U.S.S. CERO (SS-225) — war patrol report SS-225_CERO_Part2.pdf

— page 1 —
35225/AL6-3
Serial ( 014 )

CONFIDENTIAL

Date: 24 Oct 45
Time: 0745
Plane on SD at 22 mts. Submerged.
(Abrupt contact No. 11).
Surfaced.
Sighted plane, float type, at 14
mts. Submerged. (Abrupt con-
tact No. 12).
Surfaced.
Sighted small abunanced boat
awash bearing 109°Tg, 6 mts.
(Ship contact No. 10).
Entered Sibutu Passage.
Plane on SD at 6 mts. Submerged.
(Abrupt contact No. 13).
Surfaced.
SD radar interference. Exchanged
recognition signals by SJ with
NAVHAL. (Ship contact No. 11).
Exchanged reconnaissance signals by SJ
with MINGO. (Ship contact No. 12).
Entered radar. SD not reported again
unless specifically stated in this
report.
On minute prior to dawn dive radar
contact 320°T, range 10000 yds.
Not sighted. Drove with morning twil-
light coming on rapidly. Estimated
target on 2°W. Early course and
course to normal approach course. In
morning twilight radio out small un-
identified outbound, about 15 kts.
Unable to close. It could have been
a submarine or a small power boat.
Commended periscope patrol south of
Pemilican Island. (Ship contact No. 13).
Sighted sailboat bearing 203°T, 7000
yds. (Ship contact No. 14).
While making routine periscope SWCD
at 58 ft., COD sighted a paratroop
closs aboard by ringing 260°T. (On post-
tion Last, 9-22N Long 123-54E). Nothing
on sound. After dipping this scope
could not find the intruder ag in so
want to 200 ft. and rigged for silent
running as a pre-audition.

-4- EXPLOSURE (A)

— page 2 —
2225/A16-3
Serial (014)

CONFIDENTIAL

Date: 25 Sept 1854
Time: 1845
Surfaced.
SJ radar interference to north.
Exchanged recognition signals by SJ with MINGO (Ship Contact No. 15).
This was confusing as she was not due in this area until the night of September 30. Attempted to communicate by VHF at MINGO's request to confirm identification and receive information, but finally had to resort to 2880 voice.
Both satisfied as to identity so at same alongside MINGO and learned of her special mission in regard to NAUTILUS.
Informed her we would keep clear of Bohol Strait and arranged rendezvous for following night.
Received message from MINGO "An return in to area, our friend okay". Heard undiant on 2880 tell MINGO "I am touring your area. As we had received all CTF 71 serials, with no dope on MINGO or NAUTILUS this whole procedure was confusing to us and we could only guess at what was transpiring. For hcps the periscope sighted this afternoon was MINGO. Did not take time to ask her. With MINGO's mission coming to a close, we return to south-eastern exit of Bohol Straits for day patrol.
Converted #4 PET to a MET and sub- norged to flush the tank out.
Surfaced.
Dawn dive, periscope patrol south of Panilom Island covering SS Exit of Bohol Strait.
Sighted aircraft, Lilly type (7) bearing 003T, which landed on Panglas Island (Airport contact No. 14).
While raking routine periscope sweep at 60 ft., OOD sighted at least 5 ft. of periscope bearing 2500T. Our posit (Lat 9-20N Long 123-56S). Sighting verified by QM. (The OOD probably thought I would view this with suspicion.) Tapered part painted light grey. Again heard nothing by sound. Went to 200 ft. and rigged for silent running as a procuration.
-5- ENCLOSURE (A)

— page 5 —
1. USS SS225 (SS225) 2. Serial (014) 3. CONFIDENTIAL 4. Date: 5. Time: 6. Oct. 9 7. 2300 8. 2400 9. Oct. 10 10. 0317 11. 1306 12. Oct. 11 13. 1345 14. Oct. 12 15. 1011 16. Oct. 13 17. 0415 18. 0915 19. 1017 20. 1117 21. 1209 22. 0530 23. 1618 24. 8 - ENCLOSURE (A)

— page 6 —
1. USS CRERO (SS225)
: 2. SS225/A16-3
: 3. Serial (014.)
: 4. CONFIDENTIAL
: 5. Date: 17 1618
: 6. Time: Cont'd.
: 7. Period from October 17 to November 3 conducted Special Mission No. 1.

CRERO had 8 ship contacts and 56 air craft contacts while conducting special mission No. 1. Details of these contacts are included in the special report.

Ship contacts Nos. 1, 2 and 4 wore friendly submarines, with whom recognition signals were exchanged.

Contact #3 was a single enemy escort vessel which was contacted at night, October 25, while CRERO was searching for a convoy reported by COD to be in the vicinity. No convoy was contacted.

Contact #5 was made at night, October 27, on the surface and consisted of two enemy small craft, a Sea Truck and a large, ramp-bow landing craft proceeding along the coast. These were attacked by gunfire, damaged and driven ashore.

( See Attack Data, Para. H.)

The next contact was made while submerged during daylight, and consisted of three slow speed convoy escorts (Unident) escorted by three U.S. Ident and three aircraft. These were avoided since CRERO's orders prohibited attacking escorted merchantmen. (Contact #6).

Contact #7 was a large (estimated 8000 - 10000 tons) AP the bow of which had been blown off, escorted by 2 WAKATAKE DD's, 2 CHIDORIS, and aircraft, contacted during d.ytimo while submerged. CRERO got right in the middle of this outfit but the target was an enemy aircraft until the range had closed considerably. It was hard to let this go by unmolested, but again ordos prohibited attacking.

— page 7 —
15/16
SS225/AL6-3
Serial (014)
CONTINUED:

Date: 17 1618
Cont'd.

Contact #8 consisted of an RO-type
energy sub whose diving officer permitted her
to broach as she fired a torpedo at CERO.
It dawned CERO sighted the sub on her port
quarter, range 1500 yards. We turned tail
and parallel the airrig torpedo fired.
The torpedo passed at a range of about
150 yards, broached and sank. No counter-
attack was instigated by 0.0.D. whose
orders were not to attack any submarine
unless positively identified as enemy
to the known presence of friendly subar-
rays. In the area, and by the time he had
completed his maneuver to avoid there was
no point of aim and the range was excessive.
CERO was making 18 kts., zig-zaging on a
spacial "Dawn-DUSK" zig-zag plan (70%).
The O.O.D. (It. J.2. HOKR, USN), and the
Executive Officer (1ct-Cmdr. C. D. MAGE,
USN), who was on the bridge at the time,
are commended on their prompt action in
avoiding the torpedo. The Jap diving
officer is recommended for the BRONZE
BANNA with Poison Oak Leak Cluster.

Nov. 4 1300
Special Mission No. 1 considered torpedo
sunk. CERO submerged in Iazon Str.its
15 miles southeast of Sebtaing Island, on
and headed for Sabtang Island channel on
course 338T.
1433 Sighted aircraft bearing 030T, biplane
type, southbound. (Aircraft Contact No.28).
1438 Heard pinging baring 312T coring from
general direction of Seitang Island. This
soon developed into a petrol vessel con-
ducting a submarine search off the south-
ern channel entrance. (Ship Contact No.20).
1512 C/o to 290T to present small silhouette to
petrol vessel and obtain a better position
to look into the channel between Sabtang
Island and Ibuhos Is. The petrol (PC type)
was pinging part of the time, and listen-
ing part of the time. At this time he
was headed for us.

- 10 - ENCLOSURE (A)

— page 9 —
1918-03-17
Serial: (014)
CONFIRMATION: I

Date: Nov. 4
Time: 1701
Cont'd:
Sighted two patrol vessels standing into anchorage from southwest entrance, hugging the east side of Ibuhos Island. It is noteworthy that no vessels wore seen to use middle of the channel, which I interpreted as indicating the presence of a mine field. As darkness fell blinker lights from a vessel close to Subtong Island were sighted. As soon as it was suffloidantly dark, came to radar depth and at 1816 Surprised the enemy from the channel entrance on course for 7000 yds. On our starboard beam (sighted and identified as escort vessel) and one at 9000 yds. on our port quarter. Not sighted. Tracked these targets and determined they were milling around, shore contact No. 221. As we surfaced, sound (our escort) reported that somebody took several pings on us from about 270° latitude. Nothing there by radar or sight, the nearest vessel being 900 yds. on our port quarter. If this was true, it was a submarine, and in all probability a friendly mine a number of times were known to be in the vicinity.

1827
SJ radar interference bearing: 270°.
Decisive: Tracet r ar e at cts were not part of convoy and as we had covered any possibility of convoy heading SE at 1842 0/2 to 270°. Both the radar contacts of 1816 were lost at this time.

1850
Received report of a ship we had on our stub beam on surfacing and also a new contact on 3 ships bearing 320T, extreme ranges varying from 1000 to 13000 yds.

Ortonaced tracking these targets and determined that they were milling around also and apparently tracking us as well.

1900
Received despatch orders from CTF 72 to conduct special mission (our second special mission this patrol).

- 12 - INCLUSION (..)

— page 16 —
1 2 3 4
SS225/A16-3
Serial ( 014 )
CONTENTDETAIL

(G) - (IRRIGRAFT CONTACTS)

CONTACT NUMBER: 1 2 3 4
S Dcto : 9-19-4 9-20-4 9-20-4 9-22-4
U Time (Zono) : 1720 1240 1536 0840
B Position: Lat. : 12-168 9-22S 8-51S 5-55S
M Long. : 130-36 128-00B 127-45 119-48B
A Speed : 18 14.5 15 16
R Course. : 295. 334. 334. 345
I TrIn : Surf Surf Surf Surf
N Minutes Since Last:
E, SD Rad. Search : 0 0 0 0

Numeric:
I Type : Pat. : 5 1 1
R Probable Mission : Pat. : Unk. : Unk.
C How Contested : SD SD SD SD
R Initial Range : 18 m1. 24 m1. 8 m1. 7 m1.
A Elevation Angle : 20. 70° Unk. Unk.
F Range & Relative :
T Bearing of Plane :
Won It Detected : 340 Unk. Unk. Unk.
S/M : 7 m1. Unk. Unk. Unk.

(C) State
(C Bn (Boufort) : 1 1 1 1
O Direction(Rel) : 340 134 130 075
N Visibility(Miles) : 12 15 15 15
D (Holeht : 4500 4500 7500
I ( in ft.) :
T Clouds: ( Percent
I Overcast : 0 7 7 9
N Moon:)(Boarling
(Rel.) : 340
(Angle : 45
(Porcent : 0.2
Illum. :

- 20 - INCLOSURE (A)

— page 17 —
5 : 6 : 7 : 8
SS225/A16-3
Serial (014)
CONFIDENTIAL

CONTACT NUMBER:
5 : 6 : 7 : 8
S Date : 9-22-44:9-22-44:9-22-44:9-23-44
U Time (Zone) : 1106 : 1205 : 1516 : 0631
B Position: Let. : 6-29S : 6-19S : 6-13S : 3-33S
M Long. : 119-39B:119-37B:119-37B:118-30B
A Spool : 16 : 15 : 16 : 17.5
R Course : 290 : 317 : 315 : 34A
I Trim : Surf : Surf : Surf : Surf
N Minutes 5:00:00 : 30:00:30:

— page 18 —
9 : 10 : 11 : 12
S Date : 923-44 : 9-24-44:9-24-44
U Time (Zone) : 1243 : 0600 : 0845 : 0955
B Position: Lat. : 2-595 : 0-585 : 1-23N : 1-29N
M Long. : 118-30:117-37N:119-53N:119-48E
A Speed : 17.5 : 17.9 : 17.5 : 17.5
R Course : 350 : 350 : 350 : 070
I Trn : Surf. : Surf. : Surf. : Surf.
N Miles Since Last. : 30 sec. : 30 sec. : 30 sec. : 30 sec.

N
A Type : 1 : 1 : 1 : 1
I F Celestial Mission : Unk. : Unk. : Unk. : Unk.
R Hov. C. Intercepted : Unk. : Unk. : Unk. : Unk.
C Int. C. Range : 20 mi. : 14 mi. : 22 mi. : 6 mi.
R Elev. Elev. Angle : 10° : Unk. : Unk. : 70°
A Range & Relative bearing of Plane : Unk. : Unk. : Unk. : Unk.
T When it Doctored : Unk. : Unk. : Unk. : Unk.

C Sea : 1 : 1 : 1 : 1
O (Direction(Rol) : 150 : 160 : 220 : 220
N
D Visibility (Miles) : 15 : 8 : 16 : 15
I (Height in ft) : 7000 : 4500 : 5000 : 5000
I Clouds : 5 : 6 : 2 : 3
O (Percent Overcast) : : : : :
N
S (Bearing(Rol) : : : : :
Moon: (Angle : : : : :
(Parent : : : : :
Illum. : : : : :

- 22 - ENCLOSURE (A)

— page 19 —
15 : 16
: 9-25-44: 10-2-44: 10-6-44
: 0720 : 1236 : 1033 : 1115
: 6-24N : 9-28N : 8-22N : 7-53N
: 120-9E : 123-45E: 121-25E: 122-6E
: 17.7 : 1.8 : 14 : 2.7
: 026 : 090 : 235 : 220
: Surf. : Per. : Surf. : Per.
: 30 seo. : 1.1 : 1.1 : 1.1 : 1.1

Number | State (Beaufort) | State (Direction(Rel) | State (Visibility (Miles) | State (Height in ft) | State (Clouds) | State (Percent Overcast) | State (Bearing(Rol) | State (Moon: Angle) | State (Percent Illum.)
--- | ---
1 | 1 | 170 | 3 | 15 | 7 | 9 | 9 | 9 | 9
1 | 1 | 4500 | 6 | 65 | 7 | 7 | 7 | 7 | 7
1 | 1 |

— page 21 —
21 22 23 24
: 10-11-44:10-12-44:10-12-44:10-12-44
: 1:134 : 1:116 : 0:314 : 0:500
: 2-56N : 2-56N : 2-09N : 1-58N
: 128-18E : 128-18 E:131-46E :132-10E
: 18 : 18 : 16 : 18
: 076 : 076 : 104 : 104
: Surf : Surf : Surf : Surf
: 0 : 0 : 0 : 0

Number | Type | Unk. | Unk. | Unk. | B-24
:---:|:---:|:---:|:---:|:---:
1 | Type | Unk. | Unk. | Unk. | Unk.
I | Probable Mission | Unk. | Unk. | Unk. | Unk.
R | How Contacted | SD | SD | SD | SD
C | Initial Range | 15 | 36 | 16 | 17
R | Elevation angle | Unk. | Unk. | Unk. | 30
R | Range & Relative | : | : | : | :
F | Bearing of Plane | : | : | : | 12 mi.
T | When it Detected | : | : | : | 90 S
S/M | : | Unk. | Unk. | Unk.

