U.S.S. TREPANG (SS-412) — war patrol report SS-412_TREPANG_Part1.pdf

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START OF REEL
JOB NO. [HANDWRITTEN: H-108]
OPERATOR [HANDWRITTEN: L. Frye]
DATE [HANDWRITTEN: 9-12-80]

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THIS MICROFILM IS
THE PROPERTY OF
THE UNITED STATES
GOVERNMENT

[SEAL: DEPARTMENT OF DEFENSE, UNITED STATES OF AMERICA, with eagle]

MICROFILMED BY
NPPSO-NAVAL DISTRICT WASHINGTON
MICROFILM SECTION

REEL TARGET - START AND END
NDW-NPPSO-5210/1 (6-78)

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[HANDWRITTEN: NRS 1980-18]

[HANDWRITTEN: TREPANG (SS-412)]
[HANDWRITTEN: WORLD WAR II: PATROL FILE]
[HANDWRITTEN: ACTION REPORTS]

[HANDWRITTEN: ALL MATERIAL ON THIS REEL IS DECLASSIFIED]

[HANDWRITTEN: FOR DECK LOGS MAY 1944 - JUNE 1945 CONSULT]
[HANDWRITTEN: NATIONAL ARCHIVES WHICH HAS CUSTODY.]

[HANDWRITTEN: J.A. KOONTZ]

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Division of Naval History
Ships' Histories Section
Navy Department

HISTORY OF USS TREPANG (SS 412)

All combatants in the Pacific war were primarily dependent upon
transport since there was relatively little land transport available in this usu-
ally primitive theater of operations. The sea made an excellent road for
those who controlled it and a barrier to those denied it. When Japan controlled
the sea in the Far East her offensive rolled ahead through a series of
practically unbroken victories, pushing the boundaries of her Empire to the
Malay Barrier and the Solomon Islands. By means of the sea she could isolate
Allied strongholds, deny them all reinforcements, concentrate her own forces
and attack when and where she desired. When she lost control of the sea these
conditions were exactly reversed. Before the end of 1943 the slow creeping
Allied advance through the jungles was over and the swift advances over the sea
had begun. The Empire of Japan melted away almost as rapidly as it had grown.

Our Submarine Force waged constant, relentless and effective war upon
this Japanese sea potential. During the war years they sank 1,750 merchant
ships and 194 combat vessels of all classes, more than 56% of the total of
such losses. The USS TREPANG did not join the fray until the summer of 1944,
but in her year of battle she downed eleven Japanese ships for a total tonnage
of 23,850 tons. Awarded five Battle Stars for her successful patrols, she was
also awarded the Navy Unit Commendation for her heroism in action during her
First War Patrol.

The keel for the SS 412 was laid at the Navy Yard, Mare Island,
California on 25 June 1943. At the launching on 23 March 1944 Mrs. R. M Daven-
port, wife of the first commanding officer, served as sponsor. The submarine
was christened "TREPANG" for a fish of the Actinopyga family, which are
caught in northern Australia and the East Indies; boiled, dried, smoked, and
then shipped to China for making soup. The sleek new submarine was accepted
by the Navy and turned over to her first skipper, Commander Davenport at the
commissioning ceremonies on 22 May 1944.

Shakedown and training cruise were conducted out of San Diego, California,
and the TREPANG departed for the Pacific theater on 15 August 1944. On 13
September she steamed out on her first patrol. This was to be conducted in
the area just south of Honshu, the main Japanese home island. On 1 October
she contacted a fast enemy task force that was making a night sortie from Tokyo
Bay. The enemy's speed, considerably greater than the TREPANG's, made it
necessary to attack on the surface, with very little time to maneuver into an
advantageous position. She must have been in sight for at least six minutes
prior to reaching firing position, but she was able to launch her torpedoes,
sink the freighter TAKUNAN MARU, and escape on the surface. On 11 October she
sank the TRANSPORT No. 105 for another 1,000 tons. In the same action she
severely damaged a battleship and a destroyer. On 23 October she returned to
Majuro for refitting by the USS BUSHNELL.

On 16 November the TREPANG steamed out for her second run, which was to
be conducted between northern Luzon and Formosa. She never got past Luzon.
It was dark, rough and windy on that 6th of December. The TREPANG had surfaced
after her day's submerged, inshore patrol, and had just set course for more open
[HANDWRITTEN: 1A]

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-2- USS TREPANG (SS 412)

waters, when she detected a group of ships approaching from the north. Upon
investigation, they proved to be a slow speed convoy of seven large ships and
three escorts, heading for the Philippines. The TREPANG radioed the news to the
RAZORBACK and SEGUNDO, then went in for a submerged attack. The first attack
resulted in the sinking of cargomen BANSHU MARU NO. 31 and JINYO MARU, and the
damaging of a third. Just as the submarine was about to administer the coup-
de-grace to the latter, the FUKUYO MARU obligingly blew up and sank. A short
while later, the SEGUNDO arrived on the scene, followed closely by the RAZOR-
BACK. The TREPANG singled out a fourth member of the now scattered convoy.
It stayed afloat long enough to receive the submarine's remaining torpedoes,
then sank in a mass of flames. Meanwhile, the other two boats were deliver-
ing their torpedoes to the fleeing remnants of the convoy. The SEGUNDO
promptly dispatched two of the survivors, one an ammunition ship, and damaged
a third. The RAZORBACK, polished off the cripple. Now out of torpedoes, the
TREPANG arrived in Pearl Harbor in time for Christmas. Here Commander Daven-
port was releived of command by Commander F. A. Faust, USN.

On her third patrol the TREPANG again was off Honshu. In company with
the submarines PIPER, POMFRET, BOWFIN and STERLET, she made an anti-picket
boat sweep past Tempo Shoto, the eastern island chain south of Tokyo. This was
done to clear the area for the FIFTH Fleet assault on Iwo Jima. No targets
while targets were encountered, and she was assigned to lifeguard station for
the carrier strikes on Tokyo. She deviated from this duty long enough to sink
a small freighter on 24 February 1945, and blow the bow off another small
coastal freighter. The latter was stopped, but while the TREPANG was maneuver-
ing to finish it off, several small anti-submarine vessels appeared from
behind the nearby headland and converged on the raider. The TREPANG escaped
damage, but she was pinned down for seven hours by the depth charging. No
aviators were in need of the TREPANG's services during her time on lifeguard
duty, and she returned to Guam for her third refit in early March 1945.

For her fourth patrol, the TREPANG was ordered to the Yellow Sea. This
area was classified as a "hazardous duty" area due to the shallowness of the
Sea. Aside from this consideration, it had long been considered a choice
assignment, proven by a succession of lucrative patrols in the area. The
TREPANG's was no exception. In separate attacks, during the first week in the
area, she fired all her torpedoes and sunk a medium-sized landing craft on 28
April; a large, heavily laden freighter-transport on the 30th; and the large
destroyer-escort, who blew sky high with a hit in the magazines, on 4 May.
The TREPANG also gunned a wooden junk, carrying a load of lumber during this
period. After she left the Yellow Sea, she did a short tour lifeguarding
for B-25s off Shanghai and for the continuing B-29 strikes on Tokyo, then
returned to Guam for her fourth refit.

The TREPANG'S fifth and last patrol was divided into two parts. The
first half was spent lifeguarding for Iwo-based Mustangs and Superforts from
Guam, Saipan and Tinian. The second half was devoted to an offensive patrol
off northeastern Honshu and eastern Hokkaido. She was first stationed a few
miles southeast of Tokyo, for a fighter strike on the capital by P-51s. Having
experienced two previous patrols of fruitless lifeguarding, she was expecting
a series of long, dull days spent steaming in circles, squares or triangles,
with possibly an occasional visit by an enemy plane to break the monotony.

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-3- USS TREPANG (SS 412)

However, shortly before noon on the first day, a parachute was spotted, and a
few seconds later a huge geyser of water shot up from a crashing plane. The
TREPANG raced for her first rescue, and completed her first rescue. While
she was maneuvering for this rescue, the TREPANG received a message from
another pilot requesting permission to bail out. The second Mustang circled
slowly, then the pilot executed a perfect jump, landing in the water about
400 yards from the submarine. In five minutes, he too was aboard.

Three days later the rescued aviators were transferred to the homeward
bound TIGRONE. In the middle of the transfer, TREPANG intercepted a search
plane's report of a B-29 crew down about seven miles off the coast south of
Nagoya. Their plane had been shot down during the previous day's superfort
strike, and the men had been in the water for 24 hours already. Again the
TREPANG shot ahead under full power, followed a few minutes later by the
SPRINGER. Five hours later, the TREPANG arrived at the reported position, and
found eight survivors in four groups of rafts, spread out over about four miles
of ocean. The rescue search plane led the submarine to each group in turn.
The TREPANG had seven on board when the SPRINGER reached the eighth.

At the conclusion of the first phase of her patrol, the TREPANG was
ordered to rendezvous with the inbound DEVILFISH to transfer her latest crop
of fliers. Enroute she encountered a 492 ton minesweeper. The target
carried only two 37 millimeter machine guns, so the submarine surfaced and sank
it with deck guns.

The eastern coast of Honshu from Tsugaru Straits to Sendai Bay was one
of the lifelines of Japanese industry. Ore from the vast coal and iron mines
of Hokkaido was transported by sea to the industrial centers of Honshu. The
contours of the ocean floor are such that the Japanese were able to plant an
almost continuous minefield from the Strait to Tokyo Bay. In only a few
places did the shipping lanes emerge from behind their wall of explosives and
become vulnerable to undersea attack. One such spot is the very northern tip
of the Honshu coastline, Shiriya Saki, at the mouth of Tsugaru Strait. This
is the spot the TREPANG chose for her submerged patrol on a day in the
middle of July 1945. Submerging at dawn, she crept to within a mile and a half
of the beach, and settled down for a day of quiet waiting and watching.

All morning the area teemed with patrol vessels dashing back and forth,
pinging furiously in the hope of detecting any submarine that might be lurk-
ing in the area. Time and again they passed close aboard the TREPANG,
but none ever detected her. The submarine with-held her fire in the hope that
these small craft might be forerunners of a more valuable target. Suddenly
around noon, as if on a signal, all the patrol boats either returned to port
or headed down the coast and soon passed out of sight, leaving the ocean to
the TREPANG and a tiny,sea going tug who all morning had been working
smokey way southward with two heavy ore barges in tow. About half an hour
later, she sighted a convoy of three unescorted coastal freighters. The
TREPANG scored two clean hits to sink the lead freighter, the KOUN MARU No.2.
The second zigged, and escaped from three torpedoes unscathed. The TREPANG's
crew pointed her nose seaward, feeling quite smug. Suddenly two jarring ex-
plosions shattered the stillness and tore at the welds of the submarine's hull.
Instinctively, she groped for the bottom to escape her unseen assailant, mean-
while bracing for further blows. None came. The attack was delivered by a lone

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-4- USS TREPANG (SS 412)

plane that spotted the TREPANG's shadow beneath the surface. Fortunately, it
carried only contact-detonated bombs which could not reach beneath the surface,
and a quick survey showed that little damage had been done.

The war was moving fast by now, and before long the TREPANG was again on
lifeguard duty. This time it was for the large-scale strikes on northern
Honshu and Hokkaido. She picked up one carrier pilot during this period. On
14 July the submarine had a ring side seat for the Allied bombardment of the
Japanese coastline. The TREPANG returned to Pearl Harbor just in time to watch
the tumbling succession of events in August. First the atomic bomb, then Russia's
declaration of war, Japan's tentative acceptance of terms, rumors, denials,
more rumors, and finally, Peace!

Upon completion of refit the TREPANG left Pearl Harbor and turned east-
ward toward the United States and home. She arrived in San Diego on 3 September
1945, one year and nineteen days from the time she passed under the Golden Gate
Bridge bound for the war zone.

The USS TREPANG was awarded the Navy Unit Citation for her First War
Patrol, with the text of the citation reading as follows:

"For outstanding heroism in action during her First War
Patrol in the Tokyo Bay Area of the Japanese Empire, from
September 13, to October 23, 1944. Operating in bold defiance
of persistent and severe hostile counter-measures, the USS
TREPANG maneuvered to strike at a heavily escorted Japanese
battleship sighted leaving Tokyo Bay. Going in under relent-
less depth-charge and air opposition, she penetrated the
enemy's formidable screen to deliver accurate and intensive
torpedo fire against her targets and, by her daring and
tenacious tactics, succeeded in sinking a large Japanese
landing craft and in seriously damaging the battleship and
a destroyer. Constantly ready for combat despite unfavorable
attack opportunities, the TREPANG served with distinction in
carrying the Battle of the Pacific into the enemy's home
waters, and her gallantry in action reflects the highest credit
upon her skilled and courageous officers and men and upon the
United States Naval Service."

She also received five Battle Stars on the Asiatic-Pacific Area Service
Medal for participating in the following operations:

1 Star/Iwo Jima operation
Assault and occupation of Iwo Jima -- 15 February - 16 March 1945
FIFTH Fleet raids against Honshu and the Nansei Shoto -- 15 -16
February 1945, 25 February and 1 March 1945

1 Star/Okinawa Gunto operation
Assault and occupation of Okinawa Gunto -- 17 March - 21 June 1945

1 Star/THIRD Fleet operations against Japan -- 10 - 17 July 1945

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-5- USS TREPANG (SS 412)

1 Star/First Submarine War Patrol -- 13 September - 23 October 1944
1 Star/Second Submarine War Patrol -- 16 November - 22 December 1944

By Directive dated January 1947, the USS TREPANG was placed out of com-
mission in reserve, U.S. Pacific Reserve Fleet, and berthed at Mare Island,
California.

STATISTICS

OVERALL LENGTH 312 feet
BEAM 27 feet
SPEED 20 knots
DISPLACEMENT 1525 tons
COMPLEMENT 8 officers and 72 men

Compiled: 8 January 1954

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SS412/A16-3
Serial (011)
[STAMP: DECLASSIFIED]
[STAMP: CONFIDENTIAL]

U.S.S. TREPANG (SS412)
[STAMP: DECLASSIFIED-ART. 0445, OPNAVINST. 5510.1C]
BY [HANDWRITTEN: OPG 9B1K] DATE [HANDWRITTEN: 6/20/77]
c/o Fleet Post Office,
San Francisco, Calif.,
23 October, 1944.

From: The Commanding Officer:
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, United States Pacific
     Fleet.
     The Commander Submarine Force, Pacific Fleet.
     The Commander Submarine Squadron FOURTEEN.
     The Commander Submarine Division ONE HUNDRED
     FORTY-ONE.

Subject: U.S.S. TREPANG, Report of War Patrol number
         One.

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

1. Enclosure (A), covering the first war patrol
of this vessel conducted in the Empire Area south of Honshu
during the period September 13, 1944 to October 23, 1944,
is forwarded herewith.

[SIGNATURE: Roy M. Davenport]
Roy M. DAVENPORT.

[STAMP: FILMED]
[STAMP: 93739]

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```
CONFIDENTIAL
SS312/A16-3
Serial (001)
(A) PROLOGUE

U.S.S. TREPANG (SS412)
Report of First Patrol.

The U.S.S. TREPANG was completed at Mare Island Navy Yard on 11 July, 1944. On completion of training on the West Coast, departed Mare Island, California, on 15 August, 1944. Arrived Pearl Harbor on 22 August, 1944, and commenced 15-day training period on 26 August. Installed AP-1 and various equipment and installed additional conditioning equipment in the control room for the forward part of the ship. Training period was reduced by two days to try to improve the resistance readings on the series field leads of 3 main motors which were below the allowable limit. Installed spindle type firing valves and fired ten (10) exercise torpedoes. Readiness for sea 13 September, 1944.

(B) NARRATIVE

13 September
Underway from Submarine Base, Pearl Harbor, T.H. at 1331 (VW) in company with U.S.S. SEA DOG and escort. Set course for Midway. Made trim dive. Released escort at dark. Conducted daily training dives and tracking drill with SEA DOG as target.

17 September
Moored starboard side to Berth Sells-3 at Submarine Base, Midway Island. Received fuel and water; transferred one Mark XVIII-1 torpedo to Midway because of bad ground our torpedoes had been unable to eliminate. Received replacement Mark XVIII-1 torpedo.

1549 (Y)
Underway from Submarine Base, Midway Island in company with U.S.S. SEA DOG. Set course for area at two engine speed, arriving, zero float.

2030 (X)
Lost contact with SEA DOG, proceeding independently.

19 September Crossed International Data Line.
1640 (Y)

2152 (Z)
Following last dive of the day the contractors of the turbo blower controller (both fingers and rotating drum-Portsmouth Navy) burned so badly that emergency reports that would insure proper operation of this blower through-
```

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)
Report of First War Patrol

out the patrol. Since we have only one low
pressure blower and we were less than twenty
four hours out of port, we considered it ad-
visable to return to Midway for repairs. There-
fore we set course for Midway at best surface
speed and sent our serial 191130 of September,
1944 reporting our condition to Commander
Submarine Force, Pacific Fleet and Commander
Task Group 17.5.

19 September Crossed International Date Line.
0130 (Y)

1753 (Y) Moored starboard side to Berth Sail-3, Submarine
Base, Midway Island. Commenced repairs to turbo
blower controller and took on fuel and water.
After mooring, a set of resistance readings were
taken on the main motors. It was found that
main motor series field cables had dropped to a
new low of 75,000 ohms.

Submarine Base began treating these cables in
an effort to drive the moisture out of them.
The turbo blower was in commission by daylight
on the 20th, therefore the motor repairs became
the governing job.

Following treatment the reading was only 60,000
ohms. Although this was below the allowable
standard established by the Bureau of Ships, it
was considered safe for the ship to proceed on
patrol. These cables should be replaced during
next refit.

21 September Underway from Submarine Base, Midway Island for
0640 (Y) patrol area at two engine speed carrying zero
float. Conducted routine training dives and
all standard forms of training enroute to area.

1948 (Y) Crossed International Date Line.

24 September Commanding Officer conducted church services
1300 (M) for the crew in the crew's messroom.

28 September Radar interference was noted on the SD for a
0900 (K) period of ten minutes. A railing effect ex-
isted and rendered the SD useless. Nothing
was observed on the APR, and the interference

-2-

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)

Report of First War Patrol.

periscope; a daily dive to 300 feet to check
for density layers. When it is planned to be
submerged all day, the inboard ventilation, maneu-
vering and engine induction flappers will be
dogged down.

1053 (K) Sighted plane (A/C #2) identified as a "Betty"
on course 210° T., distance 1.5 miles. Lat.
30°-42'.9 N., Long. 133°-17'.0 E.

1923 (K) Surfaced, set course to patrol in the vicinity
of Lat. 30°-00' N., Long. 133°-10' E.

2115 (K) Sighted searchlight bearing 237° T., distance
about 40 miles. This light would have been a ship-
born. It was not seen again. Lat. 30°-20'.9 N.,
Long. 132°-50'.2 E.

2230 (K) Sighted a floating object ahead which we passed
100 yards to starboard. Circled, and came back
alongside for good identification. Object proved
to be a floating mine some 30 inches in diameter
with horns that were not at all tempting. Lat.
30°-12'.7 N., Long. 132°-52'.5 E. This was the
time that we were exceedingly grateful for the
moon and all its brilliance, because it was only
by reason of the full moon that we were able to
see the mine.

We now set about the task of sinking the mine
without sinking ourselves while doing it. At
first it was several times with the carbine and
Thompson machine gun, but these shells didn't
seem to penetrate it. We then fired four pans
of 20MM at it. While getting only a couple of
hits, it was still floating, but possibly lower
in the water.

The 5" gun was now resorted to. Even on a moon-
lit night a mine is hard to hit in the water.
One of four shots fired was so close as to pro-
bably knock a horn off or cut the side of the
mine. Within a few minutes it sank.

4 October Radar contact at 250° R., distance 1,800 yards.
0525 (K) Immediately swung right and put object astern.

-9-

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```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
Ss/12/A46-3                Report of First War Patrol.
Serial (011)

Put all main engines on propulsion. When the bearing was 180° R, the range had closed to 1,400 yards and the contact was then lost. It was an extremely bright night with almost a full moon. We thought it was a periscope until a few seconds later radar had a contact at 105° R, distance 1,100 yards closing. Turned away with full rudder to put contact astern. During turn lost contact. This would indicate two submarines, one of which did not seem probable. The path was small but steady, and definitely wasn’t a return from a wave. Our only solution was that it was a bird (though none were seen) or gremlins. Cleared the immediate vicinity and resumed patrolling Lat. 29°-13' N., Long. 132°-55' E.

0624 (K)
Submerged, periscope patrol.

1926 (K)
Surfaced, patrolling in the vicinity of Lat. 30°-00' N., Long. 133°-10' E.

5 October
0344 (K)
Sighted empty oil drum, sank with carbine. Lat. 30°-08.5' N., Long. 133°-03' E.

0526 (K)
Sighted a floating plane "tear shaped" bulb, possibly a large smoke float or flare. The nose was approximately 24 inches in diameter. It was about 36 inches long and had four vanes at the tail 90° from each other. It was open at the tail and was extremely light. From the sound of the shells hitting it, it could be judged that the thickness of the metal was possibly 1/16" or more. It was sunk by gunfire. Lat. 30°-02.8' N., Long. 133°-10.5' E.

Sighting a mine on the 3rd has made our lookouts especially observant of objects in the water. Submarines that operate in these waters cannot be encouraged too strongly to keep a sharp lookout for floating mines.

0630 (K)
Submerged, seas rough and visibility extremely poor due to almost continuous rain squalls and high winds. We wouldn’t be able to see anything even if it did come near us.

-10-
```

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)

Report of First War Patrol.

1954 (K) Surfaced, made preparations to convert ¼ fuel
          ballast tank to a main ballast tank.

2245 (K) Radar contact bearing 155° T., range 3,700 yards.
          Turned away to place contact astern and increased
          speed. Contact lost.

