid each other.
1850 Surfaced.
2010 Green aircraft flare burst overhead. Dove.
2030 Surfaced.

4 July 1944.
0030 Sighted small vessel in moonlight bearing 2540(T).
Radar did not pick up.
0148 Dropped down to radar depth, then to periscope depth. Vessel turned out to be PC type patrol vessel and passed us at about 3,000 yards, echo ranging, nothing else in sight in bright moonlight. His course about 1100(T), speed 12 knots. Latitude 70 36' N, Longitude 1330 17' E.
0230 Patrol vessel out of sight. Surfaced. No further contacts.

5 July 1944. Submerged Patrol.
1845 Sighted patrol vessel bearing 1750(T) distant 3,000 yards, on easterly course. Latitude 70 41' 30" N, Longitude 1320 23' E.
1918 Surfaced and followed him for two hours in case he might be joining up with other vessels. No further contacts.

6 July - 9 July 1944.
Submerged Patrol.
10 July 1944.
Commenced surface patrol. Enough fuel now on hand to complete patrol on surface. Moved into next area.

11 July - 12 July 1944.
Surface Patrol.
- 7 -

INCLUSIVE (A)

— page 242 —
15 July 1944.
1600    Surface Patrol.
    3, D. contact at 30 miles.
    14 July 1944.
    0721    Surface Patrol.
    1201    S.D. contact at 21 miles.
    1306    D.V. contact at 10 miles.
    Fire control.

— page 243 —
2121 0030 1845
Date: 6-19-44 7-4-44 7-5-44
Time: 1420' N 070 361' N 070 411' 30" N
Depth: 1370' 04' E 1330 17' E 132° 22' E
Type: Unclassified: Patrol Patrol
Type: Trawler Patrol
Type: Patrol

— page 244 —
1 2 3 4
Date: 6-11-44 6-17-44 6-17-44 6-17-44
Time (Zone): 1206 0724 0757 0816
Position: Lat. 23002'N 16003'N 16003'N 16003'N
Long. 143041E 13650'E 13650'E 13650'E
Speed: 9 9 9 9
Course: 256 250 000 270
Thin: Surf. Surf. Surf. Sub.
Minutes since last: 0 0 0 19 Min.
SD radar search: 0 0 0 0

A: Number 1
B: Type 1
C: Probable Mission 1
D: Torpedo Contact 1
E: Initial Range 1
F: Elevation Angle 1
G: R.A. & R.L. Relative bearing of plane when it detected S/S: 1D 1D 1D 1D

C: (State: (Base-)
D: Sec.: (Fort)
E: (Direct.: (Rel)
F: Visibility (miles)
G: Clouds: (Height in)
H: Clouds: (Percent)
I: Overcast)
J: (Bearing(Rel)
K: Moon: (Angle)
L: (Percent)
M: Illum.)

TYPOT 5/M Camouflage on this patrol - Light Gray.

LENGTH: P - Periscope
R - Radar
SD - Sighted Day
SN - Sighted Night

- 10 -

ENCLOSURE (A)

— page 245 —
5 6 7 8
Date: 6-18-44 6-18-44 6-18-44 6-18-44
Time (Zone): 1016 0634 1211 1145
Position: Lat. 15028M 16006N 15014L 15003N
Long. 136051E 136055E 136051E 137005E
Speed: 9 9 9 14
Course: 200 220 180 130
Trim: Surf. Surf. Surf. Surf.
Minutes Since Last
SD Radar Search: 0 0 0 0

A Number: 1 1 1 2
Type: Unk Unk Unk SBD
Probable Mission: Unk Unk Unk Patrol
How Contacted: R R R R
Initial Range: 13 16 12 30
Elevation Angle: Unk Unk Unk 30
Range & Relative
Bearing of Plane:
When it Detected: ND ND ND ND
S/L:

(State/Beaufort): 2 2 2 2
Sea: (Direction(Rel)): 300 230 320 320
Visibility (Miles): 50 50 50 50

(Height in
Clouds): (ft. - - - -
Percent
Overcast): 4 4 4 4

(Searing(Rel) - - - -
Moon: (Angle - - - -
Percent
Illum.): - - - -

Type of 3/M Count: 3/M Count - Light Gray.

LCCMD: P - Periscope SD - Sighted Day
R - Radar SN - Sighted Night

- 11 -

ENCLOSURE (A)

— page 246 —
6-19-44 6-19-44 6-20-44 6-20-44 6-20-44
T: 0020 1011 0457 0569 0930
B: 13957 13603 13704 13505 13609
I: Long. 9 9 9 9 9
A: Course 090 210 320 030 320
R: Thrin 9 Surr. 9 Surr. 9 Surr. 9 Surr.
F: Minutes since last 0 0 0 0 0
E: Radar search 0 0 0 0 0

| Type | Number | Type | Number | Type | Number | Type | Number |
|------||------||------||------||
| CRITICAL INSTRUCTIONS | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| CRITICAL INSTRUCTIONS | 1 | 1 | 1 | 1 | 1 | 1 |

— page 249 —
U.S.S. FINBACK (SS330)
C-O-I-F-I-D-E-N-T-I-A-L

(3) AIRCRAFT CONTACTS (Continued)

CONTACT NUMBERS 24 25 26 27 23

Date 7-2-44 7-3-44 7-13-44 7-14-44 7-15-44
Time (Zone 1940 0946 1600 0421 0905
Position: Lat. 7039'N 7012'N 9008'N 9017'45"N 6037'N
Long. 132012'E 132012'E 136032'E 136031'45"E 141001'E
Speed 9 3 9 9 17
Course 000 180 000 109
Trim Sub. Sub. Surf. Surf. Surf.
Minutes since last
SD Radar search - - 0 0 0

A. Number 1 1 1 4
B. Type UnK Bother UnK UnK UnK
C. Probable Mission UnK Patrol UnK UnK UnK
D. How Contacted SN P R R R
E. Initial Range 6 8 30 31 32
F. Elevation Angle 30 4'0 UnK UnK UnK
G. Range & Relative
H. Bearing of Plane
When it Detected ND ND ND ND ND
S/M

C (State(Beau-)
C sea: (fort) 2 2 1 1 1
D (Direction(iel) 210 350 180 260 340
E Visibility (Miles) 5 5 30 40 5

T (Height in
T Clouds: (ft. - - - - -
F (Percent
O Overcast) 10 6 3 3 8

S (Bearing(Rcl) - - - - -
Moon: (Angle - - - - -
F (Percent
I Illum.) - - - - -

Free of S/M (Canonflage on this patrol - Light Gray.

LIGHT: P - Periscope SD - Slight Day
R - Radar SN - Slight Night

EXCLUSIVE (A)

- 15 -

— page 250 —
7-16-44 7-18-44
Tie (line): 1930 0950
Long.: 04661E 156051E
Sweep: 14 14
Course: 090 090
Train: surf, surf.
Minutes since last
SD Radar Search: 0 0

A: Number: 1
Type: Unit
Probable Mission: Unit
How Contacted: SD
Initial Range: 12
Elevation Angle: 10
Range Relative: 20
Bearing of Plane: ND
Given it Detected: ND

C: (State/Beau-)
Sea: (port) 1 1
(Direction/rel) 315 000
Visibility (miles) 10 10
(Target in Cloud(s): - -
(Percent Overcast): 7 2
(Beam: - -
(Percent Illum.): - -

There are 37% of the ship's patrol on this patrol - 1% per day.

LANDED: 2 - Periscope
A - Radar
SD - Sighted Light

- 16 -

HYDROSURF (4)

— page 254 —
0-0-1-R-I-D-E-N-T-L-L-L
No density layers were found on station, but the following were encountered, enroute to station:

| DATE | LATITUDE | LONGITUDE | DEPTH | DEPTH |
|------|||-------|-------|
| 6-1-4 | 27° 05' W | 153° 27' W | -30 | 300 ft. |
| 6-2-4 | 23° 03' W | 179° 06' W | -140 | 173 ft. |
| 6-5-4 | 23° 29' W | 177° 43' W | -30 | 111 ft. |
| 6-6-4 | 23° 03' W | 172° 00' W | -30 | 110 ft. |
| 6-7-4 | 23° 32' W | 167° 31' W | -30 | 110 ft. |
| 6-8-4 | 23° 29' W | 158° 38' W | -70 | 100 ft. |
| 6-9-4 | 23° 44' W | 155° 06' W | -130 | 100 ft. |
| 6-10-4 | 24° 30' W | 149° 12' W | -140 | 100 ft. |
| 6-12-4 | 23° 06' W | 143° 53' W | -80 | 100 ft. |

(P) 1.

— page 256 —
1. FINBACK Ninth War Patrol.
From: The Commander Submarine Division ONE HUNDRED ONE.
To: The Commander-in-Chief, U.S. Fleet.
Via: (1) The Commander Submarine Squadron TAN.
(2) The Commander Submarine Force, Pacific Fleet.
(3) The Commander-in-Chief, U.S. Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Ninth War Patrol - Comments on.

1. FINBACK Ninth War Patrol, the first for a new Commanding Officer as such, extended from 30 May to 21 July 1944. Nine days were spent on various stations west of the Marianas in positions to intercept any enemy forces which might attempt to oppose the amphibious Saipan operations; six days were spent in searching for downed aviators in this same vicinity; and fifteen days were spent in Palau patrol areas.

2. On 17 June FINBACK sent a contact report of a low-wing monoplane and on 18 June sent report of contact on searchlights and numerous unidentified planes. These contact reports must have been of considerable value to the OTC in his evaluation of enemy location and intentions. After dark on 19 June a task force was contacted by radar and sight. No attack was attempted because of inability to identify as enemy beyond possibility of a doubt. It was extremely unfortunate that the radio transmitter failed on the attempt to send a contact report of this force at 2331(I) and could not be repaired in time to be of value.

3. During the search for downed aviators a considerable quantity of debris, oil and belly tanks were sighted. A searchlight loom was seen on the evening of 23 June; investigation failed to reveal its source.

4. The Commanding Officer very properly conducted part of his Palau patrol submerged during daylight because of fuel limitations. He covered the more remote sections of his areas in the belief he would have more opportunities to attack any convoys approaching Palau. Two patrol boats were the only surface contacts during this period.

5. A normal refit is being accomplished alongside SPEAKY.

K. G. HENSEL.

— page 257 —
1959-10/ALG-3
Serial 0183
CO-PROF. THAL
SUBSCRIBE TO THE CHIEF OF STAFF
TO: The Commander Submarine Squadron Ten.
Via: (1) The Commander Submarine Force, Pacific Fleet.
(2) The Commander in Chief, U.S. Pacific Fleet.

Subject: U.S.S. FINBACK, Report of Ninth War Patrol - Comments on.

1. Forwarded, concurring in the remarks of Commander Submarine Division One, under.

2. Information relative to the location of enemy forces on the evening of 19 June was of primary importance to the Commander, Fifth Fleet. Finback's inability to transmit that information was therefore one of the costly misfortunes of war.

3. Finback's condition with respect to cleanliness was excellent upon her return from patrol.

Copy to:
Consubdiv 101.
CO. FINBACK.

— page 258 —
8 02844
hcn
FT12-10/A16-3(15)/(16)
Serial 01578
CONFIDENTIAL
THIRD ENDORSEMENT to
FINBACK Report of
Ninth War Patrol.
CONSUBSCAP PATROL REPORT NO. 487.
U.S.S. FINBACK - NINTH WAR PATROL.
From: The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, U. S. Pacific Fleet.
Subject: U.S.S. FINBACK (SS230) - Report of Ninth War Patrol.
(30 May to 21 July 1944).
1. The ninth war patrol of the FINBACK was the first for the new Commanding Officer, as such. The patrol was conducted in the area west of the Marianas and the vicinity of Palau.
2. The first part of this patrol was spent west of the Marianas patrolling at a possible interception point of the enemy task force expected during the Saipan operations. This was followed by a week's search for lost friendly aviators. The remainder of the patrol was spent in the Palau area. A large task force encountered on the 19th of June could not be closed. No other contacts worthy of torpedo fire were made.
3. This patrol is designated as "Not Successful" for Combat Insignia Award.

DISTRIBUTION:
(Complete Reports)
ComInCh (7)
CNO (5)
CinCpac (6)
Intel.Cen.Pac.Ocean Areas (1)
ComServPac (1)
CinClant (1)
ComSubSlant (8)
S/M School, NL (2)
ComSoPac (2)
ComSoMesPac (1)
ComSubSoMesPac (2)
CTF 72 (2)
ComNorPac (1)
ComSubPac (20)
SUDAD, MI (2)
ComSubPacSubOrdCom (3)
All Squadron and Division Commanders, SubS Pac (2)

C. A. LOCKWOOD, Jr.

(2)
(1)
(

— page 259 —
SS230/AL6-3
Serial: (030)
DECLASSIFIED

Front:
To:  The Commander-in-Chief, United States Fleet.
Via:  (1) The Commander Submarine Division 281.
        (2) The Commander Submarine Squadron FOUR.
        (3) The Commander Submarine Force, Pacific Fleet.
        (4) The Commander-in-Chief, United States Pacific Fleet.

Subject:  U.S.S. FINBACK (SS230) - Report of War Patrol
Number TEN.

Enclosure:  (A) Subject report.
        (B) Track chart.

1. Enclosure (A), varying the Tenth War Patrol of this vessel conducted in the BONIN Islands area during the period from 16 August to 4 October 1944, is forwarded herewith.

R. R. WILLIAMS.

DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C

BY OP-04283C DATE 3/26/22

DECLASSIFIED

— page 260 —
U.S.S. FINBACK (SS230)
C-O-N-T-I-D-E-N-T-I-A-L

(A) PROLOGUE:
Arrived Majuro 21 July 1944 from Ninth War Patrol. Commenced refit on 22 July and completed refit on 5 August 1944.

On 2 August 1944, Lieutenant Commander R. R. WILLIAMS, Jr., U.S. Navy, relieved Lieutenant Commander J. L. JORDAN, U.S. Navy, as Commander, Officer.

Commenced six day training period on 7 August 1944. Fired 2nd and radar practices, battle surface, and received indoctrination depth charging.

Five minutes before scheduled departure, discovered broken piston in hull induction valve hydraulic power cylinder. Departure delayed 25 hours while U.S.S

— page 261 —
23 August 1944.
1135 Plane Contact #4. Two engine plane sighted, distance 6 miles. Angle on bow 300 port.
1212 Surfaced.
1455 Plane Contact #5. Sighted plane, distance 10 miles. Divded.
1544 Surfaced.
2230 SJ interference bearing 1680(T). Received challenge and sent reply on radar. Communications too slow to permit identification.

24 August 1944.
1730 Entered area. A.
2024 changed course to 1000(T) heading for KITA IWO JIMA, having SJ contact on it at 88,000 yards.
2200 Converted #4. F.B.. to M.B.T.

25 August 1944.
0430 Changed course to 1800(T) heading for IWO JIMA.
0601 Submerged.
0855 Plane Contact #6. Sighted plane through periscope.
0937 Ship Contact #7. Sighted mast of two ships hull down below. About 0600(T). Came to normal approach but could not close range before both ships entered shallow water to west of IWO JIMA. Similar to CRIDORI with another smaller vessel. Pinging heard shortly after sighting at estimated range of 12,000 yards. Plane was circling IWO JIMA for period of half hour prior to sighting.
1120 Sighted small DE or PO patrolling area to west of IWO JIMA.
1135 Sighted large landing barge patrolling same area. All this activity makes it look as if an arrival was expected. During the afternoon, during the afternoon

— page 262 —
26 August 1944.
0533 Dived 20 miles west of HAH JIMA. Patrol led on southerly course.
1922 Surfaced and reversed course enroute vicinity MUKO JIMA.

27 August 1944.
0530 Changed course to 090°(T).
0620 Dived. Changed course to 180°(T), to patrol along 100 fathom curve.
1925 Surfaced. Chg. course to 250°(T).

28 August 1944.
0612 Dived, heading southwest.
1921 Surfaced.

29 August 1944.
0623 Submerged west of IWO JIMA.
1408 Plane Contact, sighted SALLY on patrol.
1932 Surfaced.
1943 Sighted flashing white light in vicinity of KAKA IWA. Sighted a "ormittently for about fifteen minutes.
2045 Changed course to 350°(T).

30 August 1944.
1200 Changed course to 175°(T), enroute assigned lifeguard station.

31 August 1944.
0500 In position for air strike on IWO JIMA.
0648 Planes at 19 miles on SD. Tried IFF momentarily with no response. Commenced heading for IWO JIMA.
0752 Sighted many planes to SW about 12 miles, heading away from island. No IFF response.
0830 Plane sighted lookout at 6 miles. Dived. Felt that strike would commence any minute now, so ran up periscope at 55 feet for good look.

- 3 -

ENCLOSURE (A)

— page 263 —
0902
No plane in sight and no activity on island which was about 9 miles away. About ready to surface when at
heard bomb close aboard. Ducked and changed course to 35th.
0923
Heard several explosions with water swishes. Believe this to be shells from the beach fired to keep us down.
1040
Surfaced.
1045
Dived when lookout reported a DD heading for us at 5 miles. Proved to be a small rock north of
Iwo, range 9 miles.
1057
Surfaced.
1104
Plane sighted low at six miles heading in. This plane was low and in line with island. Dived and received two bombs, not close, as we passed
60 feet.
1117
Heard one dull explosion. Delivered to b
bombing on island.
1148
One dull explosion.
1238
Surfaced.
1240
Dived with plane on SD at 6 miles.
1350
Surfaced, half-heartedly. We are now about 20 miles west of island. There has been no communication with friendly planes at all.
1630
Connected another approach on the island with half the ship's company manning the SD.
1643
Sighted planes over the island and AA fire from the island.
1712
Circled 12 miles from island.
1733
Yellow-white plane for about 3 seconds followed by dance black smoke at spot about three-quarter
1750
Clerked and westcrly course.
1807
Followed by 2 in on radar to 10 miles and then
1939
divided. Plane was KATE. We waited until
to surface, as he could be seen circling over
our diving point until 1900. Headed NW to get
clear.