(State | 1 | 1 | 1 | 1
:---:|:---:|:---:|:---:|:---:
G | Son: (Beaufort) | : | : | : | :
O | (Dircotion(Rel) | 180 | 180 | 040 | 135
N | Visibility(Miles) | : | : | : | :
D | : | : | : | : | :
I | (Height in ft) | 60 | 60 | 4500 | 4500
I | Clouds: | : | : | : | :
O | (Percent | : | : | : | :
N | Overcast | : | : | : | :
S | (Bearing(Rel) | : | : | : | :
Moon: (Angle | : | : | : | : | :
(Percent | : | : | : | : | :
Illum. | : | : | : | : | :

- 25 - ENCLOSURE (A)

— page 22 —
25 : 26 : 27 :
S Data : 10-12-44:10-12-44:10-12-44:
U Time (Zone) : 0623 : 1355 : 1523
B Position: Lat. : 2-00N : 1-33N : 1-28N
M Long. : 132-26E : 134-20E : 134-34E
A Speed : 18 : 18 : 18
R Course : 104 : 108 : 108
I Trim : Surf. : Surf. : Surf.
N Minutes Since Last : 0 : 0 : 0
E SD radar Search : 0

| Type | Date | Time | Location | Speed | Course | Trim | Minutes Since Last | SD Radar Search |
|------|------|------||-------|-------|-------|||
| A    | I    | C    | O    | N    | D    | I    | T    | I    |      |      |          |       |       |       |                |                |
| I

— page 24 —
1. SS225/16-3
Sori:1 (014)
CONTACT: DANTT, L

(H) ATTACK DATA:
U.S.S. CERO GUN ATTACK NO. 1 PATROL NO. 6
TIME: 2256(H) Date 10-27-44 POSIT - West Coast Luzon
TARGET DATA: DANGER INFLICTION

Damaged:
1. Sea Truck (MIS)(JU) 100 Tons
1 Landing Craft (HIS)(JU) 100 Tons

These targets were soon through the periscope at 1200 yards on a bright moonlight night and it appeared the sea truck was towing the landing craft as only one set of screws was heard in direction of sea truck. They were running very close to the beach.

Damage determined by:
Both targets were observed to run on the beach and small fires were soon in the direction of the targets.

DIST. LIS OF ACTION

Battlesurface in moonlight and opened fire with 4 inch, 1/2 20MM and 40MM guns, at range of 2,000 yards. The targets were hard to see against the beach, and the gun flashes from the 4 inch gun blinded all hands. The shoot-ing was erratic but a good volume of fire was main-tined for 3 minutes, and when fire was checked the targets were soon to be beached and burning. Action was broken off at this point because of the very great possibility of causing considerable needless damage and injury to friendly natives. Swilling along the beach. The range could not be closed for more accurate shooting because of navigational dangers.

(I) MINES

None seen.

(J) ANTI-SUBLIME NEGATORS AND EVASION TACTICS

On the night of 25 October, a single PC type escort vessel was contacted heading south along the west coast of Luzon. He was pinging and apparently was on a submarine hunt. Our mission prevented attacking this contact and when he detected us and headed for us, we avoided at high speed.

- 28 - ENCLOSURE (1)

— page 30 —
1. Ship or station: U.S.S. CERRO (SS225)
2. Position, bearing, and altitude when on enemy radio signals were observed: East Coast of Luzon.
3. Position of transmitting station: East Coast of Luzon.
4. Deto of jamming: 11/3/44. Tito: From 05552 to 0820Z.
5. Frequencies jammed: 8470, 8290, 4235, 12705.
6. Described signal jammed: - Keyed ON.
7. Use of circuit (t.otical, administrative): - Tactical.
8. Has the enemy jamming signal stable: - Yes.
9. What was retio of strength of own signal to enemy jamming signal: - About 1 to 1.
10. What was power output of own transmitter at time of jamming: - 200 W.
11. Location of enemy jamming: - Unknown.
12. Type of jamming: - C/I - Radio keying and MOT.
13. Effectivness of jamming: - Highly effective.
14. Action taken to overcome jamming: - Rapid shifting of frequency of transmission after enemy jamming began.
15. Bandwidth covered by enemy jamming signal: - Undetermined.
16. Did jamming transmitter appear to be monitored by a lockheed receiver?
17. If frequency was shifted, how long before enemy jammed now frequency: - Approximately 15 minutes.
18. Narrative:
    - The jamming encountered near Luzon was especially effective in that it covered nearly every ship to share frequency and was very powerful. The enemy rapidly would known station calls such as WHH, NPH, NTT, etc., and requests VTs. In some cases, the nationality of the jamming station was easily recognized, but in others, it was quite difficult.

— page 34 —
25 November 1944
FEB-282/A16-3
Serial: (036)
CONFIDENTIAL:
FIRST ENDORSEMENT to
CO USS CERO (SS225) Report
of Sixth War Patrol.
From: The Commander Submarine Division TWO EIGHTY TWO.
To: Commander-in-Chief, United States Fleet.
Via: (1) The Commander Submarine Squadron FOUR.
(2) The Commander Submarine Force, Pacific Fleet.
Subject: USS CERO (SS225) - Report of Sixth War Patrol.
1. The sixth war patrol of CERO was conducted under the operational control of Commander Task Force Seventy One. It was a decidedly long patrol lasting seventy-three days, fourteen of which were submerged, and entailing a total of 19,168 miles steamed. Two special missions were conducted.
2. Assigned areas were well covered and it is regretted that no contacts which could be developed into attacks were made except during a period when attacks on anything but important warships were prohibited in order not to jeopardize the special mission on which CERO was then engaged.
3. The commanding officer, officers and crew are congratulated on the completion of a long and well conducted patrol. Lieutenant Commander C.D. Naco and Lieutenant J.E. Hokr, whose alertness in detecting and avoiding the submarine torpedo fired at CERO on October 17, 1944, are especially commended.
4. CERO arrived in very excellent state of cleanliness and will require no voyage repairs before proceeding to the West Coast for overhaul.

— page 35 —
28 November 1944.

FC5-4/Al6-3
Serial: 0494
C-O-N-F-I-D-E-N-T-I-A-L
SECOND ENDORSEMENT to
USS CERO (SS225) Report
of Sixth 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: USS CERO (SS225) - Report of Sixth War Patrol.

1. Forwarded, concurring in the remarks of Commander Submarine Division TWO HUNDRED EIGHTY-TWO.

2. The Commander Submarine Squadron FOUR congratulates the Commanding Officer, officers and crew of the USS CERO upon completion of this patrol and special missions.

3. It is recommended that the USS CERO be credited with the following:

DAMAGED
1 - MIS (EU), 100 tons
1 - MIS (EU), 100 tons
Total Damage 200 tons

W. V. O'REGAN.

— page 39 —
1. USS CERO (SS225) - Report of Seventh War Patrol.
: (A) PROLOGUE

Arrived Pearl Harbor from Sixth War Patrol on 24 November 1944.
After completing voyage repairs proceeded to Navy Yard, Mare Island,
for scheduled yard overhaul. Commended yard overhaul on 6 December
1944. Departed Navy Yard, Mare Island, on 26 February 1945, after
having received a good overhaul which included the following major
alterations:

Installation of ST radar equipment.
Installation of range halving device on TDC.
Installation of additional torpedo charging panels and of
hydrogen burner circuits in torpedo rooms.
Replaced material to eliminate smoke main engine exhaust.
Installed modification to target designation system in-
cluding MK-8 TBT.
Installed MK-7 DRT.
Replaced 750 GPD with 1000 GPD vapor compressor stills.
Installed DCDI.
Installed 7-MC announcing system.
Installed hydraulic type signal ejector.
Lengthened conning tower and installed STS elliptical head.
Installed hydraulic periscope hoists.
Installed 5" gun and ammunition suttle aft and 40mm gun
forward.

From Mare Island Navy Yard proceeded to Monterey, California,
for nine days services in anti-submarine aircraft exercises. De-
parted Monterey, California, on 7 February 1945, and proceeded to
Pearl Harbor, arriving 14 March 1945. Received complete voyage
repairs, including installation of TDM and APR-1, from Submarine
Division 142 and U.S.S. BUSHNELL. Underwent twelve day training
period commencing 19 March 1945 and terminating on 29 March 1945.
At night, 24 - 25 March, was drydocked for emergency repairs to
negative tank liquidometer. During training period fired nine
exercise torpedoes, made two bottle surface firing runs on target,
conducted two days special exercises and participated in two convoy
exercises.

On 6 February 1945, Lieutenant Commander R. BERRTHRONG, USN,
relieved Commander E. F. DISSETTE, USN, as Comm.ning Officer.

During overhaul and training period, the following transfers
were effected:

- Detached: Lieutenant Commander C. D. NACE, USN.
  Lieutenant (jg) W. D. TAYLOR, USNR.
  Lieutenant (jg) S. R. CROOKS, USNR.
- Reported: Lieutenant (jg) J. E. GARR, USN.
  Ensign A. L. FRAKZ, USNR.
  Ensign W. P. SHUMAN, Jr., USN.

— page 40 —
U.S.S. CYRO (SS225)
CONFIDENTIAL
Subject:  USS CYRO (SS225) - Report of Sixth War Patrol.
(A) PROLOGUE: Cont.
Tr. nsforrod thirty-two (32) enlisted men.
Recoived thirty-four (34) enlisted men.

(B) MARCH, 1945
31 Mar. 1945
1400 (VH) Departed Pearl Harbor, T.H., aroouto Gun for further orders, in accord now with Comm. and Sub. rine Force, Pacific Fleet, adm.istr. tive Conv. and, Operation Order Number 46-45, (disp. toh.311845 of Hrdt.). Escorted by P01078 until d.rk. The following officers are on board:
PRV. V.R. P.TROLS
N.E.T.
It. Condr. R. myond B. RTHROIC, USN - USS S.L.R.VIN - 3
It. Joseph D. HOKR, USN - USS C3RO - 4
It. Thomas C. JONJS, Jr., USNR - USS C3RO - 1
It. (jg) Roy L. DRAON, Jr., USNR - USS C3RO - 1
It. (jg) John J. C.L.R., USN - USS C3RO - 3
It. (jg) John J. C.L.R., USN - USS C3RO - 1
Ens. C.r. Cdr. DELITTE, USN - USS C3RO - 1
Ens. Adonir.n L. PACK, USN - USS C3.R.VIN - 1
Ens. Willi.m P. SHULIN, Jr., USN - Nona
The following chief petty officers are on board:
N.E.T. PRV. V.R. P.TROLS
J.RVIS, Will.r.d. D. CLOIN(T)(SS) None
J.NKINS, J.ros. H. CLOIN(T)(SS) USS S.L.R.VIN - 4
H.XMALL, Dgdr C. CLOIN(T)(SS) None
HILLAR, Born.r.d F. OB.(P.)(SS) USS C3RO - 5
ROSE, Gerald L. COBH.(...) (T)(SS) USS C3RO - 6
SOURRS, Rot.rot. E. COBL.(...) (T)(SS) USS C3RO - 6

2015 (VH) Reloc.sed escort and proooded singly.
1 .pril 1945 1200 (V) Position Lt. t 20° 43' N; Long 162° 30' V.
Colbr.t.d T.stor nroute Cu.rn.
2 .pril 1945 1200 (V) Position Lt t 20° 44' N; Long 167° 54' V.
Niroute Guam, holding tr.ining drills nd divos.
3 .pril 1945 1200(X) Position Lt t 20° 26' N; Long 173° 20' V.
4 .pril 1945 1200(Y) Position Lt t 20° 18' N; Long 179° 02' V.

-2-

— page 42 —
15 April 1945
USS CRO (SS225) - Report of Seventh War Patrol.
(B) NARRATIVE CONT.
15 April 1945 1200 Position Lat 18° 52'4" N; Long 137° 32' E.
Proceeding to area holding routine training exercises and drills. Contacted numerous friendly planes during the day.

16 April 1945 1200 Position Lat 24° 01' N; Long 137° 32' E.
17 April 1945 1200 Position Lat 27° 16.2' N; Long 137° 16.8' E.
0034
Recoiled ComSubSwea dispatch 161132 and commenced search for downed aviator, reported position only 25 miles from us. Piped groon Vory stars at 30 minute intervals until daylight. Search complicated by numerous radar contacts on birds.
0652
Tr-ensittod CDRO's first, giving ENI at aviator's reported position.
0705
Sighted friendly submarine to Northward. Exchanged recognition signals and calls with U.S.S. GATO.
0730
Commended carrying out circular search plan in conjunction with G.TO. Origin of search 27° 14' N, 137° 08' E.
0940
SD and sight contact on N34Y2.
1349
Sight and SD contact on navy B-29 planes at high altitude.
1415
Xchanged calls with U.S.S. TIR.NET. Told her of search plan in off. TIR.NET joined search.
1700
Intercepted message from aircraft (properly authenticated) quote: Yellow jacket - 270° 50' N, 137° 65' E, unquote. Possibly pilot for whom we had been searching. Was told by rescue plane that our assistance was not desired.
2017
Scoured from search and proceeded to station in accordance with ComSubSwea 170406.
2050
Corroced receiving 198 rns signal on ATR-1.
2105
TR-1 contact on 198 rns beacon scattered, so tried changing course and speed to lose contact. Succeeded for about two minute intervals only.
2108
ST radar contact 11,800 yards, closing rapidly. Dived.
2138
Surfaced. 198 rns contact soon back on us but apparently not very interested. Received no IFF response, but bellowed planes were friendly.

18 April 1945 1200 Position Lat 29° 58' N; Long 135° 05' E.
0137
ST radar contact 3550 T, range 8,000 yards, voided, and at
0145
exchanged recognition signals with U.S.S. SNAP. Transmitted CDRO's second to ComSubSwea giving ENI at assigned lifeguard station.

— page 44 —
1253
1255
1527

: 1654
2003

20. _pril 1945
1017
1053
1210
1441
1914
1939
2115

21. _pril 1945
0307
0630
0830
0853
0855
0920
1800
2316

22. _pril 1945
1052
1056
1230

1200

— page 45 —
1300  TARGET CHANGED BASE COURSE TO 250° T. . .t 1500 YARDS
tARGETS: appeared to be of some type as those sighted on 19 . . .pril; about 150 tons.
1608  SURFLOAD AND CORRIDOR TACKING FAVORABLE POSITION FOR GUN ACTION.
1635  ST PLOCKED UP ON TARGET AT 14,000 YARDS.
1657  Navy CORRIDOR FIRING RANGE 10,000 YARDS; ALL
splashes, FIRED IN RAGGED SALVOS OF THROE OR FUR
ROUNDS EACH, WERE ABOUT 4,000 YARDS SHORT.
1701  CORRIDOR FIRING WITH 5 INCH AT TARGET, RANGE
7500 YARDS, BOTH PILOT'S CLOSING WITH ZERO ANGLE ON
THE BOW, BUT TARGET UNDER FIR FIRING FROM 1400 YARDS
RANGE ALIGNED TO 6,000 YARDS. . . .TARGET COURSE TO MAINTAIN RANGE BETWEEN 5 AND 6 THOUSAND YARDS.
1705  TARGET, ANNOYED IN SPOOK AND FLAMES, SLOWED AND TURNED AWAY. SHIFTED TO 12 TARGET WHO WAS CONTAINING TOWARD CORR.
1715  .2 TARGET SLOWED AND CORRIDOR SOTTING BY THE STERN.
CORRIDOR FIRING.
1716  .2 TARGET SANK. SITUATED AT TARGET TO OSTRWARD, FIRING
CAPPARENTLY OUT BUT WITH 180° ANGLE ON THE BOW. CORRIDOR
TARGET WAS ROCKED BY A ROCK

— page 46 —
U.S.S. CERO (SS225) - Report of Seventh War Patrol.