2246 (K) Radar contact bearing 320° T., range 3,500 yards.
          Turned away to place astern and lost contact.
          It was a fairly dark night such that small sam-
          pans could have been on those bearings without
          being seen from the bridge. If it had been a
          plane, the bridge watch would surely have seen
          or heard it as it passed overhead.

2304 (K) Radar contact bearing 060° T., range 4,300
          yards, closing. Turned away.

2305 (K) Submerged. When passing 50 feet, the range had
          closed to 2,300 yards. Nothing was seen on the
          SD. If it were a plane, it didn't drop anything
          on us. The change in range indicated a relative
          speed of 21 knots on a constant bearing. This
          practically rules out the possibility of a plane
          being our target. Nothing was seen from the
          bridge nor could screws be heard after submerg-
          ing. It looked as if we had more gremlins.

10 October Surfaced. We had been using the SJ on a con-
0004 (K) stant slow sweep, we now took a slow sweep every
          2 to 3 minutes, varying the interval each time.
          Nothing further was sighted and the work of con-
          verting ¼ fuel ballast tank was completed.

0243 (K) Submerged to flush out ¼ fuel ballast tank.

0255 (K) Surfaced. Set course to patrol in the vicini-
          ty of Lat. 34°-00' N., Long. 138°-20' E. to
          perform Special Scouting Mission.

0616 (K) Submerged, conducting periscope patrol.

1920 (K) Surfaced, patrolling across the shipping lanes
          from Tokyo Harbor which lie to the west of
          Zeni Su.

-13-

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)

Report of First War Patrol

periscope spread was used. Following this
firing, swung right to bring the bow tubes to
bear on the near target.

0515 (K) First of three hits on the tanker--forward,
          center, and aft of center. He was immediately
          enveloped in heavy black smoke. As the smoke
          cleared it could be seen that he was going down
          by the bow. Sound reported his screws stopped.

0517 (K) First target almost under, only after section
          him showing. Second target zigged toward us
          presenting a small angle on the bow. It was
          clear that she was coming too close for us to re-
          main safely at periscope depth, so started to go
          to 150 feet.

0518 (K) Sound heard loud and distinct noises of a ship
          breaking up. These sounds were verified by the
          Commanding Officer to be that of a ship sinking.
          The amount of target showing at 0517 (K), to-
          gether with these sounds, verifies the sinking.

0519-30 (K) Heard the second target pass close aboard us,
          and started back to periscope depth.

0521 (K) Heard the screws of the escort coming in loud
          with the bearing changing fast. Started deep,
          rigged for depth charge and silent running.
          Leveled off at 450 feet.

0525 (K) First and only depth charge--a large one at
          probably 1,500 yards. The one torpedo that
          missed was not heard to explode at end of run.
          Ran to the east at 80 R.P.M., keeping the es-
          cort astern.

0542 (K) Lost contact with escort. Escort only listened,
          and no pinging was heard at any time.

0627 (K) With it almost light enough to see, started up
          to periscope depth.

0700 (K) At periscope depth, all clear. Secured from
          battle stations and commenced reload aft.

-15-

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CONFIDENTIAL
U.S.S. TREPANG (SS412)
SS412/A16-3
Report of First War
Serial (011)
Patrol.

0854 (K) Sighted a good looking LST standing south from
Tokyo, angle on the bow 30° starboard, range
approximately 6,000 yards (S/C #4). Turned
right to 110° T. to close the track and went
to battle stations submerged.

The seas were from 270° T. with waves from 4 to
7 feet high. We estimated that the LST would
draw at least 6 feet and under the sea conditions
we felt that a depth setting of less than 4 feet
should not be used.

0902 (K) Attack #4. Commenced firing four torpedoes for-
ward, firing interval 10 seconds, with torpe-
does set for 4 feet using a periscope spread
covering all the target. Relative bearing 332½°,
angle on the bow 80° starboard, range 1,510 yards,
gyro angle 349°, torpedo run 1,500 yards, track
angle 94° starboard, and target speed 8 knots.

One torpedo may have broached as the Commanding
Officer saw some water thrown into the air along
the track of the torpedoes. The torpedo itself
was not seen. The torpedoes were fired almost
exactly with the sea.

0905 (K) All torpedoes missed; turned to the right to
fire again. Set two torpedoes forward on zero
feet.

0909 (K) First of two end of run explosions. These
alerted target and he turned away. He seemed to
have the situation pretty well figured out for
he turned toward the explosions.

Our set-up was checking nicely when we fired,
and the track, torpedo run, and gyro angle were
practically ideal. The spread should have made
two or three hits. Our only conclusion is that
the target drew less water than four feet.

In size he resembled our LST's. There was a
ramp forward, and the engines and bridge were
aft. The bridge was more pronounced than ours
are, and was perhaps further forward. Aft of
the bridge was a light weight tripod mast with

-16-

— page 25 —
CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)

Report of First War Patrol.

a heavy cross-tree near the top. Noticeably
different was the sloping stack indicating
steam power and not diesel power. It was a
disappointment to miss this ship.

0931 (K). Secured from battle stations. Commenced reload
forward. We now have only six torpedoes forward
and four aft.

1119 (K) Heard a very distant explosion.

1916 (K) Surfaced, commenced patrolling across the ship-
ping lanes from Tokyo Harbor which lie to the
west of ZENI SU. Plan to patrol off Iro Saki
tomorrow.

12 October
0525 (K) Submerged eighteen miles southwest of Iro Saki.
During the day the visibility was poor and the
sea had a light surface chop. No land was
sighted except by radar at time of diving.

1635 (K) Sighted aircraft (A/C #5) type "Dave", distance
about 3 miles, which was conducting a search
at low altitude. Lat. 34°-06'.5 N., Long.
138°-46' E.

1923 (K) Surfaced. As we were very close to land we
took only a single sweep on the SJ to insure
that all was clear, and then turned off the
transmitter output. Set course to the south-
west.

1940 (K) To establish our position by radar we commenced
a sweep, and the first contact we had was on a
ship bearing 067° T. at 15,300 yards (S/C #5).
Ordered all engines on propulsion, and rang up
full speed. Stationed the radar tracking party.
This ship was coming out of Tokyo Bay.

1947 (K) Radar reported two ships. The range was closing
rapidly and plot had the targets making 23 to 24
knots. We blew safety and negative and put the
low pressure blower on all the tanks. Ordered
maneuvering to make everything they could--it
wasn't enough--the Bendix Log read only 17.2
knots (Fuel in #3 and #5).

-17-

— page 27 —
CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)
Report of First War Patrol

The two large ships, later identified as two
battleships of the YAMASHIRO class, were in
column, and two destroyers of the TERUTSUKI
class (DD-UN-1 class) were acting as screens.
One screen was close aboard on the port bow of
the leading battleship and the other one was on
the starboard quarter of this same ship, and
about 500 yards from his track. The targets
stood out clearly in their bright phosphorescent
wakes.

Just prior to firing it was noted that the tar-
gets were not aircraft carriers, but it was then
too late to order another depth setting. About
a minute before firing slowed from flank speed
to 2/3 speed, however the ship had slowed to
only 13 knots during firing. A zig towards us
during our run in helped to close the track. The
targets were zigging about every five minutes.
The TBT was used for bearings, and ranges were
taken from the radar. TDC had a good set-up.

2032 (K) Attack No. 5. Commenced firing the bow tubes at
the leading target spread 75 yards between tor-
pedoes with two of them fired at the center of
the target. Relative bearing 335½°, range 1200
yards, torpedo run 1500 yards, track angle 131°,
starboard and gyro angle 039°. The phosphores-
cent wakes of the first three torpedoes were
noted momentarily. All torpedoes ran straight
and normal as far as is known.

Just before firing, the destroyer on the port
bow of the leading ship was seen to range
slightly ahead so that his bow overlapped the
bow of the battleship. The near destroyer was
broad on our port bow, racing towards us on
almost a collision course. We expected him to
head directly for us at any moment, but he held
to his course and his superior speed (23 knots)
carried him past our bow. After firing the fifth
torpedo, left 15° rudder was ordered. The desroy-
er was then about 20° on the port bow at less
than 600 yards. We got a good look at him as we
passed each other within 500 yards. After firing
the sixth torpedo swung left with full rudder.

-19-

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)
Report of First War Patrol.

As we swung to the left the stern tubes were
set on three feet and made ready to fire at this
screen as it appeared that he was turning toward
us. However, he continued on his course while
the second battleship moved up into position.
He was on a different course from the first tar-
get and TDC was notified of this. It was quickly
decided to fire at this target without trying to
reset the torpedo depth. Using radar ranges,
angles on the bow and TBT bearings from the
bridge, prepared to fire with a 100° starboard
angle on the bow.

2034-21 (K) Observed and heard two explosions, one in the
middle of the battleship near #3 turret and one
in the forward part of the port screen. With
these explosions taking place even before we had
launched our four after torpedoes, the chances
of their hitting diminished with elapsed time.

2035 (K) Attack No. 6. Commenced firing the stern tubes
at the second battleship spread 75 yards between
torpedoes with a ten second firing interval.
Relative bearing 146½°, range 1,260 yards, torpedo
run 2,500 yards, track angle 148° starboard, and
gyro angle 208°. Just after firing, this ship
turned away and all torpedoes missed. The mark
XVIII torpedoes were at a slight disadvantage
against these high speed targets. The attack
having been made, the retirement phase was very
much in order. We hoped to clear the area on
the surface if we could, so took an opposite
course to that of the targets and went to flank
speed. At about

2036-30 (K) The second battleship turned on a powerful
searchlight and swept the water from ahead and
to the left of the leading ships around to the
right where it stopped thirty to forty degrees
from our bearing. It was then turned off. When
the light first came on we cleared the bridge
except for the Captain, Officer-of-the-Deck,
Junior Officer-of-the-Deck, and the Quartermaster.
A few seconds later the searchlight was turned
on again, and this time it was trained directly
on the damaged battleship. We could easily see

-20-

— page 29 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS412/A16-3                 Report of First War Patrol.
Serial (011)

— page 37 —
CONFIDENTIAL
U.S.S. TREPANG (SS412)
SS412/A16-3
Report of First War Patrol.
Serial (011)

Pilot, Vol. II, 1940, Japanese Sailing Directions, Vol. 4
(H.O. Misc. No. 9965) and JICPOA Bulletin No. 38-44.

During the period of the typhoon (Oct. 6-8) position Lat.
31°-30' N. and Long. 133°-05' E., a normal set of northeast
and drift of 2 to 3 knots should have been experienced, but
the action of the typhoon resulted in a set of 290° T. and
a drift of 0.5 knots.

(E) NAVIGATIONAL AIDS

No navigational aids were sighted.

-29-

— page 38 —
CONFIDENTIAL

U.S.S. TREPANG (SS412)
Report of First War Patrol.

SS412/A16-3
Serial (011)
(F) SHIP CONTACTS

NO | TIME     | LAT.     | TYPE(S) | INITIAL | COURSE | HOW  | REMARKS
   | DATE     | LONG.    |         | RANGE   | SPEED  | CONT |
---||||||------|
1  | 0001 K   | 31-08.3N | 2 AO    | 10 miles| 210° T | SNR  | Made submerged ap-
   | 10/1/44  | 138-29.0E| 1 AK    |         | 7.5 K  |      | proach firing at 1
   |          |          | 1 TB    |         |        |      | large AO and 2 large
   |          |          | 2 UNK   |         |        |      | tankers. Sank 1
   |          |          | Escorts |         |        |      | large AO with 1
   |          |          |         |         |        |      | torpedo hit. Tank-
   |          |          |         |         |        |      | ers were in loaded
   |          |          |         |         |        |      | condition.
2  | 1326 K   | 33-25.0N | 1 AP    | 4½ miles| 295° T | P    | Sighted through
   | 10/9/44  | 135-46.5E| 1 XAM   |         | UNK    |      | periscope but could
   |          |          |         |         |        |      | not close range to
   |          |          |         |         |        |      | permit firing
3  | 0120 K   | 33-58.5N | 2 AO    | 10 miles| 215° T | SNP  | Made submerged ap-
   | 10/11/44 | 138-15.0E| 1 DD    |         | 15 K   |      | proach firing four
   |          |          |         |         |        |      | torpedoes at one
   |          |          |         |         |        |      | large AO. Sunk with
   |          |          |         |         |        |      | 3 hits.
4  | 0854 K   | 33-19.0N | 1 LST   | 2½ miles| 184° T | P    | Sighted through
   | 10/11/44 | 138-56.0E|         |         | 8 K    |      | periscope. Fired 4
   |          |          |         |         |        |      | torpedoes. All mis-
   |          |          |         |         |        |      | sed. This was a
   |          |          |         |         |        |      | good looking ship
   |          |          |         |         |        |      | (EU) 2,000 tons.
5  | 1940 K   | 34-07.0N | 2 BB    | 7½ miles| 215° T | SNP  | Surface approach on
   | 10/12/44 | 138-21.0E| 2 DD    |         | 23 K   |      | 2 BB(EC) YAMASHIRO
   |          |          |         |         |        |      | CLASS & 2 DD(EC)
   |          |          |         |         |        |      | TERUTSUKI CLASS.
   |          |          |         |         |        |      | Fired 10 torpedoes.
   |          |          |         |         |        |      | Damaged 1 BB with
   |          |          |         |         |        |      | 1 hit and sank 1
   |          |          |         |         |        |      | DD with 1 hit.
6  | 2200 K   | 33-18.0N | Sampans | 2 miles | UNK    | SNR  | Probably sampan,
   | 10/14/44 | 137-46.0E|         |         |        |      | did not sight.
7  | 1340 K   | 32-58.0N | 1 SS    | 2½ miles| 350° T | P    | U.S.S. GREENLING
   | 10/15/44 | 138-23.0E|         |         | 12 K   |      |
8  | 1204 K   | 30-52.9N | 3 patrol| 7 miles | 020° T | LO   | Fishing trawlers -
   | 10/17/44 | 149-52.5E| boats   |         | UNK    |      | patrolling.

-30-

— page 41 —
CONFIDENTIAL
                                                                U.S.S. TREPANG (SS412)
SS412/A16-3
Serial (011)                                                    Report of First War Patrol.

— page 45 —
```
CONFIDENTIAL                U.S.S. TRIGGER (SS412)
                             Report of First War Patrol.
Serial (Oil)

(H) ATTACK DATA
U.S.S. TRIGGER (SS412)
Torpedo Attack #3          Patrol #1
Time: 0512-45 K  Date: 10/11/44  Lat: 33° 18.0' N Long: 137° 42.0' E

Target Data - Damage Inflicted
Description: Two (2) AO - Large Fleet Type Tankers (EU) (10,000 tons each).
One (1) DD - Unidentified (EU) (1,500 tons).
Ships Sunk: One (1) Large AO (EU) (10,000 tons).
Ships damaged: None

Damage determined by: Observed three hits - forward, center, and aft of center. Tanker enveloped in heavy black smoke. Observed to be going down by the bow; was almost under tenet heard definite breaking up noises by sound. Sound heard screws stop when torpedoes hit.

Target Draft: 28' Course: 200° T. Speed: 15 K Range (at firing)

Own Ship's Data
Speed: 3.2 K  Course: 105° T. Depth: 61'  angle (at firing)

Fire Control and Torpedo Data
Type attack: Night submerged radar approach to 3,950 yards and then periscopes. Fired four stern tubes at the leading tankers of a column of two tankers. Three torpedoes hit. On second firing tube #1, torpedo spread with torpedoes in 4 feet. Bearing 20° R., range 2,580 yards, angle angle 173° torpedo run 2,600 yards, angle 160° torpedo run, and angle on bow 70° port. Mark XVIII - torpedoes.

-37-
```

— page 49 —
CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)

Report of First War Patrol.

(H) ATTACK DATA

U.S.S. TREPANG Torpedo Attack #5 Patrol #1
Time: 2032 K Date: 10/12/44 Lat. 33°-52.0' N Long. 138°-09.0' E

Target Data - Damage Inflicted

Description: Ships similar to
Two (2) BB - YAMASHIRO CLASS (EC)(29,330 tons each)
Two (2) DD - TERUTSUKI CLASS (EC)(2,300 tons each)

Ships Sunk: One (1) DD - TERUTSUKI CLASS (EC)(2,300 tons)

Ships Damaged: One (1) BB - YAMASHIRO CLASS (EC)(29,330 tons)

Damage Deter- Observed one (1) hit in bow of DD, and radar report-
mined by: ed this target sank almost immediately. There had
been four (4) definite radar targets. During the
next five and one-half hours only three (3) targets
were seen from the bridge and on radar.

Observed one (1) hit in BB near #3 turret. A tre-
mendous explosion took place that sent flames high
into the air and far out from the side of the ship.
A fire was started amidships and an explosion sent
flames all the way up the foremast. Target speed
slowed from 23 to 16 knots.
Target Draft BB - 29'6" Course 250° T. Speed 23 K Range 1200 yds
DD - 10' (at firing)

Own Ship's Data

Speed 13 K Course 165° T. Depth Surface Angle Surface

Fire Control and Torpedo Data

Type Attack: Night surface attack. Made approach from starboard
flank on BB in column with second BB. Fired six
bow tubes - obtained one hit in BB and one in DD
which sank later. TBT for bearings. Ten second
firing interval with 75 yard spread between tor-
pedoes. Bearing 335½° R., range 1,200 yards, tor-
pedo run 1,500 yards, track angle 131° starboard,
and gyro angle 039°. Mark XVIII-1 torpedoes.

-41-

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)
Report of First War Patrol.

(K) MAJOR DEFECTS AND DAMAGE

ELECTRICAL - On Oct. 6, 1944 the following troubles were
incurred while operating in a heavy sea:
(1) Trip switch for #2 main generator was grounded out.
(2) Voltmeter and ammeter for #2 main generator were
grounded out.
(3) Voltmeter fuse panel for #2 main generator was burned
up.
(4) The brush-rigging on the feed pump motor for the
evaporators was grounded out.
(5) The shut down pump motor on #2 main engine was grounded
out.
(6) Rheostat on #2 evaporator compressor motor was grounded
out.
(7) Two lighting fixtures in the forward port side of the
forward engine room were grounded out.
(8) Hull opening and exhaust indicating panel in forward
engine room was grounded out.
(9) The auxiliary generator cables were flooded out at
#2 generator. Insulation resistance dropped to
50,000 ohms.

The above was all due to taking in water through the
engine room induction valves.

(10) Fresh water entered #3 and #4 main generators from
condensation on the cooling coils of each generator.

On Oct. 11, 1944 the trip switch on #1 main generator
grounded out. When trip switch was removed from panel a
salt deposit was noted on switch.

The above was all repaired at sea with the exception of
the trip switches on #1 and #2 main generators, the volt-
meter and ammeter for #2 main generator, and #2 main
generator voltmeter fuse panel. These items were discon-
nected from the various circuits. All units are now in
operation.

Complete repairs will be made during present refit period
and spare parts used will be replaced.

MAIN MOTORS - The cables to #3 main motor series field
have continued to drop in resistance since leaving the
builder's yard. The lowest reading ever obtained was

-46-

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CONFIDENTIAL
SS412/A16-3
Serial (011)

U.S.S. TREPANG (SS412)

Report of First War Patrol.

(R) MILES STEAMED - FUEL USED

Pearl Harbor to Area   3,902 miles   45,890 gals.
In Area               1,791 miles   18,180 gals.
Area to Majuro        2,728 miles   43,600 gals.
TOTAL                 8,421 miles  107,670 gals.

(S) DURATION

Days enroute to Area - - - - - - - 19
Days in Area 13
Days enroute to Base - - - - - - - 8
Days submerged 16

(T) FACTORS OF ENDURANCE REMAINING

Torpedoes         Fuel         Provisions     Personnel Factor

0             26,757 gals.   35 days        25 days

Limiting factor this patrol was expenditure of torpedoes,
however, three additional days were spent in the area until
relieved by another submarine.

(U) RADIO AND RADAR COUNTERMEASURES

Radar: On the SJ, interference was noted at several times
    and was ascertained to be friendly by noting the
    PRF.

    On the SD, interference was noted about 400 miles
    directly north of the Marcus Islands. A railing
    effect was exhibited and was believed to be caused
    by local rain and electrical storms. The date of
    this interference was 0900 (K), 28 September.

Radio: Enemy interference on the Haiku bands was intermit-
    tent and irregular, being encountered about 40% of
    the time. It consisted of normal code and of long
    dashes. It was at all times annoying, but did not
    prevent copying of the schedules.

    After shifting to the new submarine fox, no inter-
    ference was encountered.

-54-

— page 65 —
SUBMARINE DIVISION ONE HUNDRED FORTY-ONE

FB5-141/A16-3                                        Care of Fleet Post Office,
Serial: 035                                          San Francisco, California,
                                                     24 October 1944.

C-O-N-F-I-D-E-N-T-I-A-L

From:        The Commander Submarine Division One Hundred Forty-One.
To :         The Commander-in-Chief, UNITED STATES FLEET.
Via :        (1) The Commander Submarine Squadron FOURTEEN.
             (2) The Commander Submarine Force, PACIFIC FLEET.
             (3) The Commander-in-Chief, U.S. PACIFIC FLEET.

Subject:     U.S.S. TREPANG (SS412) - Report of First War Patrol.

             1. The first war patrol of the TREPANG was conducted in the areas
south of HONSHU. It lasted for a period of thirty-nine (39) days, of which
thirteen (13) days were spent in her assigned area, the patrol being terminated
by expenditure of all torpedoes.

             2. Area coverage was excellent, resulting in five (5) good contacts,
of which four (4) were closed sufficiently to enable the TREPANG to deliver six
(6) aggressive and damaging attacks on the enemy, with results as follows:

             Torpedo Attacks One and Two. Position was obtained on the port
bow of a convoy consisting of 2 AU's, 1 AK and 3 escorts. One torpedo was fired
at the MOT of a CHIDORI type torpedo boat, depth setting two feet. It missed.
Five torpedoes were subsequently fired at the two large tankers which were over-
lapping at the time at a range of 3,800 yards, resulting in one hit amidships
in the leading tanker. He was seen to go down twenty minutes later. Evasion
was accomplished at periscope depth.