1 September 1944.
0030
Transmitted Serial ONE to Consubhace, then headcd for lifeguard station.
0500
In position in air strike.

- 4 -

ENCLOSURE (A)

— page 264 —
0720 Signed 20 friendly planes over IWO JIMA.
0820 Four F6F's overhead, reporting on station over us.
0849 AA fire from island. Held position about 10 miles SE of reference point.
0927 More AA fire from island.
1020 One F6F dropped message fifty feet on starboard beam (which came like a rock) and waggling his wings, headed in the island on course about 060°.
1122 Commenced following. Could hear nothing on 4475 kcs. Tried to edge around to easterly course to clear southern tip of IWO JIMA but planes kept heading NE. Followed until at range of 4½ miles from island, Japs opened up. Two shots, on in range but off in deflection, landed 150 yards astern. So at
1122 Dived, heading away from island.
1221 Surfaced and over cover picked up immediately. Received position of downed plane on 4475 kcs., so headed east with 9½ miles between us and the beach. Worked around to course 060° finally, when lookout picked up a sun. sh on the horizon. Approached and picked up the following TBF crew at 1345: Ensign Thomas KENTTE; File No. 298972, USNR; STOVALL, James T., 850-15 30, ACNJ3C, USNR; and DOHERTY, John R., 205 17 79, ARLJ3C, USNR.
1535 Air cover secured for the day, telling us that he knew of no other planes down.
1600 Reversed course and headed for tomorrow's station. Interference on identification as distant SJ or SG, bearing east. Position 15 miles east of KITA IWO JIMA. Interference present until 0500, and thought to be carrier task force.

2 September 1944.
0200 Strong odor of fuel oil lasting for 30 minutes.
0624 Nothing sighted seen on radar.
Sighted planes, Picked up by SJ at 14 miles.

- 5 -

ENCLOSURE (A)

— page 265 —
0645
Two F6F's overhead as escort. Headed east for island. Closed 30 miles and maintained this position.
0933
Received word of plane down 9 miles NE of MINAMI JIMA. Started around southern end of CHICHI JIMA, maintaining a range of 7 miles to island.
1156
Picked up Lt. (George H.N. BUSH, File No. 173464, USNR, pilot of plane T-3 of VT-51, U.S.S. SAN JACINTO, who stated that he failed to see his crew's parachutes and believed they had jumped when plane was still over CHICHI JIMA, or they had gone down with plane. Commenced search of area on chance they had jumped over water.
1236
Received word of rubber boat seen from air. Position given was in hills of HAINA JIMA but started south anyway, asking for jis, repetitions, and conformance, until we heard one plane state he was circling over the boat. An unknown plane on the circuit was heard to mention a spot west of HAINA. This was at least as good as any dope we had, so headed for a position about 9 miles west of HAINA. This seemed to make our cover feel better, although they tried to con us through the island a few times. Plane reported that the raft, about 1 miles from beach, was being shelled. Spirits of all hands went to 300 feet.
1505
Dived to 55 feet with planes in sight zooming a spot in water 1 mile W of MIGAINE INA.
1530
Sighted rubber boat.
1550
Roared by the rubber boat, backing full and still making 4 knots. We must have misjudged his masthead height a bit. We twisted around and started stalking him.
1620
Pilot hooked on and we headed out away from beach. Tried to make it. -thirds speed, but the pilot had one arm at the raft with a bailing bucket bringing up the rear. Stopped to see if he would get in the boat. This took about 10 minutes, during which a discussion developed below concerning the precedence of simultaneous orders to blow, pump, and flood. Finally got way on towing pilot in his boat. Two-thirds speed fired the boat, and there he was in the water again. Finally came up to 38 feet to keep him out of the water until at range of 5 miles from beach, placed up and opened the hatch.

— page 266 —
1855
C-O-C-I-F-I-D-E-N-T-I-A-L

Get on 4 engines and cleared area to westward.
Pilot was Ensign James W. Beckman, File No. 301442, USNR, VF-20, U.S.S. INTERPRISE, who stated that it was known that only one man had parachuted from BUSH's plane. This decided us to discontinue any further search of that area, particularly as our air cover had left.
Changed course to 330°(T).

2 September 1944.
0055 Plane Contact #25. SJ picked up plane at 6 miles, 60 miles WNW of CHIOHI JIMA. Dived.
0159 Surfaced.
0800 Changed course 070°(T), patrolling area NW of NUKO JIMA group.

4 September 1944.
0841 Sighted NELL bearing 040°(T), distance 7 miles. Dived and changed course to 090°(T), hoping that plane indicated some shipping.
1833 Surfaced.

5 September 1944.
0200 Changed course +250°(T).
08. J Dived for subsea patrol.
1835 Surfaced.
1916 Ship Contact #2. Simultaneous sight and radar contact on ship bearing 060°(T), distance 16,000 yards. Slowed but was afraid to turn away as we were in a light sector. Raided until 1930 when range was 10,000 yards and tried to turn away. After completing the turn, we sighted a blinking blue light on the target. Went to radar depth and tracked.
1938 Target closed to 7200 yards and then turned away. S1 commenced to act up, reporting 3-1/2,070, 1,170, and 1,000 yards on bearing 195°(R), so made ready the horn tubes. As this did not coincide at all with target movements, thought it was a second s, and with a report that the SJ was not operat, properly, started deep.

- 7 -

— page 267 —
1953
Flying on 18 kcs, on long scale interspersed with hand keying was hard intermittently.
Up to radar depth. Nothing sighted, so surfaced and headed for target's last bearing. Ran on this course 10 miles, then turned east to try to intercept the target if she headed for MUKO JIMA.
Target was equipped with radar. Beam was observed sweeping over this ship at about 8,000 yards, but was never steadiest on us. Believe target was a DD or DE.
Turned south to 3 off FUTAMI KO by dawn, as this was probable destination of target.

6. September 1944:
0711
Submerged 13-miles off FUTAMI KO with all islands in periscope, although hazy. Stayed off harbor all day on 100 fathom curve.
1916
Surfaced. Cleared to northeast.

7. September 1944:
Patrolling N-S line about 30 miles NE of CHICHI JIMA.
0614
Submerged and approached islands.
1.222
Surfaced and cleared to west.
2235
Changed course to 140° to intercept convoy. Hoping that speed less than 10 knots, as they will be just about in port if 10 knots is correct. Increase to 3 engine speed.

8. September 1944:
0028
Change course to 180°(T), slowed to 2 engines to port. Progress convoy's reported course.
0100
Change course to 290°(T), reverse or convoy's course.
0200
Slow to 1 engine speed.
0700
Submerged.
1145
Surfaced.
1245
Change course to 180°(T).
1330
Submerged and changed course to 000°(T).
1830
Surfaced.
1945
Changed course to 045°(T).

- 8 -

ENCLOSURE (A)

— page 268 —
9 September 1944.

0620. Changed course to 090°(T).
0730. Dived for submerged patrol northwest of MUKO JIMA and changed course to 250°(T).
1305. Surfaced, listening on aircraft frequency.
1455. Submerged, having heard nothing.
1831. Surfaced.

10 September 1944.

0200. Changed course to 075°(T).
0631. Made trim dive.
0701. Surfaced.
1304. Sighted plane through periscope (Aircraft Contact #27). Dived.
1321. Surfaced. Changed course to 090°(T).
1428. Changed course to 210° and increased to 3 engine speed to intercept convoy reported by aircraft.
1756. Sighted smoke bearing 194°(T). Turned toward and began tracking. Tried to close range to insure contact after dark, but at 1839 the escort turned toward us. Ran away until escort ceased chasing us and then turned to 290° to regain contact.
2047. Radar contact at 18,000 yards. Commenced tracking and working ahead. His zigzag plan appeared to be alternate 1.5° 50' right and left of base course, with legs 5 to 10 minutes long. Unable to keep radar contacts on other ships 3,000 yards astern of him. Got in position ahead for an approach with stern tubes when he evidently lengthened his right leg. Came around to approach from starboard bow. At this time target and three other vessels could be very plainly seen at 7,000 yards.
2336. Fired four Mark 23 torpedoes, set on 4 feet. Second torpedo seemed to broach 50 yards ahead, then settled and ran normally. After firing four, decided two more would help. All six torpedoes evidently ran up or target. Target turned toward and closed range slightly, dropping depth charges here and there. Convoy did not change course or speed.

- 9 -

ENCLOSURE (A)

— page 269 —
0136-57
: 0137-29

---

### Submerged Target
Turned away and rounded the formation astern. Drew up alongside port beam, waiting for the escort to do something. He settled down on starboard quarter of convoy, so we came right for a 900 port track.

---

### Submerged Target
Fired three Mark 23's at largest target. Fired three Mark 23's at following target. C.O.O.D. saw this in two ships and saw one of these sink. Formation recrossed course and then stopped, heading east. Escort patrol led abaft the formation, showing a red masthead light and blinking CPD-SN and U2 to the convoy. Range to the escort 6,000 yards, yet he didn't seem to be looking for us. Decided on another approach on the escort visit. Mark 18's and headed up moon for the escort. Radar had reported ships where we could see nothing, but when a low white light appeared on the water and radar reported pip at 4,000 yards at that bearing, decided it was a submarine. Turned away and increased to flank speed. A second pip bearing 250°(R), distance 4,150 yards, kept up with us for about five minutes before range to 4,000 yards. I believe these were sub-marines, perhaps traveling in the formation although they were never seen. Steadied on course 270° at two engine speed with formation astern. Submerged and changed course to 045° to patrol enemy probable track. Sailed with the following: 0811, 1830, 2122, 2245

---

### Submerged Target
Divod west of SOFU GAN. Surfaced. Hit SOFU GAN as a target, synchronized all radar bearing indicators, TBT's, and true-roll indicators. Than headed southeast for vicinity of JUKO JIMA.

---

### Submerged Target
Submerged thirty miles northwest of MUKO JIMA one hundred fathom curve. Surfaced.

---

### Submerged Target
ENCLOSURE (A)

— page 270 —
14 September 1944.
0230    Changed course to 270°, heading for NISHINO SHIMA.
0600    Sunburned with NISHINO SHIMA distant 7 miles
1233    Surrounded by 300°T. Changed course to 230°.
1430    Sunburned.
1912    Starboard.
2250    Chars. course 140°.

15 September 1944.
0000    (S.S. "Fritz" I). Latitude 26° 03' N, Longitude 125° 00' E. All hands on bridge suddenly saw small
    sunspots about 400 yards on port beam. Turned
    away and increased to flank speed. Submarine
    had all angle on bow. Bridge and periscope
    sighted visible. Radar sighted him up astern at
    1,000 yards after we had turned and tracked him
    out to 3,000 yards where he disappeared gradually.
    Lockout had swum his position within a minute or
    two of sighting, and radar had no contacts until
    coached on by "ge, so believe that the submarine
    had surfaced or reached the surface. On
    our beam. No, but fair starlight.
0030    Changed course to 130°(T).
0100    Radar sight at 1,800 yards, bearing 200°(T). Turned
    away. "Nothing visible.
0120    Changed course to 135°.
0200    Slow to 25 knots.
0522    Submerged 35 miles northwest of IWO JIMA.
1138    Ship's son in law, in barge standing out from IWO
    JIMA. "Came up 7 knots. In
    line of sight. In between them. Position
    15 miles to the west of IWO JIMA.
1210    Barge passed close aboard.
1030    Nothing sighted. "Get. Opened out from island
    to surface.
1925    Surfaced. A bright white light was shown inter-
    mittently in view. "It lay of anchorage off southwestern
    part of IWO JIMA.
2330    Changed course to 030°(T). Transmitted FINBACK
    Serial TWO to COsubjace.

- 11 -

ENCLOSURE (A)

— page 271 —
16 September 1944.

0530 Passed KITA IVC MA aboard to starboard, distance 14 miles.
0807 Periscope sighted bearing 1650(T), 1500 yards. Quartermaster positive it was a periscope. Submerged. (It is hoped that lowering the bridge will improve the acoustics. O.O.D. could not hear the quartermaster on the after part of the bridge, thought he reported "plane"). Nothing on sound.
1009 Surfaced during scheduled air strike. Used SD about 20 seconds, then secured before surfacing.
1023 Sighted 2 engined plane (BETTY?) bearing 1450(T), distance 10 mi-3, zero angle on the bow.
1045 Submerged.
1120 Secured listening. Patrolled at 60 feet.
1556 Ship Contact #6. Sighted smoke bearing 1500(T). Headed for it.
1607 Sighted single engine plane patrolling vicinity of smoke. Lost plane and smoke within 15 minutes.
1709 Surfaced. Sighted plane and smoke bearing 1920(T). Periscope showed escort and two sets of masts, range about 13 miles.
1720 Submerged to stay hidden from plane. Followed smoke at two-thirds speed. Targets changed course to 2300. Correct course for IWO JIMA about 1750(T). Fanged course to 2150(T).
1909 Surfaced with main squalls ahead. Nothing in sight. Chased at 3 engine speed.
2100 Pip on radar bearing 2620(T), 14,600 yards. Appeared to be on NW course. If this is the target, he's taking the long road to Japan. This would be a change of course of 1500 for him, so don't believe it is our target.
2152 Rounded KITA IWO JIMA to westward, distance 10 miles and changed course to 1630, heading for IWO.
2320 Picked up IWO bearing 1630(T) at 30,000 yards. Could distinguish an intermittent white light in vicinity of

— page 272 —
2325
Changed course to 340° and slowed to 2 engines. Believe that the targets change of course to 230° was a routine while before settling down on his base course after dark, and that one of the group or the escort broke off after dark and headed NW. *no* has about seventy miles lead.

17 September 1944.
. 0856
Submerged south-west of NISHINO SHIMA.
1336
Surfaced.
1900
Headed east to patrol NW of MUKO JIMA.

18 September 1944.
. 0300
Changed course to 0450(T).
0615
Changed course to 2300(T).
1607
Changed course to 0800(T).
2149
10 miles west of MUKO JIMA-hundred fathom curve, skirted curve to northward and patrolled across possible lanes for traffic coming from the north and northwest.

19 September 1944.
. 1908
Spent the day north of MUKO JIMA, heading south at to patrol off stern coast of CHICHI JIMA to-morrow.

20 September 1944.
. 0918
Dived 14 miles southeast of CHICHI JIMA on northwesterly course.
1901
Surfaced.
2310
Changed course to 1930(T) and increased to 3 engine speed.

21 September 1944.
. 0430
HAHA JIMA aboard to starboard at 15 miles.
0533
Changed course to 2400(T).
1230
Surfaced. Char. d course to 1420 heading for IWO JIMA.
2031
Sighted intermittent white light over horizon.
2100
Two flashing white lights visible on IWO JIMA.

- 13 -

ENCLOSURE (A)

— page 273 —
2141
Changed course to 0000(T) Detected radars on 103 and 107 megacycles, civil, for IWO JIMA, steady signal. Range 12 miles to the island.

22 September 1944.
0629 Submerged, spec. ing the day west of IWO JIMA. 1933 Surfaced, heading southwest down moon. 2005 Changed course to 1300(T). 2009 Plane on SJ class from 4 miles to 2 miles. Submerged. The plane evidently saw us as soon as we crossed the moon. 20:5 Surfaced, para. ling moon streak. 2135 Changed course to 0000(T), moonst having occurred.

23 September 1944.
0000 Changed course to 0650(T). 1303 40 miles east of HAWAII. Sighted MAVIS at 14 miles bearing 0000(T), evidently patrolling. 1325 Dived when plane closed to 8 miles. Cumulus clouds enveloped him some of the time, but don't think he saw us. 1705 Surfaced on course 0000(T).

24 September 1944.
0308 Changed course 0900(T) and departed area, enroute MIDWAY. 1304 Sighted aircraft ahead, 10 miles. 1432 Surfaced.

30 September 1944.
1700 (Hi) Crossed 180th American, changed date to 29th.

30 September 1944.
0550 Sighted escort planes. 0925 Located port side to pier in berth S-1 at MIDWAY. Received 23,6000 tons of supplies. Transferred aviators to IWO JIMA for air transportation to PEARL. 1606 Departed MIDWAY for PEARL.