Subject:  USS CERO (SS225) - Report of Seventh War Patrol.

(B) NARRATIVE CONT.

0923
Sighted friendly submarine. Exchanged recognition signals and calls with POGY. Was informed by POGY that her transmitter had been repaired and that she would transmit the information required by ComSubsPac's 220506. Cero will stand by until message has been sent.

1000
Exchanged movie.

1127
Dived for trim. Found that both screws would ovitate very badly at 100 foot at 2/3 speed and at 1/3 speed at porisope depth. Noise could be heard through hull in Conning Tower. Some of the cmpty 5" cases must have hit the screws yesterday.

1225
Sighted 'Privateer' on southerly course.

1235
Surfaced.

1431
SD contact 12 miles, no FPF.

1433
Range 8 miles, divod. Surfaced at 1522.

1545
POGY informed us by VHF that a flooded antenna trunk had held up sending her message to ComSubsPac.

1600
Took leave of POGY, onroute crea. Transmitted Cero serial five giving info on POGY.

24 April 1945 1200 Position Lit 339 18:40 N Long 1440 05:51 E.

0100
Commascod converting #3 and #5 fuol ballast tanks to main ballast. Completed in 35 minutes.

0145
Stopped, flooded down forward and put shallow water diver over the storm to examine suspected bent propellor blades. (Soe dafects). Blades were discovered bent over in several spots on leading adges. After inspection was completed remaining darkness did not give sufficient time to complete repairs.

0330
Dived to soo if work accomplished had decreased cavi-tation. It had. Surfaced at 0422.

0921
Submerged.

1254
Surfaced for sun line.

1327
Divod.

1913
Surfaced.

2105
Stopped and put shallow water diver over storm to complete work on screws.

2330
Diver's work on screws completed. Set course for rendezvous with P.R.PER.

MILLER, B. F., CBM(PA)(SS), USN, and NAVLOR, J. M., EMLo(SS), USN, cno highly commando for their courageous, and very arduous work, in cold water and under difficult diving conditions, which successfully removed the nicks from both screws.

- 8 -

— page 47 —
25 April 1945
1008
Completed rendezvous with U.S.S. PARCHE, received by
line a copy of PARCHE's track chart and by voice
(megaphone) much valuable information.
1045
Set course for assigned area.
1058
Submerged for eviction test. Test completed,
repairs wore successful.
1344
Surfaced.
1807
Entered area "Throop".

26 April 1945
0628
Divd for submerged patrol. Took observations at
50' throughout day.
2012
Surfaced and patrolled on easterly then southerly
courses.

27 April 1945
0013
SJ radar contact on land, 113,00 yards.
0441
Submerged and surfaced closing line to conduct patrol
southeast of TUDO SATE.
1158
Detected distant pingling bearing 3280 T (ship contact #3).
1205
Mado cut ship in haze, angle on bow about 10° port.
Heard two different pingers; one to right of target,
one on same bearing as target. Sighted 20 type
escort to right of target, angle on bow zero. Float
type plane over target. Lost target in fog against
land background. Only escort in sight, (bearing 80°
relative, angle on bow zero) until
1228
sighted target again, angle on the bow 300 port, range
approximately 5500 yards. Escort was now on our
starboard beam, angle on bow zero, pinging, range
about 4500 yards.
1241
Went to 100 feet to allow escort to pass.
1247
Portescope dorth. Escort angle on the bow 100° ster-
board, range about 500 yards, identified as a CHIDORI.
Target very difficult to see in list against land
background. angle on the bow approximately 60° port,
range about 2800 yards. Could not see target again
until
1251
target had zigged away, range 3500 yards, angle on
bow 120° port. Did not fire because of excessive
torpedo run. Tontification of target was very
doubtful in poor visibility. Apparently he was a
medium sized MIM freighter.

- 9 -

10

— page 48 —
1302
Changed course to eastward to open range to land, now only 3500 yards.
Sighted small sampan close to shore on northerly course (ship contact #4). Visibility has now increased.
Sighted another small sampen on northerly course (ship contact #5).
Surfaced.

28 April 1945
1200 Position Lat 38° 58.8' N; Long 142° 04' E.
0630
Dived for submerged patrol off KOBE SAKI.
1543
Sighted two small samp:ns close to shore (ship contact #6).
1545
Sighted single engine flot plane on water close to beach. One of sampens soomed to be standing by this plane.
2010
Surfaced.

29 April 1945
1200 Position Lat 39° 06.5' N; Long 142° 01' E.
0443
Dived for submerged patrol off O'SAKI.
0818
Sighted ship (ship contact #7), bearing 340° T, range approximately 12,000 yards. Changed course to close land.
0824
Went to battle stations and commenced approach.
0843
Commoned firing first of four Mk-18-2 torpedoes from bow tubes at medium sized tanker. Gyro angles nearly zero, track angle 115 port, range 3000 yards, depth set six foot, torpedo track with sea, spread from aft forward.
0843-50
Firedlist of four torpedoes.
0847
Hoard one solid explosion. Observed ship to slow, settle aft, and take list to port.
0852
Hoard breaking up noises by sound gear. Ship no longer in sight at 4500 yards.
0853
Hoard one very loud explosion, followed by more breaking up noises heard through hull. We are sure this tanker sank.
0900
Set course to proceed submerged down the east to patrol off KOBE SAKI.
1025
Sighted single engine flot: type d:roraft, range eight miles, bearing 006° T. Searching whoro we had been.
1228
Sighted plane again still to north of us.
1253
Sighted sampen, (ship contact #8), bearing 326° T, range 8,000 yards, proceeding down the coast.
1304
Hoard pinging bearing 010° T, commenced approach.

- 10 -

— page 49 —
1307
Sighted CHIDORI (ship contact #9), on same bearing as
pinging and tracked him on various courses apparently
searching for us.
1351 CHIDORI reversed course and retired to northward.
Closest range 6500 yards. Continued patrol off KOBE
SAKI.
1525 Sighted CHIDORI (ship contact #10) again, bearing
0300 T, 12,000 yards, on southerly course. He had two
friends with him this time, both CHIDORIs. Commenced
evading at periscope depth.
1615 Hunter-Killer group reversed course and commenced
searching to northward, closest range 6000 yards.
Heard distant explosion, possibly earthquake
rumbling.
1923 Surfacod.
2013 Surfacod.

30 April 1945 1200 Position Lat 38° 38' N; Long 142° 04' E.
0245 SJ radar contact bearing 050° T, range 21,000 yards.
Probably a plane from change in bearing.
0246 Lost contact so commenced search steering 050° T.
0353 Sighted aircraft exhaust at low altitude. Submerged.
On way down picked up plane on SJ, range 7500 yards.
Deadlined to remain submerged to patrol just outside
100 fathom curve off SHIZAKAWA WAN.
1815 Surfacod.

1 May 1945 1200 Position Lat 41° 07' N; Long 143° 08' E.
0800 Commenced surface patrol about fifty miles south of
ERTIMO SAKI. Visibility varying from 5000 - 10,000
yards.
1130 Commenced receiving strong air at contact on 72 moga-
cycle: probably from land based radar although the
variations of intensity and this sweep look more like
airborne radar.
1845 Lookout sighted possible periscope (ship contact #11)
just after periscope, close board. avoided.

2 May 1945 1200 Position Lat 39° 15' N; Long 142° 08.5' E.
1107 Divd to close coast for submerged patrol off O SAKI.
1446 Sighted small ship (ship contact #12) bearing 253° T,
range approximately 7000 yards, angle on the bow 70
starboard. Visibility was very poor.
1447 Identified ship previously sighted as yacht type
escort vessel. Sighted two small engine craft ships
beyond this coast. Convoy was proceeding up coast
at eight knots. Unable to close to attack position,
minimum range 5000 yards.

- 11 -

— page 50 —
1500
USS CHRO (SS225) - Report of Seventh. 1st. T. control.
Sighted one unescorted small BMF freighter (ship contact, 13) proceeding down coast, estimated speed seven knots. Corriered approach. Broke off approach when he entered K.M.I.S.H. H.R.BOR and did not reappear. Sound heard nonentity pinging on bearing 210° T. Could see nothing. Pinging not heard again.
2030 Surf. oed. 8T radar contact bearing 043° T, 20,000 yards; possibly a plane. Changed course to 043° T but did not regain contact.

3 May 1945
1300 Position Lat 39° 25' N; Long 142° 05' E.
0430 Sighted GLow of light bearing 280° T. Probably from iron works at K.M.I.S.H.
0506 Dived and corriered along coast for submerged patrol south of TODD S.KI.
0735 Sighted Train (train contact, 11) which passed aboard to port proceeding on southerly course down coast. Coro patrolling 2500 to 3500 yards off booch. JK picked up this train (ship contact, 14) bearing 335° T, 1600 yards. Identified ship as very small escort to 2000 yards. Identified ship as very small escort freighter, estimated 600-800 tons. Did not fire.
1107 Sighted plane, probably corriered by enemy, to south of course.
1235 Sighted two float type nonplc.ncs.
1552 Sighted group of about 13 small single wing planes on westerly course, passing over TODD S.KI.
2027 Surf. oed. and corriered opening range to coast. During day sighted total of eight ships, all close to coast. Sound normally picked up thcir srowea bofore periscope sighted thcir.

4 May 1945
0430 Dived to close coast for submerged patrol south of TODD S.KI.
0802 Sighted 2 small flat-top type bipl.nos apparently searching.
0820 Sighted small ship bearing 243° T (ship contact, 15), corriered approach. Ship had air cover but no surf. face escort.
0840 Identified ship as very small engine aft. K. similar to S.MKO MRU. Infirm. range 1800 y. rds. Did not fire because of unloaded condition of very small target.
0933 Sound picked up pinging (17.5 kcs) bearing 349° T.
0935 Sighted subchaser (ship contact, 16) standing out of Y.M.D. M.N. Subchaser turned south and headed south along coast. Woided.

- 12 -

13

— page 51 —
1237
USS CDR (SS225) - Report of Seventh War Patrol.
Sighted two ships (ship contact #17): rounding TODD
SALT, went to battle stations and commenced approach.
Convoy consisted of three small HMI type JCs loaded,
one yacht type escort pinging on 14.5 kcs and possible
air cover. JCs were in column proceeding south close
to shore, escort about 2500 - 3000 yards on thoir port
bow.
Escort pressed to seaward of Coro, pinging generally
in opposite direction.
Commoned firing two torpedoes at loading JCs, and two
torpedoes at second JCs.
Heard and saw torpedo hit in bow of loading JCs.
Observed torpedo explosion at shore line behind
targets.
Second torpedo explosion at b.c. of oiler behind tar-
gets. Observed loading JCs well down by the bow,
second target reorvasing course and third target
turning toward Coro. Escort now heading towards us
and dropping depth charges at random.
Sighted bottom of loading JCs who had rolled over while
sinking. Depth charges and possible aerial bombs
(explosions from cpposisto sidos of ship by DOD) were
getting closer so at
Went deep, 250 feet this close to the bow, and
rigged for depth charges. Evaded on southerly course
nearly parallel to coast at first, hoping escort
would expect us to open coast as readily as possible.
He did.
Heard last of 12 depth charges, none of which wore
very close.
Portsocoro depth, all clear.
Surfaced. Today sighted total of 14 sampans close to
coast.
Commoned transitting Coro's serial six to CorSubs-
Pec giving results of last two attacks.

5 May 1945
1200 Position Lat 38° 48' N; Long 142° 24' E.
Sighted ship (ship contact #18) bearing 3200 T, range
31000 yards. Picked up target by 8T radar and
tracked on course 260° T at 19 knots. Unable to
identify target so commenced trying and around. 8T
radar tracked target to 38,550 yards, loboswitching,
then suddenly lost target. Continued and around.
Sighted target in on range 342° T. 8T radar picked
up target after being ordered on, range 33,000 yards.
Identified target as 8T type escort vessel or CHIDORI,
having very heavy formation with a large boarding
radar antenna. Rounded at masthead. PR picked up
radar interfornoco on 152 rags. PR had been search-
ing constantly all night with no interfornoco until

- 13 -

— page 52 —
0734
: 0757
: 1545
: 2004
: 2328

: 6 May 1945
: 0122

: 0330
: 0400

: 0416
: 0419

: 0745
: 0800
: 0845

: 0912
: 0918
: 1105
: 1108

: 1124
: 1130

: 14 -

— page 53 —
1152
USS CDR (SS225) - Report of Seventh War Patrol.
Commended firing three bow tubes at medium sized MPM
frightener; range 3200 yards, 95 starboard track with
small gyro angles. Depth set six feet in nearly calm
water.
Heard one small explosion.
Another small explosion, neither of those explosions
wore loud enough for torpedo hits nor were they pro-
perly timed. Perhaps they were soon bombs from 68-
oort of southbound convoy.
Torpedoes have missed.
To avoid southbound convoy of small ships which was
rounding KOBE SAKT at this time, or as a normal course
change, TMD solution, and Navigational plot both had
been checked very well before firing.
Watch target go over the hill to northward.
Sound detected pinging bearing 316° T.
Sighted PC boat (ship contact #24) bearing 346° T on
westonly course.
Surfaced.
7 May 1945 1200 Position Lat 39° 07.8' N; Long 141° 59.5' E.
0306
0343
SJ radar contact bearing 025° T, range 50,000 yards.
SJ radar contact 022° T, 27,400 yards, a different
target. SJ interference, apparently unfriendly, on
same bearing as this target.
Divod for submerged patrol.
Flat calm - hardly a ripple. Corrooned closing coast.
Sighted PC or CHIDORI (ship contact #25), bearing
328° T, (15 kos pingling), course about 210° T, lost
at about 0600.
More pinging bearing 235° T approximately.
Sighted top of pinger, PC or CHIDORI (ship contact
#26), bearing 271° T.
Another PC, pinging and nicking smoke bearing 310° T.
Two now in sight gradually moving to the south.
Cormanoed sighting many scranps and hearing many light
fast soroas, all scranps.
Sarnap apparently sighted periscope for he suddenly
spooded up and headed for us. Want doop to avoid
possible fishing nets or towed depth charges.
Hoard searing along starboard side. Nothing
happened.
Surfaced.
8 May 1945 1200 Position Lat 39° 23.8' N; Long 142° 14' E.
0010 Picked up apparently friendly SJ interforcano bearing
approximately 340° T.
0100 Exchanged recognition signals and calls with U.S.S.
BOWFIN.
- 15 -

— page 54 —
0421
0450
0650

0930
1117
1358
1750
1923
1956

9 May 1945
1442
1929
2150
2155

10 May 1945
0833
1426
1431
1500

1200 Position List 41° 19' N; Long 142° 40' T.

Wind and sea have been increasing steadily from North-east visibility averaged about 3000 yards. Patrolling on surface southwest of RITMO S.K.I. Had radar interference on. RT from three search-squad stations.

Submerged for afternoon meal.

Surface and surfaced closing 35.5N S.K.I. Radar, apparently from 35.5N S.K.I., steady on by. RT.

Secured 50.