             Torpedo Attack Three. A submerged night attack on one of two
escorted tankers. One large tanker was sunk with three hits out of a four tor-
pedo salvo. A planned attack on the second tanker was thwarted by radical man-
euvers of the target and a hold-down by the escort.

             Torpedo Attack Four. An unescorted IST was contacted and attacked
during daylight. Four torpedoes were fired with a depth setting of four feet and
on an excellent set-up. No hits were observed. It is believed that the torpedoes
underran the target, though the Commanding Officer felt that it was drawing at
least six feet at the time. A shallower depth setting was not used due to the
existing sea conditions.

             Torpedo Attacks Five and Six. A most aggressive night radar
attack was made on two BB's of the YAMASHIRO class, escorted by two TERUTSUKI
class destroyers. Moving in at high speed on a fast moving force and in good
visibility, six torpedoes were fired at a range of 1,200 yards on the leading
BB, one of these hitting its mark and causing a tremendous explosion, and an-
other ending the life of one of the TERUTSUKI's. A swing to the left lined up
the stern tubes on the second BB and four more torpedoes were fired. A turn
away by this target caused all four to miss.

                                       - 1 -

— page 66 —
SUBMARINE DIVISION ONE HUNDRED FORTY-ONE

Care of Fleet Post Office,
San Francisco, California,
24 October 1944.

FB5-141/A16-3
Serial: 035

C-O-N-F-I-D-E-N-T-I-A-L
Subject: U.S.S. TREPANG (SS412) - Report of First War Patrol.

— page 67 —
SUBMARINE SQUADRON FOURTEEN

Care of Fleet Post Office,
San Francisco, California,
25 October 1944.

FC5-14/A16-3
Serial 0115

CONFIDENTIAL

SECOND ENDORSEMENT to
U.S.S. TREPANG Report
of First War Patrol.

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

Subject: U.S.S. TREPANG (SS412) - Report of First War
Patrol; Comments on.

1. Forwarded, concurring in the remarks of Commander
Submarine Division 141.

2. The attack on the high speed Task Force on the
night of 12 October was an outstanding example of great courage
and skill. As a result of this attack the enemy will be with-
out the services of one battleship for a considerable period of
time.

3. It is a great pleasure to welcome this splendid
fighting ship to Squadron 14 and to congratulate her Commanding
Officer, officers and crew on this outstanding patrol and for
the severe damage done to the enemy.

[SIGNATURE: W. D. Wilkin]
W. D. WILKIN.

Copy to:
Comsubdiv 141
CO TREPANG

— page 68 —
FF12-10/A16-3(15)
Serial 02487
CONFIDENTIAL

THIRD ENDORSEMENT to
TREPANG Report of
First War Patrol.

COMSUBSPAC PATROL REPORT NO. 563
U.S.S. TREPANG - FIRST WAR PATROL.

From:
To :
Via :

Subject:

1.
the area south

2.
trained new sub-
warded with five
aggressive attacks.
battleship will
line for some time
troyer in this same

3.
authorized.

4.
tulates the com-
sive and highly
troyer and damag-
of which the TREPANG
having inflicted
trol:

1 - Large AO
1 - Large AO
1 - DD (TERUTSUKI Class)

TOTAL SUNK

1 - BB (YAMASHIRO Class)

TOTAL SUNK & DAMAGED

Distribution and authentication
on following page. SUBMARINE FORCE, PACIFIC FLEET
[HANDWRITTEN: mr]
Care of Fleet Post Office,
San Francisco, California,
[STAMP: 9 NOV 1944] 8 November 1944.

NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
ENTERING PATROL AREA.

The Commander Submarine Force, Pacific Fleet.
The Commander-in-Chief, United States Fleet.
The Commander-in-Chief, U.S. Pacific Fleet.

U.S.S. TREPANG (SS412) - Report of First War Patrol.
(13 September to 23 October 1944).

The first war patrol of the TREPANG was conducted in
of Honshu.

This veteran commanding officer, in an extremely, well
marine, maintained very good area coverage and was re-
good contacts, four of which were developed into six
The splendid attack made on a YAMASHIRO class
keep this formidable ship out of the enemy's battle
to come, and the loss of a TERUTSUKI class des-
attack is one that the enemy can ill afford.

Award of Submarine Combat Insignia for this patrol is

The Commander Submarine Force, Pacific Fleet, congra-
manding officer, officers, and crew for this aggres-
successful patrol. Sinking two tankers and a des-
ing a battleship during her first patrol is a record
can well be proud. The TREPANG is credited with
the following damage upon the enemy during this pa-

S U N K
(EU) - 10,000 tons (Attack No. 2)
(EU) - 10,000 tons (Attack No. 3)
(EC) - 2,300 tons (Attack No. 5)

22,300 tons

D A M A G E D
(EC) - 29,300 tons (Attack No. 5)

51,600

- 1 - [SIGNATURE: C. A. LOCKWOOD, Jr.]

— page 69 —
FF12-10/A16-3(15)
Serial 02487
CONFIDENTIAL

SUBMARINE FORCE, PACIFIC FLEET

Care of Fleet Post Office,
San Francisco, California,
8 November 1944.

THIRD ENDORSEMENT to
TREPANG Report of
First War Patrol.

COMSUBSPAC PATROL REPORT NO. 563
U.S.S. TREPANG - FIRST WAR PATROL.

Subject: U.S.S. TREPANG (SS412) - Report of First War Patrol.
(13 September to 23 October 1944).

NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
ENTERING PATROL AREA.

DISTRIBUTION:
(Complete Reports)
Cominch (7)
CNO (5)
Cincpac (6)
Intel.Con.Pac.Ocean Areas (1)
Comsubpac (1)
Cinclant (1)
Conservpac (1)
Comsublant (8)
S/M School, NL (2)
CO, S/M Base, PH (1)
Comsopac (2)
Comsowespac (1)
Comsubwespac (2)
CTF 72 (2)
Comnorpac (1)
Comsubspac (40)
SUB.D. II (2)
ComsubspacSubordcom (3)
All Squadron and Div.
Commanders, Pacific (2)
Substrainpac (2)
All Submarines, Pacific (1)
[SIGNATURE: E. L. Hynes]
E. L. HYNES, 2nd,
Flag Secretary.

— page 70 —
[STAMP: DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C]
[TYPED: CONFIDENTIAL]
BY [HANDWRITTEN: C.P.G.H.] DATE [HANDWRITTEN: 6/20/72]

SS412/A16-3
Serial (025)

c/o Fleet Post Office;
San Francisco, Calif.,
22 December, 1944.

From: The Commanding Officer:
To: The Commander-in-Chief, United States Fleet.
Via: The Commander-in-Chief, United States Pacific
Fleet.
The Commander Submarine Force, Pacific Fleet.
The Commander Submarine Squadron FOUR.
The Commander Submarine Division FORTY-FIVE.

Subject: U.S.S. TREPANG - Report of War Patrol Number
Two.

Enclosure: (A) Subject Report.
(B) Task Group 17.15 Supplementary Patrol
Instructions.
(C) Task Group 17.15 Supplementary Communica-
tion Plan.
(D) Track Chart (ComSubsPac).
(E) Area Assignment Chart (ComSubsPac).

1. Enclosure (A), covering the Second War Patrol
of this vessel conducted in the area north of Luzon during the
period November 16, 1944 to December 22, 1944, is forwarded
herewith.

2. The Commanding Officer was also in command of
a Coordinated Attack Group consisting of the TREPANG, SEGUNDO,
and RAZORBACK, and known as "Roy's Rangers". The TREPANG'S
War Patrol Report, therefore, also contains his report as
Task Group Commander. Reference is therefore invited to the
U.S.S. SEGUNDO'S and U.S.S. RAZORBACK'S Second War Patrol
Reports.

[SIGNATURE: Roy M. Davenport]
Roy M. DAVENPORT.

[STAMP: FILMED]
[HANDWRITTEN: 102100]

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U.S.S. TREPANG (SS412)
Report of Second War Patrol.

(A) PROLOGUE

Arrived Majuro Atoll from First War Patrol on 23
October, 1944. Completed refit by Division 141
Relief Crew on 6 November, 1944. Renewed two cables
to series field of #3 main motor and raised
resistance of the other cables through treatment.
The four day training period was reduced to three
days to permit readiness for sea on 16 November, 1944.

(B) NARRATIVE

16 November Departed Majuro Atoll for Second War Patrol in
1330 (L) company with U.S.S. SEGUNDO (SS398) as part of
Coordinated Attack Group Seventeen point fifteen
to be known as Roy's Rangers; attack group to con-
sist of U.S.S. TREPANG (SS412), U.S.S. SEGUNDO
(SS398) and U.S.S. RAZORBACK (SS394) with Commanding
Officer, U.S.S. TREPANG as Task Group Commander.
Set course via Safety Lane to Lat. 20°-00' N., Long.
169°-00' E. to rendezvous with U.S.S. RAZORBACK.
Made trim dive.

2005 (L) Radar contact at 23,000 yards, range closing rapidly.
SEGUNDO and TREPANG increased speed to avoid while
escort closed vessel to identify.

2039 (L) Vessel identified as friendly by escort. Escort did
not rejoin; continued up safety lane.

17 November Conducted daily training dives and radar tracking
exercises enroute to rendezvous. Many plane contacts
by radar; all were friendly.

20 November Sighted submarine on horizon; exchanged signals with
0527 (L) U.S.S. RAZORBACK.
0615 (L) U.S.S. RAZORBACK joined formation; set course for
Saipan. Ships in line of bearing at easy signaling
distance. Conducted tracking drills and made rou-
tine dives daily. Exercised at pack communication
drills.

23 November Formed scouting line on line of bearing, with RAZOR-
0800 (K) BACK Seven miles north of lane axis, TREPANG on

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U.S.S. TREPANG (SS412)
Report of Second War Patrol.

25 November     Commander Task Group Seventeen point fifteen held
0815 (K)        a conference with Commanding Officers, Executive
                Officers, and Communication Officers of Task Group
                Seventeen point fifteen. The plan for conducting
                the patrol was discussed and copies of Task Group
                Seventeen point fifteen Supplementary Patrol In-
                structions and Supplementary Communication Plan
                together with an area assignment chart of the
                patrol area with a schedule for patrolling was
                furnished each ship.

1556 (I)        Underway from alongside U.S.S. FULTON in company
                with other Rangers and in addition the U.S.S.
                SPEARFISH. Set course for assigned area via safety
                lane at two engine speed.

1715 (I)        All submarines made a trim dive. Submarines were
                in line of bearing at convenient signaling distance.
                SPEARFISH kept to the northern edge of the safety
                lane and proceeded independently.

2150 (I)        Entered safety lane and released escort.

26 November     SPEARFISH notified us on area frequency that she
1330 (I)        had been fired at by a submarine and had sighted
                it's periscope. We were well clear of the area of
                the contact.

1852 (I)        SJ-radar contact 308° T. at 8,000 yards. Exchanged
                recognition signals with U.S.S. REDFISH and U.S.S.
                SHAD on opposite course.

27 November     Left safety lane and set course for assigned area.
0300 (I)        Formed scouting line normal to course with sub-
                marines twenty miles apart.

30 November     Submerged for all day dive to avoid plane detection
0740 (H)        prior to entering area and to provide training for
                diving sections. Will enter area tomorrow.

1741 (H)        Exchanged recognition signals with the RAZORBACK
                via SJ.

1 December      Entered area. TREPANG patrolling east of Babuyan
0000 (H)        Island with Segundo to the north and RAZORBACK to

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Report of Second War Patrol.

BACK to the south of us, there is still a chance that the Rangers may get him.

1747 (H)
Heard three loud explosions at a great distance that sounded like end of run explosions. These were undoubtedly from the RAZORBACK.

1803 (H)
Surfaced, patrolling east-west courses in area east of Babuyan Island.

1930 (H)
Received SIGINT: 010230 report, convoy passed west of Balintang Island on southerly course. Ob-
served 1810 (H). Convoy not sighted but only heard. Observed seven or more planes in air cover. This was the same convoy we had seen.

SECOND suggested patrolling off northern coast of Luzon on the 2nd. They undoubtedly had in mind that this convoy would pass there tomorrow. The Patrol Commanders considered that time present are held prospects of further positions and that three boats could not take up positions off the Luzon coast prior to daylight. For these reasons the patrol off Babuyan Island was continued.

1942 (H)
Exchanged signals with RAZORBACK with S. I. They reported a daylight attack at 1738 (E) on a convoy of 1 AK, 1 AP, and 3 escorts with air cover. Enemy course 160° T, speed 9 knots. Negative results.

2024 (H)
AFR contact on 155 megacycles (A/C #3). Strength of signal varied over a period of an hour.

2123 (H)
Submerged when AFR contact reached saturation. Plane could not be seen on SD too far from the bridge. Lat. 19°-26' N., Long. 122°-30' E.

2140 (H)
All clear on AFR and SD, surfaced.

2 December
0037 (H)
Submerged for AFR contact on 155 megacycles (A/C #4).
No. 155 must have been on his way home. Did not see SD. Lat. 19°-27' N., Long. 122°-25' E.

0335 (H)
All clear on AFR and SD, surfaced.
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0515 (H) Submerged for periscope patrol. Seas increased dur-
           ing the day to condition #5; depth control was dif-
           ficult.

1817 (H) Surfaced, commenced patrol same area.

2130 (H) APR contact on 153 megacycles (A/C #5). Lat. 19°-26'
           N., Long. 122°-28' E.

2231 (H) Submerged when APR contact reached saturation. Plane
           could not be seen on SD radar nor from the bridge.

2302 (H) All clear on APR and SD, surfaced.

3 December APR contact on 153 megacycles (A/C #6). Lat. 19°-21'
0320 (H) N., Long. 122°-25' E.

0345 (H) Submerged when APR contact reached saturation. As
           it was near daylight, remained submerged for the day.
           Seas have increased to force 6. Extremely difficult
           to control the boat at periscope depth and visibility
           only about 1,000 yards. Observation once an hour.

1300 (H) Commanding Officer held church services for the crew.

1812 (H) Surfaced. Weather extremely bad. The Rangers were
           to transit Balintang Channel and patrol in the vicini-
           ty of Lat. 20°-00' N., Long. 120°-45' E. on 4 Decem-
           ber; however, because of the continued bad weather
           Commander Task Group Seventeen point fifteen (CTG 17.15)
           031025 to the RAZORBACK and SEGUNDO saying to remain
           in present area until further orders. All boats had
           been using radar fixes on the Babuyan Islands since
           the first of December. We had hoped for better
           weather than this.

2230 (H) APR contact on 154 megacycles (A/C #7). Saturation
           was never made although we had the contact for over
           an hour. Lat. 19°-27' N., Long. 122°-42' E. As long
           as diving did not interfere with operations considered
           it advisable to dive when contact reached saturation.
           By following this procedure we never were detected
           and as a result weren't bombed. It would be helpful
           to know just what the range is at the time of satura-
           tion.

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ENCLOSURE (A)

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alerted by our first transmission and had changed
base course, the Group Commander decided against
sending further information until after attacking
to avoid a possible delay in delivering the initial
attack. If this convoy was to be prevented from
entering Babuyan Channel an attack would have to be
made soon.

The convoy was in two columns of 3 and 3 ships
respectively with escorts ahead and on each flank.
Fortunately the ships were grouped extremely close
together and the four ship column was on our side.

The starboard escort was on the starboard quarter
of the vj ship. Just prior to attacking, our position was sharp on the escort's starboard bow at 3,000
yards. We placed him on our starboard bow, and when
the stern beam of him turned toward the convoy pivot
#2 and #3 ships as our targets for the bow tubes.
Those two (2) large A's, while the target for
the stern tubes, tie #6 ship, was a large A. All
torpedoes set for fire.

2044-40 (H)  Attack No. 1:  Commenced firing the six (6) bow tubes
at #2 and #3 targets which were overlapping. These
were mark XVIII-1, spread 75 yards between torpedoes
with a ten second firing interval. Relative bearing
010, range 1,775 yards, torpedo run 1,970 yards,
tracked angle 12° starboard, and gyro angle 122°.
Immediately after firing changed course to the left
to avoid running the target—we cleared him by
650 yards. This was to be our target for the stern
tube, so our course was adjusted to the immediate
firing of these tubes. The after T.B.T. was used
for bearings and the radar for ranges.

2046 (H)  First of fire hits from the bow tubes, three (3) in
#2 target and two (2) in #3 target. Two hits had
been obtained before the stern tubes were fired,

2046-40 (H)  Attack No. 2:  Commenced firing the four stern torpedoes.
These were marks XVI-3 and mark XVIII torpedoes,
spread 75 yards between torpedoes with a ten second
firing interval. Relative bearing 160°, range 1,700
yards, torpedo run 2,000 yards, track angle 160°
starboard and gyro angle 113°.

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ENCLOSURE (A)
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Report of Second War Patrol.

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2301-30 (H) First of three hits distributed over the length of the target were observed from the bridge. The target took a slight list to starboard, but did not look to be in particular difficulty although smoke was rolling out of her forward and after holds.

2303-30 (H) Observed several explosions to the south where the SCUDDOW were apparently attacking the last remaining ship.

2307 (H) The moon had just risen making it extremely light.

2310 (H) SEGUNDO reported attack completed.

With the target now so close to a haven of safety and with the moon making it brighter every minute, decided that further torpedo fire was required to assure sinking this valuable target. Took position on port side of target so torpedoes would be fired with the sea. The target was now on 080° T, making very little speed. Six torpedoes remained forward with none aft.

2318 (H) RAZORBACK reported commencing radar approach.

2326-20(H) Attack No. 5. Presenting a very small angle on the bow, approached the target on the surface to within 1,000 yards and commenced firing tubes 1, 2, 3, and 4. We must have been very close to the target, but they did not fire on us. They may have been expecting us on the starboard side, and we spread Mark XVIII-1 torpedoes on fleet, and spread 50 yards between two spreads with 10 second firing interval. Relative bearing 000°, torpedo run 1,000 yards, torpedo angle 90° port, gyro angle 080°, target course 080° T, target speed 7.0 knots.

2327-30 (H) Observed the first and the rear of two boats, one in the middle and one in the well dock aft. The latter hit set the after part of the dock on fire. With the smoke billowing out made a beautiful firing. There were many internal explosions in this ship and finally at about 2332 [UNCLEAR: best guess] it began to sink stern first.

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EXCLUDE (A)
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U.S.S. TREPANG (SS412)
Report of Second War Patrol.

to the side of the ship and told him to hold
tight to the life ring. Although he probably didn't
understand us, common sense should have told him
to hold on tightly to the life ring. He was still
holding on to the board as we pulled him up on to
the side of the ship. With him practically aboard
he lost his grip on the ring and fell back into the
water. He then drifted away from us to a point
where we couldn't see him. We tried to get him to
yell so as to locate him, but he never did utter a
word, not even when he was hauled part way aboard.
We couldn't risk using any kind of a light in our
rescue operations.

0029 (H) Sighted ship burning to the south.

0040 (H) Having spent over an hour trying to pick up sur-
          vivors decided that any further attempt was futile.

0043 (H) Secured from battle stations and radar tracking
          party, and set course to close the burning ship.

          Observed first of a series of many explosions from
          the burning ship that lasted over the next few hours.

0135 (H) Exchanged recognition signals with the SEGUNDO and
          asked if she had attacked ship that was burning to
          the south. SEGUNDO reported that she had stopped
          it, but that the RAZORBACK had then set him on fire.
          SEGUNDO reported two sunk, one damaged. With our
          four sunk, this accounted for the entire convoy.

          It was truly a beautiful three hours of action with
          ships blowing up simultaneously all around the hori-
          zon. To have had the pleasure of seeing this entire
          convoy destroyed was something we'd always hoped to
          see. The three escorts couldn't be called friendly,
          but on the other hand they weren't unfriendly. Al-
          though there were many explosions, none were identi-
          fied as depth charges.

All five of the TREPANG'S attacks were made on the
surface, and it is believed that the SEGUNDO made
all surface approaches. The RAZORBACK'S approach
was made at radar depth, however she was on the

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that we would guard the required frequencies and
be ready to render whatever assistance we could.

1253 (I) SD radar had group of planes going north at 27
miles. Several groups were observed going north.

1500 (I) SD radar had group of planes going south. Between
this time and 1657 (I) observed thirteen (13) B-29's
to pass over us and saw an additional ten to fifteen
on the radar that were not seen from the bridge. We
now turned on our ABK to identify ourselves to them.
No planes were observed to be in trouble and no help
was asked for.

1730 (I) Set course to transit the Nanpo Shoto passing between
Sumisu Shima and Tori Shima. Running on four engines.

1811 (I) APR contact on 150 megacycles. This contact con-
tinued for about thirty minutes never getting any
stronger and never reaching saturation. It didn't
look like a shore installation; however, if it were
a plane it is hard to understand how the signal re-
mained at a constant value for so long a time.

1857 (I) SJ radar contact on patrol craft bearing 223° T.
at 5,350 yards. The night was quite dark and the
contact was not seen. Worked around this contact
on the surface (S/C #6). Lat. 30°-46' N., Long.
139°-51' E.

1904 (I) SJ radar contact on Tori Shima bearing 123° T.,
range 50,000 yards.

2030 (I) Took departure with Tori Shima bearing 189° T., dis-
tance 20.5 miles. It now seemed that we were really
on our way home.

2137 (I) SJ radar contact on small patrol craft bearing 130°
T. at 5,800 yards. Contact was not seen and we
worked around him on the surface (S/C #7). Lat.
30°-44' N., Long 140°-48' E.

14 December SJ radar contact on small patrol craft bearing 107°
0153 (I) T. at 9,800 yards. Contact was not seen and we
worked around him on the surface. Night was dark
and the swells running very high from 320° T. A gun

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action was again out of the question. (S/C #8).
At this same time saw a plane firing tracer bullets.
He was at a great distance from us. Lat. 30°-45' N.,
Long. 142°-10' E.