4 October 1944.
Noored Submarine Base, Pearl Harbor, T.H.

- 14 -

EMCLOSURE (A)

— page 275 —
1. SHIP CONTACTS:
   - #1: 0937
   - #2: 1120
   - #3: 1135
   - #4: 1310
   - Date: 8-25
   - Lat.: 25000'N
   - Long.: 141006'05"E
   - Type(s): 1 CHIDORI
   - Initial Range: 10,000 Yds.
   - Est. Course: 1800(T)
   - Est. Speed: UNK
   - How Con-: P
   - Remarks: NONE
   - Leg-end: P - Periscope
   - SD - Sighted Day
   - SN - Sighted Night

2. ENCLOSURE (A)

— page 276 —
1908 : 1916 : 1756 : 2352
: 8-25 : 9-5 : 9-10 : 9-14
: 25001'05"N : 28025'15"N : 27038'00"N : 26007'00"N
: 141009'05"E : 141921'00"E : 141024'00"E : 140003'00"E
: Barge : Destroyer : DE : RO Class : 4 Small IARUS: SUBLIRINE
: 4,000 Yds. : 15,000 Yds. : 25,000 Yds. : 400 Yds.
: 1800(T) : 2200(T) : 2800(T) : 2200(T)
: UNK : 14 knots : 10 knots : 2 knots
: SD : SD : SN
: NONE : NONE : NONE

LEGEND:
P - Periscope
SD - Sighted Day
SN - Sighted Night

ENCLOSURE (A)

— page 277 —
9/10
Time: 11:38
Date: 9-15
Lat: 24°58'00"N
Long: 14°10'05"E
Type(s): 2 BARGES
Est. Course: 3000(T)
H.J. Col.: P
Range: 3000(T)
Est. Time: 7 knots
S.S. Speed: 18,000 Yds.
H.J. Col.: P
Range: 3000(T)
Est. Course: 3000(T)
H.J. Col.: P
Range: 3000(T)
Est. Time: 7 knots
S.S. Speed: 18,000 Yds.

LEGEND:
P = Periscope
SD = Sighted Day
SN = Sighted Night

- 18 -

EXCLUSIVE (4)

— page 278 —
3-16 3-16 3-23 3-23 3-23
U  Time (Zone) 1246 1245 1108 1130 1455
B  Position:Lat. 08001'N 08005'N 22009'N 22000'N 22003'N
N  Long. 170927'E 170931'E 148012'E 143055'E 143015'E
A  Speed 14 14 14 14 14
R  Course 320 320 270 270 230
T  Trim  Surf.  Surf.  Surf.  Surf.  Surf.
E  Minutes since last 0 0 0 0 0
D  SD Radar search

A  Number 3 1 1 1
R  Type  UNK  Bonber  Bonber  UNK
C  Type  PAT.  PAT.  PAT.  PAT.
R  Range 30 28 10 5 10
A  Angle  UNK  UNK  UNK  UNK  UNK
T  Time when it  ND  ND  ND  ND  ND
left: 6/6/1943

C  'Date(Beau- 2 1 1 1
fort) 2 090 180 270 270
D  Position(Rel)090 35 20 20
T  Time(Miles) 30 4000 5000 2000 2500
T  Right in  (Percent
C  (Percent
S  Overcast) 30 30 90 100 90
S  (Bearing(Rel) -
  (Percent
  (Illum.) -
  (Percent
  (Illum.) -
Type of S/M Camouflage this patrol - Light Gray.

LEGEND: P - Periscope  SD - Sighted Day
R - Radar  SN - Sighted Night

- 19 -

ENCLOSURE (A)

— page 279 —
6 7 8 9 10

S Date 8-25 -35 8-25 8-25 8-29
U Time (Zone) 0855 37 1045 1208 1408
B Position: Lat. 25001'N 25051'N 24053'N 24051'N
M Long. 141009'E 141012'E 141012'E 141007'E 141007'E
A Speed 2 2 2 2 2
R Course 150 140 050 270
I Trim Sub. Sub. Sub. Sub. Sub.
N Minutes since last - - - -
E SD Radar search

A Number 1 1 1 1 1
I Type JILL ZAKE SALLY ZAKE SALLY
R Probable Mission PAT. PAT. UNK UNK PAT.
C How Contacted P P P P
R Initial Range 10 8 3 5
A Elevation Angle 30 30 40 40
F Range & Bearing ND ND ND ND
T of plane when it
Detected S/M

C (State (Beau-
O Sea: fort) 2 2 2 2 1
N (Direction (Rel) 040 040 040 130 130
D Visibility (Miles) 30 30 30 30 30

I Height in
T Clouds: ft.) 3000 3000 3000 3000 5000
O Percent
N Overcast) 80 80 80 80 30

(SBearing (Rel) - - - - -
Horn: Angle - - - - -
(Percent
Illum.) - - - - -

Type of S/M Camouflage this patrol 1 - Light Gray

LIGHT D: P - Periscope SD - Sighted Day
R - Radar SN - Sighted Night

- 20 -

MELOSURE (A)

— page 280 —
U.S.S. FINBACK (SS230)
:  C-O-N-F-I-D-E-N-T-I-A-L
:  (G)  AIRCRAFT CONTACTS (Continue)
:  CONTACT NUMBER  #11  #12  #13  #14  #15
:  S  Date  8-29  8-31  8-31  8-31  8-31
:  U  Time (Zone)  14:58  15:57  06:40  07:52  11:04
:  B  Position:Lat.  24°51'N  21°52'N  24°49'N  24°50'N  24°41'N
:  M  Long.  14°07'E  14°07'E  14°05'E  14°07'E  14°08'E
:  A  Speed  2  2  14  14  14
:  R  Course  000  000  090  270  270
:  I  Trim  0  0  0  0  0
:  N  Minutes.since last  -  -  -  -  -
:  E  SD Radar search  -  -  -  -  -

:  A  Number  1  1  1  1  1
:  R  Type  SALLY  SALLY  UNK  ZEIG  UNK
:  C  Probable Mission  UNK  UNK  Intercept  A/S
:  R  How Contacted  P  P  R  SD  R
:  R  Initial Range  6  6  19  12  10
:  A  Elevation Angle  20  ND  ND  ND  ND
:  F  Range & Bearing  ND  ND  ND  ND
:  T  of plane when it
:  Detected S/M

:  C  (State(Beau-)
:  O  Sea:  fort)  1  0  0  0  0
:  N  (Direction(Rel)110  -  210  030  030
:  D  Visibility(Illies)  30  20  20  20
:  I  (Height in
:  T  Clouds: ft.)  3000  5000  4000  4000  4000
:  O  (Percent
:  N  Overcast)  30  30  50  50  50
:  S  (Bearing(Rel)  -  -  -  -  -
:  Moon(Angle  -  -  -  -  -
:  (Percent
:  Illum.)  -  -  -  -  -

Type of SYNT Camouflage this patrol - Light Gray

LEGEND:  P - Periscope  SD - Sighted Day
    R - Radar  SN - Sighted Night

- 21 -

ENCLOSURE (A)

— page 281 —
U.S.S. FINNACK (SS230)
C-O-N-P-I-D-E-N-T-I-A-L
(3) AIRCRAFT CONTACTS (Continued)
CONTACT NUMBER 16 17 18 19 20
S Date 8-31 8-31 8-31 9-1 9-2
U Time(Zone) 1240 1540 1807 0720 0624
B Position:Lat. 24041'N 21048'N 24041'N 24019'N 26056'N
M Long. 141003'E 140056'E 141001'E 140056'E 141035'E
A Speed 14 14 14 14 14
R Course 270 090 270 180 340
T Trim Surf. 0 Surf. 0 Surf. 0 Surf. 0
N Minutes since last 0 0 0 0 0
E SD Radar search

A Number 1 12 1 10 2
I Type Bomber FOF ZEKE P6F F6F
R Probable Mission A/S Surfing 4/S Strafing Escoort
C How Contacted SD R SD SD
R Initial Range 6 11 15 14
A Elevation Angle 60 11K UNK 30 10
F Range & Bearing 190 ND ND ND 155
T of plane when it
Detected S/H

C (State(Beau-
O Sea: fort) 0 0 0 0 1
N (Direction(Rol)030 020 030 240 080
D Visibility(Miles) 20 20 20 30 30
I (Height in
I Clouds: ft.) 4000 4000 4000 3500 3000
O (Percent
O Overcast) 50 30 40 70 40
S (Bearing(Rcl) -
I Moon: (Angle - - - - -
(Forecast
I Illum.) - - - - -

Type of S/M Camouflage this patrol - Light Gray

LEGEND: P - Periscope SD - Sighted Day
R - Radar SN - Sighted Night

ENCLOSURE (A)

— page 282 —
21
: 22
: 23
: 24
: 25

|   | Date    | Time (Zone) | Position: Lat. | Long. | Speed | Course | Trim | Minutes since last SD Radar search | Number | Type | UNK | UN

— page 283 —
26
: 27
: 28
: 29
: 30

|   | Date    | Time (Zone) | Position: Lat. | Long. | Speed | Course | Trim | Minutes since last SD Radar search |
|----|||||||------||
| S |           |              | 9-16        | 1026   | 26009'N| 14130'E| 13.5  | 13.5                          |
| U |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| B |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| M |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| R |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| E |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| E |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| S |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| R |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| I |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| H |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| A |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| T |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| C |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| N |           |              | 9-16        | 1026   | 26019'N| 14103'E| 13.5  | 13.5                          |
| D |           |              | 9-16        | 1026   | 26019'N| 14103

— page 286 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-E-N-T-I-A-L
(H) ATTACK DATA.
U.S.S. FINBACK
... TORPEDO ATTACK NO. 1
PATROL NO. 10
Time 2335(K) Date 10 September 1944 Lat. 27°40'N Long. 14°03'7'E
Target Data - Range Inflicted
DESCRIPTION:
The convoy consisted of two small oilers, two small AK's, and one other ship (seen on radar, not visually), all escorted by a CLIOIR type torpedo boat. When first seen late in the afternoon, they were arranged in two columns with escort ranging astern. At 6 to 10 minutes legs 50' either side of base course. Six torpedoes were fired at escort on a sharp starboard track.
Ship's / Sunk
NONE
Ship's / Damaged
or probable sunk
NONE
Target Draft
6 feet
Course
315
Speed
11
Range
3500
CUN SHIP DATA
Speed
15
Course
170
Depth
Surface
0
Angle(at firing)
0
FIRE CONTROL
TORPEDO DATA
Type Attack: Night, Surface, Radar.

ENCLOSURE (A)

— page 287 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-D-N-T-I-A-L
(H) ATTACK DATA (Continued)
Tubes Fired 1 2 3 4 5 6
Track Angle 44S 44S 45S 48S 51S 55S
Gyro Angle 11R 11R 13R 11R 17R
Depth Set 4 4 4 4 4 4
Power H H H H H H
Hit or Miss M M M M M M
Erratic No No No No No No
Mk.Torpedo 23 23 23 23 14-3A 14-3A
Serial No. 41103 33855 52781 41347 26717 26701
Mk.Exploder 6-4 6-4 6-4 6-4 6-4 6-4
Serial No. 133 11641 11614 1436 1915 3165
Actuation Set Imp. Imp. Imp. Imp. Imp. Imp.
Actuation Actual - - - - - -
Mk. Warhead 16-1 16-1 16-1 16-1 16-1 16-1
Serial No. 3146 3392 12597 9959 3098 11658
Explosive TPX TPX TPX TPX TPX
Firing Interval 8 Seconds
Type Spread Divergent
Sea Conditions 1
Overhaul Activity U.S.S. SPERRY.
REMARKS: Shot #2 breached fifty feet from bow, then appeared to run normally. Torpedoes appeared to pass under target.

- 28 -

ENCLOSURE (A)

— page 288 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-F-I-T-T-I-A-L
(H) ATTACK DATA (Continued)
U.S.S. FINBACK TORPEDO ATTACK NO. 2 PATROL NO. 10
Time 0136(K) Date 11 September 1944 Lat. 27°37'N Long. 14°02'1'E
Target Data - Damage Inflicted
DESCRIPTION:
    After Attack #1, the escort dropped depth charges at random along starboard side of convoy, and then took a position on starboard quarter of convoy. Convoy did not break formation or change course. Attack #2 was made on port side of convoy.
Ship's / Sunk 1 Small Oilec. : about 1,000 tons.
Ship's / Damaged 1 Small AK, 800 to 1,000 tons.
or probable sunk
Damaged Determined by 0.0.D. saw oiler sink and saw two hits in AK.
Target Draft Course Speed Range
6 feet 280 2200
OVN E. T DATA
Speed Course Depth Angle(At Firing)
15 010 Surface 0
FIRE CONTROL AD TORPEDO DATA
Type Attack: Night, Surface, Radar.

ENCLOSURE (A)

— page 289 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-E-N-T-I-A-L
(1) ATTACK DATA (Continued)
Tubcs Fired 1 2 3 4 5 6
Track Angle 88P 89P 90P 85P 86P 87P
Gyro Angle 10L 12L 11L 7L 10L 8L
Depth Set 4 4 4 4 4 4
Power H H H H H H
Hit or Miss M M M H H
Erratic No No No No No No
Mk.Torpedo 23 23 23 23 23 23
Serial No. 41046 41067 26859 41215 26845 41501
Mk. Exploder 6-4 6-4 6-4 6-4 6-4 6-4
Serial No. 18268 11241 1066 1340 17686 17408
Actuation Set Imp. Imp. Imp. Imp. Imp. Imp.
Actuation Actual - - - Imp. Imp. Imp.
Mk. Warhead 16-1 16-1 16-1 16-1 16-1 16-1
Serial No. 3117 3057 12672 11297 1287 11501
Explosive TPX TPX TPX TPX TPX
Firing Interval 8 Seconds
Type Spread Divergent
Sea Conditions 1
Overhaul Activity U.S.S. SPERRY
RELATORS: None

- 30 -

EXCLUSIVE (A)

— page 290 —
0-0-N-T-I-D-E-N-T-I-A-L
(I) MINDS.
No observation.
(J) ANTI-SUBMARINE INTERFACES AND TACTICS.

The convoy attacked on the night of 10-11 September is believed to have contained a or more enemy submarines or else had them stationed close by to be called in in case of a submarine attack on the convoy. From the peculiar maneuvers of the convoy after our last attacks, it would seem that they were possibly milling about in the same vicinity long enough for their own submarine(s) to make a submerged attack on us in the bright moonlight. This would also explain why the CHIDORI did not attempt to chase us after the second attack.

Our two submarine contacts later in the patrol also bear out our belief that the Japs are applying "dog-eat-dog" tactics in this area.

All convoys had air cover during daylight hours. There was no evidence of moonlight patrols or radar equipped planes. However, it appears that a ne from IYO JIMA was sent out after sunset to patrol the area in which we had been submerged during the day of 22 Sept. SD indicated all clear at time of surfacing. It was then secured. SJ picked up the plane at 4 miles closing to 2 after we had changed course to cross the moon path, believing we were sufficiently far from the island.

Radar interference of 103 and 107 megacycles was encountered off the north end of IYO JIMA.

(K) MAJOR DEFECTS AND DAMAGE.

1. Main Power Casualty.

On September 14, 15, while running in parallel 2 position on two main engine, there was a loud report and much smoke in the control cubicle, resulting in the loss of power on the starboard side of the ship.

Inspection showed a copper bar 1 x 1 inches wedged, almost welded, between SR-4 contactor and the frame of the stand causing a short circuit, this direct short circuit had automatically caused overload 62 to trip resulting in the opening of SS-1, SS-2, SS-3, and SS-5 contactors causing the loss of main power on the starboard motors.

- 35 -

ENCLOSURE (A)

— page 292 —
1. S.T.-a.
The performance of the S.T.-a radar was very good through-out the patrol. Minor casualties were experienced.

The main casualty was:

Improper centering of PPI sweeps, V( )10 and V( )11. The resistance of which dropped from it's proper value of 7.0 megohms to 300,000 ohms was apparently caused by the failure of R( )43 and R( )47 in the intensifier circuit of the PPI-unit. Replaced all three resistors to clear trouble. I would advise the carrying of two type R( )44 resistors. This casualty caused the loss of approximately one hour of operating time.

The modifications made for emergency recognition proved successful. However, difficulty was experienced in distinguishing the code letters above other IF noises when receiving.

Maximum ranges were:

90,000 Yds. on land 3,000 feet altitude.
28,000 Yds. on land 12 feet altitude.
19,000 Yds. on a DE.
15,000 Yds. on a T.M.R.U.

2. SD-a.

The operation of the SD-a was very good. The casualties experienced were all minor and confined to tube troubles. Approximately one-half hour of operating time was lost. Planes were easily picked up at 30 miles and could be tracked out to 40 miles.

3. I.F.F.

The operation of the I.F.F. equipment was excellent. Difficulty was experienced in reading the code on the SD-a scope.

- 33 -

ENCLOSURE (a)

— page 294 —
0-0-N-F-I-D-E-N-T-I-A-L
(Q) PERSONNEL.
The policy of requiring unqualified men to qualify in two runs continued to give good results.
The rescued aviator, [name], was put on watch as J.O.O.D.'s and lookouts, and turnkey, [name], good jobs. Although they were anxious to get back to their air groups, they all seemed to enjoy their experiences aboard a submarine.

(R) MILES STRAMED - FUEL USED.
| Mileage | Type of fuel | Quantity |
||||
| 2,300   | Gasoline     | 29,630   |
| 6,000   | Gasoline     | 54,250   |
| 1,200   | Gasoline     | 24,520   |
| 1,200   | Gasoline     | 16,200   |

(S) DURATION.
Days enroute to area: 9
Days in area: 30
Days enroute to base: 11
Days submerged: 19

(T) FACTORS OF DURANCE REQUIRED.
| Torpedoes | Fuel | Provisions | Personnel Factor |
||------|||
| 12        | 6,300 | 5 days     | Indefinite      |

Limiting factor this patrol - Operation Order.

(U) REARERS.
1. Four Mk. XVIII and four Mk. XVIII-1 torpedoes were carried aft. None were fired. No difficulties or unusual circumstances were encountered in upkeep.