The PR signal from 35.5N S.K.I. was lost entirely and another signal from probable airborne radar (145 miles) picked up. Changed course radio-lily and 145 miles east-south of 35.5N S.K.I. but continued searching until 0200. SJ refrained scored.

1200 Position List 41° 30.6' N; Long 141° 40' T.

Divod and examined closing SHIRLY. S.K.I. for submerged patrol.

Shifted search (ship on at 29) bearing 269° T. Escueded closing land.

Shifted float type bilance near smoke.

Picked up three sets of engine from direction of smoke. Still no target in sight.

- 16.

— page 55 —
1515
2033
2355
11 May 1945
0320
0325
12 May 1945
0455
1300
1758
2304
13 May 1945
0400
0425
1050
1345
1347
1414-30
1415-45

U.S.S. CHERO (SS225)
CONFIDENTIAL

USS CHERO (SS225) - Report of Seventh War Patrol.

Smoke rounded SHINITA SAK1 lighthouse, range nine thousand yards. No ship sighted. One pinger remained with smoke, other two returned into TSUGARU STRATOS.

Breaks off approach.
Surfaced - using ST radar only. No shorebased radar steadied on us.
Radar interference on S7. Apparently friendly; probably from SANDLANE. Triad to exchange recognition signals without success.

1200-Position Lat 40° 26' N; long 142° 33.5' E.

S7 is about at 11,200 yards. 300° T, probably.

S7 is about at 11,200 yards. 300° T, probably.

Excerpt from the SANDLANE. He was using roog-nering radar. Rechanged roognering to xeno-nering. Radar was to patrol area. In the area of 41-30 N; Coro to south.

12 May 1945
0455
1300
1758
2304
13 May 1945
0400
0425
1050
1345
1347
1414-30
1415-45

13 May 1945
0400
0425
1050
1345
1347
1414-30

— page 56 —
1418
: 1421
: 1507
: 2309
: 2348
: 14 May 1945
: 0040
: 0340
: 0513
: 0705
: 0719
: 0721
: 1138
: 1208
: 1320
: 1347
: 1355
: 1450
: 1456
: 1508

U.S.S. CIERO (SS225)
CONFIDENTIAL

USS CIERO (SS225) - Report of Seventh War Patrol.

Hoard brocking up noises through hull.
Hoard one end of run explosion frpm torpedo which had run into YOSHIHIMA WAN.
Saw first of navy planes sighted during the rest of the afternoon. Last sighted at 1805.
Surfaced.
SJ radar contact (ship contact on base course 030° T, 14,000 yards. Tracked target at 12 knots. Reported light 10 on radar intercepting on bearing of this target.
Radar contact (ship contact #31B) on second target bearing 2750 T, range 12,900 yards. Tracked this target on base course 2100 T, speed 6 to 12 knots.

1200 Position Lat 39° 23.01' N; Long 142° 08' E.

Slowed and listened with OB on bearing of target. Detected pinning on 15.1 kcs. Left pinner and proceeded towards position for submarine patrol south of TODD SIKI.
TIM chonical recorder indicated torpedo wake, bearing 045° relative. Maneuvered to avoid end than determined. Indicated to be caused by own ship noises.
Radar fired to definite source nontholoss.
Dived for submerged patrol.
Sighted smoke bearing 2240 T.
Detected pinning on sea bearing. Sighted CHIDORI patrollining on east end of TODD SIKI. He remained in that vicinity for three hours.
Sighted float type biplane over TODD SIKI. Commenced closing land suspecting a target moving south along coast.
JT sound hoard heavy sowros (64 RY4) bearing 340° T same general bearing as riano. Sighted 8C type escort vessel (ship contact #34) bearing 341° T. Unable to sight any other ship. Whatever it was probably entered YIMDO KO.
Scoured from battle stations.
Detected pinning bearing 165° T and drawing right slowly.
Sighted SC type anti-sub vessel (ship contact #35)

- 18 -

— page 57 —
1515
- USS CHRO (SS225) - Report of Seventh War Patrol.
- bearing 180° T, range 8000 yards, angle on bow ten starboard, speed about 10 knots.
- SC spooled up to 240 rpm, by turn count, but continued long scale pinning, angle on bow still 10 starboard.
- 1520 Went to 300 foot.
- 1530 Heard two explosions.
- 1532 Heard two more explosions.
- 1550 Lost screws on sound gear.
- 1610 Came to periscope depth.
- 1727 Sighted CHIDORT (or DD) (ship contact #36) bearing 301° T, 12,000 yards, patrolling along 100 fathom curve pinglings. No other ships in sight.
- 1736 Heard last of days depth charges; total logged was thirty.
- 2041 Surfboard.
- 2100 Interference on S2 radar, probably from anchor S2. Challenged but received no reply. Believe this was TORSK.

15 May 1945
- 1200 Position Lat 38° 32' N, Long 144° 01' E.
- 0130 Last of S2 interference which had been getting gradually weaker.
- 0155 Heard two distant explosions, two close together for probable torpedo hits. Was patrolling well off land, hoping to intercept TORSK. Had been unable to decode part of her probable rendezvous message.
- 1420 Divod for trim.
- 1756 Surfboard.
- 1952 Received weak S2 interference bearing 350° T. Closed, exchanged recognition signals and calls with U.S.S.
- 2035 SNDL.NO.
- 2330 Exchanged calls with U.S.S. TORSK. Unable to exchange recognition signals. Received message by S2, with no indication of course 0000. Being sure TORSK had sent message one to course 2000. S2 interference grew stronger but still was unable to exchange recognition signals at 0300. Continued zigging wildly.

16 May 1945
- 1200 Position Lat 38° 41.5' N, Long 142° 44' E.
- 0326 Lost all radar interference suddenly. Roversod course, proceeding to section 1 coast we had been patrolling. Son had built up to force 4.
- 1420 Received TORSK message asking for convenient rendezvous position.
- 1500 Sent position of rendezvous to TORSK. Irradically after transmitting offective Jap jarring went into

- 19 -

20

— page 59 —
1306
- Sighted spherical horned type mine. Lt 40° 32' N;
- Long 144° 06' E.
- Commenced attempting to sink mine with 20mm and 50 caliber fire, TORSAK close-in at high speed.
- Mine still floating after several 20mm hits; TORSAK close aboard. Docked to proceed to patrol station.
- Leaving mine to TORSAK. Our position recently obtained checks f.irly well with position received from TORSAK.
- TORSAK detonated mine.
- Departed station after Guam in accord. no. with Operation Order and CombusBS-0 170309. Fuel running very low.

20 May 1945.
- 1200 Position Lat 37° 47' N; Long 143° 54' E.
- 1025 Submerged for trim.
- 1126 Surfaced.
- 1331 Sighted smoke (shl. : contact 737) be ring about 1970 T.
- 1340 Sighted small ship bearing 1960 , range approximately 20,000 yards. Commander and round on target which was on course 290° T. but sight knots.
- 1502 Sighted smoke bearing 2885 T, a different target not sighted. gain through course was towards him.
- 1550 Divd on targets tried to identify in sight by periscope.
- 1622 Sighted target and identified him as a deep sea trawler type similar to SHINYO I.RU (208-7 misel-lanous). Too high for 40m gun.
- 1707 Trawler passed about 100 yards ahead.
- 1904 Sonatlas surfaced hull for periscope, possibly a log; no danger.
- 1932 Surfed and confirmed close-in target.
- 1935 Sighted smoke bearing 300° T; sounded and around.
- 2043 8d radar contact on target bearing 2600 T, 13,250 yards.
- 2242 Divd for submerged night radar approach. .st depth of 45 feet, when unable to pick up target on 5d, picked it up using Sd radar, range 11,000 yards.
- 2351 Commander firing two torpedoes from forward tubes, range 980 yards, track 1250 starboard, gyros small, depth set 3 foot down. force 1 - 2 sea.
- 2352 Saw and heard one torpedo hit under stock of target. Three seconds later, and saw another explosion further forward on target, Possibly second torpedo hit.
- 2358 Heard one very loud explosion, believed to be targets boilers, Ship had definitely sunk.
- 2400 Surfaced.

21 May 1945
- 1200 Position Lat 36° 08' N; Long 143° 03' E.
- 0007 Passed through wreckage and oil slick from target.

— page 60 —
0035
0740
2025

---

**Subject:** USS CERO (SS225) - Report of Seventh War Patrol.

---

**B) NARRATIVE**

Heard one Jap in water yelling and moaning, believed him to be badly wounded. The boiler explosion should have killed any survivors in the water and there was no wreckage seen large enough to support a man out of the water.

Set course to clear area enroute Guam.
Departed area.
Commoned transmitting Coro's serial seven and eight to ComSubSpac. Clogged message by 2100.

---

**22 May 1945**

1200 Position Lat 32° 33' N; Long 141° 57' E.

Slowed and converted #4 fuel ballast to main ballast; completed conversion at 0058.
Submerged - surfaced at 0210.
SJ contact on TORI SHILA, 65,000 yards, bearing 225° T.

---

**23 May 1945**

1200 Position Lat 28° 57' N; Long 139° 25' E.

Sighted B-25 turning toward, range about 3 miles.
Submerged. Fired two grenades and surfaced at 1404.
Sighted or had SD contact on friendly aircraft frequently during rest of patrol.

---

**24 May 1945**

1200 Position Lat 24° 18' N; Long 139° 35' E.

SJ radar contact bearing 2050 T, range 28,000 yards.
Tracked three ships on course 300° T at 15 knots.
Assumed to be friendly and avoided.
SJ radar interferences bearing 2450 T.
Exchanged recognition signals and calls with U.S.C. GUIT.RRO.
SJ radar contact on GUIT.RRO at 17,800 yards.

---

**25 May 1945**

2152
2231
2318

---

**26 May 1945**

1200 Position Lat 15° 22' N; Long 141° 35.5' E.

---

**660**

---

**22**

**23**

— page 61 —
27 May 1945
0426
0837

: 1200 Position - Apra Harbor, Guam.
Sighted escort, U.S.S. OSMS (DE701) and proceeded in company.
Entered Apra Harbor, Guam, and moored alongside U.S.S. APOLLO.

-28-

— page 62 —
1-XXRA.
HYDRO
(D) TIDAL INFORMATION
No tides or currents were encountered which differed from those described on current charts or in H.O. publications.

(E) NAVIGATION
The lighthouses on TODO SUI, KYORI SAI and SHIRIY. SAI were of great help during submerged patrolling near the beach.
- Steady white light on TODO SAI was exhibited for a short time at 0330, 8 May 1945.
- A steady red light was seen in the proximity of KYORI SAI on the night of 12-13 May 1945.
- The glow of the iron works at KAIISHI KO was visible several times.
- The Loran gear, recently installed, was used experimentally on this patrol. Good fixes were obtained at night between Pearl Harbor and up to 1000 miles of Guam from stations in the Marshall Islands. The tables aboard do not include stations in the Marianas, China, or Philippines. By the use of air charts approximately positions were obtained 1500 miles north of Guam. A complete set of Loran tables will be a tremendous aid to the Navigator.

Page 24 of 25

— page 63 —
1. SHIP CONT.CTS
No.  Time  Date  Lat.  Long.  Type  Initial  Estimated  Course-Speed  How  Contacted  Remark
2  Stationary  SJ  Sunk on...
1  C330 4/19/45 31-03N 137-00E  Pockets  1,000  260°  6  Surface  Battle Sur-
2

— page 65 —
(F) SHIP CONTACTS
No. Time Date Lat. Long. Type
26. 0648 5/7/45 39-02N 142-03E
27. 0930 5/8/45 39-26N 142-09E
28. 1117 5/8/45 39-26N 142-09E
29. 1426 5/10/45 41-31N 141-32E
30. 1345 5/13/45 39-01.5N 141-53E
31. 2309 5/13/45 38-55N 142-08E
32. 0720 5/14/45 39-19.5N 142-07.5E
33. 1320 5/14/45 39-28.2N 142-06.8E
34. 1355 5/14/45 39-25.8N 142-04.5E

:  Initial Statistic
Name Durance Durance-Swiss Contested
PG cr 8,000 180°
DD cr 5,000 150°
Childcr1 6,000 200°
Uniden- about 16,000 150°
tified 6,000 200°
Small 10,000 0309 9.5
UNK 14,000 220°
boljovcd 2 PCs
PC or Childcr1 8,000 150°
PC or Childcr1 8,000 150°
Childcr1 0900 270°
PC or Childcr1 7,500 270°
Various speeds and courses.
PC 7,000 2000

:  New
Durance-Swiss Contested
F 1,000 180°
F 5,000 150°
F 10 10
F 9.5 9.5
F 220° 10
F 220° 10
F 150° 15
F 150° 15
F 270° 15

— page 67 —
U.S.S. CERRO (SS225) - Report of Seventh War Patrol.
(H) ATTACK DATA
U.S.S. CERRO (SS225) TORPEDO ATTACK NO. 1 PATROL NO. 7
Time: 0916(K). Date: 4-19-45. Lat 31° 08' N. Long 136° 59' E.

TARGET DATA - DAMAGE EFFECTS

Description: Two Japanese picket boats of medium size, estimated 130 feet long, 150 tons. Picked up by SJ radar at 8500 yards and tracked out to 11,800 yards on a dark night.

Ships Sunk: One Picket Boat, estimated 150 tons.

Ships Damaged: None.

Damage Determined by: Heard and saw one torpedo hit. Observed 7/8 of ship disintegrates.

Target Draft: Unknown. Course: (Heading) 270° T. Speed: (drift) 3 kt. Range: 650 yards at firing.

OUN SHIP DATA

Speed: 3 knots. Course: 356°. Depth: 64 feet. Angle: 0.

FIRE CONTROL AND TORPEDO DATA

Type Attack: Submerged daylight torpedo attack. Fired using 'set bearing' method for both torpedoes.

Tubes Fired: 1/1 2
Track Angle: 89° 89P 89P
Gyro Angle: 008-10 006-40
Depth Set: 21 21
Power (speed in kts): 27.8 27.8
Hit or Miss: Hit .1ss
Eruption: No No
Mark Torpedo: 18-2 18-2
Serial No.: 99382 99393
Mark Explorer: 8-7 8-7
Serial No.: 15871 10991
Actuation Set: Contact Contact
Actuation Actual: Contact
Mark Message: 18-2 18-2
Serial No.: 4821 5413
Explosive: TPX TPX
Firing Interval: 12 sec.
Type Spread: IR
Sea Conditions: Force 2 (fired with the sea)
Overhaul Activity: S/MBase, S/MBase, P.H.T.H., P.H.T.H.

- 29a - 460
30

— page 69 —
30a - 32

CONFIDENTIAL: U.S.S. CERRO (SS225)
SUBJECT: USS CERRO (SS225) - Report of Seventh Mar Patrol.
(H) ATTACK DATA:
U.S.S. CERRO (SS225) TORPEDO ATTACK NO. 2 PATROL NO. 7
Time: 0843(K).  Date: 4-29-45.  Lat 39° 15.5' N.  Long 141° 58.5' E.

TARGET DATA - D.T.T. (DEFINED INSTRUCTIONS)
Dosorptition: One, apparently new or freshly painted, medium sized engine aft ship. probably a tanker, having raked bow, two stick masts, rectangular bridge amidships, medium sized stick located well aft, type stern not determined. Target was unescorted, making smoke at intervals, no air cover detected. Picked up target by periscope, visibility fair to good. Target hard to see at long range against shore background.