0517 (I)
SJ radar contact on small patrol craft bearing 070°
T. at 8,000 yards. This ship was seen from the
bridge as it was beginning to get light. Worked
around this patrol craft prior to it getting light
enough for him to see us (S/C #9). Lat. 30°-47' N.,
Long. 143°-08' E. Transiting this area two months
ago we made no contacts with patrol craft except
north of Marcus. To have made six contacts in less
than twenty-four hours indicates that the Japs are
trying to prevent surprise attacks on their mainland.

0620 (I)
Made a trim dive to flush out #5 fuel ballast tank.

15 December
1705 (K)
Rigged the vents on #4 fuel ballast tank for a bal-
last tank.

1715 (K)
Exchanged recognition signals with the U.S.S. TINOSA.
We advised Dick Latham of the many patrol boats we
encountered in the vicinity of the Nanpo Shoto.

The TINOSA reported that they had experienced unex-
plained radar interference on 3,000 megacycles on
the night of 14-15 December in the vicinity of Lat.
30°-05' N., Long. 157°-42' E. The TREPANG kept a
sharp lookout for similar conditions when passing
through this area, however, nothing was observed.

16 December
0843 (L)
Stopped the port shaft to renew badly worn brushes
on #4 main motor that were sparking. Replaced
thirty-five brushes.

1234 (L)
Repairs completed to #4 main motor. Went ahead on
both shafts.

17 December
1300 (L)
Lieutenant Robert W. Stecher, U.S.N., assisted by
the Commanding Officer conducted Divine Services for
the crew.

18 December
0325 (M)
Reported TREPANG'S 1630 zebra positions to ComSubSPac
and requested an escort for the 22nd.

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ENCLOSURE (A)

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(E) NAVIGATIONAL AIDS
                                                                U.S.S. TREPANG (SS412)

                                                                Report of Second War Patrol.

No navigational aids were sighted. Excellent radar fixes
were obtained while in the Area by using the PPI-scope for
centering the bearings. Bearings taken in this manner
plotted in perfect fixes.

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U.S.S. TREPANG (SS412)
Report of Second War Patrol.

(F) SHIP CONTACTS

NO|TIME AND|LAT AND|TYPE(S)|INITIAL|COURSE|HOW | REMARKS
  | DATE   | LONG  |       | RANGE |SPEED |CONT|
--||-------|-------|-------|------|----|
1 | 1623 H | 19-27N|1 AK,  |       |160° T|P   | Originally contacted
  | 12/1/44|122-00E|1 AP   |25,000 |9 K   |    | by sound at 40,000 yds.
  |        |       |3 PC's |       |      |    | Later saw through
  |        |       |       |       |      |    | periscope, could not
  |        |       |       |       |      |    | close. Heavy air cover.
  |        |       |       |       |      |    | RAZORBACK attacked but
  |        |       |       |       |      |    | missed.
--||-------|-------|-------|------|----|
2 | 0050 H | 20-18N|2 PC's | 6,500 |030° T|R   | Two(2) small patrol
  | 12/6/44|120-29E|       |       |8 K   |    | craft. Did not fire
  |        |       |       |       |      |    | due to heavy seas.
--||-------|-------|-------|------|----|
3 | 1844 H | 19-01N|3 AK,  |       |120° T|R   | Seven ship Philippine
  | 12/6/44|120-30E|1 AP,  |19,700 |5.5 K |    | bound convoy. Sank 2
  |        |       |2 AO,  |       |      |    | AK, 1 AO & 1 AP. Other
  |        |       |1 AE,  |       |      |    | three ships sunk by
  |        |       |3 PC's |       |      |    | SS394 and SS398.
--||-------|-------|-------|------|----|
4 | 0905 I | 30-39N|Trawler|12,000 |340° T|SD  | Small trawler type pa-
  | 12/13/44|137-21E|       |       |6 K   |    | trol vessel in vicini-
  |        |       |       |       |      |    | ty of plane guard sub-
  |        |       |       |       |      |    | marines. Machine gun on
  |        |       |       |       |      |    | bow, depth charges aft.
  |        |       |       |       |      |    | Rough seas prevented
  |        |       |       |       |      |    | gun attack.
--||-------|-------|-------|------|----|
5 | 1036 I | 30-32N|Trawler|18,000 |350° T|P,SD| Same as #4.
  | 12/13/44|137-34E|       |       |6 K   |    |
--||-------|-------|-------|------|----|
6 | 1857 I | 30-46N|UN     | 5,350 |---   |R   | Small patrol vessel;
  | 12/13/44|139-51E|       |       |      |    | did not see.
--||-------|-------|-------|------|----|

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ENCLOSURE (A)

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(G) AIRCRAFT CONTACTS (Cont'd)

CONTACT NO. 12 :
S (1) : 12/14/44 :
U (2) : 1811 I :
B (3) : 30-42 N :
M (4) : 139-28 E :
A (5) : 17 K :
R (6) : 090° :
I (7) : Surf. :
N (8) : --- :
E : :

A (1) : One
I (2) : Unk
R (3) : Unk
G (4) : APR 150 MC:
R (5) : Unk
A (6) : ND
F :
T :

C (1) : 3
O (2) : 29
N (3) : 6
D (4) : 20
I (5) : 60
T (6) : ---
I (7) : ---
O (8) : ---
N :
S :

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U.S.S. TRIPANG (SS412)
Report of Second War Patrol.

(H) ATTACK DATA (Cont'd)

|             | ATTACK #3 | #4        | #5        | #6        |
||||||
| Tubes Fired | 54 S      | 54 S      | 55 S      | 58 S      |
| Track Angle | 357°      | 355°-20'  | 354°-50'  | 356°-10'  |
| Gyro Angle  | 7'        | 7'        | 7'        | 7'        |
| Depth Set   | 7'        | 7'        | 7'        | 7'        |
| Hit or Miss | Miss      | Miss      | Miss      | Miss      |
| Erratic     | No        | No        | No        | No        |
| Mark Torpedo| 18-1      | 18-1      | 18-1      | 18-1      |
| Serial No.  | 56559     | 54665     | 55852     | 56639     |
| Mark Exploder| 8-5       | 8-5       | 8-5       | 8-5       |
| Serial No.  | 9338      | 9511      | 8772      | 9849      |
| Actuation Set| Contact   | Contact   | Contact   | Contact   |
| Actuation Actual| ---       | ---       | ---       | ---       |
| Mark Warhead| 18-2      | 18-2      | 18-2      | 18-2      |
| Serial No.  | 2672      | 1613      | 3041      | 2639      |
| Explosive   | TORPEX    | TORPEX    | TORPEX    | TORPEX    |
| Firing Interval| 10 sec.   | 10 sec.   | 10 sec.   | 10 sec.   |

Type Spread                               1½° divergent Fwd to Aft.
Sea Conditions                            5
Overhaul Activity                         U.S.S. BUSHNELL
Remarks                                   Speed set in accordance with ComSubsPac dis-
                                          patch Nov. 091013. Fired into the sea, own
                                          speed 3.2 K. It cannot be definitely stated
                                          whether torpedoes broached or not. A phos-
                                          phorescent wake was observed for about 30 yds
                                          ahead of the bow from each torpedo.
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(H) ATTACK DATA (Cont'd)
U.S.S. TREPANG Torpedo Attack #4 Patrol #2
Time: 2300-20(H) Date: 12/6/44 Lat. 18°-59'N Long. 121°-05'E

Target Data - Damage Inflicted
Description: One (1) large AP (EU) 10,000 tons.
Ships Sunk: None.
Ships Damaged: One (1) large AP(EU) 10,000 tons.
Damage deter- Observed three (3) torpedo hits distributed
mined by: along the length of the ship. Smoking fore and
aft with list to starboard.
Target Draft 28' Course 050° T. Speed 6.5 K. Range 1480 yds.

Own Ship's Data
Speed 9 K. Course 110° T. Depth On surface Angle Zero

Fire Control and Torpedo Data
Type Attack: Surface radar attack using the four stern tubes
with Mk. XXIII and XIV-3A torpedoes spread 50
yards between torpedoes and set on 10 feet.
Relative bearing 175°, range 1,570 yards, torpedo
run 1,450 yards, track angle 60° starboard, and
gyro angle 182°. Firing was across a condition
5 sea. Three hits.

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(.) ATTACK DATA (Cont'd)

                                                              U.S.S. TREPANG (SS412)

                                                              Report of Second War Patrol.

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U.S.S. TREPANG (SS412)
SS412/A16-3                                       Report of Second War Patrol.
Serial (025)

— page 110 —
CONFIDENTIAL
U.S.S. TREPANG (SS412)
Report of Second War Patrol.

SS412/A16-3
Serial (025)

NOTE: Upon arrival at Saipan the repair force on board the
U.S.S. FULTON renewed 53 broken brushes in #2 main motor.
All brushes on board are the GE Type SA 45 and have been
given the standard 20 milli-volt drop test between pig tail connec-
tion and brush.

On 18 December secured auxiliary generator because of a zero
ground on shunt field circuit. Ground was located on shunt
field leads on cable entering generator frame. The leads were
badly deteriorated from oil and salt scale due to faulty stuff-
ing of stuffing tube. Lead was reinsulated and readings brought
to 7 1/2 megs. The generator was then placed back in operation.

To prevent the recurrence of such failures in the future it
is recommended that a water-tight junction box be placed con-
venient to generator in after engine room to facilitate renew-
ing present shunt field cable, and that the stuffing tube
entering generator frame be turned down to allow sea water to
drain off.

On 19 December the #4 main motor brushes that were not replaced
on 16 December had worn down to the safety point, and consider-
able sparking occurred at #2, #4, and #6 brush holders (posi-
tive brushes). The port shaft was stopped and #4 main motor
was completely checked. 39 brushes were replaced. They were
the same type of faulty brushes that were removed on 16 December.

It was also found that #6 brush holder was 1/2 the width of
one segment out of line with the commutator segments. An
attempt was made to realign the brush holder. Lacking the
proper equipment very little change could be made. #4 main
motor was placed back in operation and for 12 hours of full
power operation no sparking was noted. It is recommended that
the top half of the end bell be removed and the complete brush
rigging checked for alignment and electrical zero.

Forward Engine Induction: It is recommended that a shield be
placed over the ventilation intake line just below the main
induction valve to prevent spray from entering this line. With
this accomplished the supply ventilation line can be used very
satisfactorily for the forward engines when operating in rough
weather. The TREPANG has a large hinged section below the
supply inboard valve that is used when dogging down the supply
valve for depth charge attacks. This section can be left
open for emitting the air directly to the engine room. As this
opening is aft of the engine instrument board it would elimin-
ate salt water spray from being drawn across this board as now
happens when using the regular engine induction.

10
ENCLOSURE (A)

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CONFIDENTIAL
SS412/A16-3
Serial (025)

U.S.S. TREPANG (SS412)
Report of Second War Patrol.

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CONFIDENTIAL
U.S.S. TREPANG (SS412)
SS412/A16-3
Report of Second War Patrol.
Serial (025)

(N) SOUND GEAR AND SOUND CONDITIONS

Only three sound contacts were made during this patrol. The
first was at 1422 (H), 1 December, on a convoy of one ship
and two escorts. Seas were calm with excellent visibility.
An SBT card taken at 0530 that morning showed water isothermal
to 320 feet followed by a 6 degree negative gradient. Initial
contact was made practically simultaneously by the JP on screws
and the JK on pinging at an estimated range of 40,000 yards.
Sound contact was lost at 1508 (H) when the boat went to 150
feet, but was regained at 1541 (H) at that depth. Targets were
not sighted until 1623 (H) at about 25,000 yards.

During the approach on two small patrol boats in the early
morning of 6 December, echo ranging was detected by the JK
at about 3,000 yards. The screws were not heard at all.

During the night surface attacks on 6 December, the JK sound
gear was manned to listen for echo ranging. Echo ranging was
heard at about 5,000 yards prior to the initial attack on the
convoy.

Material condition of the sound gear was excellent throughout
the run.

(O) DENSITY LAYERS

Seven SBT cards were taken and are being forwarded to the Vice
Chief of Naval Operations. The following density layers were
encountered (all depths are to SBT blister):

CARD NO:|TIME & DATE:|POSITION      |:CHARACTER OF DENSITY LAYER
2-1    |:0530       |:19°-59' N    |:Isothermal to 240 ft.
       |:11/27/44:  |133°-01' E    |:
2-2    |:2130       |:19°-29.2'N   |:Isothermal to 320 ft. 5° drop to
       |:11/31/44:  |122°-19.5'E   |:420 ft.
2-3    |:0400       |:19°-28.8'N   |:Isothermal to 200 ft., where nega-
       |:12/1/44    |:122°-07.7'E  |:tive gradient started.
2-4    |:1040       |:19°-30' N    |:Isothermal to 180 ft. Iso-
       |:12/2/44    |:122°-12' E   |:
2-5    |:2200       |:18°-54' N    |:2° positive gradient to 80 ft. Iso-
       |:12/5/44    |:120°-35' E   |:thermal to 160 ft. Erractic 16° drop
       |:           |:             |:to 450 ft. 6° rise at 60 ft. dur-
       |:           |:             |:ing day.

-44-                               ENCLOSURE (A)

— page 115 —
```
CONFIDENTIAL          U.S.S. TREPANG (SS412)
                       Report of Second War Patrol.

                       Serial (025).

CARD NO:  OCC-DATA:  POSITION:  CHARACTER OF DENSITY LAYER
2-6  -  12/6/44;  19° 37' N.;  100 ft.;  drop to 100
          1200-2400;  1.5° N.;  rise to 100 ft. during day.
2-7  -  12/7/44;  210°- 58° N.;  Isothermal to 320 ft.

(P) HEALTH, FOOD, AND HABITABILITY

The health of the crew was excellent. During the early part
of the patrol there were a few cases of hot rash and fungus
infection due to climatic conditions. On our return trip
two cases of catarrhal fever developed when we experienced
cold weather in the vicinity of Latitude 31° North.

The food was again excellent. An outstanding Commissary
Department with good foods to work with made this possible.

Habitability has been good, and the ship was extremely com-
fortable throughout the patrol.

(Q) PERSONNEL

Again the outstanding performance of duty of all officers and
men was exemplified on the night of 6 December when four ships
of a seven ship convoy were sunk in less than three hours time.

Each attack was driven home in an aggressive manner to in-
sure destruction of the enemy. The Commanding Officer es-
pecially wishes to commend the following officers and men
who had key positions in these actions. Their performance
of duty was outstanding in every respect and aided materially
in the success of the TREPANG's Second War Patrol.

Lieutenant R. S. Garvey, USNR - Executive officer and
                             -  XO Operator.
Lieutenant R. M. Barrow, USNR - Director of the Deck.
Lieutenant R. H. Stetcher, USNR - Assistant to Operator.
Lieut. (jg) J. B. Pugh, USNR - Radar Officer.
Ensign W. A. Kemp, USNR - Plotting Officer.
Ensign P. D. Farley, USNR - Radar Operator.
Shaver, R. N., CHT, USN
-45-
E: CLOSURE (A)
```

— page 116 —
CONFIDENTIAL
U.S.S. TREPANG (SS412)
SS412/A16-3
Serial (025)
Report of Second War Patrol.

The performance of duty of the officers and crew throughout
the patrol left nothing to be desired. It was in every
sense in keeping with the highest traditions of the Naval
Service.

Church services were held every Sunday afternoon and a
Thanksgiving Day service was conducted. The same welcome
response was again made to these services as has been pre-
viously experienced. Prior to leaving Majuro the BUSHNELL'S
Chaplain, Father Joseph M. Geary, held mass in the forward
torpedo room.

There is a definite desire from a large percentage of our
submarine crews to have a weekly religious service. This
has been amply proven by the several submarines that have
Sunday services. Knowing the help and comfort these services
provide for the men, the Commanding Officer of the TREPANG
recommends that all submarines give proper consideration to
having a religious service of one form or another each Sunday.

(a) Number of men on board during patrol - - - - - 74
(b) Number of men qualified at start of patrol - - 48
(c) Number of men qualified at end of patrol - - - 68
(d) Number of unqualified men making their
    first patrol. 3
(e) Number of men advanced in rating during
    patrol 6

(R) MILES STEAMED - FUEL USED

Majuro to Saipan           2,823 miles     31,340 gals.
Saipan to Area             1,672 miles     14,850 gals.
In Area                    1,210 miles     10,500 gals.
Area to Pearl Harbor       5,151 miles     75,940 gals.
TOTAL                     10,856 miles    132,630 gals.

(S) DURATION

Days enroute to Area 15
Days in Area 8
Days enroute to Base 15
Days submerged 10

-46-
ENCLOSURE (A)

— page 118 —
U.S.S. TREPANG (SS412)
Report of Second War Patrol.

CONFIDENTIAL
SS412/A16-3
Serial (025)

the ground was discovered to be in the motor. There was
a small amount of salt water in the compartment. In ad-
dition the commutator and brushes were corroded. After
cleaning the motor, drying it out, and removing the salt
water the ground had dropped to 3 volts on the positive
side and 0 volts on the negative side. The torpedo was
then charged and placed in the reload position.

This torpedo again had a large positive ground (104 volts)
when inspected prior to the charge on 1 December. This was
an accumulative ground and was traced down to #2 cell. The
cell was then discharged and jumped out. The ground dropped
to a 3 volt positive ground and a zero volt negative ground.
The torpedo appeared to be in good shape when routined and
charged on 6 December.

The remaining torpedoes were in excellent condition and ap-
peared to give good runs when fired. There is some possi-
bility of erratic runs (broaching) in attack #3 as the tor-
pedoes were fired directly into a very rough (state #5) sea
with a seven foot depth setting. The Commanding Officer
saw what could have been torpedoes broaching. If so the
broaching was undoubtedly due to firing into a heavy sea.
In accordance with latest instructions speed reduction cor-
rections for shallow depth settings were used as follows:
The speed was reduced 1.1 knots for the six foot settings
in attacks #1 and #2, 0.90 knots for the seven foot settings
in attack #3, and 0.5 knots for the ten foot settings used
in attacks #4 and #5.

As the "Rangers" operated as a unit for only a week a complete
test was not placed upon the doctrine, the communications and
the plan of patrol. However, in the opportunity that was
presented on 6 December for the pack to work together, only
praise can be said of the SEGUNDO'S and RAZORBACK'S action
following receipt of the TREPANG'S contact report. Every
one knew what to do and how to do it, and all ships of the
convoy were relentlessly pursued until they were destroyed.

Prior to the 6 December action the RAZORBACK made a submerged
attack on a convoy on 1 December and on 5 December made a
submerged attack on a destroyer. In the first attack she was
unsuccessful; however, in the second three hits were obtained.

-48-
ENCLOSURE (A)

— page 120 —
CONFIDENTIAL
SS412/A16-3
Serial (025)

U.S.S. TREPANG (SS412)
Report of Second War Patrol.

Task Group 17.15 Supplementary Patrol Instructions.

1. Enclosure (A) shows patrol areas 11 DESTROY, 11 DELETE,
and 11 DETAIN as well as the waiting areas 11 DEER and 11 DETAIN,
divided into squares and sometimes into irregular shaped
areas to conform to the geographical outline of the patrol area. These
areas are appropriately numbered and these numbers will be used
when designating areas to be patrolled.

2. Each square or area is divided into three sections.
Depending on how the squares are laid out one boat will always be
to the north, the east or the northeast; another will always be in
the center; and the third will be to the south, the west or the
southwest. Unless otherwise ordered, the order of boats from East
to West will be: SEGUNDO, TREPANG, and RAZORBACK.

3. The schedule for patrolling the individual areas will
be furnished by separate correspondence. A signal may be sent at
anytime changing the area assignments. Normally a submarine will
be able to surface not later than 2000 local time. The shift from
one area to an adjacent one may be started about this time and on
one engine speed the submarine should be in her new area about
0300. On surfacing, submarines should try to be near the center of
their individual lanes so that a rendezvous can be quickly accom-
plished if ordered.

4. Submarines will patrol submerged during the day, but
will remain on the surface or will surface when in hot pursuit
of shipping if conditions permit. It is recommended that submarines
zig-zag on the surface both day and night when in the area.

5. In the event information is received concerning enemy
forces the Group Commander will give appropriate signals in order
to intercept the enemy. When contact is made, broadcast your posi-
tion in latitude and longitude and give the bearing and distance
of the enemy.

6. Once contact is made submarines will operate in ac-
cordance with the "Coordinated Attack Doctrine".

7. All submarines keep their track charts and patrol reports
up to date. On leaving the pack the submarine will be required to
rendezvous with and submit to the Group Commander a copy of the
track chart and a rough narrative copy of the patrol report. The

-50-
ENCLOSURE (B)

— page 121 —
CONFIDENTIAL
U.S.S. TREPANG (SS412)
SS412/A16-3
Report of Second War Patrol.
Serial (025)

track chart will be on tracing cloth, the scale will be that of
the small area plotting sheet for the area. All submarines keep
minus eight time.

/s/ Roy M. DAVENPORT,
Commander, U.S.N.,
Commander Task Group 17.15

ENCLOSURE (B)

Task Group 17.15 Supplementary Communication Plan.

AREA FREQUENCY: The basic system of pack communication will be
CW on area frequencies specified in Wopaco. All submarines will
maintain continuous transmitter-receiver watch in accordance with
the frequency shift schedule set forth therein. Use of frequency
meter in making set-ups is mandatory. Area frequency will be
used for all pack communications except as noted below. Messages
will be encrypted in Wopaco #1. Callups will consist of addressees
call sign from Wopaco followed by an alert signal repeated twice.
Callups will not be acknowledged and will be followed immediately
by the message. Messages will be sent through completely, then
repeated. Receipts must be sent promptly by all addressees in
numerical order of Task Unit Designation. Messages and receipts
must be authenticated. Each boat will number serially despatches
which it originated and will include the serial number of each
despatch in the encoded text.