- 35 -

ENCLOSURE (A)

— page 296 —
9 October 1944
From: The Commander Submarine Division Two Eighty One
To: The Commander in Chief, United States Fleet.
Via: (1) The Commander Submarine Squadron FOUR.
       (2) The Commander Submarine Force, U. S. Pacific Fleet.
       (3) The Commander in Chief, U. S. Pacific Fleet.
Subject: U.S.S. FINBACK (SS230) - Report of TENTH War Patrol.

1. The TENTH war patrol of the U.S.S. FINBACK, the first of the present commanding officer as such, was conducted in the BONIN ISLANDS area. It was of fifty day's duration, thirty of which were spent in the assigned area, and was terminated by the provision of the operation order.

2. From 31 August to 2

— page 297 —
9 October 1944.
Subject: U.S.S. FINBACK (SS230) - Report of TENTH War Patrol.

6. A third approach was commenced but broken off when it was suspected that FINBACK was being hunted by an enemy submarine. The identification of this bogey as a submarine is not entirely satisfactory. The fact that it could not be seen at 4000 yds and that it showed a light suggests a small boat, possibly a life boat or raft.

7. 'A two ship convoy was sighted on 16 September but air cover prevented it from being closed and attacked.

8. The observation previously made that the enemy is using submarines for anti-submarine craft is amply substantiated by FINBACK's experience.

9. The inadequacy and shortcomings of the present SD radar are well established. As the enemy is forced back to his homeland air opposition can be expected to increase in which case an efficient, secure aircraft warning radar is imperative.

10. On her return from patrol FINBACK was clean and shipshape and in very good material condition. The main power controllers will be carefully inspected and steps will be taken necessary to prevent a recurrence of the near serious casualty experienced on 14 September. It is noted that FINBACK had her share of the difficulties with drum type motor starters which are fast becoming cronie in the submarine force.

11. The FINBACK is congratulated on the damage inflicted on the enemy and on the service she rendered to the air arm.

L. H. CHAPPELL

— page 298 —
11/tel
Fleet Post Office,
San Francisco, California,
12 October 1944.

From: Commander Submarine Squadron FOUR.
To: The Commander-in-Chief, United States Fleet.
Via: (1) The Commander Submarine Force, PACIFIC FLEET.
       (2) The Commander-in-Chief, U. S. PACIFIC FLEET.

Subject: U.S.S. FINBACK - .port of Tenth War Patrol.

1. Forwarded, concurring in the comments of the Commander Submarine Division TWO-EIGHTY-ONE.

2. It is a pleasure to congratulate the Commanding Officer, officers, and crew of the FINBACK on the results of this patrol which included the successful rescue of five (5) aviators.

3. It is recommended that the FINBACK be credited with inflicting the following damage upon the enemy:

| SINK | 1 AK (small) | 1

— page 299 —
14 OCT 1944
Serial 02245
CONFIDENTIAL
THIRD ENDORSEMENT to FINBACK Report of Tenth War Patrol.
CCMSUBSPAC PATROL REPORT NO. 542.
U.S.S. FINBACK - TENTH WAR PATROL.
From: The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in- chief, U.S. Pacific Fleet.
Subject: U.S.S. FINBACK (SS230) - Report of Tenth War Patrol.
(16 August to 4 October 1944).

1. The tenth war patrol of the FINBACK was conducted in the Bonin Islands area. Her mission included lifeguard duty as well as offensive operations.

2. The FINBACK covered her area in an aggressive, thorough manner. Her one good contact was developed into two aggressive attacks which resulted in the sinking of a small oiler and two hits in a small freighter. In addition, as a result of her alert and daring performance of duty as lifeguard, the FINBACK was fortunate in being able to rescue and bring home five downed aviators. Comments regarding enemy submarines being present as part of the anti-submarine defense forces of the convoy attack on 10-11 September, and the later sighting of a submarine and periscope in the area are noted.

3. This patrol is designated as "Successful" for Combat Insignia Award.

4. The Commander Submarine Force, Pacific Fleet, congratulates the commanding officer, officers, and crew for this aggressive, successful patrol. While the evidence presented in the patrol report is not conclusive concerning the sinking of the small freighter, it is felt that a ship of this size could not survive two torpedo hits. The FINBACK is credited with having inflicted the following damage upon the enemy:

| Item | Description |
|------||
| 1 - Small AO (EU) | 1,000 tons (Attack No. 2) |
| 1 - Small AK (EU) | 900 tons (Attack No. 2) |

TOTAL SINK: 1,900 tons

Distribution and authentication on following page.
C. A. LOCKWOOD, Jr.

— page 300 —
11/10/46-3(15) SUBMARINE FORCE, PACIFIC FLEET
SERIAL 0245
COSTFIDENTIAL
THIRD ENDORSEMENT to
INBACK REPORT of
'onth War Patrol.
JOMSUBSCAP PATROL REPORT NO. 542.
J.S.S. FINBACK - TENTH WAR PATROL.
subject: U.S.S. FINBACK (SC 2) - Report of Tenth War Patrol.
(16 August to 4 Oct 1944).

DISTRIBUTION:
(Complete Reports)
ComInCh (7)
JNC (5)
JincPac (6)
Intel.Ccn.Pac.Ocean Areas (1)
JomScrPac (1)
JincLant (1)
JomSubsLant (8)
S/M School, NL (2)
ComSoPac (2)
ComSoVesPac (1)
ComSubSoVesPac (2)
TTF 72 (2)
JomNorPac (1)
JomSubsPac (40)
SUBAD, MI (2)
ComSubsPacSubordCom (3)
'11 Squadron and Division Commanders, Pacific (2)
ubstTrainPac (2)
11 Submarines, Pacific (1)

D. L. HYNES 2nd, Flag Secretary.

— page 302 —
1-5 November 1944.
1330/1 Departed Pearl in company with U.S.S. DRAGONET.
1130/5 Entered Midway. Held for three days by cracked high pressure air compressor head replacement. (See paragraph K).

8 November 1944.
0715 (Y) Departed Midway for Dunker's Derby. Held control drills, battle problems, and training dives daily.

14 November 1944.
2315 (K) Changed route to head for lifeguard station. Unless otherwise stated, all times will be KING.

ENCLOSURE (A)

— page 303 —
16 November 1944.
Port shaft out of commission from 0800 to 1215 while repairs were made to reduction gear lub oil line. (See paragraph K).

17 November 1944.
0400. On station. Submerged when SD contact on 3 planes closed from 14 to 9 miles. (Plane Contact #2).
1740. Surfaced.

18 November 1944.
0932. Submerged on lifeguard station on SD contact at 9 miles. (Plane Contact #4).
1747. Surfaced. Test fired 40 mm gun.

19 November 1944.
0600. On station. Heard many stations testing on 4475 kcs.

20 November 1944.
1220. Headed for BONINS. With KITA I/0 bearing 3040(T), distance 65,000 yards, received instructions to be on lifeguard station in morning. Reversed course.

21 November 1944.
1300. Arrived on station 25 minutes before receiving word that strike was postponed. Again reversed course, heading back to KITA I/0.

22 November 1944.
0100. Patrolling route between HAHA and I/0. (Ship Contact #1). Sighted sampan bearing 1000(T), distance 8 miles, on NE course. Estimated length 45 feet. No action taken because of nearness to HAHA.

ENCLOSURE (A)

— page 304 —
23 November 1944.
Patrolling same route. Submerged three times on Radar plane contacts below 10 miles. Heavy overcast prevented seeing planes until very close.

: 24 November 1944.
Submerged with two bearing 202°(T), distance 16 miles, for submerged patrol.
(Ship Contact #2). Sighted saman on southerly course bearing 0100(T), distance 6 miles.
(Ship Contact #3). Sighted 40' sloop bearing 0820(T), distance 8 miles, southerly course. No action because of nearness to IWO.
Ran at 50 feet listening on 4475 kcs. on SD mast during strike on CHICHI.
Back to periscope depth.
Surfaced.

: 25 November 1944.
Surface patrol between HANA and IWO.

: 26 November 1944.
Surface patrol between HANA and IWO.
Headed for lifeguard station.

: 27 November 1944.
(Plane Contact #22). SJ detected 3 planes at 8. miles closing to 6 miles. Dived.
Surfaced.
(Plane Contact #23). SD contact at 22 miles closing to 4. Dived. Can't locate them with APR.
Surfaced.
Patrolling lifeguard station.
(Plane Contact #24). Sighted SALLY, and tracked him in from 10 to 5 miles. Dived.
Up for a look. SD contact at 7 miles closing to 4. Sounded.
Surfaced. All clear.

- 3 -

ENCLOSURE (A)

— page 305 —
1634
: 1826
: 28 November 1944.
: 0130
: 0515
: 30 November 1944.
: 0330
: 0452
: 1812
: 1905
: 0000
: 0600
: 0743
: 1233
: 1915

U.S.S. FINBACK (SS230)

(Plane Contact #25). Three planes closed from 12 to 6 miles. Dived. Surfaced. Radio caught bits of conversation, and "70 PICKLED EEL 125". Later a plane said "Reference Point is IWO". Headed for spot on 4 engines.

In position. Searching area, firing green star every half hour. ComSubPac said all planes returned. Started to circumnavigate the BONINS up the west coast and down the east coast.

Reversed course to head for station.

(Plane Contact #30). At 50 miles SE of HAH, lookout reported "a bunch of flares, shooting all over", just as SJ reported interference. O.O.D. saw tracers and dived. APR not in use at the time because VHF receiver in use was connected to APR antenna since VHF antenna was flooded out. Surfaced, steering up moon. Occasional 155 mcs, signal heard, apparently sweeping. (Plane Contact #33). SJ picked up plane at 12 miles, closing. Submerged. Surfaced.

On station. Strike postponed. Started for CHICHI. (Plane Contact #34). Sighted NELL coming out of clouds bearing 2300(T), distance 6 miles. Dyed. One bomb exploded as we passed 80 feet. Estimate 500 yards away. Surfaced. Patrolled area NW of JUKO JIMA during afternoon. Received word that GROUPER would have this area, so started southwest to pass near NISHINO SHIMA.

ENCLOSURE (A)

— page 306 —
2 December 1944.
1320
1451
Sighted NISHINO SHIMA.
Changed course to 1420(T) heading for HATA JIMA.

3 December 1944.
0630
0910
Patrolling lifeguard station.
(Plane Contact 936). Lookout sighted plane circling at 8 miles. Appeared to be B-29.
(Plane Contact 940). Sighted tracer fire and occasional cannon fire in clouds bearing 0500(T). SD contact at 16 miles. Plane snowing, sighting passed ahead on course SE at 4 miles. Plane turned searchlight downward while he was within 5 miles of us, then turned it off. Opened out to 16 miles on SD and disappeared.
2005
One or more planes on SD for next hour.

4 December 1944.
1645
Patrolling lifeguard station.
Raid delayed, so headed for position of lifeboat or raft 70 miles west of IWO. No previous action on this as distance would have kept us off station for entire flight time.

5 December 1944.
1100
Searching reported position for raft.
Visibility 1-3 miles.
Ceased search.

1700

6 December 1944.
1350
Patrolling northwest of IWO.
(Plane Contact 947). Sighted SALLY, flying low, distance 7 miles, on course 0500(T).
Dived and commenced submerged patrol.
(Plane Contact 948). Sighted 10 SALLYs on course for IWO. I believed these were replacement flying to IWO. (Broadcast on 8 December reported 10 planes raiding SLPAN).

- 5 -

ENCLOSURE (A)

— page 307 —
7 December 1944.
1020
Sighted debris and lifering in position
Lat. 26°59' N, Long. 139°37' E. Maneuvered
to get lifering when two planes were seen.
(Plane Contacts #49 and #50). Changed our
minds and dived.
1226
Surfaced.
1800
Headed for lifeguard station for strike on
IWO.

8 December 1944.
0930
On station, 15 miles bearing 165° from IWO.
Heavy overcast. Dived to wait until strike
commenced.
1000
Surfaced. Series of heavy explosions and
much smoke on island. Planes all over the
radar. Couldn't see any planes at 3 miles,
so submerged.
1335
Surfaced. Cleared area on course 070°(T).
Reversed course returning to lifeguard station,
155 mcs, signal heard on APR, intensity in-
creasing as we neared IWO. About 2330
when IWO bore 080°(R), 15 miles, signal was
directed at us for periods up to 3 minutes.
Put IWO astern, and the signal immediately
began sweeping across us without pausing.

9 December 1944.
1105
Circled IWO at 20 miles range.
(Plane Contact #78). Sighted MAVIS at 8
miles, bearing 250°(T), heading for us.
Dived and commenced submerged patrol.
1803
Surfaced and patrolled area north of KITA
IWO.

10 December 1944.
0917
(Plane Contact #79). Sighted 3 planes at
4 miles, bearing 015°(T), 5 starboard angle
on the bow. Dived and started submerged
patrol.
1809
Surfaced.

- 6 -

ENCLOSURE (A)

— page 308 —
11 December 1944.

0100
0500
1130
1143
1850
2023

12 December 1944.

0000
0100
0350
0355
0437

13 December 1944.

0400
1330
1610

14 December 1944.

0510

Patrolling routes heading for IWO.
Dived with IWO bearing 210°(T) at 14 miles.
Heard several small explosions.
Saw AA fire on IWO. No planes in sight.
Made inspection of western shore at 4 miles.
No ships there.
Surfaced with IWO bearing 180° at 15 miles.
Immediately four searchlights illuminated,
one trained vertically, three trained at
600. Also a white steady light momentarily
seen on northern part of IWO. Radar intercepts on 155 and 160 mcs. Lights lasted
about 15 minutes.
Five searchlights on IWO, followed by three
or four reddish flare-ups. Probably bomb
bursts. Range to IWO, 40 miles.

0.0.D. reported a momentarily small white
light, distance unknown, at 0300(T). Steering this course until 0100, but saw nothing
further.
Changed course to 270°(T).
0.0.D. and lookouts saw a low broad flare
bearing 100°(T), over the horizon, lasting
about 30 seconds. Nothing in sight on
periscope. Our position: Lat. 25° 51' N,
Long. 141° 22' E.
(Plane Contact #80). 0.0.D. saw plane with
naviational lights bearing 190°(T), distance
4 miles, course 080°(T). Dived.
Surfaced. Headed for lifeguard station.

Patrolling on station.
Saw about twenty-five B-29's flying north.
Saw about twenty-five B-29's flying south.

HEADED SOUTH for plane reported down west
of IWO.

- 7 -

ENCLOSURE (A)

— page 309 —
14 December 1944 (Continued).

1600 Received aircraft contact report of 8 small AK's and 1 DD at CHICHI; also information that downed plane we are looking for is about 400 miles north of us. Wrong reference point was used in reporting his location. Slowed to two engines and headed for CHICHI.

1525

0725

1510

1545

1844

1930

2311

16 December 1944.

0012

Radar contact at 14,700 yards bearing 041°(T). SJ reported intermittent radar interference. Nothing heard on APR during ensuing attacks. Did not listen above 300 mcs. No interference noted after first attack. Contact developed into three merchant ships in line with three ships; believed to be PC's, as port, starboard, and after escorts. Course 125°, zigzagging 40° either side of base course every 4 to 8 minutes, speed 10 knots. Radar reported seven ships, but only six could ever be seen.

- 8 -

ENCLOSURE (A)

— page 310 —
16 December 1944 (Continued).

Made approach from starboard quarter, intending to select target after a better look.
Fired tubes 4, 5, and 6 with zero depth on 130° starboard track, range 2350 yards to trailing escort.
No hits. Gyro setters not cut in. Pulled out and tried again as no one seemed to mind our presence.
Fired tubes 1, 3, and 5 with 007 gyro, zero depth on 117° track at 2150 yards to trailing escort. First torpedo prematurely about 200 feet off the bow. Pieces hit bridge and hull over maneuvering room. Turned left and at fired tubes 8, 9, and 10 at same target on 135° starboard track. No hits at all. Escort reversed course and dropped charges at random. We pulled around stern of formation and commenced approach from port beam. Port escort crossed ahead as we turned right. Selected biggest ship and one on his starboard beam as targets. At fired tubes 1, 2, and 3 on 120° port track, range 2800 yards to nearest ship. At fired tubes 4 and 6 at ship on his starboard beam on 118° port track, range about 3600 yards.
Two hits in first target. Blew up and sank in four minutes. No hits in second target. All ships grouped together and turned left to course 100°, evidently heading for shallow water north of CHICHI. Crossed to starboard quarter as trailing escort came up astern to join formation. Slowed down and as he passed astern fired tubes 8, 9, and 10 on 850 starboard track at 3000 yards.
Sound charged torpedo hit. No hit seen. Commenced another approach from starboard flank and at fired tubes 3, 4, and 5 on 760 starboard track at 1900 yard run, again trying to get the trailing escort. No hits. Broke off approach and reversed course as we haven't time to get ahead for daylight attack, and 100 mcs. has been on us steadily for last half hour.

- 9 -

ENCLOSURE (A)

— page 311 —
16 December 1944 (Continued).

The one ship hit was 430 feet in length by binocular formula. She either had a catwork or a deck cargo. No burning after four minutes, so assumed she was an AK rather than an A0. She was similar to 'WINNIEIOU HARI, page 290, or 'NAIKO HARI, page 292 (ONI 288 J). Changed course to 3200(T). Changed course to 0720(T) enroute MIDWAY.

17 December 1944.

0530 Departed area enroute MIDWAY.

24 December 1944.

Arrived MIDWAY.