Ships Sunk: One medium sized tanker.

Ships Damaged: None.

Damage Determined by: Hoor'd one solid explosion and then obscured ship to slow, took a list to port, and settle aft. .about six minutes later another very loud explosion was heard, followed by rumbling breaking up noisys heard through the hull. The ship was no longer in sight through the periscope at 4500 yards range.

Target Draft: 18' estimated. Course: 1880 T.  Speed: 8½ knots.
Range: 3000 yards at firline.

ON SHIP D.T.T.

Speed: 3 knots.  Course: 2500 T.  Depth: 64 foot.  Angle: 0.

FIRST CONTROL AND TORPEDO D.T.T.

Type attack: Submerged daylight periscope attack. Pired using the 'set bearing' method for torpedoes /1 and /3, and generated bearings for /2 and /4.

- 30a - 32

— page 70 —
USSS CERO (SS225) - Report of Seventh Torpedo Patrol.

| Subjct: | USS CERO (SS225) - Report of Seventh Torpedo Patrol. |
|||
| (H)  | TT. OK D.T.                                                      |
|        | TORPEDO TT. OK NO. 2                                          |
|        | #1 115P 005 61 27.1 18s 18s 18-2

— page 71 —
1. USS CERO (SS225) - Report of seventh War Patrol.
   (H) LT. CRD. D.T.

U.S.S. CERO (SS225) TORPEDO. LT. OK NO. 3. PATROL NO. 7
Time: 1317(K). Date 5-4-45. Lat 39° 28' N. Long 142° 04' B.

TARGET DRAFT: 12' (estimated). Course: 185° W. Speed: 7 knots.
Range: 2000 yards at firing.

O/N SHIP D.L.

Speed: 2.8 kts. Course: 249° 30'. Depth: 64 feet. Angle: 0.

FIRST CONTROL. 2ND TORPEDO D.L.

Type .tttack: Submerged daylight parisopos attack. Fired using the 'set bearing' method for torpedo 1, and a gun-rotated bearing for 2.

- 31a -

660

34

— page 74 —
1.1 knot spool reduction w.s. used for the 3rd depth of 6' in accordance with the Newport test firing data. This was a 'snap set-up' and it is believed that the targets spool was estimated at one knot too high. One torpedo was observed to explode on the beach behind the target.

- 32b -

— page 76 —
U.S.S. CERO (SS225)
CONFIDENTIAL
Subject:  U.S.S. CERO (SS225) - Report of Seventh War Patrol.
(H)  .TT.CK D.T.
TORRADO .TT.OK NO. 4

Remarks:
.fter firing this first torpedo depth control was lost momentarily .nd it was a few minutes before the target could be soon.  Tho next 'look' found the target with a 1250 angle on the bow and no change of spood.

Tho TDC solution was shocking very well at the time of firing, therforo, it is possible that the target altorod course cither to void a southbound convoy of small ships rounding KOB. SAI or as a normal course change.

A navigational fix taken after firing indicated that the firing range must have been about 2500 yards instead of the guaranteed value of 3280.

. 1.1 knot spool reduction was used for tho sot depth of 6' in accordance with tho Nowport test firing date.

- 33b -
- 39

— page 77 —
1. USS CRO (SS225) - Report of Seventh Patrol.
: (H) ATT.CK D.T.
: USS CRO (SS225) TORPEDO ATT.CK NO. 5 P.TROL NO. 7
: Pinc: 1414-30(K).  Date: 5-13-45.  Lt 390 07.5' N. Long 141 57.5' J.
: TARGET D.T. - D.C. 3 INFLICTED

Description:
Small Japanese IFFI .K in a lightly loaded condition.

Ships Sunk: One small Japanese .K.

Ships Damaged: None.

Damage Detr. by: Hood and saw one solid torpedo explosion slightly abaft the stack. Saw this ship sink within one minute and thirty seconds after the hit and had broken up noises both on the sound gear and through the hull.

Target Draft: 10' (estimated). Course: 023°. Speed: 9 knots. Range: 600 yards at firing.

O'NS SHIT D.T.

Speed: 2.8 knots. Course: 081° T. Depth: 65 foot. Angle: 0.

FIRST CONTROL IN TORPEDO D.P.

Type Attack: Submerged d.ylight periscope attack. Fired using the 'cast bearing' method for tube 78 and generated values for 9 and 10.

- 34a -
- 40

— page 80 —
35b -
USS CDR (SS225) - Report of Seventh War I.trol.
TORRADO _TT.CK NO. 6

Tubos Fired: #1 #2
Track angle: 125.35 128.53
Gyro angle: 007-30 012
Depth Sot: 3' 3'
Lower (spoed in kts): 27.8 27.8
Hit or Miss: Hit (possible hit)
Brratio (yes or no): No No
Mark Torpedo: 18-2 18-2
Serial No.: 99360 58226
Hark Exploder: 8-7 8-7
Serial No.: 10645 10972
.ctur:tion Sot: Contact Contact
.ctuation .ctur: Contact Contact
Mark Approach: 18-2 18-2
Serial No.: 5398 5358
Explosive: TIX TIX
Firing Interval: 10 soo.
Type Spread: 3/4 L 3/4 R
Sea Conditions: - Forco 1-
Overhaul .ctivity: S/Basc, S/IBasc,
H.T.H. I.H.T.H.

Remarks: Used a 1.75 knot speed rudder for set depth of 3 foot in accordance with Newport for set firing data. Hoard two distinct explosions. However, the interval between them was about 3 seconds, the

— page 82 —
36b - 45

CONFIDENTIAL
SUBJECT: USS CRO (SS225) - Report of SOVNth Car Patrol.
(H) ATT.CK DATA
GUN ATTACK NO. 1

DOT. I.I.S OF ACTION CONT.

During this entire engagement the 5" gun was fired by hand as the foot firing pedal was out of commission. After sinking the smaller target the recoil of firing apparently jarred loose the internal structure of the pointers toloscope, because the wires rotated 45° within the toloscope.

Radar spotting in range was attempted, but did not prove to be successful because of the rapidly changing bearing due to radial course changes of own ship and the target. Spotting in deflection was done by the use of A1 periscope. The TDO was used as a range-keeper.

— page 84 —
USNS C-RO (SS225) - REPORT OF SOV.NTH WAR PATROL.
Subject:  USS CRO (SS225) - REPORT OF SOV.NTH WAR PATROL.

After one attack the yacht type escort dropped 14 depth charges, none close. No apparently did not have contact on us at any time and was searching directly to seaward from ship which was sunk. No evaded by running south nearly parallel to coast before heading to sea. F40 DESANT

On several occasions when a Vessels were near, small explosions, possibly some bombs, were heard.

Unquestionably the landbased radar stations in the vicinity of TSGUG RST.ITS (SHIRTY, SKI, FSM, S.K.I. and RIIO S.K.I) could detect our 3J and take bo.rings on it. No landbased radar w.s noted close to NODO S.K.I.

Radar equipped planes were detected on several occasions but only once came close enough to cause Cargo to dive. Our S.J, when in use, was being keyed, two or three fast sweeps every minute or two, the entire time in the area. No radar planes were detected when the patrol aircraft mentioned above were operating in the vicinity.

After each attack made the S.J. activity increased radically for a day or two, random depth charges were heard all day, constant sweeps were made by XCS, SCS, CHIDRICS and aircraft along the coast, and scamps appeared to do more looking than fishing.

(J) J- JOR DETRICS, ND D.L.G. BOSHIPS

HULL & I.C.HI.C.H.RY

On 13 .pril 1945, having topped off with fuel from U.S. HOLL and on the 12th, a fuel lock was noticed on the starboard side aft at-frome No. 100. It was believed the lock was anywhere forward of this frame, and below the rolling shock, thus allowing the fuel to travel aft under shock. During the next day the ship was attacked by depth charges. By placing 15 fuel b.llast tank on service, the source of fuel for the lock was eliminated before arriving in area. It is intended that this damage be repaired in drydock during the next non-mal refit.

H- X- XRA

- 38 -

- 47

— page 85 —
40 DESIGNATION: U.S.S. CRO (SS225)
CONFIDENTIAL: U.S.S. CRO (SS225) - Report of SOV.nth Far Patrol.

(1) ANTISUBMARINE INCLOSURES - NO VASION T.CITICS CONT.

After one attack the yacht type escort dropped 14 depth charges, none close. No apparently did not have contact on us at any time and was scaringly directly. to seaward from ship which was sunk. No evaded by running south nearly parallel to coast before heading to sea.

F40 DESIGNATION:
On several occasions when AS vessels were near, small explosions, possibly some bombs, were heard.

Unquestionably the landbased radar stations in the vicinity of TSGUN SIRIUS (SHIRIY.S.KI, 7S.S.N.S.I. and XRIIO S.KI) could detect our 5J and take bearings on it. No landbased radar was noted close to NODO S.KI.

Radar equipped planes were detected on several occasions but only once came close enough to cause Cargo to dive. Our S.J, when in use, was being keyed, two or three fast sweeps every minute or two, the entire time in the area. No radar planes were detected when the patrol aircraft monitored above were operating in the vicinity.

After each attack made the S.J activity increased radically for a day or two, random depth charges were heard all day, constant sweeps were made by 2Cs, 3Cs, CHIDORKS and intercept along the coast, and squads appeared to do more looking than fishing.

(2) J-OR DEPOTES - N.D.D.G.Y.

HULL & LICHTERY

On 13. -pril 1945, having topped off with fuel from U.S.S. HOLLID on the 12th, a fuel lock was noticed on the starboard side aft at frame No. 100. It was believed the lock was anywhere forward of this frame, and below the rolling choke, thus allowing the fuel to travel aft under choke. Deserter was delayed two hours while a diver went over the side to investigate source. A small spherical indentation in the outer hull at frame No. 78 was found. Two small cracks in the hull at the dished-in sector were noted to be emitting fuel oil. This opening was approximately five feet under the rolling choke, measuring along the skin of the ship. It is believed this defect was incurred during sound tests in San Francisco by, at which time the ship was bottomed. Since that time, to the best of our knowledge, this ship has struck nothing that could have caused said defect. By pl. oing, 5 fuel ballast tank or service, the source of fuel for the lock was eliminated before arriving in area. It is intended that this damage be repaired in drydock during the next normal refit.

4-XRA - 38 - 460 47

— page 93 —
U.S.S. CERO (SS225) :  CONFIDENTIAL

Subject:  USS CERO (SS225) - Report of Seventh War Patrol.

| Date | Time | Location | Type | Notes |
|------|------||------|-------|
| 9/22/45 | 17:45 | 1/1/45 | 1/1/45 | 1/1/45 |
| 9/22/45 | 17:45 | 1/1/45 | 1/1/45 | 1

— page 95 —
1/2" COMMUNICATIONS, RADAR, AND SONAR
| Date | Type | Freq. (ms) | IRF (pps) | Pulse Width (micro-seconds) | Pulse Shape | Sweep Rate | Remarks |
|------|------|||||||
| 4/21/45 | 30-19 N | 253 | 250 | 10 | 1" pulse, lock | 1" | 1" pulse, lock |
| 4/21/45 | 30-10 N | 183 | 60 | 10 | steady | 1" pulse, | 1" | 1"

— page 97 —
1/8" pulse, Slow sweeping antenna.
2. 1/8" to 1/4" pulse, 1/8" keyed or sweeping antenna.
3. 1/16" to 1/8", Interference.
4. 1/8" to 1/4" pulse, 1/8" keyed or sweeping antenna.
5. Signal interlocked from 1/16" until it re-echoed 3 minutes.
6. 1/8" to 1" fluctuation, Signal was on for only 6 seconds and disappeared.
7. 1/8" pulse, Slow sweeping antenna. This frequency was clear until exactly 0530 each morning.
8. 1/8" to 1", Sweeping radar characteristics.

59

— page 98 —
5/6/45 39-07 N 160 to 5 0scr 1/8" pulse. 3 rins. 46 0010 142-35 E 400 3 rins. then sto dy on. 5/8/45 39-30 N 400 Unk 1" pulse. 3 rins. 47 2100 142-34 73 400 3 rins. 3 rins. 5/9/45 40-18 N 400 3 rins. slow 48 0635 142-40 74 400 3 rins. 3 rins. 5/9/45 41-21 N 400 3 rins. 49 2250 142-30 145 500 7 3 rins. 5/10/45 41-21 N 400 3 rins. 50 0600 142-30 B 98 500 5 rins. 5/15/45 39-33 N 400 20 51 2235 143-26 E 78 500 3 rins. 5/16/45 40-00 N 37 0 to 400 3 rins. 52 1400 143-00 B 300 300 Unk 300 vary fl. 3 rins. steady 1/6" to 1" pulse. 1" transmittin after. transmitting a message this ran- dom noise level ap- peared on the TM-1 and the TM-2 units up to 300 mcs. The inten- sity varied at different frequencies. Lasted for 10 mins. and at one time went as high as 700 mcs. .11 radio receivers were also jammed at the same time.

— page 99 —
5/20/45 37-40 N 80 400 to 25
: 5/20/45 37-40 N 72 to toll, 20 two on same fro quency.
: 5/20/45 37-40 N 77 500 Possibly 20 to 30
: 5/21/45 38-04.5 N 80 500
: 5/21/45 37-40 N 95 300
: 5/21/45 37-40 N 41 60
: 5/21/45 37-39 N 87 100 to 88 200
: 5/21/45 37-39 N 87 100 to 7 to 8
: 5/21/45 37-40 N 87 100 to 7 to

— page 100 —
5/22/45 31-49 N
: 60 1606 141-31 E
: 5/22/45 29-19 N
: 61 1620 139-24 E
: 5/22/45 30-37 N
: 62 1715 141-22 3
: 5/22/45 30-58 N
: 63 2205 140-50 3
: 5/22/45 30-58 N
: 63 220

— page 101 —
USN (33225) - Report of Seventh War Patrol.

Subject:  USS CDR (33225) - Patrol of Seventh War Patrol.

(C) CHINOOK, H.M.D.R., 5th U.S. Submarine Squadron, C.N.T.

NRB  B 5 3 1/2  C 3

— page 108 —
1/2-10(A)/A16-3(18) SUBMARINE FORCE, PACIFIC FLEET
Serial 01427
Confidential
Chief Commander:
CERO Report of
Seventh War Patrol.

QUANTITY OF PATROL REPORT NO. 776
U.S.S. ZEALOUSOVIC, 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. ZEALOUSOVIC (SS225) - Report of Seventh War Patrol
(31 March to 27 May 1945).

1. The seventh war patrol of the CERO, under the command of Lieutenant-Commander Raymond Berthrong, U. S. Navy, was conducted off the coast coast of Fonshu and south of Eokhaido. During the latter part of the patrol the CERO became a part of a coordinated attack group composed of the U.S.S. TOSUK and U.S.S. SALDALANCE, with the commanding officer of the TOSUK as group commander.