VISUAL: Visual will be used whenever possible during daylight.
At night blinker tube may be used at discretion when circumstances
permit. Messages will not be encrypted.

SJ RADAR: SJ radar will be used when practicable during low visi-
bility. A submarine will call another by matching his pulse rate
to that of the submarine called. Upon first contact, submarines
will exchange recognition signals for major war vessels, followed
by an exchange of visual calls. Messages sent by SJ will be en-
crypted in Wopaco and will not be authenticated. In general,
blinker is preferrable for long messages when it is certain that
the area is clear of enemy forces.

-51-

ENCLOSURE (C)

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CONFIDENTIAL
SS412/A16-3
Serial (025)

U.S.S. TREPANG (SS412)
Report of Second War Patrol.

SJ radar will not be used for communication during an approach
when it is not needed for tactical use. In this case, area frequency
will be used.

VHF: VHF will be used for transmitting messages after a rendez-
vous when weather, limited time, or other circumstances make the
use of visual means impossible or undesirable. VHF equipment will
be manned at all times when within 10,000 yards of another sub-
marine unless ordered secured. When messages are being sent by VHF
all submarines will close the range to maximum of 6,000 yards of
the OTC and conform to his movements in order to maintain this
range. Channel four will be used habitually unless another is spe-
cified. Standard voice procedure, as found in Communication In-
structions will be used. Voice calls will be the last number of
task unit designation preceded by the word "Station". Messages
will be encrypted in Wopaco and will not be authenticated.

SHIP-SHORE FREQUENCY: The first responsibility of the first sub-
marine to make a contact which he considers worthy of a coordinated
attack is to notify the other subs of the pack via area frequency.
Immediately following this and if the nature of the contact war-
rants, he will send out a contact report on the ship-shore frequency
for rebroadcast on the submarine fox schedules.

When advisable following an attack, a single report will be sent
by the OTC reporting the results for the pack as a whole.

Administrative despatches, such as requests for entrance rendezvous,
will be originated by the OTC.

The following general procedure will be followed in sending despatches
on area frequency during a coordinated attack.

First ship making contact:
(a) Initial report giving location of own ship and target
plus additional available information such as number
of ships and escorts (surface and air), course and
speed, types of ships. The important factor to stress
in giving initial location of contact.
(b) As soon as possible give accurate amplifying data as
to course and speed, number, type, whether radar-
equipped, etc.
(c) Thereafter report changes of data given above.
(d) Report start of attack, then maintain radio silence un-
til completion of attack.

-52-
ENCLOSURE (C)

— page 125 —
SUBMARINE DIVISION FORTY-FIVE
Care of Fleet Post Office,
San Francisco, California,
24 December 1944.

FB5-45/A16-3

Serial: 0142
C-O-N-F-I-D-E-N-T-I-A-L
FIRST ENDORSEMENT
TREPANG Conf. ltr. SS412/A16-3
Serial 025, of 12/22/44 - Re-
port of SECOND War Patrol.

From: The Commander Submarine Division FORTY-FIVE.
To: The Commander-in-Chief, United States Fleet.
Via: (1) The Commander Submarine Squadron FOUR.
(2) The Commander Submarine Force, PACIFIC Fleet.
(3) The Commander-in-Chief, U.S. PACIFIC Fleet.

Subject: U.S.S. TREPANG - Report of SECOND War Patrol.

1. The SECOND war patrol of the U.S.S. TREPANG was conducted in the
area north of LUZON ISLAND. The patrol was of thirty-eight days duration and
was terminated due to expenditure of torpedoes after eight days in the area.
The Commanding Officer also commanded a Coordinated Attack Group consisting of
TREPANG, SEGUNDO, and RAZORBACK during this period.

2. In the afternoon of December 1st, the first day in area, a convoy
later found to consist of one AP, an AK, three escorts and heavy air screen was
detected east of BABUYAN ISLAND. A change in course of the convoy while TREPANG
was covered by the air screen prevented TREPANG from attacking this convoy. It
is interesting to note that initial contact with this convoy was made on the JP
sound gear at a range of about 40,000 yards. It is also noteworthy that the
five bombers in the air screen of this convoy were flying only a few feet above
the water indicating they may have had special submarine detection equipment.
The planes were over TREPANG for about one hour during which time the convoy
made the evasive course change. The disposition of the Coordinated Attack Group
was such that RAZORBACK was able to attack this convoy, but without success.

3. Shortly after midnight on December 6th, off CAPE BOJEADOR, radar con-
tact was made on two ships which were later identified as two small patrol boats
after a radar and periscope depth approach in bright moonlight. No torpedoes
were fired because the sea was too rough for shallow depth settings.

4. Just after surfacing for the night on December 6th radar contact was
made with a southbound convoy consisting of seven large ships escorted by three
small patrol vessels. The seven ships in this convoy were destroyed by "Roy's"
Rangers" within three hours.

ATTACK NO. 1 - This was a night surface attack at 2044(H) in which six Mk.
18-1 torpedoes were fired from the bow tubes of the TREPANG at two overlap-
ping large AK's of the convoy, range 1775 yards, gyro angles 022°, track
angle 124°, 162° starboard, depth setting 6 feet. Three hits were obtained in
the first target and two in the second. These ships sank within 2 minutes.

ATTACK NO. 2 - Two minutes after the above attack four steam torpedoes were
fired from TREPANG's stern tubes at a large tanker, after clearing her by
650 yards while turning, range 1700 yards, gyro angles 113°, track angle
162° starboard, depth setting 6 feet. Two hits were seen in this tanker
which exploded and sank one hour later while TREPANG was closing to finish
her off.

— page 127 —
[HANDWRITTEN: 130]

SUBMARINE SQUADRON FOUR
Fleet Post Office
San Francisco, California.

27 December 1944.

FC5-4/A16-5
Serial: 0590
C-O-N-F-I-D-E-N-T-I-A-L
SECOND ENDORSEMENT to
USS TREPANG (SS-412) Report
of Second War Patrol.

From : The Commander Submarine Squadron FOUR.
To : The Commander-in-Chief, UNITED STATES FLEET.
Via : (1) The Commander Submarine Force, U.S. PACIFIC FLEET.
(2) The Commander-in-Chief, U.S. PACIFIC FLEET.

Subject: U.S.S. TREPANG (SS-412) - Report of Second War Patrol.

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

2. The Commander Submarine Squadron FOUR congratulates
the Commanding Officer, officers and crew of the U.S.S. TREPANG for
an excellent patrol, and for her leading role in the destruction of
an important enemy convoy.

3. It is recommended that the U.S.S. TREPANG be credited
with the following:

SUNK
1 - AK(EU), 7,500 tons
1 - AK(EU), 7,500 tons
1 - AO(EU), 10,000 tons
1 - AP(EU), 10,000 tons

Total Sunk 35,000 tons

[SIGNATURE: J. V. O'Regan]
J. V. O'REGAN.

— page 128 —
```
FF12-10/A16-3(15)
Serial 014
CONFIDENTIAL

THIRD ENDORSEMENT to
Patrol Report of
Second War Patrol.

COLUMBIA PATROL REPORT NO. 624.
U.S.S. TREPANG (SS-412) - Report of Second War Patrol
(16 November to 22 December 1944).

Subject: U.S.S. TREPANG (SS-412) - Report of Second War Patrol
(16 November to 22 December 1944).

DISTRIBUTION:
(Complete reports)
ComNav
CNO
CinCPac
Intel.Cen.Pac.Ocean Areas
ComServPac
ComCinch
Consultant
S.F. School, NL
CO, S.F. Base, PH
Cosmospace
ComSubPac
ComSubBase
CTK 71
ComOrdnance
SubMar, L
ComSubBase
ComSubBase
All Squadron and Division
Commodores, Pacific
Submarine
All Submarines, Pacific

NOTE: THIS REPORT WILL BE DESTROYED PRIOR TO ENTERING PATROL AREA.

[HANDWRITTEN: E. H. HIGGINS]
[SIGNATURE: B. L. HYNES 2nd, Flag Secretary]
```

— page 129 —
```
SUBMARINE FORCE, PACIFIC FLEET

FF12-10/A16-31(5)
Serial 014
CONFIDENTIAL

THIRD ENDORSEMENT to
THIRD Report of
Second War Patrol.

COMSUBPAC PATROL REPORT NO. 624.
U.S.S. TREPANG - SECOND 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. TREPANG (SS512) - report of Second War Patrol
         (16 November to 22 December 1944).

1.  The second war patrol of the TREPANG was conducted in
the area north of Luzon. The patrol along with the U.S.S. SQUALL
(SS398), and the U.S.S. RAZORBACK (SS394) formed a coordinated attack
group with the Commanding Officer of the TREPANG, Commander Roy
Bavenport, U.S. Navy, as the group Commander.

2.  This patrol was highlighted by a series of expertly con-
ducted aggressive attacks against surface targets on a seven-ship convoy which
resulted in four of the ships being sunk by two TREPANGs and the other
three by the SQUALL and RAZORBACK. The distribution of our artillery
convey in a period of about three hours was an illustrious accomplishment,
and a severe blow to the enemy.

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

        The Commander Submarine Force, Pacific Fleet, congratulates
the group commander and commanding officer, officers, and crew
of the TREPANG for their well coordinated and highly successful patrol.
The TREPANG is credited with having inflicted the following damage
upon the enemy during this patrol:

        SU X

1 - Large AK (EU)                7,500 tons (attack No. 1)
1 - Large AK (JU)                7,500 tons (attack No. 2)
1 - Large AO (JU)               10,000 tons (attack No. 3)
1 - Large AK (NU)               10,000 tons (attacks 4 and 5)

TOTAL SUNK                       35,000 tons

Distribution and authentici-
cation on following page.

- 1 -

C. A. LOOKOOD,
[STAMP: EXTRA  ORIGINAL]
[STAMP: SOR.  MICRO]
[STAMP: PHOTO-10-43-16]
[STAMP: RETURN TO F4235]
```

— page 130 —
SS412/A16-3
Serial (01)
[STAMP: DECLASSIFIED]
[HANDWRITTEN: DECLASSIFIED ART. 0445, OPNAVINST 5510.1C]
[HANDWRITTEN: BY Gpg 50K DATE 6/20/78]

U.S.S. TREPANG (SS412)

c/o Fleet Post Office,
San Francisco, Calif.,
25 March, 1945.

From: The Commanding Officer.
To: The Commander-in-Chief, United States Fleet.

Via: (1) Commander Submarine Division TWO HUNDRED TWO.
     (2) Commander Submarine Squadron TWENTY.
     (3) Commander Submarine Force, Pacific Fleet.

Subject: U.S.S. TREPANG - Report of War Patrol No. Three.

Enclosures: (A) Subject Report.
            (B) Track Chart.
            (C) Special Report on Torpedo Firing.

1. Enclosure (A), covering the third war patrol of
this vessel conducted in Empire Area off HONSHU and KYUSHU during
the period 25 January, 1945 to 25 March, 1945, is forwarded here-
with.

[SIGNATURE: A. R. Faust]
A. R. FAUST.

[HANDWRITTEN: Filmed]
[HANDWRITTEN: 115201]

— page 131 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)
Report of Third War Patrol.

(A) PROLOGUE

Arrived Pearl Harbor 22 December, 1944 from Second War
Patrol. Assigned to Submarine Division FORTY-FIVE.
Commenced 19 day refit; originally scheduled as a 14 day
refit, a two day's extension was necessitated in order
to pull the armature on #4 main generator. Later an ad-
ditional three day's extension was granted in order to
install ST radar, the material for which did not arrive
until the middle of the refit period. On 30 December,
1944, Commander Roy M. Davenport, U.S.N., was relieved
as Commanding Officer by Commander Allen R. Faust, U.S.N.
In addition Lieutenant (junior grade) Paul E. Huffman,
U.S.N., was detached and Lieutenant (junior grade)
Elliot W. Carlson, U.S.N.R., reported aboard. Eighteen
members of the crew were transferred and twenty new mem-
bers received on board. It is considered that the refit
was very satisfactory. A 9 day training period was as-
signed, including 2 days special training and 2 days ex-
ercises with pack.

(B) NARRATIVE

List of Officers & CPOs             Number of War Patrols
                                    Including TREPANG'S 3rd

A.R. FAUST, Comdr., USN.             2
R.S. GARVEY, Lt., USNR.             12
R.W. STECHER, Lt., USN.             3
J.M. BARRETT, Lt., USN.             8
E.W. CARLSON, Lt.(jg), USNR.        1
J.B. POTTER, jr., Lt.(jg), USNR.    3
D.H. DENTON, Lt.(jg), USN.          10
C.F. NAGEL, Lt.(jg), USNR.          2
P.D. FARMER, Lt.(jg), USNR.         3
W.A. KEMP, Ensign, USNR.            3

DARNELL, Ivan L., 315 95 09, CTM(SS), USN. 10
KENNEHY, James R., 201 48 53, CQM(S3), USN. 10
HARRINGTON, Melvin H., 375 88 54,
    CMOMM(AA)(T)(SS), USN.          7
KENRICH, Chester M., 611 06 10,
    CRT(AA)(T)(SS), USNR.           6
LOCKLIN, William J., 562 79 76,
    CEM(AA)(T)(SS), USNR.           3
MARLIN, John M., jr., 336 89 14, CFC(SS),
    USN.                            10
NILES, Thomas E., 375 80 94, CTM(AA)(T)(SS),
    USN.                            5

-1-                                 ENCLOSURE (A)

— page 133 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)
Report of Third War Patrol.

3 February
1200 (L) Position: Lat. 20-23.0 N.
Long. 160-27.7 E.

4 February
1200 (L) Position: Lat. 19-49.8 N.
Long. 155-16.4 E.

5 February
1200 (K) Position: Lat. 18-18.5 N.
Long. 149-12.0 E.
1612 Lookout and Quartermaster sighted periscope on starboard
beam, distance 1,000 yards. Turned away at flank speed,
notified rest of pack on FM, and sent contact report to
Commander Task Group 17.7 and ComSubsPac.

6 February
1200 (K) Position: Lat. 16-23.1 N.
Long. 145-03.4 E.
1453 Moored alongside U.S.S. FULTON at SAIPAN. Transferred
one man with chronic seasickness and received replace-
ment. Voyage repairs accomplished by U.S.S. FULTON.
Received 52,127 gallons fuel.

8 February
0838 (K) Underway in company with task group in accordance with
Commander Submarine Force, Pacific Fleet, Operation Order
#37-45.
1532 Made 15 minute trim dive.
2055 SJ contact on friendly surface ship--probably picket of
which we had been warned.
2331 SJ contact on friendly submarine heading toward SAIPAN.

9 February
1200 (K) Position: Lat. 18-34.6 N.
Long. 147-57.5 E.
Made 3 training dives during the day.

10 February
1124 (K) A/C #1 SD contact at 22 miles, closed to 12; dived for
30 minutes.

-3-
ENCLOSURE (A)

— page 138 —
```
CONFIDENTIAL
U.S.S. TREPANG (SSL12)
SS12/A16-3
Serial (01)

Report of Third War Patrol.

0937
Surfaced. Would very much like to see some friendly fighters at this point.

0942
A/C #1 - SD contact at 6 miles, sighted at 5. Definitly not a Helicat; could have been same type, but did not wait to see this time. Dived to 200 feet.

1045
Surfaced.

1139
A/C #1 - SD contact at 17 miles, closed to 12, then opened.

1200
Position: Lat. 34-10.0'N.
Long: 137-51.8'E.

1239
A/C #2 - SD contact at 22 miles, closed to 8 miles, then opened.

1300
Intercepted part of a message referring to the call of our station on VHF. Our own SD causes interference on VHF and it happened to make us unable to get in the middle of the transmission. Opened up on VHF to answer.

1315
Heard reference to our station call on 4475 KCS - message unintelligible. Opened up on 4475 KCS - no success.

1345
Attempted communication by voice on 4475 KCS with PIER - no success.

1730
A/C #3 - SD and sight contact at 14 miles, closed to 12, then opened.

1800
Set course to southward and patrolled same area as last night.

2150
Received ComSubPac's 170945.

18 FEBRUARY
0712 (K)
Div'd for periscope patrol in vicinity of lifeguard station but in case strike should continue, although assume we would have received despatch orders in that case.
```

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CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)
Report of Third War Patrol.

1101       Surfaced to see if there were any indications on radio
           of carrier activities. Only English heard was obviously
           a spotting group at IWO directing bombardment fire.

1122       Dived, now convinced that strike is over.

1200       Position: Lat. 34-04.0 N.
                     Long. 138-05.1 E.

1845       Surfaced. Patrolled in same general area as previous
           nights.

19 February
0330 (K) Received ComSubsPac's despatch concerning search for
           downed aviators. The only one in which we could possibly
           aid plots on land.

0704       Dived for periscope patrol.

1200       Position: Lat. 34-10.8 N.
                     Long. 137-48.9 E.

1358       Surfaced on lifeguard station.

1445       A/C #14 - SD contact at 34 miles: During
           remainder of afternoon had 20-25 SD contacts on B-29s
           returning from strike.

           For next 4 days will patrol across NAGOYA-BOMIN sea
           lane as heretofore. Plan to conduct day submerged
           patrol just outside the 100 fathom curve off ISE WAN and
           between SHIONO MISAKE and DAIO SAKI. This seems to be
           the best bet for intercepting any major task force
           leaving the NAGOYA Area, which is our primary objective
           until the landings at IWO JIMA are secured.

20 February
0654 (K) Dived for periscope patrol.

1200       Position: Lat. 34-14.2 N.
                     Long. 137-23.8 E.

1927       Surfaced.

2050       Received ComSubsPac's despatch 200312.

2350       Received ComSubsPac's correction to position of aviator;
           not near our area.

-9-
ENCLOSURE (A)

— page 142 —
```
CONFIDENTIAL
U.S.S. TRIPANG (SS-412)
SS/412/A16-3
Serial (01)

Report of Third War Patrol.

1900
Observed both patrol boats (range now 12,000 yards) signaling toward us, one using red blinker, the other white. Believe we were sighted by picket and thus notifying the patrol boats.

During next half hour had 6 or a small pids on SJ at ranges inside 3,000 yards. Twice observed something in water on bearing of these contacts, but believe most were either birds or false radar targets, probably the latter, as we have never picked up birds heretofore. Ranges on several of them changed quite rapidly, indicating a 15 or 20 knot speed.

1935
Strong AFR signal at 155 MCS, rapidly reached saturation.

1940
A/C #17 - SD contact at 6 miles, closing. Dived.

2015
Surfaced.

2010
AFR again, saturated at 155 MCS. Two different signals this time, one weaker than the other.

2025
A/C #18 - SD contact 12 miles, closing. Used SD on 1 minute checks. At 9 miles plane turned off his radar but continued closing.

2020
Dived with range decreased to 5 miles.

2035
Surfaced. No further anti-submarine activity.

2223
Transmitted TRIPANG's second, weather report and results of attack (24/1230).

25 February
0136 (I)
Dived to check torpedoes which had been in flooded tubes and to get some rest for tomorrow's lifeguarding.

0541
Surfaced on lifeguard station.

0619
S/C #3 - Sighted masts of 2 ships bearing 350° T., range about 25,000 yards, course about 250°. Commenced tracking and end-round, but knew we couldn't make attack in view of specific directive that lifeguard for earlier strike took preference over attacks. Closed enough to identify them as merchant types.

0700
A/C #19 - Sight contact through periscope with 2 BMTIES patrolling up and down track of convoy. SD range from
-12-
```

— page 143 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
S. S. 12/2 (A16-3)         Report of Third War Patrol.
Serial (01)

12 to 20 miles; With the advantage of a complete overcast, gray day, believe we could have gotten in for an attack, but instead turned back to lifeguard station.

0830
Intercepted traffic on L4775 indicating strike was underway. Tried to raise a station which was apparently a carrier with no success. Finally sent contact report on convoy and in hopes someone would intercept it.

1025
A/C #20 - In communication with 2 CAP fighters. A few minutes later sighted them at 6 miles. Sent contact report on convoy through one of them. Last report a destroyer led it and was forwarding it for action.

1150
CAP planes left us - reliefs not yet arrived, nor did they arrive. Can't much blame them, considering the state of the weather, constant rain and heavy overcast.

1200
Position: Lat. 3-11.1 N.
         Long. 137-52.0 E.

1355
A/C #21 - SD contact on 30-40 B-29s at ranges from 4 to 40 miles.

26 February
0355 (T)
Received ComSubPac's despatch 251736.

0600
Made 15 minute trim dive. On lifeguard station.

1200
Position: Lat. 1-34.9 N.
         Long. 138-5.0 E.

1307
A/C #22 - SD contact at 28 miles, open.

1500
Assumed that strike had been cancelled, and set course southward away from station.

2300
Received ComSubPac's despatch 261036.

27 February
0030 (T)
Exchanged recognition signals with PIPER on SJ.

0557
Used 50 minute trim dive. On lifeguard station for carrier strike.

0946
A/C #23 - SD contact at 26 miles on 2 planes. Had these planes off and on all morning at 20 to 30 miles. Suspect they were air cover for a slow convoy along coast.