(C) WEATHER:

During the period 8 November to 16 November enroute BONINS' area, heavy winds and seas from a general westerly direction were encountered. Several storms were skirted. Conditions in the area generally favorable to submarine operations, with a good chop most of the time. There were very few days so rough as to make depth control difficult. Prevailing winds were from northeast.

(D) TIDAL INFLUENCE:

Strong ocean current (set 190°, drift 1.1 knots) was observed over a twelve hour period on 4 December while on lifeguard station in vicinity of Lat. 25-00 N, Long. 144-00 E. On 11 December, between 0900 and 1400 (K), about eight miles north of IJO JIMA, there was current of about .75 knots with a set of 1450(T).

(E) NAVIGATIONAL AIDS:

No remarks.

- 10 -

ENCLOSURE (A)

— page 312 —
11-11-22 14-1-17 E
1. 1110 26-30 N 1 Sampan 6 010°(T) SD -
11-22 14-1-53 E 10 knots
2. 0900 25-02 N 1 Sampan 3 215°(T) P -
11-24 14-1-17 E 6 knots
3. 1130 25-01 N 1 Sail- 2 170°(T) P -
11-24 14-1-16 E boat 3 knots
4. 0012 27-33 N 3 AK's or 7 120°(T) R See
12-16 14-1-10 E A0's & 3 11 knots Attack: #1,2,3,4,
Escorts (FC) 5.

- 11 -

ENCLOSURE (A)

— page 313 —
U.S.S. FINEGO (SS230)
C-O-N-F-I-D-E-N-T-I-A-L
(G) AIRCRAFT CONTACTS:
NO.  TIME  LAT.  TYPE  INITIAL EST.SPD.  HON. CON-  NO.OF  RELARKS
    DATE  LONG.  RANGE  & COURSE TACTED  PLANES
1.  1001  26-46 N  UNK  40  UNK  R  1  -
11-16  14-03 E
2.  1029  24-58 N  UNK  14  UNK  R  3  -
11-17  14-59 E
3.  1202  25-01 N  UNK  30  UNK  R  1  -
11-17  14-01 E
4.  0932  24-51 N  UNK  9  UNK  R  1  -
11-18  14-51 E
5.  1220  24-54 N  UNK  4  UNK  P  1  -
11-18  14-00 E
6.  1325  24-36 N  UNK  13  UNK  R  3  -
11-19  14-00 E
7.  1558  24-47 N  UNK  20  UNK  R  1  -
11-19  14-54 E
8.  1800  25-03 N  UNK  30  UNK  R  4  -
11-19  14-10 E
9.  1130  25-10 N  UNK  30  UNK  R  1  -
11-21  14-39 E
10.  1015  26-28 N  UNK  32  UNK  R  1  -
11-22  14-44 E
11.  1505  25-52 N  UNK  28  UNK  R  1  -
11-22  14-55 E
12.  0845  25-36 N  UNK  20  UNK  R  1  -
11-23  14-47 E
13.  1115  25-13 N  UNK  18  UNK  R  1  -
11-23  14-33 E
14.  1525  24-36 N  UNK  8  UNK  R  1  -
11-23  14-00 E

LEGEND:
P = Periscope  SD = Sighted Day
R = Radar  SN = Sighted Night

- 12 -  ENCLOSURE (A)

— page 314 —
U.S.S. FINBACK (SS230)
C-C-N-F-I-D-E-N-T-I-A-L
(G) AIRCRAFT CONTACTS (Continued).
NO. TIME L&T. TYPE INITIAL EST.SPD. HOW CON- NO. OF REARKS
DATE LONG. RANGE & COURSE TACTED PLANES
15. 1045 26-16 N UNK 20 UNK R 1 -
11-25 141-46 E
16. 1210 26-16 N UNK 30 UNK R 5 -
11-25 141-54 E
17. 1220 26-16 N UNK 19 UNK R 1 -
11-25 141-54 E
18. 1501 26-01 N UNK 30 UNK R 1 -
11-25 141-40 E
19. 1636 26-15 N UNK 32 UNK R 4 -
11-25 141-45 E
20. 1130 26-22 N UNK 14 UNK R 1 -
11-26 141-43 E
21. 1450 25-55 N UNK 12 UNK R 2 -
11-26 141-45 E
22. 0030 25-41 N UNK 8 3 -
11-27 142-24 E
23. 0155 25-43 N UNK 22 UNK R 1 -
11-27 142-29 E
24. 1342 25-10 N SALTY 10 UNK SD 1 -
11-27 144-27 E 165(T)
25. 1547 25-03 N UNK 20 UNK R 2 -
11-27 144-30 E
26. 1634 24-58 N UNK 20 UNK R 2 -
11-27 144-35 E 110(T) SD
27. 0702 24-19 N UNK 30 UNK R 1 -
11-28 142-19 E

LEGEND:
P = Periscope
SD = Sighted Day
R = Radar
SN = Sighted Night

- 13 -

ENCLOSURE (A)

— page 315 —
U.S.S. FINBACK (SS230)
C-O-IN-F-I-D-B-N-T-I-A-L

(G) AIRCRAFT CONTACTS (Continued).

NO.  TIME  |  LAT.  |  TYPE | INITIAL | EST. SPD. | HOW CON- | NO. OF | REMARKS
DATE   | LONG. | RANGE | & COURSE | TACTED | PLANES

28.  1010 | 24-47 N | UNK | 21 | UNK | R | 1 | -
11-28 | 14-2-35 E

29.  1636 | 25-44 N | BOMB. | 8 | UNK | SD | 2 | -
11-28 | 14-1-54 E | 180(T)

30.  0330 | 25-33 N | UNK | 1 | UNK | SN | 1 | STRAING

11-30 | 14-2-23 E

31.  0740 | 25-43 N | SALLY | 12 | UNK | SD | 2 | -
11-30 | 14-2-53 E | 320(T)

32.  1130 | 26-37 N | SALLY | 12 | UNK | SD | 2 | -
11-30 | 14-2-59 E | 200(T)

33.  1812 | 29-49 N | UNK | 12 | UNK | R | 1 | -
11-30 | 14-2-41 E | 180(T)

34.  0743 | 27-48 N | NELL | 6 | UNK | SD | 1 | -
12-1 | 14-3-28 E | 050(T)

35.  0705 | 26-00 N | B-24 | 8 | UNK | SD | 1 | -
12-3 | 14-4-18 E | 200(T)

36.  0910 | 25-04 N | B-29 | 13 | UNK | SD | 1 | -
12-3 | 14-4-14 E | 000(T)

37.  1140 | 25-04 N | UNK | 40 | UNK | R | 1 | -
12-3 | 14-4-14 E

38.  1215 | 25-03 N | UNK | 40 | UNK | R | 1 | -
12-3 | 14-4-14 E

39.  1842 | 24-52 N | UNK | 7-40 | UNK | R | SEV- IPF
12-3 | 14-4-14 E | ERAL

40.  1915 | 24-55 N | UNK | 23 | UNK | R | 1 | -
12-3 | 14-4-11 E

LEGEND: P - Periscope  SD - Sighted Day
R - Radar  SN - Sighted Night

- 14 -

ENCLOSURE (A)

— page 316 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-E-N-T-I-A-L

(G) AIRCRAFT CONTACTS (Continued).

NO.  DATE  LAT.  TYPE  INITIAL  EST. SPD.  HON  CON-  NQ. OF  REMARKS
    TIE  LONG.  RANGE  & COURSE  TACTED  PLANES

41.  2002  24-57 N  UNK  30  UNK  R  1  -
    12-3  144-11 E

42.  2010  24-57 N  UNK  12  UNK  R  1  -
    12-3  144-11 E

43.  2040  24-57 N  UNK  10  UNK  R  1  -
    12-3  144-11 E

44.  2053  24-57 N  UNK  10  UNK  R  1  -
    12-3  144-11 E

45.  2058  24-57 N  UNK  18  UNK  R  2  -
    12-3  144-11 E

46.  1029  24-54 N  UNK  10  UNK  R  1  -
    12-5  140-19 E  050(T)

47.  1350  26-21 N  BOMB.  7  UNK  SD  1  -
    12-6  141-36 E  050(T)

48.  1620  26-21 N  SAILY  5  205 mph  P  10  -
    12-6  141-41 E  193(T)

49.  1048  26-51 N  SAILY  7  UNK  SD  1  -
    12-7  139-37 E  040(T)

50.  1049  26-51 N  SAILY  9  UNK  SD  1  -
    12-7  139-37 E  250(T)

51.  0930  24-27 N  UNK  9  UNK  R  1  -
    12-8  141-27 E

52.  1013  24-30 N  UNK  5  UNK  R  1  IFF

53.  1014  24-27 N  UNK  4  UNK  R  5  IFF

LEGEND:  P - Periscope  SD - Sighted Day
    R - Radar  SN - Sighted Night

- 15 -

ENCLOSURE (A)

— page 317 —
U.S.S. FINBACK (SS230).
C-O-N-T-I-D-E-N-T-I-A-L

(G) AIRCRAFT CONTACTS (Continued).

NO.  DATE  LAT.  INITIAL  EST.SPD.  HGN  CON-  NO.OF  REMARKS
    TIME  LONG.  TYPE  RAN  GE  &  COURSE  TACTED  PLANES

54.  1016  24-27 N  UNK  4  UNK  R  1  -
    12-8  141-26 E

55.  1020  24-27 N  UNK  5  UNK  R  2  -
    12-8  141-24 E

56.  1023  24-27 N  UNK  1/2  UNK  R  1  -
    12-8  141-24 E

57.  1035  24-27 N  UNK  9  UNK  R  2  -
    12-8  141-24 E

58.  1036  24-27 N  UNK  10  UNK  R  1  -
    12-8  141-24 E

59.  1039  24-29 N  UNK  12  UNK  R  1  -
    12-8  141-24 E

60.  1040  24-29 N  BATTY  10  UNK  P  1  -
    12-8  141-24 E  O90(T)

61.  1042  24-29 N  UNK  11  UNK  R  1  -
    12-8  141-24 E

62.  1048  24-28 N  UNK  14  UNK  R  2  -
    12-8  141-24 E

63.  1057  24-28 N  UNK  11  UNK  R  1  -
    12-8  141-24 E

64.  1108  24-29 N  UNK  12  UNK  R  1  -
    12-8  141-23 E

65.  1114  24-29 N  SE2c  12  UNK  P  1  -
    12-8  141-23 E  328(T)

66.  1115  24-29 N  UNK  5  UNK  R  1  -
    12-8  141-23 E

LEGEND:  P - Periscope  SD - Sighted Day
    R - Radar  SN - Sighted Night

- 16 -

ENCLOSURE (A)

— page 318 —
U.S.S. FINBACK (SS230)
C-O-N-P-I-D-E-N-T-I-A-L

(G) AIRCRAFT CONTACTS (Continued).

NO.  TIME  LAT.  TYPE  INITIAL  EST.SPD.  HQT  CON-  NO. OF  REHARKS
    DATE  LONG.  RANGE  & COURSE TACED  PLANES

67.  1116  24-29 N  UNK  6  UINK  R  1  -
    12-8  141-23 E

68.  1138  24-29 N  UNK  5  UINK  R  1  -
    12-8  141-21 E

69.  1155  24-29 N  ZERO  1  UINK  P  1  -
    12-8  141-21 E  274(T)

70.  1353  24-26 N  UINK  8  UINK  R  1  -
    12-8  141-30 E

71.  1451  24-28 N  UNK  15  UINK  R  1  -
    12-8  141-31 E

72.  1452  24-28 N  UNK  10  UINK  R  1  -
    12-8  141-31 E  240(T)

73.  1506  24-29 N  UNK  10  UINK  R  1  -
    12-8  141-34 E  305(T)

74.  1510  24-29 N  UNK  10  UINK  R  1  -
    12-8  141-34 E  290(T)

75.  1511  24-29 N  UNK  15  UINK  P  5  -
    12-8  141-34 E  225(T)

76.  1544  24-31 N  UNK  21  UINK  R  1  -
    12-8  141-42 E

77.  0048  24-14 N  UINK  7  UINK  R  1  -
    12-9  141-03 E  100(T)

78.  1105  25-51 N  NAVIS  6  180 m.p.h.  SD  1  -
    12-9  141-28 E  225(T)

79.  0917  25-40 N  UNK  4  UINK  SD  3  -
    12-10  141-37 E  145(T)

LEGEND:  P - Periscope  SD - Sighted Day
    R - Radar  SN - Sighted Night

- 17 -

ENCLOSURE (A)

— page 319 —
U.S.S. PINKACK (SS230)
C-O-N-F-I-D-E-N-T-I-A-L
NO.  TIME  LAT.  TYPE  INITIAL  EST.SPD.  HON. CON-  NO. OF  REMARKS
    DATE  LONG.  RANGE  & COURSE  TACTED  PLANES
80.  0355  25-51 N  UNK  10  UNK  SN  1  -
    12-12  141-22 E  250(T)
81.  1247  28-54 N  B-29  2  UNK  SD  7  -
    12-13  139-06 E  320(T)
82  1254  28-54 N  B-29  10  UNK  SD  3  -
    12-13  139-06 E  320(T)
83.  1304  28-54 N  B-29  12  UNK  SD  7  -
    12-13  239-07 E  320(T)
84.  1320  28-50 N  B-29  12  UNK  SD  6  -
    12-13  139-10 E  320(T)
85.  1340  28-49 N  B-29  10  UNK  SD  7  -
    12-13  139-12 E  320(T)
86.  1410  28-47 N  UNK  35  UNK  R  3  -
    12-13  139-13 E
87.  1603  28-40 N  D-29  8  130(T)  R & SD  1  -
    12-13  139-19 E
88.  1615  28-40 N  B-29  11  UNK  R  1  -
    12-13  139-19 E
89.  1626  28-35 N  B-29  16  UNK  R  2  -
    12-13  139-25 E
90.  1639  28-35 N  B-29  12  UNK  R  1  -
    12-13  139-24 E

NUCLEAR FLIGHT CONTACTS UNTIL 1852 - THESE WERE ALL B-29'S.

91.  1215  26-34 N  SALTY  10  UNK  SD  1  -
    12-14  138-54 E  160(T)
92.  0725  26-52 N  ZIEGE  9  UNK  SD  1  -
    12-15  141-52 E  095(T)

LEGEND:  P - Periscope  SD - Sighted Day
    R - Radar  SN - Sighted Night

- 18 -

ENCLOSURE (A)

— page 321 —
1 P.C. - Trailing Escort of Convoy.

Ship's / Sunk: NONE
Ship's / Damaged or probable sunk: NONE

Target Draft: 5 feet
Course: 160
Speed: 9
Range: 2350

C.T.N SHIP DATA

Speed: 12
Course: 095
Depth: 0
Angle (at firing): 0

FIRE CONTROL AND TORPEDO DATA

Type Attack: Night, Surface, Radar.

- 20 -

ENCLOSURE (A)

— page 322 —
U.S.S. FINBACK (SS230)
C-O-N-T-I-D-E-N-T-I-A-L

(1) ATTACK DATA (Continued).

Tubes Fired 4 5 6
Track Angle 130 S 131 S 132 S
Gyro Angle 016 017 018
Depth Set 0 0 0
Power - - -
Hit or Miss Miss Miss
Erratic No No No
Mark Torpedo 18-1 18-1 18-1
Serial 56501 56769 55811
Mark Exploder 8-5 8-5 8-5
Serial Number 10245 10478 10591
Actuation Set Contact Contact Contact
Actuation Actual - - -
Mark 'Arched 18-2 18-2 18-2
Serial Number 4115 4099 4213
Explosive Torpex Torpex Torpex
Firing Interval 10 Sec. 10 Sec. 10 Sec.
Spread Divergent Divergent Divergent
Sea Condition 2 2 2
Overnail Activity Submarine Base, Pearl Harbor, T.H.

REMARKS:
Torpedo tubes zero gyro angle. Regulator not
out.

[CLOSURE (4)]

J. R.

— page 323 —
U.S.S. FINBACK (SS230)
C-O-N-N-I-D-E-N-T-I-A-L
(E) ATTACK DATA (Continued).

Tubes Fired 4 5 6
Track Angle 130 S 131 S 132 S
Gyro Angle 016 017 018
Depth Set 0 0 0
Power - - -
Hit or Miss Miss Miss
Erratic No No No
Mark Torpedo 18-1 18-1 18-1
Serial 56501 56769 55811
Mark Exploder 8-5 8-5 8-5
Serial Number 10245 10478 10591
Actuation Set Contact Contact Contact
Actuation Actual - - -
Mark 'Arched 18-2 18-2 18-2
Serial Number 4115 4099 4213
Explosive Torpex Torpex Torpex
Firing Interval 10 Sec. 10 Sec. 10 Sec.
Spread Divergent Divergent Divergent
Sea Condition 2 . 2 2
Overnail Activity Submarine Base, Pearl Harbor, T.H.

RELATES:
Torpedoes fired with zero gyro angle. Regulator not out in.

- 21 -

INCLUSIVE (4)

— page 324 —
1 P.C. - Trailing Escort of Convoy.

Ship's / Sunk: NONE
Ship's / Damaged or probable sunk: NONE

Target Draft: Course: Speed: Range:
5 feet: 120: 8.5: 2150

O/N SHIP DATA

Speed: Course: Depth: Angle (at firing):
12: 050: Surface: 0

FIRE CONTROL AND TORPEDO DATA:

Type Attack: Night, Surface, Radar.