2. This well planned, aggressive, and expertly conducted patrol resulted in six torpedo attacks and one gun attack. One medium tanker, two small freighters, one large trawler, and two picket boats were sunk, and an additional picket boat was damaged. Throughout the patrol the enemy was sought out and attacked close to the beach in the face of heavy anti-submarine activity. The commanding officer's determination to remain in the area and attack the enemy is well exemplified by the repairs to damaged propellers, which were effected by divers while at sea.

3. Award of Submarine Combat Insignia for this patrol is authorized.

4. The Commander Submarine Force, Pacific Fleet, congratulates the commanding officer, officers, and crew of the CERO for this tenacious and highly successful patrol. The CERO is credited with having inflicted the following damage upon the enemy during this patrol:

| S U N K | 150 tons (Attack No. 1) |
|||
| 1 - Picket Boat (EC) | 5,000 tons (Attack No. 2) |
| 1 - Medium AO (EU) | 2,000 tons (Attack No. 3A) |
| 1 - Small AK (EC) | 2,000 tons (Attack No. 5) |
| 1 - Small AK (EC) | 500 tons (Attack No. 6) |
| 1 - Trawler (EC) | 150 tons (Dam Attack No. 1) |

TOTAL SINK: 9,800 tons

EXTRA: ORIGINAL
SORG. MICRO
PHOTO LAB. OP-16
RETURN TO F-4253

— page 109 —
1 - Patrol Boat (3J) - 150 tons (Gun Attack No. 1)
    - TOTAL SUM: 9,950 tons

DISTINGUISH:
(Complete reports)
- Cominch (7)
- 2D (5)
- Cinepac (6)
- JIQP04 (1)
- AdiCP04 (1)
- Comservpac (1)
- Cinelant (1)
- Consublant (8)
- S/M School, HL (2)
- CO, S/M Base, PH (1)
- Consopac (2)
- Consoveepac (1)
- Consub#7#H#1 (Fwd Echelon) (2)
- Consub#7#H#1 (Janr Echelon) (2)
- Comorpec (1)
- Consubpac (3)
- Consubspac#4Comd (40)
- SUBD, NI (2)
- Consubspac#Subordcon (3)
- All Squadron end Div. (2)
- Commanders, Pacific (2)
- Substrinpac (2)
- All Subrimes, Pacific (1)

SIGNATURE:
- [Signature]
- [

— page 110 —
26
SS225/AL6-3
Serial: 026
c DECLASSIFIED I AL

From:
To:
Via:

Subject:
Enclosure:

1. Enclosure (A) covering the HIGHWAY War Patrol of this vessel, conducted in areas South and East of HONSHU and in the Southern KURILLUS during the period from 27 June to 30 July 1945, is forwarded herewith.

2. Enclosure (A) covering the HIGHWAY War Patrol of this vessel, conducted in areas South and East of HONSHU and in the Southern KURILLUS during the period from 27 June to 30 July 1945, is forwarded herewith.

DECLASSIFIED
DECLASSIFIED. 0445, OPNAVINST 5510.10C
BY _OP-0949C-DATE_ 5/25/72

— page 113 —
29 June 1945
(1200 Position Lat 21° 02' N; Long 139° 27' E.)

30 June 1945
(1200 Position Lat 25° 33' N; Long 139° 35' E.)

1:28
Surfaced from training dive and exchanged calls with U.S.S. TIGRONT (SS419) on 5 Jul, range 8000 yards.

1:17 1945
(1200 Position Lat 30° 01' N; Long 139° 12' E.)

1:22
Entered lifeguard area, received torpedo crew assignment from Fock Corvette, porting to escorting lifeguard, signal sent. Recoded torpedo position for 2-3 July night, bomber strike. Will look for picket boats on 200 and 250 mile circles until it is to be on station.

2:34 1945
(1200 Position Lat 30° 21' N; Long 136° 37' E.)

3:35
Sighted spherical horned mine (#1). Finally exploded mine with 20ft. fire after such effective 40ft. and 20ft. practice. Two six inch penetrators had no apparent effect. Exchanged recognition signals and calls with U.S.S. PHILIPPI.

1:08
Submerged for drills. Submerged for

— page 114 —
2205
USS CERO (SS225) - Report of Night War Patrol.

(B) N.M.TIVE
2205
SD and sight contacts on many friendly northbound planes during next two hours.

0115
On liftoff station. Contacted B-17 over plane by sight, liftoff from 35-12N, Long 137° 25' E.

0140
Many SD and sight contacts in sight. Cover plane departed. No planes over. Contacted patrol in northeast during intercept towards N.N.O SHOTO to close track of fighters taking terrorow's strike on TOKYO area.

1402
Sighted and sank schoriol horrid type plane (#3).

1434
Submerged for drills and return to target.

1839
Surfaced.

2200
Recoived orders from ConsBus. No contact to intercept. Contacted ConsBus. Charged course to comply, point for special intelligence. Charged course to comply, SD and SD radar contact three and a half miles. No I.FR. Divod. Surfaced at 2367.

5 July 1945
(1200) Position Lat 31° 54.5' N; Long 141° 44.5' E.

3301
Sighted SUIS. SHIM. (Smith Is.) bearing 072° T. Closed range to South Island to 8000 yards; no signs of habitation noted. Coronated sighting by friendly plane, escorting numerous 1-51s on northerly course. Numerous SD and sight contacts on friendly planes on southerly course. (Units of fighter strikes on this way home.) 1418
Submerged for drills. Surfaced at 1523.

(Note: In liftoff I assume enemy friendly planes are in sight. Only those which are sighted will be entered. If not sighted, the ship is listed. Horrofter, all plane contacts will be entered.)

6 July 1945
(1200) Position Lat 31° 06.2' N; Long 144° 44.5' E.

0010
Ticked up weak 5J interference bearing 135° T. Probably 52. 10.0CMB. 0855
SD and sight contact on Divod or at 12, 12

— page 115 —
0350
USC  CHNO (SS225) - Report of Night War Patrol.

(B) N.R.R.TIVE

0350
SU contact bearing 1320 T, range 17,600 yards, unable to exchange reconnaissance signals by 5D, Sighted U.S. submarine and was unable to visually recognize signals with U.S.S. TORPINE. AUGUST 5D keying system and
fidelity extended to all by 5D radar.
SD contact nine miles, no IFF. Submerged.
Surf. cod.
Submerged. Surf. cod at 1820.
Commended anti-bloch port sweep in accord with
Opord. Scouting course 3210 T, dist. no. 14 miles,
speed of 4V.no. 8 knots; Core the north of 6th
of seven ship scouting line on critical.
under corr. and rf Corr. and r. H.H.MON, U.S.S.
THOMSON.
Rock 3D interfer. no. boric 226 T. Probably U.S.S.
C.H., next ship in scouting line.

8 July 1945 (1200 Position Lat 32° 25' N; Long 143° 56' E.)

0539
Submerged for tri. Surf. at 0626.
Week 5D interference boric 230 T. apparently C.H.
is using 5D only intermitently.
Submerged. Surf. at 1752.
Week 5D interference boric 236 T.

9 July 1945 (1200 Position Lat 33° 44' N; Long 143° 56' E.)

0457
Sighted plane, (approximately 1 mile), out of.
Surf. cod.
SD contact 8. miles with IFF, range on.
Sighted tops of U.S.S. C.H. bearing 206 T. Opened
to northeast.
Submerged for tri. Surf. at 1804.
Sighted U.S.S. C.H. bearing 213° T. He can't be
southwest.
anti-bloch boat swept complete. Clo. ran in
north by course at normal speed.
Bach. not in U.S.S. C.H. by CD radar.
Received "BOLSHIMO" area assignment visually from
U.S.S. C.H. Know we have a light. U.S.S. C.H. is
operator strike but we're not received at this
point. It's probably the one earlier we are missing.
S.S. C.H. and received no message.

— page 116 —
0914
Subj: USS CRO (83225) - Report of Eighth War Patrol.

: 1118
Sighted U.S. MON. Y 2380 T. Requested missing information for MON. Y.

: 1337
Sighted KINKAS.NY, boarding 3140 T, 84,000 yards.

: 1701
Sighted and exploded spherical iron (16). Finally got pictures of explosion.

: 2118
Received Consubmarine Sori.1 67.

: 2245
Corrooned transmitting Corps's first to NNL.

: 2258
SJ radar interforcce bearing 1500 T. Probably U.S.S., U.S.N.

: 11 July 1945 (1200 Position Lt 39° 37.5' T; Long 12° 0' C.)

: 0320
Complot transmitted. Changed course to close east.

: 0224
Sighted TODD S.K. 1 light (apparently normal characteristics), bearing 36C T.

: 2245
SJ radar contact, bearing 267° T, range 11,200 y.

: 0300
Coincident with target on course 010° T, zigzag.

: 0345
Identified these two targets as RTR 1 or 2.

: 0630
To J13, Travers reported to us as RTR 1 or 2.

: 0917
Submerged off TODD S.K.T. (ship 13, torpedo 13, 100 yards from target).

: 0920
Detected pinning bearing 2450 T.

: 0938
Sighted patrol craft bearing 237° T, apparently range 13,000 yards (ship on net at 4°).

- 6 -

— page 117 —
1004
: (B) NATIVE
: 1604
: 1721
: 12 July 1945
: 0355
: 0549
: 1030
: 1036
: 1041
: 1042
: 1100
: 1905
: 2200
: 13 July 1945
: 0405
: 1355
: 1818

U.S.S. CR 0 (SS225) - Report of Mitchell War Patrol.

Sichelt tow more ships, all three similar to 413, all pinning and listening intently at vital speeds and cursors scorching approximately on 100 fathom curve. Decided against attempting to attack this Hunter-Killer cruw, yielded, closest rone, 8000 yards. Believing that the trawls contact is best for sunrise (ship contacts 2 & 3) were the crew contacted later (ship contact 4), and that the smallest "pulp" (f or contact 2) was a smaller vessel not seen during daylight by periscope. Haze and false provender positive identification, as unable to see land at 9 miles. (Letter learned that U.S.S. 13UNNE had sunk a 413 class at hore on 10 July. Surprised, proceeded to vicinity of liferaft at 11:15.)

(1200) Location: Lat 41° 30' N, Lon 143° 00.51' E, 0355

Received TICING contact report on enemy submarine which dived at Lat 41° 34' N, Lon 142° 04' E, course 105° T.

Lat 41° 34' N, Lon 143° 00' E, course 105° T.

Lat 41° 34' N, Lon 143°

— page 119 —
1520
Two Corsairs circling close aboard, still attempting to establish communications with War. Exploded two more substitutes for RUMBLE.

1527
Sighted plane, apparently a bomber, bearing 18° T, five miles east.

1538
Surface. C'vor has departed, maybe chasing plane F; which we dive.

1610
Critical one Corsair, which is still on course, circling with his whols down. Notabilished corrning it's in War, and after he had satisfied himself that we were friendly (by rdering course changes), received further notice that there were three, ran in after five to 5:15. 32° T, 10 miles from CDR. This put the 5:15. S. out of H.KODIM, well inside TUR, and the pilot plane, we could not get to the position as it seemed with two war to dive. We were still at a distance of 1,000 yards and current, and the plane "Wile, "out" in forward. Reassure to center. Corsair, who was hitting lifefor. Felt course to pass in returned 100 feet after two.

1636
Felt course to pass in returned 100 feet after two.

1809
Reached and fired per position as 8 miles bearing 30° T for 0.5°.

1820
Entered position and passed 30° T for 0.5°.

1845
Line, right, lifefor, fired at 21 miles bearing 015° for 0.5°.

1945
Carried at last over at 10 miles from CDR. SIX, before a left.

1945
Carried at last over at 10

— page 120 —
0827
: 0845
: 0945
: 1019
: 1110
: 1140
: 1225
: 1235
: 1245
: 1530
: 1900
: 16 July 1945
: 0045
: 0331
: 0700
: 1935
: 17 July 1945
: 0120

---

**Confidential**

**Subject:** USS CRO (SS225) - Report of Eighth War Patrol

**Date:** 17 July 1945

**Subject:** (E) Naval Triage

**Date:** 17 July 1945

---

**

— page 121 —
18 July 1945
: 0630
: 1110
: 1115
: 1205
: 1301
: 1533
: 1336
: 1358
: 1422
: 1437
: 1535
: 1538

CONDITIONAL:
: USS CER0 (SS225) - Report of Eighth War Patrol.

SUBJECT:
: NARRATIVE

Completed rendezvous with U.S.S. PARCHE and transferred aviators to her in rubber boat.
Transferred completed, set course for assigned area.
Submerged for trim.
Surfaced.
Sighted SHIBETONITARO ZAKI light (characteristic as normal) (northern tip SHIKOTANI JIMA).

(1200 Position Last 450 14' N; Long 148° 41' E.)

Visibility varying between 100 and 2000 yards. Preceding towards sea-lined area along east coast of ETOROPU JIMA intending to transit ETOROPU KAIYTO.
Visibility increasing rapidly to northward.
Sighted smoke and tons of small stocks at trawler or fishing vessel (ship contact #7), bearing 310° T, range approximately 14,000 yards. Reversed course and reentered fog. Commenced and round to get radar contact.
Radar contact be-ring 340° T, range 7800 yards. Continued on ground in fairly heavy fog. Target course 245° T, speed 85 knots.
Submerged on trawler track.
Finally picked up target with ST rad r, range 3000 yards. Still unable to pick him up by sight or sound. Don't know if he is still on same course.
Sound be-rings at 1000 yards inside tend target had changed course to his left. Could not see him at 500 yards range. How went by 400 yards from us.
Surface and commenced closing in target.
Unable to see target at 400 yards. Lost pip on ST rad r in outgoing signal. Shifted to ST. Named 5", still unable to see target, range 300 yards.
ODD saw small, very dim, ship be burning COC rl " C.O. and gun's crew could not make it out. No radio blasts from a small steamer whistle apparently on starboard beam. ODD lost sight of target in very dense fog. Went chased full. Target probably passed station figuring that he was using internationl rules of the road.
Decided that if he could see us before we could hit him, we'd better secure. Was influenced by r and 500 yards to beach. Scoured gun crew, opened range to sight and then regained course for area.
Visibility commencing approximately 10 nautical miles.
Sighted right to gun and tops of pe-kas on ETOROPU JIMA, range 24,000 yards.
Camp out for fog bank; visibility, extent astern, very good. Decided to take picture of new capped p.

— page 123 —
2230
Received ComSubSpa serial 15 ordering Cero to depart area and proceed to Midway. Set course accordingly.

20 July 1945
1046
1112
1121
21 July 1945
1600
22 July 1945
1650
23 July 1945
1531
2024
24 July 1945
0120
2400
25 July 1945
0700
1140

- 13 -

— page 124 —
1500
After investigation of damage received as a result of an aircraft bomb on 18 July 1945 it was decided that the repairs and tests required were beyond the capacity of the Submarine Base, Midway. Cero received orders to proceed to Pearl Harbor, T. H.

26 July 1945 (1200 Position Lat 270 38.5' N; Long 1770 12' W)
0900 Departed Midway enroute Pearl Harbor, T. H.

27 July 1945 (1200 Position Lat 230 47' N; Long 173 15' W)
28 July 1945 (1200 Position Lat 220 29.5' N; Long 1670 59.5' W)
29 July 1945 (1200 Position Lat 220 52' N; Long 1670 59.5' W)
30 July 1945 (1200 Position - Pearl Harbor, T. H.)