                             -13-
                          ENCLOSURE (A)
```

— page 144 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)

Report of Third War Patrol.

1200         Position: Lat. 34-08.1 N.
                       Long. 137-51.0 E.

1245         Received ComSubsPac's despatch 262347.

1318         Submerged for periscope patrol on route from OMAI SAKI
             to DAI SAKI in hopes that the SD contacts were an indi-
             cation of another convoy on the same route as the one
             sighted the morning of the 25th.

1822         Surfaced. Moved into sub-area 2 as assigned by Commander
             Task Group.

28 February
0530 (I)     Dived for submerged patrol 25 miles south of IRO SAKI.

1200         Position: Lat. 34-19.8 N.
                       Long. 138-40.7 E.

1827         Surfaced.

1931         While making 12 knots in force 4 sea, taking only
             occasional spray on bridge, an unexpected and unusually
             large wave broke over the bridge and lookout platforms.
             THOMPSON, William Walter, 654 36 33, GM1c(T)(SS), V-6,
             USNR, #1 lookout, was washed overboard. Circled to
             search for man.

1940         Heard man calling and sighted him soon thereafterwards
             about 75 yards away. Could not turn into sea and boat
             was drifting away from him. Backed away to gain sea
             room for turn.

1944         Man alongside to starboard abreast forward torpedo room
             hatch. Too weak from cold, exhaustion, and injury to
             leg to help himself much. Lieutenant J. M. BARRETT,
             U.S.N., jumped over the side to aid man.

1956         Both men back on board and under treatment of pharmacist's
             mate. The Commanding Officer will make suitable recom-
             mendations in the case of Lieutenant BARRETT a subject
             of separate correspondence.

2100         APR signal at 155 MCs, 1,000 pulse rate; identified as
             radar search plane. Reached saturation numerous times
             but never closed sufficiently for us to get contact on
             SD. Suspect our searchlight was spotted from the beach
             and this plane was engaged in investigating that vicinity.

-14-

— page 145 —
```
CONFIDENTIAL
U.S.S. TREPANG (SS-412)
Serial: 12/A16-3
Serial: (01) Report of Third War Patrol.

2300
1 March
Received ComSubPac's serial-7.

0515 (T)
SJ contact on friendly submarine, probably BOWFIN.
Apparently he is joining us in submerged patrol today.

0541
Dived 20 miles south of IRO SAKI for submerged patrol.
Position: Lat. 34-29.8 N.
Long. 134-58.4 E.

1823
Surfaced. Proceeding to lifeguard station.

1845
SJ contact on and SJ interference from BOWFIN.
Received ComSubPac's 010432.

2 March
0000 (T)
Passed 11 miles south of MIKURA SHIMA. Definite indications that 150 MC, 500 pulse rate, radar picked us up at this range and lost us at about 15 miles.

0510
Received ComSubPac's 011512.

0540
Dived for submerged patrol near lifeguard station.

1200
Position: Lat. 33-56.5 N.
Long. 140-27.5 E.

1318
Surfaced for 20 minutes.

1822
Surfaced. Conducting patrol to eastward of MIKURA SHIMA,
Sea force 6, wind 30 knots from south, steady rain.
Apparently we are in the edge of a tropical storm,
judging from rise in air temperature.

3 March
0423 (T)
S/J contact on single, unescorted, southbound freighter-transport. No improvement in weather or seas.
Gained position for a sharp track in order to permit firing down seas as much as possible.

0530
Attack #3. Commenced firing 4 torpedoes forward.

0532
Two timed hits; only one observed from bridge. Ship sank in 3 minutes. Much too rough to attempt to pick up survivors.
-15
ENCLOSURE (A)
```

— page 146 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)

Report of Third War Patrol.

0538
Two end-of-run explosions.

0615
Dived for submerged patrol.

1200
Position: Lat. 34-11.1 N.
           Long. 139-56.5 E.

1255
Surfaced for 15 minutes.

1330
Detected pinging bearing 170° T. Attempted to close,
but bearing increased rapidly and soon disappeared,
indicating westerly course. Probably patrol boats
searching for survivors or us.

1820
Surfaced.

2123
Received ComSubsPac's 031125.

4 March
0543 (T)
Made 30 minute trim dive. Surfaced on lifeguard station.

0920
A/C #24 - SD and sight contact on about 75 B-29s during
next 2 1/2 hours.

0930
Sighted 1 B-29 flying low at 8 miles. Closed to 6 miles
then turned away. Probably our CAP. Sighted again a
few minutes later at 8 miles and again turned away.
Fired green recognition signal from signal gun, but
ineffective in daylight at this range. Attempted radio
communication. Raised a B-29 who attempted to tell our
CAP that we were calling. We are exactly on station,
having taken departure from a radar fix on MIKURA and
MIYAKE SHIMA at 0200, and checked with a good star fix
and sun lines since 0530.

1200
Position: Lat. 33-57.8 N.
           Long. 141-01.0 E.

0530
Received orders from PIPER to join in search for aviators
down 210 miles south of our station. Set course 168° T.,
maximum possible speed into sea, 12 knots.

2055
Received word from ComSubsPac that all planes returned
and orders for us to return to vicinity of lifeguard
station.

5 March
0518 (T)
Dived between HACHIJO JIMA and MIKURA SHIMA for periscope
patrol.

-16-
ENCLOSURE (A)

— page 147 —
CONFIDENTIAL

U.S.S. TREPANG (SS412)

SS412/A16-3                                                Report of Third War Patrol.
Serial (01)

— page 156 —
CONFIDENTIAL
SS412/A16-3
Serial (01)
U.S.S. TREPANG (SS412)
Report of Third War Patrol.

0718 Surfaced again.
0810 A/C #49 - SD and sight contact at 8 miles, turned
       toward. Dived. Definitely a Jap plane. Decided to
       stay submerged a while in expectation that our carrier
       attacks to northward would draw off planes from this
       vicinity.
1200 Position: Lat. 31-10.0 N.
                 Long. 131-58.5 E.
1306 Surfaced. Overcast, with intermittent rain.
1310 A/C #50 - Sight contact on 2 planes very low at about 5
       miles, heading eastward. Did not see us.
1317 A/C #51 - SD contact at 4 1/2 miles; dived. Identified
       through periscope as Myrt fighter. Apparently he saw us
       as he crossed the bow about 1 mile away, and turned
       toward us.
       So far today have heard nothing on the radio and have
       been unable to raise BOWFIN or POMFRET, so decided to
       stay submerged the remainder of the day, inasmuch as it
       seems impossible to remain on the surface anyway.
1830 Surfaced.
2130 Received ComSubsPac's serial 94.

20 March
0551 (I) Dived for submerged patrol.
1200 Position: Lat. 29-14.9 N.
                 Long. 135-30.7 E.
1259 Surfaced.
1329 A/C #52 - Sight contact with Jap fighter at 6 miles;
       dived.
1503 Surfaced.
1646 Sighted floating mine and exploded with 20mm fire.
1924 Exchanged recognition signals on SJ with STERLET.
2025 APR signal at 155 MCs, 1,000 pulse rate. Had these
       signals on the 150 MC band for remainder of night.

-26-                                                ENCLOSURE (A)

— page 157 —
```
CONFIDENTIAL                       U.S.S. TREPANG (SS-12)
                                   SS 412/A16-3
                                   Serial (01) Report of Third War Patrol.

varying from weak to saturated. Identified as coming from 2 or more radar search planes which apparently were tracking us, though they appeared to be on STIRLET most of the time.

2131  A/C #53 - APR signal saturated. SD contact on 2 planes at 6 and 7 miles, slowly opened.
2210  21 March
0035 (T)  A/C #54 - APR and SD contact at 12 miles.
0035  A/C #55 - SJ contact at 6,000 yards; dived. SD contact at 2 miles on way down.
0045  Surfaced.
0333  Surfaced.
0846  A/C #56 - SD contact at 6 miles; dived. Identified through periscope as Liberator.
0905  Surfaced.
0945  A/C #57 - Saturated APR signal at 150 Mcs, 250 pulse rate. SD contact at 12 miles. Sighted Lily at range of 7 miles; dived.
1009  Surfaced.
1020  A/C #58 - APR and sight contact on same Lily at 12 miles.
1027  Dived as Lily closed to 9 miles.
1107  Surfaced.
1128  A/C #59 - APR jammed throughout 75-300 Mc band. Sighted Lily at 12 miles. Closed to 8 miles crossing bow, then banked toward us and started glide down. Dived.
1200  Position: Lat: 29-16.9 N.
      Long: 135-20.7 E.
      Observed very large smoke column, apparently explosion, bearing 220° T, probably 40-50 miles distant. Concluded this was probably our own surface forces under Jap aircraft attack. This explains the extraordinary
                                                                                          [HANDWRITTEN: -27-]
```

— page 161 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412).

Report of Third War Patrol.

(G) ENEMY PLANE CONTACTS

Between forty and fifty SD radar contacts were made in the NANPO
planes during the TREPANG'S stay in Hit Parade. In the NANPO
SHOTO Area sight contact was made with nine enemy planes, six of
which were identified; they were as follows: one Judy, two Rufes
and three Bettys. The Rufes were employed as search planes, close
inshore, following our attack on their shipping. The Bettys were
used as convoy air cover. Those planes not identified were a
single float monoplane, similar in appearance to Rufe, and a bi-
plane similar to Pete having its pontoon and floats replaced by
fixed landing gear. The third unidentified plane was a single
engine monoplane.

Between 17 March and 20 March, while off the east coast of
southern KYUSHU, we encountered 11 or 12 additional enemy planes
which resulted in sight contact with five of them. Those identi-
fied were one Jill and two Myrts, sweeping the area at a very
low altitude, during a time of extremely poor visibility. Those
not identified were a single engine, low wing plane and one
other monoplane.

On 21 March sight contact was made with a radar equipped Lily
at Latitude 29-15 N., Longitude 135-24 E.

Our experience on this patrol indicates that air activity is
much greater in the KYUSHU area than off TOKYO BAY Area. This
is especially true of radar equipped search planes, which proved
a very great nuisance off KYUSHU.

-31-

ENCLOSURE (A)

— page 166 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)
Report of Third War Patrol.

(I) MINES
Two floating mines were exploded, one at Latitude 29-37.5 N.,
Longitude 133-08.2 E, the other at Latitude 29-59.2 N., Longitude
131-32.1 E. These were contact mines with 4 horns visible, and
had been in the water a considerable time as evidenced by heavy
marine growth on them. A third mine of the same type was sunk
without exploding at Latitude 29-58.2 N., Longitude 131-32.2 E.

(J) ANTI-SUBMARINE MEASURES AND EVASIVE TACTICS
The anti-submarine vessels encountered after attack #1 were
definitely second rate. From the promptness with which 4 patrol
boats appeared on the scene after this attack, we feel certain
that we spoiled a submarine trap. However, none of them ever
had contact on us and the depth charges were dropped in singles
or doubles, apparently at random. Three of these boats evidently
depended on listening equipment, as only one of them was ever
heard to ping. At one time the trim pump at 450 feet without
being picked up at an estimated range of 2,000 to 3,000 yards.
Evasive tactics used were running at 450 feet at 70 turns with
stern toward pinger as much as practicable while opening the
beach. There was no temperature gradient, so we came to peri-
scope depth as soon as we were clear of immediate vicinity of
attack. About dusk a trawler type vessel commenced using some
kind of metallic-like sound equipment which sounded like a noise
maker. At 5,000 yards the noise was very loud and consisted of
continuous metallic-like clicks. It was heard only on the super-sonic
equipment and not on JP. It appears that during the afternoon
several picket boats were stationed to cover our probable retire-
ment and at dusk the anti-submarine vessels began to move to
seaward. Also two radar-equipped planes were detailed to search
the area. There is evidence that radar false targets were planted
in the area, although it is difficult to see how the enemy radar
planes could distinguish us from the false targets.

On several other occasions radar equipped planes (146-155 MCs,
1,000 pulse rate, and 200-210 MCS, 1,000 pulse rate) made
sweeps through the area. In all cases these were detected on
the APR and when the signal reached saturation, the SD was used
for 5 second checks at 1 to 2 minute intervals. Several times
the planes seemed to switch off their radar as soon as we cut in
the SD, indicating a detector on this frequency. However, there
was no evidence that the planes could "home" on the SD when used
as above. During daylight a Lily was twice sighted which was
definitely equipped with 155 MC, 250 PR, 20 micro-second radar.
Another Lily jammed our APR very effectively from a range of 15
miles, but it did not effect SD operation.

-36-
ENCLOSURE (A)

— page 167 —
```
CONFIDENTIAL                       U.S.S. TREPANG (SS412)
SS412/A16-3
Serial (01)                       Report of Third War Patrol.

(K) MAJOR DEFECTS AND DAMAGE
Ordnance and Gunnery

Special charging panel installed during last refit was connected so as to receive the 115 Volt AC supply from the REO amplifier circuit in the after torpedo room. This overloaded the REO isolation transformer located in the radio shack. The transformer heated up and would have burnt if the defect had not been noted by ship's force. Defect was corrected by taking the AC supply for the panel from the hydrogen burner circuit located in the after torpedo room.

C & R

Air Compressors - The port air compressor which was overhauled by Pearl Harbor was a continual source of trouble for the first 3 weeks of the patrol. Both connecting rod crankpin bearings had to be renewed. Both spherical wristpin bearings had to be taken up. The rotor drive nuts were left out of the second stage cylinder during holding down nuts, and the liner dropped down enough so that the connecting rod broke the liner. A new second stage liner was installed at SALTAN. In addition, one of the border stage piston follow-up steaves broke and a new one had to be manufactured at sea. With this new overhaul conducted by the ship's force no additional difficulties were encountered.

Periscopes - The new ST periscope as installed by Pearl Harbor leaked excessively. After being repacked with Garlock packing three times no improvement was noted. Careful inspection showed the leak to be through the service lines on the periscope. The service lines on this periscope extend almost the entire length, hence there was a leak where the scope was on the buffers. At SALTAN this service lines were filled with torpedo TANK-UX and the leak was stopped for the remainder of the patrol except at deep depths (over 250 feet). As all other periscopes installed to date have given the same trouble, it is considered a matter of urgency that these service lines be filled with metal and superfluous portions of rubber be changed to eliminate all possibility of leaks for the service periscope.