- 22 -

ENCLOSURE (A)

— page 325 —
56591 exploded prematurely approximately five seconds after firing (about 200 ft. off bow).

- 23 -

ENCLOSURE (L.)

— page 329 —
0-0-N-F-I-D-R-N-T-I-I-L

(H)  ATTACK DATE (Continued).

Tubes Fired 4 6
Track angle 118 P 119 P
Gyro angle 016 016
Depth Set 0 0
Power - -
Hit or Miss Miss Miss
Erotic No No
Mark Torpedo 18-1 18-1
Serial 56566 56805
Mark Exploder 8-5 8-5
Serial Number 8625 10383
Actuation Set Contact Contact
Actuation actual - -
Mark Variable 13-2 18-2
Serial Number 3711 4089
Explosive Torpex Torpex
Firing Interval 10 Sec. 10 Sec.
Spread Divergent Divergent
Sea Condition 2 2
Overall activity Submarine Base, Pearl Harbor, T.H.
RIM-RMS: None.

- 27 -

ENCLOSURE (A)

— page 330 —
1 P.C. - Trailing Escort of Convoy.

Ship's / Sunk: NONE
Ship's / Damaged or probable sunk: NONE

Target Draft: 5 feet
Course: 100
Speed: 13
Range: 3060

C.N. SHIP D.T.T.
Speed: 9
Course: 200
Depth: Surface
Angle (at firing): 0

FIRE CONTROL...NTD TORPEDO D.T.T.

Type Attack: Night, Surface, Radar.

- 28 -

ENCLOSURE (L)

— page 331 —
U.S.S. FINBACK (SS230)
C-O-N-F-I-D-B-N-T-I-I-L

(1) ATTACK DATE (Continued).

Tubes Fired 8 9 10
Track Angle 82 S 85 S 88 S
Gyro Angle 163 165 168-30
Depth Set 0 0 0
Power - - -
Hit or Miss Miss Miss
Erratic No No No
Mark Torpedo 18-1 18-1 18-1
Serial 56638 56584 56783
Mark Exploder 4-7 8-5 8-5
Serial Number 17409 10163 10372
Actuation Set Contact Contact Contact
Actuation Actual - - -
Mark 'f'arhead 18-2 18-2 18-2
Serial Number 439 3647 3662
Explosive Torpex Torpex Torpex
Firing Interval 10 Sec. 10 Sec. 10 Sec.
Spread Divergent Divergent Divergent
Sea Condition 2 2 2
Overhaul Activity Submarine Base, Pearl Harbor, T.H.
RATINGS:
None.

-- 29 --

EXCLUSIVE (..)

— page 332 —
1 P.C. - Starboard Escort of Convoy.
Ship's / Sunk NONE
Ship's / Damaged
or probable sunk NONE

Target Draft Course Speed Range
5 feet 155 10 2350

ON SHIP DATA:
Speed Course Depth Angle (at firing)
12 050 Surface 0

FIRE CONTROL AND TORPEDO DATA:
Type attack: Night, Surface, Radar.

ENCLOSURE (1)

— page 334 —
0-0-N-T-I-D-E-N-T-I-...-L

(I) MINES:
No evidence of mining seen during our short period in BONINS. During attack on 16 December, convoy headed for nearest shallow water which was 100 fathom curve northwest of CHICH JIH. Evidently no mines in that area.

(J) INT-SUBLIME MEASURES AND EVASION TACTICS:
BONINS area is thoroughly patrolled by planes. Great number of these planes are equipped with surface search radar with a frequency of about 160 mcs., as evidenced by numerous sight contacts on planes, day and night, after observing a steadily increasing signal on the SP. and PR. FINE-BOX was bombed once during daylight while submerging to avoid a plane, and was strafed once in moonlight.

Radar equipped planes attempted hold down on night of 26-27 November. Group of three planes approached twice from ranges of 18 to 20 miles. We were using SD as soon as their presence was detected by SP, because we couldn't find their radar frequency. Interference seen frequently on SD screen. Looked like a bug crawling through the grass of the SD scope, traversing the scope in about three seconds. Submerged because they would probably have seen us in the bright moonlight before we could have seen them. Don't believe they ever saw us.

The SD was used intermittently, and then only when cloud coverage was favorable for planes. Continuous watch was stood on the SP. and PR with good results.

The convoy attacked on the 15-16 December had one radar equipped escort who was very ineffective (see Section U). After all attacks the escorts dropped numerous random depth charges. It first, the three escorts of the convoy were stationed on the flanks and trailing. After attack 3/4, the trail-cr dropped back. The convoy maintained a line of bearing throughout the five attacks, but the escorts, after being alerted, circulated around and among the ships, following no definite tactics. All evasion by FINE-BOX was accomplished on the surface.

It is believed that the 160 mcs. set on 17O JIH may be a mobile unit (OIN 222-J) and is possibly carried by planes.

- 32 -

EMICLATURE (L)

— page 338 —
0-0-N-F-I-D-E-N-T-I-A-L

(Q) PERSONNEL:

Number of men on board during patrol: 74
Number of men qualified at start of patrol: 52
Number of men qualified at end of patrol: 53
Number of unqualified men making first patrol: 15
Number of men advanced in rating during patrol: 10

(R) TILLERS STEAMED - FUEL USED:

PEARL to MIDWAY 1;294 miles (pit) 15;800 gallons
MIDWAY to area 2;222 miles (pit) 27;120 gallons
In area 6;928 miles (pit) 62;320 gallons
Area to MIDWAY 2;228 miles (pit) 20;560 gallons

(S) DURATION:

Days enroute to area 15
Days in area 30
Days enroute to base 4
Days submerged 4

(T) FACTORS OF DURANCE RELATING TO:

Torpedoes Fuel Provisions Personnel Factor
4 5,000 gal. 20 days Indefinite

Limiting factor: this patrol - Operation Order.

(U) RADIO AND RADAR COUNTERMEASURES:

Prior to attack on 16 December, SJ reported interference signal, after initial radar contact had been made. No indications after first attack had been executed. Nothing heard or seen on APR/SPA. Used low frequency coil only (30-300 mcs), as we expected to find escort radar about 150 mcs. Signal was not SJ frequency.

It is possible escort secured his radar, fearing that we would DF his transmissions, as soon as (and if) he saw our radar interference.

The following radar installations were encountered:

HAHA JIMA 100 Mcs. 800 Prf. 45 MSecs.

- 36 -

ENCLOSURE (A)

— page 340 —
5. The training given our sound operators by Lt. (jg) during one day of operations out of Pearl was amazing. I believe the efficiency of our sound operators has increased ten times. This training can not be given by ship's officers without sacrificing one of the limited opportunities for approach party training. It is recommended that a sound expert be assigned during as much of the training period as possible.

ENCLOSURE (A)

— page 341 —
1. The element was patrol of the FINBACK, conducted in the Bonin Islands area, was of fifty-four days duration. Thirty days were spent in the area. Six days in the area were devoted to lifeguard services in connection with air strikes by friendly planes.

2. Only one contact worthy of torpedo fire was made. This was a night radar contact on a convoy of three merchant ships, accompanied by three "PC" type escorts. Five night surface attacks, using Mark 18-1 torpedoes were made before dawn. The Commanding Officer originally planned to eliminate an escort first and then destroy the merchant ships.

ATTACK 1 - Three torpedoes were fired from bow.tubes at a trailing escort. No hits. Gyro setters were not cut in. The enemy was apparently unaware of FINBACK and torpedoes as no countermeasures followed.

ATTACK 2 - This attack was made forty-seven minutes later. Three torpedoes were fired from bow tubes on 117° track at the same trailing escort from about 2100 yards. The first torpedo pre-matured about 200 yards ahead of submarine. Pieces of this torpedo dropped on FINBACK. No hits. Submarine turned and fired three torpedoes from stern tubes at same target. No hits. The last three torpedoes were fired on about 135° track. Escort was obviously alerted. FINBACK successfully used surface evasion tactics. Depth setting on all torpedoes was zero.

ATTACK 3 - One hour and twenty minutes after attack 2, five torpedoes were fired from bow tubes. Three were aimed at the largest merchant ship in the formation and two at another merchant ship which was nearly overlapping astern of and which was about 800 yards beyond the largest merchant ship. Two hits in the first target sank her. No hits were noted on the second target. FINBACK evaded on surface.

— page 342 —
25-242 /A16-3
Serial: (09)
C-O-N-F-I-D-E-N-T-I-A-L
FIRST ENDORSEMENT to
U.S.S. FINNOOK (SS230) Report
of Eleventh Paratol.

Subject: U.S.S. FINNOOK (SS230) - Report of ELEVENTH Paratol.

ATTACK 1/4 - .about thirty-five minutes after attack 3, three torpedoes were fired from stern tubes on an 85' track, range 3000 yards, at an escort. Zero depth setting was used. No hits were seen; sound reported a possible hit.

ATTACK 1/5 - .about one hour after attack 1/4, three torpedoes were fired from bow tubes on a 76' track, range 1900 yards, at an escort. No hits. Zero depth setting was used.

3. The reasons for no hits on escort vessels during the four different attempts of attacks 1/2, 1/4, and 1/5 are not known. Small gyro angles were used in all attacks, tracks with the exception of the 135° track on the second salvo of attack 1/2 are considered very good. It is reasonable to expect radar ranges were accurate. Though it is possible, it is not probable that all misses were from consistently poor torpedo depth performance. Targets were small and hence very difficult to hit. The fire control gear of FINNOOK will be given thorough and extensive checks during refit to determine if any fault exists therein.

Recommended assessment, 1 AK(EU) 4,000 tons - sunk.

4. Enemy air activity in this area was heavy. Over eighty-two air contacts were made. FINNOOK was bombed once during daylight while diving to avoid a plane and strafed once during moonlight. Alert action by FINNOOK in each case averted damage.

5. FINNOOK arrived from patrol in very good material condition and in an excellent state of cleanliness throughout. Health and morale of officers and crew are excellent. It is expected to complete her refit in the normal time.

6. The persistence and determination to damage the enemy displayed during the night attacks of 16 December 1944 are very praiseworthy. It is a pleasure to congratulate the Commanding Officer, officers and crew upon the completion of this patrol and for the damage inflicted upon the enemy.

C. H. ANDREWS.

-2-

— page 343 —
16-3
Serial: 0226
C-O-N-F-I-D-E-N-T-I-A-L
SECOND ENDORSEMENT to
U.S.S. FINBACK (SS230) Report
of Eleventh War Patrol.

From: The Commander Submarine Force, Pacific Fleet,
    Subordinate Command, Navy No. 1504.
To: The Commander-in-Chief, United States Fleet.
Via: (1) The Commander Submarine Force, Pacific Fleet.
       (2) The Commander in Chief, U.S. Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Report of Eleventh War Patrol.

1. Forwarded, concurring in the remarks of Commander Submarine Division TWO FORTY-TWO.

2. While only six days, out of the thirty days in the area, were devoted to lifeguard service, the movement of FINBACK was greatly restricted by the requirements of the lifeguard mission. It is believed that submarines furnishing lifeguard services should be kept up to date and fully informed regarding air strikes in order that the offensive powers of such submarines be not wasted.

3. The Commander Submarine Force, Pacific Fleet, Subordinate Command, congratulates the Commanding Officer, officers and crew on completion of another well conducted patrol and damage inflicted on the enemy.

G. C. CHAFFORD

— page 344 —
5 JAN 1945
FFP12-10/A16-3(15)
Serial 031
CONFIDENTIAL

THIRD ENDORSEMENT to
FINEBACK report of
Eleventh War Patrol.

COLUMBUS PATROL REPORT NO. 630.
U.S.S. FINBACK - MILITARY MARITIME.
From: The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, U. S. Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Report of Eleventh War Patrol (1 November to 24 December 1944).

1. The eleventh war patrol of the FINBACK, under the command of Commander A. A. Williams, U.S. Navy, was conducted in the Bonins area. The FINBACK performed life-guard services as well as combat patrol.

2. Excellent area coverage was maintained, but only one contact worthy of torpedo fire was made. This contact was made at night and consisted of three A/C's or AO's and three PC type escorts. Five determined attacks were made, four on the PC type escorts, without success. The other attack resulted in sinking a medium AK.

3. Award of the submarine Combat Insignia for this patrol is authorized.

4. The Commander Submarine Force, Pacific Fleet, congratulates the commanding officer, officers, and crew for this aggressive patrol. The FINBACK is credited with having inflicted the following damage upon the enemy during this patrol:

SURF
1 - Iridium AK (WITHDOWN IARU Type) (LC) - 5,000 tons (Attack No. 3)

C. A. LOCKIWOOD, JR.

Distribution and authentication on following page.

— page 345 —
11/10/1945
FF12-10/A16-3(15)
Serial 031
CONFIDENTIAL

THIRD REPORT to
Fleet Report of
Eleventh War Patrol.

SUBJECT: U.S.S. FLEMING (SS230) - Report of Eleventh War Patrol
(1 November to 24 December 1944).

DISTRIBUTION:
(Complete Reports)
Commander (7)
CNO (5)
Cinepac (6)
ICPOA (1)
Conservpac (1)
Cincelant (1)
Consubslant (8)
S/1. School, NL (2)
CC, S/A. Base, PH (1)
Consopac (2)
Consowespac (1)
Consubsoowespac (2)
CTC 71.9 (2)
Comnorpac (1)
Consubspac (40)
SUBA D, MI (2)
ConsubspacSubordcom (3)
All Squacron & Division Commanders, Pacific (2)
Substraipac (2)
All Submarines, Pacific (1)

E. L. HYMES, 2nd,
Fla. Secretary.

— page 346 —
SS230/A16-3
Serial:  (27)
DETAILS:
Front:
To:  Corr. Officer
Via:  (1) The Commander Submarine Division 101.
(2) The Commander Submarine Squadron TEN.
(3) The Commander Submarine Force, Pacific Fleet.
(4) The Commander in Chief, U.S. Pacific Fleet.

Subject:  U.S.S. FINBACK - Report of War Patrol Number Twelve.

Enclosure:  (1) Subject Report.
(2) Track Chart (ConSubPac only).

1. Enclosures (1) and (2), covering the Twelfth War Patrol of this vessel conducted in the East China Sea area during the period from 20 January 1945 to 25 March 1945, is forwarded herewith.

R. R. WILLIAMS.

DECLASSIFIED-ART. 0445, OPNAVINST 5510.10
BY OP-092C-DATE 5/2/45
DECLASSIFIED

— page 347 —
20 January 1945

| Date       | Time       | Location          | Notes                                                                 |
|||||
| 0900 (I)   | Undercut by U.S.S. RUSSELL and ROGERS. Hatch cover damaged.  |
| 28 January 1945 | 0510 (K) | Div'd for plane.  | Couldn't stop auxiliary engine, which flooded while running.  It seems to be a little bent here and there. (See section N) |
| 0700       | Spoke escort to TUNER.  | Harbon in company with U.S.S. BLOOMER.  |
| 1450       | N'opred starboard side to next alongside U.S.S. FULTON.  | Command repairs to Auxiliary engine.  Tapped off with fuel and water. |

- 1 -

INVOICING (A)

— page 348 —
29 January 1945
1656 Underway for patrol area in company with U.S.S. PILOTFISH, BLOWER, and RASHER, escorted by LCI 1054.
2300 Escort turned back.

2 February 1945
0420 (I) All times I hereafter. Spoke U.S.S. PILOTFISH, on opposite course, leaving area bound for Saipan.

3 February 1945
0740 Submerged on radar plane contact. (Plane Contact #9)
0852 Surfaoed.
1130 Interference from U.S.S. PILOTFISH disappeared. Radar operator said, "U.S.S. PILOTFISH must have dived, Interference disappeared."
1300 Channel course to 235° T to approach COINETT STRAIT.
1740 Radar contact on YAKO SHIMI at 98,000 yards.
2300 Transmitted strait in company with RASHER.

4 February 1945
0924 Sighted PETE at six miles. Submerged. (Plane Contact #10).
1308 Surfaoed.
1415 Three YOKs came out of the clouds heading our way from the starboard quarter. Dived. (Plane Contact #12) Range 2 miles when mast was lowered.
1535 Distant heavy explosion.
1742 Sound heard serves, 200 RPM, bearing 240° T. Nothing in sight.
1814 Surfaoed.
2120 Radar interference developing into U.S.S. SILVERSTIX, homeward bound.

- 2 -

ENCLOSURE (A)

— page 349 —
5 February 1945.
0620 Sighted two lights. Small fishing boats on N.E. course. Evaded on surface. (Ship Contact #1)
1350 In position 300°00'W 125°31'00"E sighted mine. Tried to sink it with .50 Cal. fire and carbines, but gave up. Total damage to mine: Knocked one horn off. Drilled a hole in second horn, about ten hits in mine proper. In position 300°00'W 125°29'00"E exploded mine by gunfire.
1748 In position 300°00'W 125°04'00"E exploded mine by gunfire.

6 February 1945.
0630 Entered area. Patrolling on surface under heavy overcast. No fix since Tolosa Strait. Spoke R.S.S. R. by radar. Exchanged navigational guesses.
1600 Sent P.I.B.O.K. First to Consubapa. Have heard or seen nothing of PILOTFISH since 1130, 3 Feb. Transmitted request for rendezvous of pack tomorrow morning. No receipt from PILOTFISH. Sent rendezvous message blind twice more during night. PILOTFISH receipted for last transmission.

7 February 1945.
0400 ...t rendezvous point with R.S.S.R.
0500 Spoke PILOTFISH, left rendezvous and commenced patrolling assigned area. Heavy swells and a complete overcast.