0615 (NY) Effected rendezvous with escort vessel, PC 1078. Entered Pearl Harbor, T. H. and moored at Submarine Base, Pearl Harbor.

- 13(a) -

— page 125 —
U.S.S. CRUZ (S.S.5, CONFIDENTIAL)  (CONFIDENTIAL)
Subject:  USS CERO (SS225) - Report of Eighth War Patrol.
(C) Weather
Weather conditions were generally in accord. No. of
listions. No storms were encountered and seas were usually of force
one to three.
(D) TIDAL INFORMATION
No information can be added to that contained in sailing
directions, current tables and charts.
(E) NAVIGATION L. ADS
In the KURILES and off HOKKAIDO and HONSHU the Sugar Dig read -
was used exclusively for navigation. The navigational lights sailed
were, TUDO SAKI light, early morning 11 July, flashing white, fre-
quency not determined; on 13 July SHIRIYA SAKI exhibited a white
flashing light every 19 seconds; and on 17 July the light sighted
on SHIBETONITRO ZAKI had the characteristics described in I. C.
publication No. 123 X.

(F) SHIP CONTACTS
Time    Lt.    Init.  Course How
No.    Date    Ldr.    Type    Name  Speed  Cntr.  Remarks
1. 7/3/45  138-20 E  Forte-   2300    -    SD  Avoided
2. 7/11/45 142-20 E  AS vessels   11,200    -    CDR  Confusion at
    two more contacts, I tried
    time, and been to all
    three. Contact
3. 7/11/45 142-20 E  AS vessels   13,900    -    CDR  Unclear
    targets were not
    visible.
4. 7/11/45 142-20 E  Humber-Killer   10,000  course  JT  view.
    group    10,000  course  JT  view.
    & speeds
Depth of water 120 fathoms, sub speed and depth 65 RF, 63 foot.
Relative bearing 330°, JP 180° in use, XD detected pinning on
17.5 kts.
5. 7/13/45 141-30 E  Fishing   2100    -    Unble to
    Trawlers    12,000 8 kts    E  clear, tra-
    boid SHIRIYA SAKI radar.

- 14 -

— page 126 —
15

CONFIDENTIAL

Subject: USS CERO (SS225) - Report of Night War Patrol.

(F) SHIP CONTACTS

| Time | Lat. | Type | Init. | Course | How |
|------|------|------|-------||------|
| 7/15/45 | 41-30N | Small | 10,000 | Barge | 5D |
| 7/18/45 | 148-50E | Fishing Boat | 13,000 | 9 kts | 2430 |
| 7/18/45 | 148-50E | Fishing Boat | 13,000 | 9 kts | 2430 |

(G) .IRCR.PT CONT.CTS

It is believed that all of the many ircr.pt cont.cted in the lifeguard log were friendly. On several coast lines Corro was referred to as a friendly place, and, possibly true, enemy pl no. were sighted, believed to be "Scotty".

In the Polar Circuit the only plane that was sighted was a gull wing type similar to "Grace II" which we make a "run" on Corro. One minute after this plane was sighted his bomb exploded close aboard. This pl no had appeared sighted a few hours later. Corro had just emerged, was first seen about five or six miles from the coast. The plane was not picked up by CD radar which had been put in operation five or ten minutes earlier when visibility had increased. No ircr.pt contacts had been made prior to sighting plane. This jet pilot was either experienced very lucky. He made a good run.

- 15 -

— page 129 —
16 July 43 main engine was found to have a knock in 79 unit. Upon pulling the head cover it was found that one exhaust valve had dropped. The cause for this failure was diesel-vorax to be in valve spring locking holes. The lands on the valves shorted 2, allowing the valve to drop. The in the valves shorted 2, had been riding on the rotor than on the valve stem. The ho and piston were replaced.

On 28 June the auxiliary engine was found to be loose. On inspection it was determined to be in the 1st 2.5 inch oil. Upon pulling the head the no longer operates, that is the pressure of water from liner to ho and through the water for the, were noticed to be in bad shape. Several covers were cut entirely through and the covers were not to be held in the water. The covers

— page 130 —
U.S. CERO (SS225) - Report of Bichthar War Patrol.

(K) MAJOR DEFECTS AND DAMAGE:

(a) Hull - The two forward frames on the port side and the
evidence of distortion. The actual damage to this structure can not
be accurately determined until proper measurements are taken to check
the alignment and the ribs are not damaged. The superstructure was
thickened and the pressure hull was damaged.

(d) The aft superstructure was totally bulked at frame #47 (bulkhead
between Control Room and Forward Battery) appears to be slightly dis-
torted on the port side near the pressure hull. Extent of damage can
not be determined until X-rays of the aft superstructure are made.

(e) The superstructure was damaged in Center Room at frame #53
for the stern plane shaft, the break was not visible with the super-
structure.

(f) Many minor deficiencies are present in the superstructure
but a complete account of these can not be listed until a thorough
examination is made of all the superstructure. This examination
will be made at sea.

ORDN. NCG & QUARRY

Only one gun and was accounted for in the entire 15-12-22 18 torpedoes carried. Torpedo #99238 developed a 75 volt static
ground, the course of which was analyzed to be a cracked cell. The subsequent discharging and "jumping out" of cell #35 was not the
ground entirely and no further to the table developed.

(L) RADIO

No material difficulties were encountered except for minor
damage, quickly repaired, resulting from the aircraft bomb received
on 16 July.

The VHF, as usual, was of little use in inter-station radio
manoeuvres, but performed well with aircraft, with a rapid radio
range of about six miles. Channel 1 (plane to plane) was used with
carrier planes, and Channel 2 (all to the ground) with Army aircraft.

The SCR-610 performed well up to a range of about 10,000 yards,
using an unretested standard ship's antenna, but was in use at
range for more than 15,000 yards. Unsuccessful attempts to
make it in range were made by use of the SD antenna and the DU with
antenna.

It is recommended that no new provision for situation
operating be made for the SCR, VHF, and IFK.

- 15 -

— page 134 —
6/28/45 115 60 8
: 6/29/45 139-28 E 75 750 30
: 6/29/45 119-01 N 117 60 12
: 6/29/45 139-52 E 73 ? 15
: 6/29/45 139-52 N 75 750 30
: 6/29/45 140-28 E 93 350 20
: 6/29/45 139-20 E 70 500 20
: 6/29/45 139-20 N 74 500 46
: 6/30/45 139-36 E 180 200 5
: 7/1/45 139-18 E 75 1000 --
: 7/1/45 139-57 E 72 1000 20
: 7/2/45 136-41 E 69 600 18
: 7/2/45 136-41 E 72 750 40
: 7/2/45 136-41 E 78 750 30
: 7/2/45 136-49 B & 75 750 & 20
: 7/2/45 136-49 B & 75

— page 136 —
7/11/45 4-29 E 148 400 8
: 7/12/45 1-21 N 78 500 25
: 7/12/45 1-31 N 78 500 25
: 7/12/45 1-31 E 150 400 10
: 7/13/45 1-22-59 E 100 450 20
: 7/13/45 1-31 N 75 750 35
: 7/13/45 1-31 E 72 400 15
: 7/14/45 1-31 N 72 400 15
: 7/14/45 1-31 E 180 160 5
: 7/14/45 1-31 E 300 400 10
: 7/14/45 1-31 E 157 100 5
: 7/15/45 1-31 N 147 750 25
: 7/15/45 1-31 E 520 150 2
: 7/16/45 1-18 E 75 400 25

: 7/16/45 1-18

— page 137 —
17. 7/3/45 13-36 E 178 230' 8
: 18. 7/4/45 137-32 E 70 750 40
: 19. 7/4/45 138-42 E 82 750 35
: 20. 7/7/45 29-16 N 107 550 -
: 21. 7/7/45 137-36 E 80 750 25
: 22. 7/7/45 137-36 E 74 750 35
: 23. 7/7/45 29-12 N 78 1000 35
: 24. 7/10/45 35-39 N 152 500 35
: 25. 7/10/45 35-39 N 152 500 35
: 26. 7/10/45 38-00 N 195 500 15
: 27. 7/10/45 38-59 N 260 1260 1
: 29. 7/11/45 39-26 N 152 500 7
: 30. 7/11/45 39-26 N 147 450 12
: 31. 7/11/45 40-09 N 68 500 25

| CRITERIA |

— page 139 —
25-43/A16-3
SUBMARINE DIVISION FORTY THREE
nd
Serial: N-8108
Care of Fleet Post Office;
San Francisco, California,
30 July 1945.

FIRST DIVISION:
To:
U.S. SUBMARINE DIVISION
U.S. SUB

— page 140 —
1/2/45
Serial: 0210
FCS-10/A16-3
Fleet Post Office
San Francisco, California
11/rhb
Confidential
Second endorsement to
U.S.S. CERO (SS225) -
Report of War Patrol
Number Eight

From: The Commander Submarine Squadron TEN.
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. CERO (SS225) - Report of War Patrol
Number Eight.

1. Forwarded, concurring in the remarks of the
Commander Submarine Division FORTY-THREE.

2. The Squadron Commander congratulates the
Commanding Officer, officers and crew of the U.S.S. CERO upon
the successful completion of that vessel's Eighth War Patrol.

Signature: G. E. FERRISON.

— page 141 —
81149
Crew: 10
USS: USS (SS225) - Report of Eighth War Patrol
(27 June to 30 July 1945)

1. The eighth war patrol of the CED, under the command of Lieutenant Commander E. Garthrong, U.S. Navy, was conducted in the area south and east of Honshu. The CED operated at times during this patrol with groups under the command of a number of officers of the U.S.S.R. (SS271), and in connection with patrols under the command of the commander of the U.S.S.R. (SS215).

2. Most of this patrol, which was terminated early due to a severe enemy air attack, bomb attack which necessitated return to port, was devoted to life-saving duties. The CED's one opportunity for rescue in the hazardous waters off Honshu was the first night of the patrol. Rescue of three Naval aviators was made in the early hours of the morning of 2,000 miles off Shikoku. After they were safely in port, the CED contacted a bombardment of Shiriyu Sakai radio station and light-answer.

3. Armed of Submarine Combat Ensigns for this patrol is authorized.

4. The Commander Submarine Force, Pacific Fleet, congratulates the commanding officer, officers, and crew of the CED for this daring and successful performance of lifeguard duty. The CED is credited with having inflicted the following damage upon the enemy during this patrol:

| Damage | Description |
|||
| 1.     | Sonobe | 1.5 tons, 1.5 knots

— page 143 —
7-168
: AQ-125-78
: 1.0
: 1.1
: 1.25
: 1.4
: 1.6
: 2.8
: 2.5
: 2.2
: 2.0
: 1.8
: 1.25
: 1.4
: 1.6
: 2.8
: 2.5
: 2.2
: 2.

— page 146 —
11 April 1944
CROSS INDEX CARD

DATE: 11 April 1944
FROM: Commanding Officer USS CERO (SS-225)
TO: Submarine attacked by plane of VP-106 on search mission from
NAGASA, near misses caused minor damage.

Separately under SEVENTH FLEET ser 00916 of 8 may 44

CERO
ACTION REPORT

— page 147 —
11 April 1944
CERO
CROSS INDEX CARD

Report of circumstances surrounding bombing of submarine
(with minor damage) by friendly planes in Lat 1-00N,
Long 139-20E.

Separately under TF 72 ser 0098 of 18 Apr 44.

---

**DECLASSIFIED**
DATE 17 Oct-7 Nov 1944 NAME CERO
FROM CO - USS CERO (SS-225)
SERIAL 002
DATE 14 November 1944
SUBJECT Special Missions
Report of mission 17 Oct-3 Nov, and 5-7 Nov off LUZON
during SIXTH WAR PATROL. Cargo & personnel put ashore
28 Nov during First Mission. Conducted Lifeguard duty
off Luzon 6 Nov for Carrier Air Strikes on LUZON.
(SWESPAC- SUB-CFS)
FILED: War Diary
Separately as ORIGINAL CARBON CITY

MICROSERIAL NO. ACTION REPORT 0044 FORN 3480-13 (11-55) 1-3888

---

**DATE 22 Apr-20 May 1945**
NAME CERO
FROM C.O. USS CERO (SS-225)
SERIAL 001
DATE 27 May 1945
SUBJECT SUBMARINE ACTION REPORTS, Forwarding of
Fowards reports of three torpedo firings on SEVENTH WAR
PATROL in the Honshu-Hokkaido area. No hits claimed.

(CENPAC: SUBS)
FILED: War Diary
Separately as Enc. to SUBSPAC ser 0004/8 of 18 Jun 45

MICROSERIAL NO. ACTION REPORT 0044 FORN 3480-13 (11-55) 1-3888

— page 149 —
1. The task group was composed of three submarines, task units 17.1.4.1, 17.1.4.2, and 17.1.4.3.
2. The next higher echelon: Task Force 17.
3. Major Task Force: U.S. PACIFIC FLEET.
4. The operations of Task Group 17.1.4 were carried out in accordance with Commander Submarines, PACIFIC FLEET operation order #217-43, Serial 001347 of 25 September, 1943.
5. Enclosures (B), (C) and (D) cover the details of the activities of Task Group 17.1.4 required by reference (a); this report will cover only the broader aspects of a "Wolf Pack" operation.
6. Exercises with convoys to and from Hawaii, with the helpful cooperation of the Commander Hawaiian Sea Frontier, were conducted for several weeks prior to the departure of this Task Group. One, two and three submarines operated with the convoys, attacking singly, in pairs and in groups of three. It became apparent that three submarines would be the ideal number to use for a coordinated attack. Two could not be expected to cover all possibilities and four would be unwieldy. Until an effective means of employing and controlling more can be devised, I recommend the groups to be limited to three. However, it is quite possible and would be very effective to employ more than one group in the same general area by keeping them well separated by plan.

-1-
ENCLOSURE (A) 12 02195

— page 150 —
5. Using the game board on the wardroom dance floor at the Submarine Base, problems were set up for groups to attack single ships and groups of ships. The studies of these games produced excellent results and a doctrine of coordinated attack by three submarines was evolved.

6. On 23 September, 1943, the Force Commander (Rear Admiral G. A. Lockwood, jr., USN) authorized a group consisting of the CERRO, SHAD and GRAYBACK. The area assigned was the East China Sea.

7. The CERRO and GRAYBACK left the Submarine Base, Pearl Harbor on 26 September for Midway. Enroute various communication exercises were held and the doctrine was revised and put into shape. The SHAD joined in Midway and Task Group 17.14 left Midway on 1 October for the Area. Communication drills were held enroute and a few signals were added to the list.

8. Enemy convoys were expected to pass west of the Bonins to and from Tokyo Bay and this Group patrolled along these routes on 10 October. Submarines were submerged when GRAYBACK made a contact and attacked. The SHAD received the contact report and although various targets were sighted on 11 October, no attacks were made. The signal did not get through to the CERRO. CERRO heard about twelve depth charges but could not detect the direction. A depth charge direction indicator would have been very valuable here.