The optical system of the ST periscope is by far the best ever observed by this ship's personnel. For use on the surface periscope watch it has proven ideal.
-37-
ENCLOSURE (A)
```

— page 172 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)

Report of Third War Patrol.

APR - APR contacts are listed under Section (U). This APR has
been used continuously for three patrols without any
serious material failures. On this patrol, however, the
gear training mechanism began to wear out on the two
tuning units. They will have to be replaced.

It is interesting to note that two signals of the same or
nearly same frequency will have their pulse rates added on
the S.P.A. unless they happen to be in phase or nearly so.
This can be confusing to the operator and he may report two
500 pulse rate signals as one signal at 1,000 pulse rate.
This actually happened on 2 occasions on this patrol.

(N) SONAR AND SOUND CONDITIONS

Inspite of invariably isothermal water, sound conditions were
found to be extremely variable. Best conditions were noted on
24 February off MIKI SAKI when ranges of about 7,000 yards were
obtained. The poorest results were obtained on 6 March between
HACHIJO SHIMA and MIKURA SHIMA when two small, shallow-draft 6-
knot vessel (SC/C #5) were not picked up until ranges of 1,000
yards on the JK, with JP unable to make contact even at 500
yards. It is possible that heavy rains during the past 3 days
were a cause of this condition. On 9 March in the same area as
the 6 March contact, with a state 4 sea, JK range of 3,000-4,000
yards was obtained on two large PC type patrol boats (SC/C #6)
and one large unidentified freighter (SC/C #6).

All pinging noted was between 17.0 and 17.4 KCs except on the
24 February contact, when pinging was initially detected at 16.7
KCs. The frequency of this signal was gradually increased over
a period of about an hour, finally settling at about 17.8 KCs.

No material difficulties were encountered in the sound gear.

(O) DENSITY LAYERS

Density layer conditions were marked by the fact that no
gradients of over two degrees were encountered. Even when the
temperature near the surface varied as much as six degrees dur-
ing the day (card 3-6), this variation followed to all depths
explored by the SBT, probably due to the fact that most sub-

-42-
ENCLOSURE (A)

— page 176 —
CONFIDENTIAL
SS412/A16-3
Serial (01)

U.S.S. TREPANG (SS412)

Report of Third War Patrol.

DATE      | LOCATION   | FREQ. IN | PULSE | PULSE WIDTH | REMARKS
          |            | MEGACYCLES | RATE  | IN MICROSEC.|
2/18/45   | 33-42 N    | 153      | 500   | 8           | Strong
          | 138-14 E   |          |       |             |
2/19/45   | 34-07 N    | 97       | 350   | 20          | Strong
          | 137-49 E   |          |       |             |
          | 34-04 N    | 153      | 500   | 8           | Strong
          | 137-54 E   |          |       |             |
          |            | 74       | 350   | 30          | Weak
          |            | 75       | 500   | 25          |
2/21/45   | 33-46 N    | 74       | 250   | 15          |
          | 137-43 E   |          |       |             |
2/24/45   | 33-42 N    | 155      | 500   | 10          | Strong
          | 136-58 E   |          |       |             |
          |            | 154      | 1000  | 10          | Aircraft,
          |            |          |       |             | Saturated
          |            | 152      | 250   | 5           |
2/25/44   | 33-53 N    | 153      | 100   | 22          | Weak
          | 127-37 E   | 105      | 250   | 60          | Weak
          |            | 151      | 250   | 30          | Weak
          |            | 104      | 500   | 25          | Moderate
          |            | 97       | 350   | 20          | Weak
          |            | 104      | 350   | 50          | Strong
2/26/45   | 34-07 N    | 98       | 500   | 25          | Weak, sweeping.
          | 138-12 E   |          |       |             |
          | 34-13 N    | 104      | 500   | 25          | Moderate
          | 138-08 E   | 158      | 500   | 10          |
2/27/45   | 34-15 N    | 98       | 350   | 25          |
          | 137-50 E   |          |       |             |
          |            | 74       | 200   | 25          |
          | 34-00 N    | 151      | 500   | 5           | Weak
          | 138-38 E   | 158      | 500   | 10          |
          | 34-20 N    | 98       | 500   | 30          |
          | 138-40 E   |          |       |             |
2/28/45   | 34-10 N    | 154      | 500   | 10          | Strong
          | 138-49 E   | 155      | 500   | 5           |
          |            | 155      | 500   | 10          | Saturated

-46-
ENCLOSURE (A)

— page 180 —
FB5-202/A16-3
Serial: 010
CONFIDENTIAL

SUBMARINE DIVISION TWO HUNDRED TWO
Care of Fleet Post Office,
San Francisco, California.
26 March 1945.

FIRST ENDORSEMENT to:
CO USS TREPANG ltr. SS412/A16-3
Ser: 01 of 25 March 1945
Report of 3rd War Patrol

From: Commander Submarine Division TWO HUNDRED TWO.
To : The Commander-in-Chief, United States Fleet.
Via : (1) The Commander Submarine Squadron TWENTY.
(2) The Commander Submarine Force, Pacific Fleet.
(3) The Commander-in-Chief, United States Pacific
Fleet.

Subject: U.S.S. TREPANG (SS412) - Report of War Patrol
Number THREE.

1. The third war patrol of the TREPANG, of fifty nine
days duration, was conducted in Empire Area off Honshu and Kyushu.
Thirty five days were spent on station, twelve of which were
devoted to lifeguard duty.

2. Area coverage was good. There were but six contacts
worthy of torpedo fire. Two of these were aggressively developed
and resulted in the sinking of one ship and damage of another.
Lifeguard duty priority prevented the pursuit of a third.

3. ATTACK #1:
Off Kuki Saki the afternoon of 24 February a
periscope approach was made on a small unescorted freighter.
Three torpedoes were fired from 2950 yards. The result was one
hit which blew the bow off the enemy but failed to sink her. The
TREPANGS immediate attempt to close for another attack was
thwarted by the appearance on the scene of three or four patrol
boats. The submarine was subjected to fourteen distant depth
charges. This and all other recent reports indicate that the
Japanese are showing no improvement in their Anti-Submarine
Warfare.

4. ATTACK #2: Covered in separate supplement to this
report.

5. ATTACK #3:
In heavy seas the morning of 3 March a radar contact
at 11,000 yards was developed into a surface radar attack on an
unescorted NAGOYA type Maru. The TREPANG showed excellent judgment
in attaining a position to fire "with the sea". Four mark eighteens

-1-

— page 182 —
SUBMARINE SQUADRON TWENTY

FC5-20/A16-3/A9
Serial: 053

CONFIDENTIAL

SECOND ENDORSEMENT to
CO TREPANG Rep. of 3rd
War Patrol dated 25 Mar.
1945.

From: The Commander Submarine Squadron TWENTY.
To : The Commander-in-Chief, United States Fleet.
Via : (1) The Commander Submarine Force, Pacific Fleet.
(2) The Commander-in-Chief, United States Pacific
Fleet.

Subject: U.S.S. TREPANG (SS412) - Report of War Patrol
Number THREE.

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

2. The Commander Submarine Squadron TWENTY congratu-
lates the Commanding Officer, officers and men of the TREPANG on
the completion of a vigorously conducted patrol, notes with pleasure
the smart rescue of the man lost overboard and commends Lieutenant
J. M. BARRETT, U.S. Navy for his initiative and bravery.

3. It is recommended that the TREPANG be credited
with the following damage to the enemy:

SUNK
1 AK (NAGOYA MARU Class)(EC)(Attack No. 3) 6,100 tons

DAMAGED
1 AK (TYPE 47 MKF STANDARD D(Modified)(Attack 2,300 tons
No. 1)

Total Sunk and Damaged 8,400 tons

[SIGNATURE: L. S. PARKS]
L. S. PARKS.

Care of Fleet Post Office,
San Francisco, California,
27 March 1945.

— page 183 —
FF12-10(A)/A16-3(13) SUBMARINE FORCE, PACIFIC FLEET [HANDWRITTEN: Sory] Ga
Serial 0762 Care of Fleet Post Office,
San Francisco, California,
9 April 1945.

CONFIDENTIAL NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
ENTERING PATROL
AREA.

THIRD ENDORSEMENT to
TREPANG Report of
Third War Patrol.

COMSUBSPAC PATROL REPORT NO. 706
U.S.S. TREPANG - THIRD 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. TREPANG (SS412) - Report of Third War Patrol
(25 January to 25 March 1945).

1. The third war patrol of the TREPANG, under the command
of Commander A. R. Faust, U.S. Navy, was conducted in areas off
Honshu and Kyushu. The TREPANG was a member of a group of submarines,
with the commanding officer of the U.S.S. PIPER (SS409) as group
commander, which conducted a picket boat gun sweep and performed
lifeguard duties as well as offensive patrol.

2. The TREPANG spent some twelve days on lifeguard station
but was afforded no opportunity to effect rescue. She took full
advantage of every opportunity to attack the enemy, however, and
delivered five torpedo attacks, three of which are the subject of a
separate report. On her first attack a single hit blew the bow off
a 2,300 ton freighter. On her third attack two good hits sent a
6,100 ton freighter to the bottom.

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

4. The Commander Submarine Force, Pacific Fleet, congra-
tulates the commanding officer, officers, and crew for this third
successive successful war patrol of the fighting ship TREPANG. The
TREPANG is credited with having inflicted the following damage upon
the enemy during this patrol:

S U N K

1 - AK (NAGOYA MARU Type) (EC) - 6,100 tons (Attack No. 3)

D A M A G E D

1 - AK (Type 47 LIKE STANDARD D
MODIFIED) (EC) - 2,300 tons (Attack No. 1

- 1 - [HANDWRITTEN: EA]

— page 184 —
FF12-10(A)/A16-3(18) SUBMARINE FORCE, PACIFIC FLEET Ga
Serial 0762 Care of Fleet Post Office,
San Francisco, California.
9 April 1945.

CONFIDENTIAL NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
THIRD ENDORSEMENT to ENTERING PATROL AREA.
TREPANG Report of
Third War Patrol.

COMSUBSPAC PATROL REPORT NO. 706
U.S.S. TREPANG - THIRD WAR PATROL.

Subject: U.S.S. TREPANG (SS412) - Report of Third War Patrol
(25 January to 25 March 1945).

— page 185 —
[STAMP: CONFIDENTIAL]
[STAMP: DECLASSIFIED]
SS412/A16-3
Serial (04)
[STAMP: DECLASSIFIED-A]
[HANDWRITTEN: BY] [SIGNATURE: illegible symbol] [HANDWRITTEN: DATE] [HANDWRITTEN: 6/20/77]
[STAMP: NARA]
[STAMP: DEPT. 0445, OPNAVINST 5510.1C]

U.S.S. TREPANG (SS412)

c/o Fleet Post Office,
San Francisco, Calif.
25 March, 1945.

From: The Commanding Officer:
To: The Commander-in-Chief, United States Fleet.

Via: (1) Commander Submarine Division 281
(2) Commander Submarine Squadron 28
(3) Commander Submarine Force, Pacific Fleet.

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

Enclosures: (A) Subject Report.
(B) Track Charts (2).
(C) Photographic Film in Color (taken by official
Navy Photographer and forwarded under separate
cover).

1. Enclosure (A) covering the Fourth War Patrol of
this vessel conducted in the YELLOW SEA and EAST CHINA SEA Area
and south of the EMPIRE during the period 20 April to 22 May,
1945, is forwarded herewith.

[SIGNATURE: A. R. Faust]
A. R. FAUST.

[HANDWRITTEN: FILMED]
[HANDWRITTEN: 125975]

— page 186 —
CONFIDENTIAL
SS412/A16-3
Serial (04)

U.S.S. TREPANG (SS412)
Report of 4th War Patrol.

(A) PROLOGUE

Arrived GUAM from Third War Patrol on 25 March, 1945. Two
weeks refit by U.S.S. PROTEUS (AS19) and Submarine Division
TWO HUNDRED TWO Relief Crew and 4-day training period under
Commander R. R. MacGregor, U.S.N., both of which were con-
ducted. Transferred Executive Officer, Lieutenant R. S. Garvey,
U.S.N. and Engineering Officer, Lieutenant (jg) D. H. Denton,
U.S.N.R. as replacements Ensign C. F. Kull, jr., U.S.N.
and Ensign R. T. Hoover, jr., U.S.N.R. Transferred 10 enlisted
personnel and received 9 replacements. PALENSKE, John B.,
Phom3c, U.S.N.R., reported on board for temporary duty
in connection with photography on Submarine Motion Picture.

The below named officers and chief petty officers are on board.
| NAME | RANK | FILE OR SERV NO | NUMBER PATROLS |
|---|---|---|---|
| BARRETT, John Michael | Lieut., USN | 165872 | 8 |
| CARLSON, Elliott Wilhelm | Lt.(jg),(D)L,USNR. | 185565 | 1 |
| FARMAR, Philip Daniels | Lt.(jg),(E)L,USNR. | 269094 | 3 |
| FAUST, Allen Russell | Comdr., USN. | 77025 | 2 |
| HOOVER, Robert Thompson, jr. | Ens.,(D)L,USNR. | 359505 | 0 |
| KEMP, Ward Alden | Lt.(jg),(DE)L,USNR. | 236229 | 3 |
| KULL, Charles Frederick, jr. | Ens.,(D)L, USN. | 332918 | 0 |
| NAGEL, Charles Francis | Lt.(jg),(D)L,USNR. | 295215 | 2 |
| POTTER, Joseph Benjamin, jr. | Lt.(jg),(E)L-R,USNR. | 168616 | 3 |
| STECHER, Robert Wesley | Lieut., USN. | 165493 | 3 |
| HARRINGTON, Melvin Harry | CMOMM(AA)(T),USN. | 375 88 54 | 7 |
| LOCKLIN, William Jennings | CEM(AA)(T),V-6,USNR. | 562 79 76 | 3 |
| NILES, Thomas Elwood | CTM(AA)(T),USN. | 375 80 94 | 5 |
| OVREN, Kenneth Parmly | CMOMM(AA)(T),V-6,USNR. | 554 62 28 | 6 |
| POWERS, Wilbur Palmer | CY(AA)(T),USN. | 262 54 24 | 3 |
| SMEYKAL, Louis Joseph | CMOMM(AA)(T),V-6,USNR. | 291 24 56 | 5 |

(B) NARRATIVE

April 20
1507 (I) Underway from alongside PROTEUS in accordance Opord
83-45. Proceeding in company with SPRINGER (SS414),
RATON (SS270), and PC Escort.

2000 PC returned towards GUAM.

Conducted daily training dives and drills.

-1-
ENCLOSURE (A)

— page 191 —
CONFIDENTIAL
SS412/A16-3
Serial (04)

U.S.S. TREPANG (SS412)

Report of 4th War Patrol.

0639-25 One timed hit.

0643 Three explosions from direction of target--ahead, port,
and above (our depth about 175 feet). At this time the
DD was on the starboard beam.

0645 First of about 30 depth charges released by DD during
next half hour. Apparently he was literally caught
asleep.

0648 First of about ten minor explosions--too low for DCDI.
Thought at first that they might be hedgehogs going off
on the bottom (100 fathoms), but this later seemed im-
probable as the explosions were in singles or doubles,
scattered through a period of about five minutes and
interspersed with depth charges close at hand from the
destroyer. Not even the Japs would approve of such a
procedure of firing hedgehogs.

0650 Two distinct muffled explosions--sounded like an internal
explosion on target.

0715 Destroyer moved off toward target, starting and stopping
screws. Hope he is picking up survivors. No depth
charges now for seven minutes and no more during next
hour.

0725 Started to periscope depth.

0800 Screws louder, drawing up starboard side.

0807 At periscope depth. Range to destroyer 4,000 yards,
opening rapidly as he heads back to port. Nothing else
in sight.

0829 Sound man reports torpedo screws on bearing of DD. Was
looking at tops of his masts at this moment. Two dis-
tant explosions. Figured the sound man was imagining
things--that actually he probably heard the destroyer
speeded up as he dropped his parting salvo. Nevertheless,
ordered 100 feet.

0845 Knew there would be a killer group out from DANJO soon,
so retired to 210 feet just under a small gradient and
headed for the open sea to westward.

0902 Explosion, distant.

-6- ENCLOSURE (A)

— page 201 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS412/A16-3                 Report of 4th War Patrol
Serial (0.4)

1356                       - A/C /MAL - Sighted two PBMs, range 8 miles; dived when
                           they continued to close. Watched both planes through
                           periscope as they passed directly over us.

1400                       Surfaced.
1600                       A/C #15 - Sighted and SD contact at 14 miles, closing.
                           Dived at 10 miles. Jap bomber.
1858                       Surfaced.
2200                       On Lifeguard Station off SHANGHAI.
May 5
0255 (I)                  A/C #16 - SD contact at 5 miles. Dived.
0306                       Surfaced.
0533                       Dived.
1200                       Position: Lat. 30-59.5 N.
                           Long. 123-13.9 E.
1306                       Surfaced for 25 minutes.
1900                       Surfaced.
1915                       SJ contact on SADDLE ISLANDS at 60,000 to 80,000 yards.
1955                       LIONFISH surfaced 3,500 yards dead ahead of us--exchanged
                           recognition signals on blinker tube.
2200                       On Lifeguard Duty again.
May 6
0536 (I)                  Dived.
1200                       Position: Lat. 30-49.9 N.
                           Long: 123-57.4 E.
1301                       Surfaced for 10 minutes.
1322                       A/C #17 - sighted CORONADA through periscope.
1957                       Surfaced.
2200                       Lifeguard duty.
                           -16-
```

— page 203 —
```
CONFIDENTIAL                U.S.S. TREANG (SS412)
                             Serial (01) Report of 4th War Patrol.

Day 8
0617 (T)  Div'd.
1040      Sighted GAJA SHIMA bearing 097° T., range 25 miles.
          Position: Lat. 29-54.5 N.
                   Long. 128-53.0 E.
1200      Surfaced.
2130      Passed through KANSEI SHOTO 12 miles south of AKUSEKI
          SHIMA.
2230      Passed DRAGONET 4,000 yards abeam on opposite course.
Day 9
0112 (I)  Passed friendly submarine abeam at 11,000 yards on
          opposite course.
1200      Position: Lat. 29-36.0 N.
                   Long. 133-20.2 E.
Day 10
0545 (T)  Made 20 minute trim dive.
          On Lifeguard Station for B-29's.
1000      M/C/22 - SD contact at 22 miles. During next three
          hours had contact with about 100 B-29's.
1300      Received report from our DUBO that he had sighted a
          like raft at Lat. 30-15 N., Long. 135-30 E. Headed toward
          this position (40 miles away) at full speed. However,
          knew that this position was certain to be in error, as
          our DUBO had been unable to locate us during the past
          hour and was undoubtedly well out on his navigation. Sent
          message to SHAD to listen in search and send him to
          southeast sector. Attempted to extract additional informa-
          tion from DUBO (BOX#11) without much success. He
          wanted to search for some more and didn't determine whether
          there were survivors on board. Requested him to attempt to
          find raft again and investigate thoroughly.
1430      DUBO for his boat finding either ref or us.
          Told him to correct his navigation as soon as he had a
          fix it give us a better position if possible. Received
          a "Wilco", but never heard from him again.
-18-
```

— page 204 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-412)
SS412/A16-3                 Report of 4th War Patrol
Serial: (04)

1600    Sent a message to ComSubPac concerning search and asked
        for better information as soon as it was available.
        Maintained thoroughly searched an area 40 miles long and
        30 miles wide to westward of position of raft. Fired
        green Very's pistol rockets at hourly intervals during
        daylight. Saw SHAD doing the same to eastward of us.
        Assumed that DULLES would assist us at daylight if the
        report is determined to be correct.

May 11
0230 (K) Received message from ComSubPac that no survivors were
        sighted in the raft. Also that DULLES reported sighting
        two midget submarines in this immediate vicinity. Why
        didn't he tell us?

0440    SJ contact on SHAD at 10,000 yards.

0600    Went alongside SHAD to receive ZCM. With about ten feet
        of open water between our bows, the ZCM dropped off the
        passing line just half-way across and now rests on the
        bottom. Pulled clear and sent report to ComSubPac.

0643    A/C #23 - SD contact at ten miles, closing. Div'd.

0656    Surfaced.

1200    On Lifeguard Station. Position:  Lat.  30-05.0 N.
        Long. 135-05.2 E.

1310    A/C #24 - SD contact at 22 miles, opened. Numerous
        B-29's during remainder of day.

1349    Sighted life raft--no passengers. Large size--looks as
        if it had been in water several days. Sank with small
        arms. Have seen several whales today, so assume these
        were the DUBOIS's midget submarines.

May 12
0510 (K) Div'd.

1200    Position: Lat. 30-19.5 N.
        Long. 135-06.6 E.

1300    Surfaced.

1610    Div'd.

1959    Surfaced.

-19-                          [SIGNATURE: A]
```

— page 205 —
```
CONFIDENTIAL           U.S.S. TRIPANG (Sd.12)
SS12/A16-3            Report of 4th War Patrol.
Serial (04)

May 13
0313                  A/C signal 150 MC--Jap aircraft characteristics.
0357                  A/C #25--SD contact on Jap radar equipped plane at
                     9 miles, closed to 6 miles, then opened.
0540                  Dived.
1200                  Position: Lat. 30-18.4 N.
                     Long. 135-23. E.
1209                  A/C #26--Sighted MAVIS through periscope.
1407                  Surfaced.
1513                  A/C #27--Sight contact through periscope; dived.
1548                  Surfaced.
2230                  Passed SEGUNDO and exchanged signals.
May 14
0500 (K)             On Lifeguard Station.
0622                  A/C #28--Numerous B-29's until early afternoon.
1200                  Position: Lat. 30-02.2 N.
                     Long. 139-19.2 E.
2145                  Passed TORO. Exchanged signals.
May 15
0311 (K)             Dived.
1200                  Position: Lat. 30-53.5 N.
                     Long. 135-33.2 E.
1538                  Surfaced.
1700                  Rendezvous with SEA CAT.
                     Received ECM.
1745                  Rendezvous with SEGUNDO.
                     Received ECM.
0725                  Received ECM.
-20-
```

— page 206 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
S3121/A6-3
Serial (01)                     .Report of 4th War Patrol.

1038    A/C #29 - SD and sight contact on B-24 at 6 miles.
        Showed IFF. Turned on ASK. Plane circled at 6 miles,
        then headed towards us. Dived at range of 3 miles.

1200    Position: Lat. 30-18.1 N.
        Long. 138-04.0 E.

1404    Surfaced.

1429    A/C #30 - SD contact at 12 miles, opened.

2200    On Itugura Station.

2330    SJ contact on TORI SHIMA at 35 miles.

2557    A/C #31 - SD contact at 9 miles. Numerous contacts
        during remainder of night on B-29's.

May 17
1048 (x) Divad.

1200    Position: Lat. 29-34.5 N.
        Long. 140-00.8 E.

1600    Surfaced.

1604    A/C #32 - SD contact at 20 miles.

1700    Received orders from ComSubPac to leave area for GUAM.

2230    Passed JALALAO. Exchanged signals.

        Made daily training dives enroute to GUAM.

May 18
1200 (x) Position: Lat. 27-15.0 N.
        Long. 137-53.5 E.

2230    AHR signal 160 MCS, 500 PRF, 8 microseconds width.
        Typical Japanese ship-borne radar characteristics. Signal
        is steady. Feel certain it originates on a Jap submarine.
        Swung ship and observed minimum strength of signal at
        210°, and 120° T. Searched both bearings without con-
        tact. Lost signal at 2300. Notified ComSubPac.

May 19
1200 (x) Position: Lat. 21-42.5 N.
        Long. 137-41.7 E.

                              ENCLOSURE (A)
```

— page 207 —
```
CONFIDENTIAL
U.S.S. TREPANG (SS412)
SSL1/A216-3
Serial (04)
Report of 4th War Patrol

May 20
1200 (Tk) Position: Lat. 17-24.6 N.
                Long: 138-21.6 E.

May 21
1200 (Tk) Position: Lat. 15-44.0 N.
                Long: 141-35-8.3.

1400 Passed TIGRONE and CAPITAINE.

May 22
0900 Rendezvous with SKATE, TURN, and PC escort.
1130 Arrived GUAL.

-22- ENCLOSURE (A)
```

— page 208 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-412)
SSL12/A16-7
Serial: (0)

Report of 4th War Patrol

(c) WEATHER
The weather during our four days in the YELLOW SEA was very mild.  Usual sea was state one.  The only unusual condition encountered in this area was a characteristic haze on the horizon day and night.  The weather encountered while on lifeguard duty between NAKROE SHOTO and WANSHI SHOTO during the middle of day consisted of brisk winds with the sea varying between state two and state three.

(d) TIDAL INFORMATION
No unusual currents were encountered in the YELLOW SEA as we did not have the opportunity to close the coast.  A one to one-half knot current was encountered northeast of the SADDLE ISLANDS off SHANGHAI.  Set varied with tide as indicated on chart.  A strong one and one-half to two knot current was encountered while passing through the NAKSHI SHOTO group south of AKITSUKI SHITA.  Set was to the northwest.

(3) NAVIGATIONAL AIDS
No navigational aids were encountered.

-23-                       ENCLOSURE (A)
```

— page 209 —
```
CONFIDENTIAL                       U.S.S. TREPANG (SS412)
                                   SS/42/A16-3
                                   Report of 4th War Patrol
                                   Serial (00)

(P) SHIP CONTACTS
NO  : TITLE & LAT AND : TYPE(S) : INITIAL COURSE & HOW  : REMARKS
    : DATE & LONGO    : RANG: SPEED : CONT.
S/C 1: 2057/  3.22-31.81: trans- 19,000 :  37.0 : High - Stunk by
    :  4/28/45  124-34.98: port(UN) : yards: 16 K. : Periscope - torpedo
    :                  :          :       :        : attack.
S/C 2:  1800/  3.30-38.81: merge  13,000 :  18.0 : Transport
    :  4/30/45  124-15.21: escort  : yards:  8 K. : Radar - torpedo
    :                  :          :       :        : attack by
    :                  :          :       :        : escorts.
S/C 3:  1715/  3.18-08.0N: type 37,000 :  15.0 : sunk by
    :  5/13/45  125-23.95: yards: 14 K. : Radar - torpedo
    :                  :          :       :        : attack %5.
S/C 4:  1530/  3.15-40.0E: control 10,000 :  15.0 : searching JP
    :  5/14/45  124-40.0E: yards:  8 K. : area of periscope
    :                  :          :       :        : attack scope.
S/C 5:  2100/  3.55-55.0N: transport 12,000 :  15.0 : emerged by
    :  5/15/45  124-24.0E: yards:  6 K. : Radar - torpedo
    :                  :          :       :        : attack.
S/C 6:  1700/  5.24-07.2E: craft(IT) : yards:  6 K. : Radar - torpedo
    :  5/2/45  124-07.2E: attack.

(C) ENEMY PLANE CONTACTS
Contact was made with approximately 15 enemy planes in the YELLOW
SEA and EAST CHINA SEA areas resulting in sight contact with 7 of
them. Those positively identified were 2 JAPS and 1 enemy.
2 others sighted were believed to have been a medium bomber
(possibly a B-29) and a large bomber (possibly a NAVY). During
our stay on Lifeguard Duty between NANKIN SHOTO and NANKIN SHOTO
2 JAPS planes were sighted, 1 of them a NAVY and the other un-
identified. These 2 planes sighted resulted from a total of 4 or
5 enemy plane contacts, we can truthfully say our own planes
bothered us more this run than did the enemy's.

                                   -24-
                                   ENCLOSURE (A)
```

— page 210 —
```
CONFIDENTIAL                       U.S.S. TREPANG (SS-12)
                                   SS412/A16-3
                                   Serial (01)
                                   Report of 4th War Patrol.

(H) ATTACK DATA

                               TORPEDO ATTACK #1
                     | #1  | #2  | #3  | #4  | #5  | #6  |
                     |-----|-----|-----|-----|-----|-----|
Tubes Fired          |  1  |  2  |  3  |  4  |  5  |  6  |
Track Angle          | 92 P| 90 P| 90 P| 51 P| 53 P| 55 P|
Gyro Angle           | 22 L| 20 L| 20 L| 16 L| 18 L| 18 L|
Depth Set            |  8' |  8' |  8' |  8' |  4' |  4' |
Power                | 45.9 K| 45.9 K| 45.9 K| 45.9 K| 45.9 K| 45.9 K|
Hit or Miss          | Miss | Miss | Miss | Hit  | Miss | Miss |
Erratic              | No   | No   | No   | No   | No   | No   |
Mark Torpedo        |      |      |      |      |      |      |
Serial No.          | 65342| 65518| 65531| 6611 | 65574| 63178|
Mark Exploder       | 6-5  | 6-5  | 6-5  | 6-5  | 6-5  | 6-5  |
Serial No.          | 13559| 13571| 13572| 26200| 26524| 27053|
Mark Warhead        | 16-1 | 16-1 | 16-1 | 16-1 | 16-1 | 16-1 |
Serial No.          | 16796| 1624 | 3950 | 11468| 3313 | 20965|
Explosive           | TORPEX| TORPEX| TORPEX| TORPEX| TORPEX| TORPEX|
Firing Interval      | ---  |  9   |  9   |  26  |  7   |  9   |
Type Spread          | 3 L  | 1 L  | 1 R  | 3 R  | 1½ R | 4 R  |
Sea (State)         |  2   |  2   |  2   |  2   |  2   |  2   |
Overall Activity     | U.S.S. PROTEUS (AS19)  #3
                     | (a) Length of run (best estimate)  1900 yds.
                     | (b) Duration of run  1m, 16s.
```

— page 211 —
```
CONFIDENTIAL                       U.S.S. TREPANG (SS412)
SS412/A16-3                        Report of 4th War Patrol.
Serial: (04)

(H) ATTACK DATA (Cont'd)

TORPEDO ATTACK /1
Time: 0638(I) Data: 4/28/45 Lat. 32-24 N. Long. 128-40 E.