8 February 1945.
0909 Dived when C.O.D. thought lookout reported plane. No had actually reported a mine, but with a collection of face masks and mufflers (apt name) the word was sadly twisted.
1012 Surfaced after routing torpedoes.

- 3 -

[ENCLOSURE: (...)]

— page 350 —
9 February
0900. Contact report from PILOTFISH. Changed course to 0300(T), attempting to overtake ship reported: Sighted tows bearing 34°7(T); distance 12,000 yards. Ship steady on course, making 13-14 knots, unscorched. (Ship Contact #2). Ship identified as properly marked hospital ship. Believed to be TAKASAKO IARU. Changed course to 2700(T). Changed course to 2200(T) to return to area.

10 February
0630. Arrived at assigned area. Patrolling on surface. Train dive. Surface. Made radar contact (interference) with PILOTFISH at various times during the night as we worked down to next day's area.

11 February
0830. Dived for submerged patrol. Surface. Spoke PILOTFISH.

12 February
Patrolling on surface.

13 February
Patrolling area on surface.

14 February
0909. Dived for 2 original transport plane at 4 miles. Rounded torpedoes. Sighted. Bank with 20% hit. Plane at 7 miles, closing on SJ. Dived. Surface. Plane at 17 miles, opening on SJ. Contact lost at 37,000 yards.

- 4 -

ENCLOSURE (A)

— page 351 —
15 February
0500    Headed for area assigned by pack commander to intercept reported enemy task force.
1103    Sighted SALLY at 5 miles. Submerged.
1627    Rounded torpedoes.
    Surface.
    Radar reported contact with task force.
    Position believed garbled, as it was well west of enemy's estimated position. Took no action pending further information.
2100    R.S.S.R. reported attack on three escorts, no results.

16 February
0852    Patrolling area assigned.
1100    Orders from pack commander to try to intercept task force along track to the West of our present position. Changed course to 270°(T).
    No contact yet, and inasmuch as PIOTRICS, 20 miles further to the West, reported no contact, assumed task force had already passed by. Reversed course for assigned area.
1236    Periscope sighted dead ahead at 700 yards. Evaded on surface. Periscope was seen by all hands on bridge, and was exposed three times for well over a minute each time. Position 27-57 N, 122-41 E. (Ship Contact #3).
1515    Plane on S7 at 8,600 yards, not sighted. Submerged. Range 2,000 yards as antenna went under. Radar detector had reported a momentary indication at 165 mes a minute before.
1901    Surface.

17 February
0823    Submerged in area to routine torpedoes.
1232    Surface.
1500    Changed course for new area.
2040    Ship Contact #4. Sighted red light bearing 160°(T).
2102    Radar contact at 5500 yards. Commenced tracking two small ships on various courses at 9 knots. Both ships displayed red lights continuously. Position 27-13 N, 121-22 E.
2120    Scoured tracking party. Ships were pickets patrolling, digging from courses stcored.

- 5 -

INCLOSURE (4)

— page 352 —
18 February
0750
1657
1840
2110
19 February
1033
1843
1900
20 February
0210
1110
1240
1338
1427
1603
1653
1749
22 February
0515
0705

Ship Contact #5. Sighted sail bearing 040°(T), distance about 15,000 yards. Thought it was a ship, so dived. Surfaced after identifying slip as a seaman.
Sighted small sailing vessel, believed same as one sighted earlier this morning.
Surfaced with N.M.KI SH.LY bearing 3040(T). Soon doubt about this as there have been no fixes since entering the area.
Radar contact bearing 2780(T) distance 5,000 yards. Observed a flashing white light on target momentarily. (Ship Contact #6).
Evaded picked on surface.

Plane Contact #18. Sighted N.M.L at 2 miles so dived. Commenced submerged patrol.
Surface. Spoke RADAR at 11,000 yards.

Patrolling area on surface.

Transcribed instrument at jamming of S.J. Nearest land was 80 miles, and there was no other indication of radar.
Plane Contact #19. Sighted S.M.LY at 5 miles.
Surface.
Plane Contact #20. Sighted S.M.LY at 4 miles.
Surface.
Plane Contact #21. Sighted 3 S.M.LYS at 3 miles and submerged.
Surface.
Sighted several small fishing boats. (Ship Contact #7).

Radar contact at 4,800 yards. (Ship Contact #8). Not identified until when it was observed to be the first of a dozen seaports. Submerged to look them over. This was a mistake, as they kept coming over the hill until there were at least fifty by 1600. Finally, at

- 6 -

INCLOSURE (1)

— page 353 —
1619
surfaced in the middle of the fleet. None of them were larger than 50 feet, with most being more dories. All appeared to be laying nets. Commenced clearing the fleet to the northward when a R.P. picked up a good signal on 160 mess. Thought it could be a plane, so reversed course to the south-east, and the signal gradually faded.

23 February
0137
Sighted mine at 27-30 N, 122-16 E. Did not fire as we are being too conspicuous as it is. Sighted sampan at 8 miles. (Ship Contact #9). Plane Contact #22. Sighted NML at 4 miles. Divad.

1805
Surfaced.

24 February
0900
Plane Contact #23. Submerged when O.O.D. heard engines and looked aloft to see a WIS at 3,000 yards. Commenced submerged patrol.

1807
Surfaced.

2105
Sighted red light. Identified as properly marked hospital ship. (Ship Contact #10). She was heading north-west, evidently coming from FORIDO.

2330
Radar contact at 0120(T) distant 7,700 yards. (Ship Contact #11). Commenced tracking from anchored, allowing the range to close to make a bigger pip. At 5,000 yards there were two pips, and at 4,800 there was gunfire. Shot landed 200 yards on port bow.

25 February
0043
Submerged and turned 1800. Both ships went whistling down our surface course. Ran silent. 17 depth charges, very distant.

0221
Surfaced.

0709
Sighted NIKI bearing 3160(T), at 30 miles. Plane Contact #24. Sighted NLT at 5 miles and submerged.

1815
Surfaced.

2225
Remerged recognition with RASHER.

26 February
0115
Radar contact on two ships at 10,500 yards. (Ship Contact #12). Lost contact while turning. Contact regained at 9,700 yards. Very small pip. Commenced tracking.

0151

— page 354 —
0206
Gunfire from the target. Turned away at flank
speed. A struck fuel rack contributed a dense
black cloud effectively obscuring the targets
from the bridge. A total of seven shots were
fired, the last two at a range of 11,200 yards.
All were within 300 yards, indicating some sort
of radar. Targets high speed ceased to be 16ft-
17 knots, but I was afraid he might have a spear-
boiler or two nearing up. Aft going until 0330,
then slowed and changed course. I can't explain
how those small vessels seem able to see us before
we know they are there.
Plane Contact #25. Sighted PTT at 7 miles and
div'd.
Surfaced.

27 February
0953
1035
1037
1048
1403
1438
1504
1526
1531
1612
1622
1626
1634
1700
1703
1742
1840

1903
1917

Sighted ship at 5 miles.
Heard 7 distant explosions.
Surfaced.
Heard 6 distant explosions.
Sighted 2 distant explosions.
Heard 4 distant explosions.
Heard 4 distant explosions.
Identified ship as Sarpan.

Sighted RSM-1. She told us a cruiser was 15
miles north of our present position. Changed
course to north. Radar distance to the south-
ward.
Sighted ship bearing 020°(T). (Ship Contact #15).
Radar contact bearing 020°(T) at 10,000 yards.
Corroded tracokin. Radar found another ship at
094°(T) at 8400 yards. (Ship Contact #16). This
one could not be seen from the bridge. Sky was
overcoated with full moon filtering through.
Both ships joined and appeared to be on a south-
cry course. Radar called a ship at 23000 yards
bearing northeast. I believed this was the cruiser
beyond the escorts which we were tracking. The

- 8 -

— page 356 —
0907
1814
2116

4 March

Submerged for patrol.
Surfaced.
Radar contact 3400(T), 10,000 yards. (Ship Contact 920). Coincident tracking. Identified as our hosts in this vicinity. Three ships, 2C or 3C size, patrolling at 5 knots on irregular courses.

5 March

700 sighted torpedo wake on port bow. Track angle about 1200P. Turned away on flank speed. There was no indication on radar or sound. The visibility was about 5000 yards. I believe this was a long range shot from about that range.
Resumed patrol.
Radar contact 2700(T), 3500 yards. (Ship Contact 921). Out side three.../8 vessels of last night are here again.
Lookouts and radar simultaneously picked up a 2 engine plane bearing 3100(T) at 2 miles. Div'd. (Plane Contact 929).
Surfaced.
Spoke BMTB and exchanged positions. One of us is 40 miles out, and that isn't surprising with these conditions. One fix has been obtained in the area thus far.

6 March

1115
1329
1802

7 March

043
1250
1317
1805

8 March

043
1250
1317
1805

9 March

0700

Spoke RMTB.

- 10 -

MISCLOSURE (...)

END OF REPORT

— page 357 —
0819
Plane Contact #33. Sighted J.K.CK at 1000 yards.
Dived. One close depth bomb as we hung at 30
feet, seeing only for hours, trying to get down
while heading into sea. Broke light bulbs and
jammed maneuvering room head flushing sea valve
open. J.CK turned to make a run after we sighted
him. I didn't think the Japs could move as fast
as they do.
Sighted J.K.CK through periscope.
Sighted J.K.CK through periscope.
Pinging heard.
Sighted PC or SC at 1650(T). (Ship Contact #24.)
He was conducting a sweep, and finally faded cut
at 1100(T).
Surfaced.
Departed area. Hacced for D.NJO GUNTO.

9 March
1031 Sighted periscope bc ring 1500(T) at 1000 yards.
Evaded on surface.
Sighted plane. SD contact at 10 miles. Divcd.
Surfaced.
Sighted two SULLYS at 4 miles. Divcd.
Surfaced.

10 March
0415 Radar contact on D.NJO GUNTO at 36000 yards.
Landfall was right on the nose.
Sighted plane at 8 miles and divcd. Spont the
day submerge in order to transit COLUMBIA STR.IT
during darkness.
Surfaced.
Radar contact on Y.KU SHIL at 75000 yards.

11 March
0242 Radar contact on five pickets, at ranges from
5400 to 4000 yards. (Ship Contact #26). Evaded.
Set course for MIDWAY.
Plane on SD at 10 miles. Divcd. (Plane Contact
#40).
Surfaced.

12 March
0717 Sighted plane at 6 miles. Divcd. (Plane Contact
#41).

- 11 -

ENCLOSURE (..)

— page 358 —
1351
1357
1700

13 March
0535
15 March
2030
20 March
1500
21 March
0900
25 March
...

(C) 1st TRR:
The weather was consistent with the information furnished in Cinco-Paco Bulletin No. 120-44. The cloud coverage was 0.9 to 1.0 ninety percent of the time in the area.

(D) TIDL INTERACTION:
The set and drift varied in different parts of the area, but due to the inability to set positions, they were hard to determine. The were was, set 14DT and drift 0.6 knots.

(2) N.VIGATION LID:
No navigational lights were observed to be burning on the China Coast. D.NJO GUNTO, KUS. KII J.T., and Y.KU SH.T. lights appeared to be extinguished.

- 12 -

ENCLOSURE (..)

— page 359 —
0-N-P-I-D-E-N-T-I-L-L
(F) SHIP CONTACTS:
NO. TIME L.T. TYPE(S) INITI.L. EST. COURSE HON- REMARKS
DATE LONG. RANGE & SPEED T.CITED
1. 0620 31-34-30 3 Semapans 9000 --- SD (lights only seen)
2. 1648 29-35-00 1 Hospital 6 Miles 13 knots 0450(T) SD
2-9 124-56-00 Ship
3. 1236 27-57-30 2 Periscope 700 3 knots 0000(T) SD
2-16 122-40-30 yards
4. 2040 27-07-20 2 Picket 4 Miles 2400(T) SD
2-17 121-14-50 Boats
5. 0750 26-59-50 1 Sail- 7 Miles 2150(T) SD
2-18 121-20-40 boat 7 knots
6. 2110 27-14-30 1 Semapans 2 Miles --- R
2-18 121-23-30
7. 1749 27-17-00 7 Sail- 5 Miles Various P
2-21 121-53-00 boats
8. 0542 27-41-30 5 Sail- 4 Miles Various SD
2-22 121-56-30 boats
9. 0820 26-15-30 1 Sail- 10 Miles Various P
2-23 121-16-00 boat
10. 2115 25-54-00 1 Hospital 11 Miles 0300(T) SN
2-24 120-65-00 Ship
11. 2330 26-17-30 1 4 Miles Storzod R Divod to
2-24 120-50-10 Boat evade when he began to
chase us.

LEGEND:
P - Periscope
SD - Sighted Day
R - Radar
SN - Sighted Night

13 - ENCLOSURE (..)

— page 360 —
0-0-N-N-I-D-R-N-T-I-L-L
(P) SHIP CONTACTS:
NO. TIME L.T. TYPES(S) INITI.L EST. COURSE H.O. CON- R.M.RKS
D.TE LONG. R.NGE & SPEED T.C.THD

12. 0115 26-50-30 2 4/S 5 Miles 1800(T) R Fired at us
2-26 121-05-00 Boats 17 knots avoided at flank spec

13. 0953 28-22-00 1 Junk 10 Miles Various P --
2-27 122-27-15

14. 1626 28-07-30 1 Junk 10 Miles Various SD --
2-27 122-46-00

15. 1905 28-17-30 1 Junk 8 Miles Various SD --
2-27 122-58-00

16. 2028 28-15-00 3 Patrol 5 Miles Various R --
2-27 122-46-00 Craft.

17. 1705 28-13-00 1 Sail- 7 Miles --- SD --
2-28 122-15-00 boat

18. 0726 28-21-50 4 Sail- 5 Miles Various SD --
3-1 122-26-45 boats

19. 1820 28-01-30 3 Sail- 4 Miles Various P --
3-1 122-06-00 boats

20. 2116 26-21-22 3 4/S 5 Miles Various R --
3-4 120-59-45 Vessels

21. 0520 25-47-00 3 4/S 4 Miles Various R --
3-5 121-17-20 Vessels

22. 0309 25-53-00 1 4/S Vessel 5 Miles Various R --
3-5 121-16-00

23. 1258 27-21-45 1 Sail- 6 Miles Various SD --
3-7 121-29-30 boat

LENGTH: P - Periscope SD - Sighted Day
R - Radar SN - Sighted Night

- 14 -

ENCLOSURE (..)

— page 365 —
U.S.S. FINB.0K (SS230)

G-0-N-F-I-D-E-N-T-I-L-L

(G)  :  IRCR.FT CONTACTS:

NO.  TIME  L.T.  TYPE(S)  INITIAL  EST. COURSE  NO. CON-  REMARKS
    D.TE  LONG.  R.NGE  & SPEED  T.CITED

38.  1545  31-26-30  2 2-Eng.  4 Miles  110(T)  SD  --
    3-9   125-36-45  Bombers

39.  0715  31-29-30  1 Plane  8 Miles  350(T)  SD  --
    5-10  128-32-00

40.  1045  29-53-00  1 Plane  10 Miles --  R  --
    3-11  133-53-00

41.  0717  29-44-00  1 Plane  6 Miles  320(T)  SD  --
    3-12  136-54-00

LEGEND:
P - Periscope  SD - Sighted Day
R - Radar  SN - Sighted Night

- 19 -

ENCLOSURE (..)

— page 369 —
0-0-N-F-I-D-E-N-T-I-A-L
(M) RADAR: (Continued)
IV. Nature of Interference: Radar
B. Position at time of Interference: 27°-17'N 121°-53'E
C. True bearing of Interference: Unknown
Estimated sweep in degrees: 80
D. Intercept Equipment: SP- & PR
E. This interference emanated from radar aboard picket boat.
F. Freq: 158 msecs PRF: 700/sec Pulse Width: 4 m sec
V. Nature of Interference: Radar
B. Position at time of Interference: 27°-46'-20"N 122°-23'-00"E
C. True bearing of Interference: Unknown
Estimated width in degrees: Unknown
D. Intercept Equipment: SP- & PR
E. This interference was from airborne radar
F. Freq: 202 msecs PRF: 1000/sec Pulse Width: 5 m sec
VI. Nature of Interference: Radar
B. Position at time of Interference: 25°-41'-00"N 120°-56'-30"E
C. True bearing of Interference: Unknown
Estimated width in degrees: 8 - 10 degrees
D. Intercept Equipment: SP- & PR
E. Believed to be from land based radar on northern tip of Formosa or China Coast
F. Freq: 78 msecs PRF: 650/sec Pulse Width: 45 m sec
VII. Nature of Interference: Radar
B. Position at time of Interference: 28°-20'-45"N 122°-25'-45"E
C. True bearing of Interference: Unknown
Estimated width in degrees: 80
D. Intercept Equipment: SP- & PR
E. This interference came from radar aboard picket boat.

- 23 -

ENCLOSURE (..)