9. On the night of 11-12 October when proceeding toward area, CERRO made contact by radar. The Commanding Officer did not know just where the other two submarines were and we did not have a grid of this area. No contact signal was made. This was a fault in the plan that needed correction. CERRO attacked twice, sinking one ship and damaging another with four torpedoes. When last seen just before dark, it was low in the water with a destroyer alongside.

10. All submarines were in assigned squares on the 13th and proceeded to successive squares according to the plan.

11. On 14 October GRAYBACK made a contact. Again all submarines were submerged and signal did not get through.

— page 151 —
12 02195
: SUBMARINE SQUADRON FOUR
: CONFIDENTIAL

GRATBACK sank one ship. It became apparent that either a satisfactory means of communicating to a distance of about twenty miles submerged must be developed or group should operate in areas where submarines can patrol on the surface. The Commanding Officers of the submarines felt that surface patrolling in this area during daylight was not advisable.

12. On 22 October, GRATBACK made a contact in late afternoon. The contact signal did not get through but after dark GRATBACK's contact signal came through by radio. CERRO started toward contact fifty-miles south and going away. After about two hours running, SHAD reported contact to the north, targets heading south. CERRO changed course to intercept SHAD's contact. SHAD gave course as 180 True. Unfortunately, the course was actually 160 True and CERRO failed to contact the enemy. GRATBACK hit one ship with four torpedoes. This ship was "similar to the ASAKA MARU, sank. The SHAD hit one cruiser with three torpedoes and another with one.

13. On 25 October, BARB reported a convoy of three large transports on course 60 passing through area. Signal to group to proceed to a position to intercept and at 2320 on 26th, SHAD and CERRO picked them up on radars. SHAD reported first, so by doctrine attacked first. All ships stopped when SHAD fired. Four torpedo hits were heard by CERRO although SHAD only reported two hits. Later, one transport was found by GRATBACK stopped and smoking. A freighter was seen down by the BARB and other transport was seen making very slow speed. The CERRO saw a very large transport on its side in a sinking condition. This was ill-United by an escort searchlight. It is quite possible that the frigate had joined up with the convoy sometime after BARB's sighting. From the extent of the damage discovered, it seems as though the freighter might have rammed the transport that was seen to be stopped with personnel in boat examining the propellers. However, it is quite certain that the four ships were all damaged. The first transport hit by the SHAD was the largest of the three. It was not observed by the GRATBACK after CERRO saw it on its side and it is presumed that it went down. The evidence shows that the transport hit by the GRATBACK was sunk. SHAD and GRATBACK should divide this credit.

— page 152 —
14. 30 October, GRAYBACK closed CERO to deliver report of action of 27th. Gave Commanding Officer GRAYBACK oral orders to return to Midway, since he had but three torpedoes remaining aft and was near the end of his fuel. Gave orders SHAD and CERO to patrol own areas. On 4 November, about 9:00 p.m., CERO sighted convoy. Trailed from ahead until about 1:00 a.m., 5th, then fired nine long range torpedoes, three at each of three larger targets. These appeared to be three large AKs, two medium AKs, and four escorts. Light conditions were bad for this attack, it being dark for periscope attack yet too light to close on surface for short range attack. Since the depth of water was around thirty fathoms shoaling toward the Yangtze bank, the Commanding Officer CERO was justified in accepting the long range shots rather than to close and get sighted, which might have resulted in the loss of opportunity to get ahead again in order to attack, because of the shallow water ahead. Three hits were heard and one flash was seen. It is estimated that one of the large AKs received one hit and another two hits. No evidence of ships sinking was noted.

15. With five torpedoes aft and one forward, CERO left her area on the seventh with sufficient fuel for one engine speed to Midway and the required reserve.

16. On 11 November, CERO sighted the masts of a ship. The visibility was a little hazy and the CERO made an end-around run on what was thought to be a good target. The maneuver was very clearly executed and the CERO finally attained a firing position for using stern tubes. At this point, it was discovered that the target was an escort vessel of about 150 tons and the chaser was then in a position to be chased. No guns were seen and CERO made a battle surface when the target was about 5,000 yards away. Fifty rounds of 4" were fired and about four hits were obtained, setting the patrol craft on fire. It was interesting to note that the patrol craft headed directly for the CERO, dodging back and forth to avoid being hit. It is most probable that he was attempting to close to machine gun range. However, due consideration was given by the Commanding Officer, U.S.S. CERO, to the possibility that he was carrying a torpedo.

17. On 9 November, CERO diverted course and increased speed to attempt to intercept an enemy contact. This was not sighted. It is felt that more use should be put to es-12 02195 tablished search methods.

— page 153 —
18. Each submarine performed very well even though it was the CERO's first patrol, the Captain of the GRATBACK's first patrol and the SHAD's first patrol in the Pacific. The operations areas were in location where air attack could be expected at any time and Commanding Officers felt that the element of surprise could be best maintained by daylight submerged and night surface operating. Information of daylight contacts could not be transmitted to other submarines of the Group and the full effect of the Group could not be brought to bear.

19. While a complete analysis cannot be made, it is felt that in all cases torpedo performance was not satisfactory. CERO hit a large ship about 16,000 tons with four torpedoes and seven hours later she was still afloat. The GRATBACH hit a ship similar to the ASAKA MARU with four torpedoes and was not sure that she sunk, but it is not conceivable that she could have remained afloat. The cruiser that received three hits from the SHAD is a remarkable ship if she remained afloat.

20. Experience with this Task Group indicates that the Task Group Commander actually embarked in one of the submarines is not entirely desirable and it is felt that the Task Group Commander can serve a more useful purpose at Pearl in that he may break down information and direct submarines to proceed in accordance with a search plan which he may lay out. He should be as closely attentive to the operations as if he were actually on board a submarine. Messages concerning the Group should be directed immediately to him and he should reply or pass out the operational information without delay. The Task Group Commander is in no position when he is embarked to send out long despatches including the details of a search. This, however, can be done by radio from Pearl. It is proposed to work out Task Group problems on the Game Board employing this method of control.

21. The Group Commander feels that with the benefit of the experience gained in this Group Patrol, other Groups should prove even more successful. Most of the contacts were made during daylight when submarines were submerged.

22. It appeared that the Japs, learning of the presence of more than one submarine by the double attack on 12 October and further by hearing our radio signals, changed their counter-attack method. When a single submarine at-

— page 155 —
28. Early installation of P.P.I. screens is urged.

29. The development of the periscope radar and depth charge direction indicators should be speeded up if possible.

30. It is considered that the following damage was inflicted upon the enemy by this Group:

| Date | By  | Hits | Name and Type                | Tonnage |
|------|-----|------|||
| Oct. 12 | CERO | 2    | Like Tottori                  | 5973    |
| 14    | GRAYBACK | (?) | Kozui                         | 7072    |
| 22    | GRAYBACK | 4    | Asaka                          | 7399    |
| 27    | SHAD  | 2    | Fuji                           | 9138    |
| 27    | SHAD & GRAYBACK | 1 & 1 | Kamo                          | 8524    |

DAMAGED

| Oct. 10 | GRAYBACK | 1    | AK                              | 5000 Est. |
| 12     | CERO    | 4    | Mamiya                        | 15820   |
| 22     | SHAD    | 3    | Cruiser                       | 7000 Est. |
| 22     | SHAD    | 1    | Cruiser                       | 7000 Est. |
| 27     | SHAD    | 1    | AK                              | 3500 Est. |
| 27     | SHAD    | 1    | Cryoku                        | 7365    |

Nov. 4 | CERO | 2 in 1 | 1 in 1 | 2 AKs | 17500 |
| 11    | CERO | Gunfire | Patrol Boat | 150 | 63,335 |

TOTAL DAMAGE INFILTED TO THE ENEMY | 101,441 TONS

TOTAL DAMAGE INFILTED TO THE ENEMY | 12,92195

ENCLOSURE (A) | 8

— page 156 —
31. The Group Commander congratulates the Commanding Officer, officers and members of the crews of the CERO, GRAYBACK and SHAD on their excellent performance and recommends that awards in keeping with the policies of the Board of Awards be made to the personnel of these submarines.

[Signature]
[Date]
[Enclosure (A)]

12 02195
-8-
ENCLOSURE (A)

— page 157 —
01854
Serial: 01854
Care of Fleet Post Office,
San Francisco, California,
DEC 7 1943

FIRST ENDORSEMENT to
C.T.G. 17.14 1tr.
FC5-4/A12-1/A16-3 of
28 November, 1943.

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: Commander Task Group 17.14 War Diary.

1. This first coordinated attack group under the command of Captain C. B. Monsen, U. S. Navy, operated in the East
   China Sea. This area has in the last few months been highly productive and in it convoys of 10-12 ships had been assembled.
   Prior to his departure, the group commander had considerable experience in convoy attack exercise and was the originator of the
   convoy exercise game board. Both of these activities have proven very beneficial in giving submarines and their fire control teams
   valuable experience in convoy attack procedure.

2. The Commander Submarine Force, Pacific Fleet, consults in the statement made in paragraph 4 that the group sizes
   should be limited to a maximum of three submarines. This limitation is necessary because of the difficulty in controlling a larger
   number of submarines and also because the small size of the usual Japanese convoy does not warrant the use of more. Placing more
   than one group in an area is not considered feasible at this time, since there is an insufficient number of submarines available.

3. With regard to comments made in paragraph 20 as to
   control of the attack group, the Commander Submarine Force, Pacific Fleet, is not entirely in accord with the idea of attempting to control such a group from Pearl Harbor. Communication delays are inevitable since the Fox and Haikyu schedules must necessarily carry a very great amount of traffic in addition to submarine traffic.
   It is believed that control of an attack group must be exercised by a group leader who is actually in the area and who may be a Division Commander or the senior commanding officer of the group. This officer supervises the day by day local patrol areas of his ships.

— page 159 —
01854
Serial: 01854
COMMANDER SUBMARINE FORCE
UNITED STATES PACIFIC FLEET
Care of Fleet Post Office,
San Francisco, California,
DEC 7 1943

FIRST ENDORSEMENT to
O.T.G. 17.14 1tr.
F05-4/A12-1/A16-3 of
28 November, 1943.

Subject: Commander Task Group 17.14 War Diary.

---

(a) Position of submarine must be known. This requires frequent use of the radio; this, of course, is also a problem when control is in the area.

(b) Weather conditions are usually unknown. This does not apply when control is in the area.

(c) Visibility - The same applies as in subparagraph (b).

(d) The condition of the submarine is not known; i.e., on the surface or submerged, material condition, fuel and torpedoes on hand, etc.

6. The suspected presence of submarine groups may well cause the Japanese to change his escort tactics as mentioned in paragraph 22. If such is the case, then another advantage has been gained by grouping submarines.

12 92195
23

— page 160 —
4-3(1)(16) COMMANDER SUBMARINE FORCE UNITED STATES PACIFIC FLEET
Serial 01854
Care of Fleet Post Office, San Francisco, California,
DEC 7 1943

FIRST ENDORSEMENT to
C.T.G. 17.14 1tr.
F05-4/A12-1/A16-3 of
28 November, 1943.

Subject: Commander Task Group 17.14 War Diary.

7. The recommendations made in paragraph 26 regarding weather fronts is considered worthy of investigation. Such practice has been used by the Germans who were able to give valuable information to their submarines by means of weather stations located in the Arctic regions. If not possible now, our weather central may soon be prepared to furnish submarines with weather front information along the Empire routes such that they can take advantage of these fronts. This will be investigated.

8. By copy of this endorsement the Commander Submarine Force, Pacific Fleet, congratulates the Commander Task Group 17.14, not only for the efficient manner in which this group was organized and maintained, but for the intense study and preparation made prior to his departure.

Copy to:
C.T.G. 17.14.

G. A. LOCKWOOD, Jr.

12 32195

— page 161 —
1-5-1P
A12/SS
Serial 03174
CONFIDENTIAL
C-O-N-F-I-D-E-N-T-I-A-L

2nd Endorsement to
C.T.G.: 17-14 1tr.
FC5-4/A12-1/A16-3 of
28 November 1943.

From: Commander in Chief, U. S. Pacific Fleet.
To: Commander in Chief, U. S. Fleet

Subject: Commander Task Group 17-14 War Diary.

1. Forwarded. Paragraphs 2 and 3 of the First Endorsement are concurred in.

2. The decision of the Commanding Officer of the SHAD to spread 9 torpedoes over what he then believed to be three cruisers, is open to question. His intention was to make hits on three of them retained than limit it to two, with the hope that any ship hit would be finished off by the submarine of his own attack group. However, considering the probability of misses and "duds", and the ability of modern cruisers to stay afloat and continue at fair speed even after one or two torpedo hits, this question should be given further consideration.

3. The Commander in Chief, Pacific Fleet, congratulates the Commander of Task Group 17-14 and the officers and men of the SHAD, CERO, and CREYBACK, for their handling of this Co-ordinated Attack Group.

Copy to:
ComSubsPac
C.T.G.: 17-14

C.H. MEMORRIS
Chief of Staff

— page 162 —
10 MAY 1944
From: Commanding Officer, CE RO
To: Commander Task Force SWIFT-TWO.
Subject: Special Mission, U.S.S. GENO, April 1944.

Enclosure: (A) Diary of Period 8-10 April, 1944.

1. In accordance with despatch orders of addressee the Commanding Officer contacted Lieut. Patterson, RAN, DSIO, New Guinea, at Lingenack Bay on 5 April, 1944. Plans were made for recovery of a reconnaissance party during the period 8 to 10 April, 1944 in the vicinity of Tanah Merah Bay, New Guinea.

2. Received Allied Geographical Section, Southwest Pacific Area, Terrain Study No. 76, Confidential, Copy No. 167, giving details of terrain in vicinity of recovery point. R.J.T. O'NEAL, 3gt., Allied Intelligence, AY, radio operator in command of the original intelligence, also took aboard one large rubber boat.

3. The detailed arrangement regarding recognition signals and communications which had been made between the commanding officer of the reconnaissance party and the commanding officer DACE were adopted without change. In general, the plan was for the reconnaissance party to be at a specific point on the beach during the night 5 to 11 April, 1944. They were to flash seaward a prearranged code word, periodically during the night indicating that the party was ready to embark. Upon receipt of this signal this vessel was to acknowledge by flashing light, and close the beach to take the party aboard. Codes were arranged to cover the possibility of having to furnish one or two boats from this vessel.

4. CERO departed Lingenack Bay 5 April, 1944 and proceeded to rendezvous. Due to bad weather no navigational fix was obtained from point of departure on 5 April until 2253 April 9, at which time the fire showed CERO 55 miles west of the rendezvous. Once the position was fixed CERO remained in sight contact with the recovery point almost continuously from about 0930 until about midnight 10 April when CERO was required to depart in accordance with orders of addressee. At no time was there any indication of the party being in the neighborhood of the rendezvous. It is regretted that air

— page 163 —
10 MAY 1944
SS225/A16-3
Serial 002
Subjeet: Special Mission, U.S.S. ORO, April 1944.

5. Sgt. CREAM was disembarked at Seasider Harbor, 10 May, 1944. He conducted himself with credit during the period he was on board. In accordance with verbal orders of Lt. Patterson, the confidential publication mentioned in paragraph 2 was turned over to Sgt. CREAM.

E. F. DISSERTZ.

Page 2 of two pages