— page 370 —
1. Nature of Interference: Radar
2. Position at time of Interference: 28°-04'-20"N 122°-05'-30"E
3. True bearing of Interference: Unknown
4. Estimated width in degrees: Unknown
5. Sweep Rate: Irregular
6. Intercept Equipment: SP& & PR
7. This Interference is believed to have come from radar aboard a picket boat.
8. Freq: 157 megS PR: 1250/sec Pulse Width: 8 m sec
9. Nature of Interference: Radar
10. Position at time of Interference: 26°-08'N 121°-23'E
11. True bearing of Interference: 8°-10' minutes
12. Intercept Equipment: SP& & PR
13. It is believed that this radar interference came from land based radar on the northern tip of Fornosa.
14. Freq: 74 megS PR: 650/sec Pulse Width: 45 m sec
15. Nature of Interference: Jamming
16. Position at time of Interference: 26°-08'N 121°-15'E
17. True bearing of Interference: 28°-08'N 121°-15'E
18. Sweep Rate: Constant Jamming
19. Type of Radar: SA - Magnetron tube, 706 -Y
20. Interference could not have come from from forces and is believed to be emanating from Seven Sisters Islands & Taishan Light (400 ft) off China Coast.
21. Jamming appeared to be of the C7 type.

- 24 -

ENCLOSURE (..)

— page 371 —
0-0-N-F-I-D-Z-N-T-I-L-L

(N) SOUND GEAR AND SOUND CONDITIONS:
Three sound contacts were made, all being anti-submarine vessels. We were able to keep contact with their screws up to 8000 yards. Pinging was heard out to 10,000 yards. Two of the contacts were aware of our approximate location and used short scale pingings on 17,5 kcs. The third contact was apparently on a sweep and was using long scale pingings. It no time did these vessels make a contact on us.

(O) DENSITY LAYERS:
| DATE | L.TITUDE | LONGITUDE | DEGREES | DEPTH |
|------||||-------|
| 2-14-45| 26-13-00 N| 121-21-00 E| -4      | 100   |
| 2-23-45| 25-42-30 N| 120-56-30 E| +3      | 70    |
| 2-25-45| 26-20-00 N| 120-55-00 E| -5      | 100   |
| 2-28-45| 28-01-00 N| 122-00-00 E| -3      | 70    |

(P) HE.LITH, FOOD, AND H.BIT.BILITY:
Health and energy of the ships complicated was good. This is attributed to the cool weather. The only cases necessitating medical attention throughout the patrol were several cases of head wounds, caused by binoculars striking the face when clearing the bridge.

Food preparation was excellent in all respects with a fine variety of all types. The baking is to be especially commended this run as it no doubt helped the spirits of the crew.

Habitability throughout the ship was excellent.

(Q) PERSONNEL:
Number of men on board during patrol: 74
Number of men qualified at start of patrol: 48
Number of men qualified at end of patrol: 62
Number of unqualified men making first patrol: 12
Number of men advanced in rating during patrol: 0

- 25 -

ENCLOSURE (…)

Note: The image is a scanned copy of the original document. The text is in a typewriter font, and the document appears to be a historical naval patrol report.

— page 372 —
0-0-N-T-I-D-E-N-T-I-L
(R) MILES STEAMED - FUEL USED.
MIDLY to S.I.P.N
S.I.P.N to' area
In area
MIDLY to PERL' H.R.BOR
2586 miles (pit)
1956 miles (pit)
6151 miles (pit)
1290 miles (pit)
32;500 gallons
24;700 gallons
51;030 gallons
16;300 gallons

(S) DURATION:
Days enroute to area
Days in area
Days enroute to base
Days submerged

(T) FLOTORS OF ENDURANCE RELINING:
Torpedoes
24
4,000 gal.
Frovisions
7 days
Personnel Factor
10 days

Limiting factor this patrol - terminated by operation orders.

(U) R.DIO AND R.D.R COUNTERMEASURES:
On several occasions jamming of S.Ja Radar was noted. The jamming, on all occasions, appeared to be of the same type. It appeared to be 0' and the bearings were quite sharp, covering about 20° on the P.P.I. The jamming caused the receiver to become innofective and high R F arcing was noted on the transmitter wave guide. Our countermeasures were always the same. To detuned the receiver and keyed the S.Ja intermittently. Those measures slightly nullified the jamming effects.

JAMMING INSTRUCTIONS
1. Ship: USS FINN.OC (SS230)
2. Position: 26°-08'N 121°-15'E
3. Date & Time: 2100, 14 Feb. - 0800, 15 Feb.
4. Radar Model Jarried: S.Ja Freq: 3000 m.p.h.
5. Location: Believed to be from Northern tip of Formosa and China Coast.
6. Type: Land based
7. Range: 60 - 80 miles

ENCLOSURE (..)

— page 373 —
U.S.S. FINBACK (SS230)
:  C-O-N-F-I-D-E-N-T-I-L-L
:  (U)  RADIO ...ND R.D.R. COUNTERMEASURES:  (Continued)
:  (a)  Jamming first noted:  2100, 14 Feb.
:  (b)  Jamming was effective:  2100, 14 Feb.
:  0800, 15 Feb.
:  (c)  Land was not observed.
7. Jamming pattern observed on CR T:  Jamming deadened
   rocclvor, blocking echo return but causing no visible
   effect on the CR T.
8. The enemy did appear to be using a short space of time dur-
   ing which jamming was not observed.  This made it
   not bearing.
9. (a)  It is not known whether the enemy was using spot
   jamming, barrage jamming, --- but it is thought that
   it was of a C W type.
   (b)  Except for short periods after keying, the jam-
   ring completely blocked the rocclvor on jamming bear-
   ings.
   (c)  No window was rocclvored.
10. Windows were not used.
11. The countermeasures taken were keying the transmitter
    and slightly detuning the rocclvor.

11. 1.  Ship:  USS FINBACK (SS230)
    2.  Position:  26°-51'N  120°-51'E
    3.  Date & Time:  0630, 20 Feb.  -  0830, 20 Feb.
    4.  Radar Model Jarred:  SJA  Frog:  3000 secs
    5.  Location of enemy Jamer:  Belicvcd to be Seven
       Sisters Islands and Taishan Lichto (400 ft) off
       China Coast.
    6.  Type:  Land based.
    7.  Range:  approx.  40 miles.
    8.  (a)  Jamming first noted:  0630, 20 February
       (b)  Jamming was effective:  Throughcut period
       (c)  Target was not observed through jamming signal.
    9.  Jamming pattern observed on CR T:  Jamming deadened
       rocclvor, blocking echo return, but causing no visible
       effect on the CR T.
    10.  The enemy did appear to be using a noninterfering rocclvor
       with look-thru arrangement; because when our trans-
       nitter was keyed, there was a short space of time dur-
       ing which jamming was not observed.  This made it
       appear as though the enemy was sending out jamming
       signals on bearings caused by our interference.

- 27 -

INCLOSURE (..)

— page 374 —
9. (a) It is not known whether the enemy was using spot jamming or barrage jamming but it is thought that it was of a C.V type.
(b) Except for short periods after keying, the jamming completely blocked the receiver on jamming bearings.
(c) No window was recovered.
10. 'Windows were not used.
11. The countermeasures taken were keying the transmitter and slightly detuning the receiver.

SIGNALS ENCOUNTERED

1. Date: 3 February 1945
2. Ship: U.S.S. FINBACK (SS230)
3. (a) Position: 29°-48'N 131°-05'E
(b) Location: Flano
4. Type: .Airborne
5. Intercept equipment: .PR & SP.
6. (a) Frequency: 155 nsecs Dial Readings: 16.8
(b) PRF: --- How measured: ---
(c) Pulse Width: 10 nsecs How measured: Calibrated
(d) Sketch pulse --- Scale

(a) Has lobe switching used. Unknown. Rate unknown.
(b) Polarization of enemy signal unknown.
(c) Sweep rate: Irregular
6. (a) Has radar used for surface or air search, GL, SLC, GCI, or .I. - - surface search.
(b) .Suppression based on fact that it was attached to plane.
7. .Action of enemy, including distances and bearings to which he searched, tracked, fired, etc., - Unknown.

- 28 -

ENCLOSURE (...).

— page 376 —
21 February 1945
1. Ship: U.S.S. F.I.B.C.K (SS230)
2. (a) Position: 27°-17'N 121°-53'E
   (b) Location: Fli.et Boat
3. Type: Ship borne
4. Intercept Equipment: SPA & APR
5. (a) Frequency: 158 megahertz
   (b) PRF: 700/sec
   (c) Pulse width: 4 microsecond
   (d) Sketch Pulse
   (e) Was lobe switching used. Unknown. Rate unknown.
   (f) Polarization of enemy signal unknown. Assumption based on the fact that he was able to track us with apparent ease.
6. Action of enemy radar, including distances and bearings at which he searched, tracked, faded, etc., He seemed to be able to track us out to a range of about 10,000 yards.

V. Date: 22 February 1945
1. Ship: U.S.S. F.I.B.C.K (SS230)
2. (a) Position: 27°-46'-20"N 122°-23'-00"E
   (b) Location: Plane
3. Type: Airborne
4. Intercept Equipment: SPA & APR
5. (a) Frequency: 202 megahertz
   (b) PRF: 1000/sec
   (c) Pulse width: 5 microsecond
   (d) Sketch Pulse
   (e) Was lobe switching used. Unknown. Rate unknown.
   (f) Polarization of enemy signal unknown.
   (g) Swcop Rate: Irregular.
6. (a) Was radar used for surface or air search, GL, SLC, GCI, or AI. Surface search.
   (b) Evidence for conclusion. Assumption based upon fact that radar was airborne.
7. Action of enemy radar, including distances and bearings at which he searched, tracked, faded, etc., Unknown.

- 30 -

EMICOSURF (A)

— page 377 —
23 February 1945
1. Ship: U.S.S. FINBACK (SS230)
2. (a) Position: 25°41'-00"N 120°56'-30"E
   (b) Location: Northern tip of Formosa & China Coast.
3. Type: Land based
4. Intercept Equipment: SPA & APR
5. (a) Frequency: 78 nsec
   (b) PRF: 650/sec
   (c) Pulse Width: 45 m sec
   (d) Sketched Pulse
6. (a) Was lobe switching used. Unknown. Rate unknown.
   (b) Evidence for this conclusion. Assumption based upon comparison with own radar.
7. (a) Frequency: 158 nsec
   (b) PRF: 750/sec
   (c) Pulse Width: 8 m sec
   (d) Sketched Pulse
8. (a) Was lobe switching used. Unknown. Rate unknown.
   (b) Polarization of enemy signal unknown.
   (c) Sweep Rate: 2 - 3 minutes
9. (a) Was radar used for surface or air search, GL, SLG, GU, or AI. Surface
   (b) Evidence for this conclusion. Assumption based upon fact that he scanned to track us fairly well.
10. (a) Action of enemy radar, including distances and bearings at which he searched, tracked, faded, etc. He scanned to be able to track us up to ranges of 10000 yards.

- 31 -

ENCLOSURE (4)

— page 378 —
1 March 1945
1. Ship: U.S.S. FINBACK (SS230)
2. (a) Position: 280-04-20'N 122-05-30"E
   (b) Location: Picket Boat
3. Type: Ship borne
4. Intercept Equipment: SPA & APR
5. (a) Frequency: 157 nags
   (b) PRF: 1250/sec
   (c) Pulse Width: 8 n sec
   (d) Sketch Pulse
6. (a) Was lobe switching used. Unknown. Rato unknown.
   (b) Sweep Rate: Irregular
   (c) Was radar used for surface or air search, GL, SIC, GCI, or AI - Surface search
   (d) Evidence for this conclusion. -assumption based upon ease with which to track us.
7. Action of enemy radar, including distances at which he searched, tracked, faded, etc. He scanned to be able to track us up to ranges of 10000 yards.

IX. Date: 6 March 1945
1. Ship: U.S.S. FINBACK (SS230)
2. (a) Position: 260-08'N 1210-23'E
   (b) Location: Northern tip of Formosa
3. Type: Land based
4. Intercept Equipment: SPA & APR
5. (a) Frequency: 74 nags
   (b) PRF: 650/sec
   (c) Pulse Width: 45 n sec
   (d) Sketch Pulse
6. (a) Was lobe switching used. Unknown. Rato unknown.
   (b) Polarization of enemy signal unknown.
   (c) Sweep Rate: 2 - 3 minutes
   (d) Was radar used for surface or air search, GL, SIC, GCI, or AI. Both air and surface search.
   (b) Evidence for this conclusion. -assumption based upon comparison with our own radar.
7. Action of enemy radar, including distances and bearings at which he searched, tracked, faded, etc. Unknown.

RADIO: We have no evidence to the effect that the enemy was jamming our radio transmissions.

— page 379 —
0-0-T-T-D-R-N-T-I-I-L
Reg. No. 15-700
R. S. No.

The general weather in this area was very poor. The first two weeks, because of the heavy swells and lack of depth control.

The small escorts encountered were often picked up by sight before radar contact was made. Many completely disappeared from the screen when radio on the bow was small, at range of 500-600 yards.

Heavy overcast and lack of navigational fixes, together with a probably unjust lack of confidence in the surface radar performance made our position a source of worry. Soundings were of little help, outside of proving that we were still afloat.

The craft at 1:00 was a pleasure. There were no distractions to hinder the progress of the work, and the personnel of the relief crew seemed to want to stay. How good a job they could turn out. The sole complaint is the lack of stock carried in G3. on tender and bases, on the lack of knowledge of the steeragecapes as to what they did have in stock.

The replacement for the 3D radar will surely be welcome, if it arrives before the war is over.

LOR.N would have been very useful during our time in the area.

- 33 -

[END OF REPORT]

— page 380 —
1/6-3
Serial: (020)
CONFIDENTIAL
FIRST ENDORSEMENT to
CO USS FINBACK conf. 1tr.
SS230/116-3 serial 27
of 25 March 1945.

From: The Administrative Commander Submarine Division ONE HUNDRED THREE,
To: The Commander in Chief, United States Fleet.
Via: (1) The Commander Submarine Squadron FOUR.
(2) The Commander Submarine Force, Pacific Fleet.
(3) The Commander in Chief, Pacific Fleet.

Subject: U.S.S. FINBACK (SS230) - Report of Twelfth War Patrol.

1. The Twelfth War Patrol of the U.S.S. FINBACK was conducted in the East China Sea from 20 January to 25 March 1945. Thirty days were spent in the area, sixteen submerged.

2. This patrol was characterized by: (a) Lack of suitable targets. (b) Many contacts with patrol vessels, junks, picket boats and hospital ships. (c) Forty-one plane contacts. (d) Sixteen mines sighted of which two were exploded and one sunk. (e) Two periscope sighted. (f) Gunfire from submarine vessels apparently radar equipped. (g) Successful evasion of a long range torpedo. (h) Successful evasion of a Jap bomber.

3. The action of 26 February is of particular interest. The accurate gunfire at 11,000 yards from unseen ships indicates radar. If so, it is of frequency or type which the FINBACK is not detected.

4. The FINBACK returned from patrol clean and shipshape. She is to be given a navy yard overhaul at Pearl.

5. The Division Commander regrets that the Japs did not furnish suitable targets and congratulates the commanding officer, officers, and crew upon their return from this difficult and extremely hazardous patrol; a heart breaking job well done.

R. S. BENSON.

— page 381 —
11/15
Fleet Post Office
San Francisco, California

FC5-4/A16-3
Serial: 0250
28 March 1945.

CONFIDENTIAL
SECOND ENCLOSURE TO
USS FINBACK (SS230) Report
of Twelfth War Patrol.

From: The Commander Submarine Squadron FOUR.
To: The Commander-in-Chief, UNITED STATES FLEET.
Via: (1) The Commander Submarine Force, PACIFIC FLEET, administration.
(2) The Commander-in-Chief, U.S. PACIFIC FLEET.

Subject: U.S.S. FINBACK (SS230) - Report of Twelfth War Patrol.

1. Forwarded, concurring in the remarks of the Administrative Commander Submarine Division ONE HUNDRED THREE.

2. The Commander Submarine Squadron FOUR congratulates the Commanding Officer, officers, and crew of the U.S.S. FINBACK upon completion of this patrol.

J.P. J. O'Regan
W. V. O'Regan

— page 382 —
1. The Commander Submarine Force, Pacific Fleet.
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, U.S. Pacific Fleet.
Subject: U.S.S. FINBACK (SS230) - Report of Twelfth War Patrol (20 January to 25 March 1945).

1. The twelfth war patrol of the FINBACK, under the command of Commander R. R. Williams, U.S. Navy, was conducted in the East China Sea area. The FINBACK, along with the U.S.S. PILOTISH (SS386) and the Commander's Officer of the PILOTISH as group commander.

2. Numerous contacts with small craft and small anti-submarine vessels were made during this patrol. The anti-submarine vessels appeared to be radar equipped. Enemy air anti-submarine measures were heavy. Unfortunately the PILOTISH, with her long illustrious combat record, was afforded no opportunity to damage the enemy.

3. Award of Submarine Combat Insignia for this patrol is not authorized.

MERRILL COHSTOCK.

DISTRIBUTION:
(Complete Records)
Coninch (7)
CINO (5)
Cinepac (6)
JICPOA (1)
ADCPOA (1)
Conescrvpac (1)
Cincelant (1)
Corisubisant (8)
S/1 School, NL (2)
CO, S/1 Base, PH (1)
Conisepac (2)
Corisowospac (1)
Conusbwsowspac (2)
CTG 71.9 (2)
Comnerpac (1)
Consubspac (3)
Consubspac/AdComd (20)
SUBAID, HI (2)
ConsubspacSubordcom (3)
All Squadron and Div. Commanders, Pacific (2)
Substrainpac (2)
All Submarines, Pacific (1)

E. L. HYNES, 2nd, Extra - ORIGINAL
Flag Secretary. SORG. MICRO
PHOTO-LAB OP-16
RETURN TO F-4253