Target Data - Damage Inflicted

Description: Convoy of one (1) transport and one (1) destroyer type escort. Contact made by high periscope watch on surface during daybreak at a range of 20,000 to 22,000 yards. Because of target's high speed and rapidly improving visibility, I dived for periscope approach in 12 minutes after sighting with a range of about 10,000 yards. At these long ranges not much detail could be made out on the ships. During the approach, I risked being spotted up considerably, as always, and I considered it would be fool-hardy to leave a(I) longer than the 7 seconds it requires to get a range and bearings. The approach developed so rapidly that only 6 periscope exposures were made prior to firing—the remainder of the time was required for changing course as high speed made the best firing position. The destroyer was observed only once with less than 15° on the bow and at that time he was directly in the sun-trace; therefore it was impossible to see any detail. The following points were observed:

Transport - Heavily loaded, composite superstructure about 1/3 length of the ship, single tall stack, MPT (neglected to note this carefully, so there may have been king-posts), low superstructure on stern, very fast (used 16 knots in-
stead), below 1/2 was nearer to 20 knots, etc., and J.O.D. all thought this was a very large ship, but we have no real data for identifying him. The SPECIAL SIGN he was 2,000 tons or between 50, unless some better identification is forthcoming shall call him "unknown."

Destroyer - Very little dope on this one, tripod foremast, single stack, SHIRKER identifies him as TERUKUNI, which I probably correct. Had I been sure that a first line destroyer, I would have made the attack on him and felt a great deal safer in so doing.

Ships Sunk (UR): One (1) transport, probable.

-26-

[STAMP: ENCLOSURE (A)]
```

— page 212 —
```
CONFIDENTIAL
U.S.S. TREPANG (SS-12)
SS412/A16-3
Serial (04) Report of 4th War Patrol.

(H) ATTACK DATA (Cont'd)

TORPEDO ATTACK #1 (Cont'd)
Damage deter- One timed hit, followed by 3 heavy explosions from
mined by: direction of target (escort on opposite side of us
at this time), about 10 minor explosions and 2 muffled explosions
as from internal ship's explosions. Thirty minutes after we
hit the destroyer ceased its depth charging, which had been
pretty good, and went over to target, whose survivors had stopped
up and hit and had not been heard since. After it milled
around in that vicinity for 45 minutes, stopping and starting,
he headed for port at high speed. BROTHER sunk him on his way
in and did not see the tender proceed him. Some hours and
half after the attack observed destroyer at 6,000 yards bearing
and no sight of the transport. Soon after attack about 3
miles away. If this ship was able to proceed, it seems certain
that the DD would have accompanied him. In view of all the
circumstantial evidence, consider it certain that the ship
sank.

Target Draft 25' | Course 230° T, 197° | Speed 16 K | Range 2000 yds
(at firing, est)

Own Ship Data:
Speed 3 K | Course 240° T. | Depth 63 ft. | Angle 20 dive
(at firing)

Fire Control and Torpedo Data
Type Attack: Day periscope attack. The high-speed (16 plus knots)
of the convoy, 5 minutes radial exit plan, and the unfortunate
position which the destroyer chose to patrol had us in a dither
all the way. Apparently we were exerting target's track and
in order to keep the bow down to keep bearing, we were compelled to
turn first one way and then the other as he zigged. The high
of the ship required, coupled with being in the wind, made it
difficult to bring the final position into the picture. It is important to note
more than the barest minimum of periscope exposures. Only 6
exposures were made during the course of firing. A limited range of diving
was 11,000 yards. A telemeter range on periscope was
standing at 10,000 yards, an ST range at 6,500 yards.
We were allowed to establish an ST range point at this time
again at 2700 yards to obtain an ST range point at this time
about 1500 yards with a 15° port angle on the bow. Planned on
firing 4 torpedoes, but in view of poor data and detection of

-27-
ENCLOSURE (4)
```

— page 213 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS112/A16-3
Serial. (04)Report of 4th War Patrol.

(E) ATTACK DATA (Cont'd)

TORPEDO ATTACK #1 (Cont'd)
of zig towards while third torpedo was being fired, ordered all six fired. Knew it was time for a zig, but we hadn't been able to organize our dope well enough to shoot earlier and couldn't afford to wait any longer with a 2D almost on top of us. As our upward was ran forward onto the periscope it was 15, and 6 being applied to the right, since I rejected to purify a particular spread, whereas a more proper procedure would have been to use a wider spread of 3 torpedoes; as a result, because of under estimation of the speed, the last 3 torpedoes undoubtedly missed astern. This tactic demonstrated to me that the spread which starts at the middle and works outward is more flexible and hereafter I intend using it.

-28-
ENCLOSURE (A)
```

— page 214 —
```
CONFIDENTIAL
U.S.S. TIRPANG (SS112)
SS12/A16-3
Serial (ol) Report of 4th War Patrol.

(H) ATTACK DATA (Cont'd)

                         TORPEDO ATTACK #2
Tubes Fired                #1         #2         #3         #4
Track Angle               114 P      115 P      115 P      116 P
Gyro Angle                 9 L       9.5 L      10 L       11 L
Depth Set                 10'        10'        10'        10'
Power                     45.9 K     45.9 K     45.9 K     45.9 K
Hit or Miss               Miss       Miss       Miss       Hit
Erratic                   No         No         No         No
Mark Torpedo              23         14-3A      23         14-3A
Serial No.                63212      25019      49802      26719
Mark Exploder             6-5        6-5        6-5        6-5
Serial No.                13570      33000      26523      27073
Mark Warhead              16-1       16-1       16-1       16-1
Serial No.                14157      12748      17279      16710
Explosive                 TORPEX     TORPEX     TORPEX     TORPEX
Firing Interval           15         10         8
Type Spread               ½ L       ½ R       ¼ L       ¼ R
Sea (State)              3          3          3          3

Overall Activity          U.S.S. PROTEUS (AS19)  [UNCLEAR: best guess]
Remarks                   (a) Length of run (best estimate  3, 320 yds.
                         (b) Duration of run  2m, 10s.

-29-
ENCLOSURE (A)
```

— page 215 —
```
CONFIDENTIAL                       U.S.S. TREBANG (SS412)
                                   Report of 4th War Patrol.
                                   Serial: (04)

(H) ATTACK DATA (Cont'd)

TORPEDO ATTACK #2

Time: 1408 (Z)  Date: 4/30/45  Lat. 34-18.6 N.  Long. 124-03.9 E.

Target Data - Damage Inflicted

Description:  Convoy of one ship and three escorts, one of them a large PC or DE, another smaller type and the third unknown.  Contact was made at 3,000 yards on a clear after contact reported from STRINGER, rain and clouds with visibility on variable from 2,000 to 4,000 yards.  The ship was observed on surface in daytime at range of 1,500 yards and at night for 15 minutes at range from 400 to 1,000 yards.  It was a large freighter-transport, split superstructure, KIM, well-decked forward and aft, small superstructure, boats, or gun shielding on forward end of after poop.  Gun mounted forward, hull was straight stack, coal burner.  Length from bow to funnel was 130 feet.  Similar in appearance to ARGUN LIRU, P. 247 OT 208-(revised), but there are several other classes which look almost the same.

Ships Damaged (3C): One large freighter-transport.

Damage determined by:                Saw and heard hit.

Target Draft 28'  Course 180° T.  Speed 7.5 K  Range 3400 yards
(at firing, est)

Own Ship Data

Speed 9 K  Course 255° T.  Depth Surface  Angle ---
(at firing)

Fire Control and Torpedo Data

Type Attack: First attack on this ship-low visibility, day surface.  Compelled to fire at a longer range than desirable because of sudden improvement of visibility, can hit out of 2 torpedoes at 3400 yards range stopped ship permanently.  Used TBT bearings and visual arc on bow for final set-up, fired and then diverged because of rapidly improving visibility.

-30-

[STAMP: ENCLOSURE (A)]
```

— page 216 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS412/12/16-3               Report of 4th War Patrol.
Serial (a)

— page 217 —
```
CONFIDENTIAL      U.S.S. TREPANG (SS-412)
SS412/A16-3       Report of 4th War Patrol.
Serial (04)
(E) ATTACK DATA (Cont'd)

TORPEDO ATTACK #3
Time: 1425 (I)  Date: 4/30/45  Lat: 34-18.6 N.  Long: 124-03.9 E.

Target Data - Damage Inflicted
Description: Same as Torpedo Attack #2.
Ship Damaged: None.

Target Draft: 30'  Course 180° T.  Speed 2 K
Range 3100 yards
(estimated at firing)

Own Ship Data
Speed 3 K  Course 067° T.  Depth 63 ft.  Angle 0
(at firing)

Fire Control and Torpedo Data
Type Attacked: Day periscope, seventeen minutes after attack #2, fired 3 torpedoes at stopped target at range of 3100 yards, 110° port track. Neglected to check target speed set in TDC, having assumed it was zero. I stood TDC and Plot had rightly continued tracking target from SR ranges and periscope bearings and were getting a speed of 2 knots. All torpedoes missed ahead.

-32-  ENCLOSURE (A)
```

— page 218 —
```
CONTINENTAL                U.S.S. TREPANG (SS412)
SS412/A16-3
Serial. (01)
Report of 4th War Patrol.

(H) ATTACK DATA (Cont'd)

                         TORPEDO ATTACK #4A, #4B, & #4C
Attack No.                #4         #5         #8
Tube Fired                #4         #5         #8
Track Angle               90 S      90 S      90 P
Gyro Angle                4.5 R     1.5 R     6 R
Depth Set                 8'         8'         8'
Power                     45.9 K    45.9 K    45.9 K
Hit or Miss               Miss      Hit       Hit
Erratic                   Yes       No        No
Mark Torpedo              14-3A     23        11-3A
Serial No.                39881     63193     26736
Mark Exploder             6-5       6-5       6-5
Serial No.                17311     13858     26811
Mark Warhead              16-1      16-1      16-1
Serial No.                12233     14473     6485
Explosive                 TORPEX    TORPEX    TORPEX
Sea (State)               4         4         4

Overall Activity          U.S.S. PROTUS (AS19)  #8
Remarks: (a) Length of run (best estimate) 750 yds.  650 yds.
         (b) Duration of run                     32.6  26 s.
         (c) The torpedo on attack #4 from tube #4 was seen to breach
         directly after being fired. This torpedo was probably
         erratic in depth performance, as it was not observed to
         run erratic in direction in missing an "impossible to
         miss" target set-up.

-33-
[STAMP: ENCLOSURE (A)]
```

— page 219 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-12)
SS/12/146-3                 Report of 4th War Patrol.
Serial (O4)
(H) ATTACK DATA (Cont'd)

TORPEDO ATTACKS #1, #2, & #3

Time:  2142 (I)  Date:  1/30/15  Lat. 34-20.8 N. Long. 123-58.0 E.
       2146 (I)  Same  Same
       2145 (I)  Same  Same

Target Data - Damage Inflicted
Description:  Same as Torpedo Attack #2.

Ships Sunk (SG): One (1) large freighter-transport. Similar in
appearance to ARGUN MARU, p. 247 ONI 208-3 (revised).

Damage determined by:
Two timed hits in target.  Commanding Officer,
Officer-of-the-Deck, Junior Officer-of-the-Deck
observed two hits it target and watched it sink.
Lost on radar screen at 1500 yards.

Target Draft 32'  Course Stopped  Speed Stopped  Ranges 1000 yards
                                                         790 yards
                                                         700 yards
                                                         (at firing, est)

Own Ship Data
Speed 3 K  Course  /HLA 287° T.  Depth Surface  angle  ______
                     /H2 287° T.
                     /H3 270° T.

Fire Control and Torpedo Data
Type attack:  Torpedo attack #1 - Night surface on stopped target
or attacks #2 and #3.  Fired one (1) torpedo at range of 1000
yards, 90° port track, using true bearings.  Torpedo
broached and apparently ran erratic, though it was too dark to
tell for certain.
Torpedo attack #2 - Same as #1 at range of 790 yards.
Torpedo attack #3 - Same as #1 and #2 except used stern
tube (#3), 90° port track, 700 yards range.

-34-                       [STAMP: ENCLOSURE (4)]
```

— page 220 —
```
CONFIDENTIAL                       U.S.S. TREPANG (SS412)
SS412/12/A16-3                     Report of 4th War Patrol.
Serial (OL)
(H) ATTACK DATA (Cont'd)          TORPEDO ATTACK #s
                                   #1      #2      #3      #6
Tubbs Fired                       23      23      23      23
Track Angle                       108 S   107 S   108 S   105 S
Gyro Angle                        15 R    14 R    15 R    11.5 R
Depth Set                         4'      4'      4'      4'
Power                             45.9 K  45.9 K  45.9 K  45.9 K
Hit or Miss                       Hit     Hit     Miss    Miss
Erratic                           No      No      No      No
Mark Torpedo                      23      14-34   23      14-34
Serial No.                        65407   40225   65377   40657
Mark Exploder                     6-5     6-5     6-5     6-5
Serial No.                        25109   20776   26839   26932
Mark Warhead                      16-1    16-1    16-1    16-1
Serial No.                        14662   13348   16705   16693
Explosive                         TORPEX  TORPEX  TORPEX  TORPEX
Firing Interval                   ---     .7      16      8
Type Spread                       ½ R     ½ L     ½ R     ½ L
Sea (State)                      1       1       1       1
Overhaul Activity                 U.S.S. PROMUS (AS19)
Remarks (a) Length of run (best estimate)  2260 yds  2280 yds
         (b) Duration of run       1m, 28s.  1m, 25s.
-35-
```

— page 221 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-412)
S3l/12/416-3
Serial (04)  Report of 4th War Patrol.

(H) ATTACK DATA (Cont'd)                     TORPEDO ATTACK #5

Time: 0020 (I)    Date: 5/4/45    Lat. 34-16 N.    Long. 123-37 E.

Target Data - Damage Inflicted
Description:  Single DD or DJ on anti-submarine sweep.  Contact made at 37,000 yards on SJ radar in late afternoon.  Visibility only about 14,000 yards because of haze.

Ships Sunk: (ZU): One DD or DE (estimated tonnage 900 tons).

Damage determined by:  Saw ship explode and sink.

Target Draft: 10'    Course 080° T.    Speed 10.5 K    Range 1900 yards
(at firing)

Own Ship Data
Speed 9 K    Course 252° T.    Depth _______    Surface _______    Angle _______
(at firing)

Fire Control and Torpedo Data
Type attack:  This was a night surface radar attack after 6 hours of tracking and evading around.  It was a dark night with the target just visible at 3700 yards.  Commenced firing four torpedoes forward at 1900 yards.  Two hits.

-36-
[STAMP: ENCLOSURE (A)]
```

— page 222 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS/12/416-3                 Report of 4th War Patrol.
Serial: (04)

(H) ATTACK DATA (Cont'd)

GUN ATTACK #1
Time: 0553 (I) Date: 5/2/45 Lat. 35-48.0 N. Long. 124-41.0 E.

Target Data - Damage Inflicted
Ships Damaged (3C): One (1) wooden junk having three masts, 120 ft.
in length of approximately 100 tons.

Damage Determined By:
Observed many hits by 5"/25, 40mm, and 20mm guns.
Saw result of hits from alongside the junk.

Details of action
As the target was anchored, no difficulties of fire control were
presented. Twenty-four rounds of 5"/25 H.C. (Mark 29 fuses) were
fired at an average range of 800 yards, resulting in about 12 hits.
These hits seemed to penetrate the hull but the heavy load of logs
applied to minimize the damage done. The 5" rounds of H.E. and H.E.
40mm together with 480 rounds of H.E. and H.E. 20mm fired resulted
in comparatively small damage to the heavy wooden hull.

-37-
[STAMP: ENCL. (A)]
```

— page 223 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS412/A16-3
Serial (04)                Report of 4th War Patrol

(I) MINES
The U.S.S. TREPANG sank one mine (moored type) during her fourth war patrol, disposing of it with .50 caliber machine gun fire at lat. 29°30.1'N, Long. 133°51.8'E. Several other mines were sighted (all moored type), as noted in the Narrative; but other factors, such as approaching darkness or nearness of aircraft, made it unwise to take action on them.

(J) ANTI-SUBMARINE MEASURES AND EVASIVE TACTICS
The enemy made several anti-submarine sweeps with from 1 to 4 patrol boats, DDs or light destroyers, in the YELLOW SEA area while we were there. These were most ineffective; 3 of them managed to contact SPRINGER and TREPANG for torpedoes. All traffic was heavily escorted.

TREAPANG was contacted and depth charged by the destroyer in Torpedo Attack #1. The DD was pinging on 17.5 KCS, apparently trying to listen occasionally, divided by going deep under a 2.5 knot gradient and making 2/3 speed, keeping 1/3 to him. The surface attack was generally poor, though as managed to get out of two fairly close.

(K) MAJOR DEFECTS AND DAMAGE
HULL & MACHINERY
Auxiliary Generator - On 26 April 1945, while charging batteries on 3 main engines and the auxiliary engine, the auxiliary engine suddenly became overloaded and slowed from 1200 RPM to 600 RPM. The auxiliary generator load up to this time was 300 W. An attempt was made to reduce load but without fluid pressure with no apparent effect. After a while the generator circuit breaker was then pulled, under load, and the auxiliary engine was returned to 1200 RPM. The generator was found to have insulation and the excessive sparks resulting burned the ground lead to the shunt showing, main field was still carrying an excess shunt current. Both generators were found to be short circuited on the field circuits. The generator was opened and examined. Leads from generator to auxiliary bound read 9 megohms while leads to generator were still zero. The circuit structure leads were disconnected from generator to read 3 megohms and leads to generator leads to circuit breaker read 3 megohms and leads to generator
-38-
```

— page 224 —
```
CONFIDENTIAL          U.S.S. TREPANT (SS412) :
                       S3/12/A16-3
                       Serial: (0).
                       Report of 4th War Patrol.

read o. Upon opening inspection plates, generator was found
to be clean and dry. Surface air coolers were removed, brush rig-
ging leads disconnected and readings taken. Ammeter read 3
megohms, gages field 0, shunt field 0, and exhausting field 75
megohms. After removing field bus work, ground limiting series
fields was found to be one of the three lower field coils.
Inaccessibility made further determination impossible. Generator
was then reassembled with armature leads disconnected and a lot with
the most burning continuously. It was determined to get generator as dry as
possible. Until in the time of the casualty, ship's circuit ground
is of each battery. As no spare field coils were carried and due to
its inaccessibility for further work, the auxiliary generator was
out of commission for the remainder of the patrol.

C & R

#2 Periscope - #2 periscope still fogs consistently. When the scope
is first raised it cannot be used in high power because the exces-
sive fogging makes the field or vision a complete blur. When it is
switched to low power it is still foggy, but can be used. In low
power, a blob or blot fills the center of the field. This blot
makes the complete blur in high power.

After the scope is up for about 30 seconds it clears up somewhat and
then fogs again 30 seconds later.

The greatest trouble is encountered when there is a large temperatu-
re differential between the air and sea.

(L) RADIO

Radio reception was excellent throughout the patrol. 9090 KCs
keyed from ClUas has come into its own as a very valuable cir-
cuit since the faulty keying has been smoothed out. 9050 KCs
gave good results at night, and the 16 megacycle band was always
clear during the day.

Lifeguard frequency, 1475 KCs (Voice), gave 5 by 5 signals at
all times except in the early morning, of 17 July 1500-1900 GCT,
1167 yards position lat. 30-00 N. long. 134-50 E., when the
strength was about 3 with readability very poor, even at fairly
short range.

No radio material casualties were encountered.
-39-
```

— page 225 —
```
CONFIDENTIAL
U.S.S. TREPANG (SS312)
SS/12/416-3
Serial (04)

Report of 4th War Patrol.

- Big bright spot in center of PPI sweep, indicator light out. Reloaded bad 7 meg. resistor, also 616G. Operation returned to normal.

Timing bad. Regulated rectifier road 350V. Changed 6327's in rectifier.

Stop circuit out in range indicator. Replaced R75 plate circuit of V2 and found L-1 in delay, V.V. open. Replaced. All o.k.

Short sweeps on PPI-scope. Adjusted R56 and replaced 6587. Low gain on range indicator. Changed 6407's.

Sensitivity dropped off suddenly after using set to communicate with. Changed Xtal, 72LA, 72TA's, 5D2L, 836, and retuned. Operation again normal.

ST - The performance of the ST was again very erratic on this patrol and required constant attention. Transmitter had to be retuned every two to three days. Replaced T-R tubes and Xtal several times. It is hoped that we can obtain an entire new A.F. section this refit.

SD - The SD was used during the entire patrol and gave excellent performance. 97% of our initial plane contacts were obtained by it at distances out to 50 miles. The SD was keyed, using the plate voltage, every 30 seconds during the day and every two to three minutes at night.

Material failures were as follows:

Arold in transmitter, high-plate current. Found shorting pair on T1 leads of Dicker and had not been tightened and had slid down. Reset shorting bar, operation again normal.

Double trace, high plate current. Found one connector from scope to transceiver line was loose.

Indicator slow, very quickly, corrects itself after high studio interior. Replaced 80LA's, cleaned all other parts.

(R) SONAR AND SOUND CONDITIONS
Sound conditions in the YELLOW SAW were fair. In attack (on 2 April off DAINO CUTO, ranges of 3,000 to 4,000 yards were noted.

-41-
```

— page 226 —
```
CONFIDENTIAL      U.S.S. TREPANG (SS-12)
SS-12/A6-3
Serial: 04
Report of 4th War Patrol

on the escort by JP and JK. Following this attack by the TREPANG, the SPRINGER attacked the escort at a range of about 10,000 yards from the TREPANG. Although the target had long been lost on sound, the SPRINGER's torpedoes were fired so loudly that both the JP and JK believed us to be the target. Later that same day two patrol vessels searching the some of our attack were picked up at about 7,000 yards by JP.

During the attack on a single freighter of DAI KOKUZAN REHITO on the night of 30 April, the two escorts were tracked to about 6,000 yards.

The only material casualty in the sound gear was the failure on 22 April of the thermal element of the bathythermograph. The cause was a fracture in the copper tubing, resulting as a result of three patrols of consistently bad weather. In replacing the thermal element, the lookouts on the pressure element were partially stripped so that the zero depth adjustment now reads 40 feet. Aside from this the SDT performed satisfactorily with the spare thermal element installed.

(0) DENSITY LAYERS

During the short time in the area only five Bathythermograph cards were taken. They are being submitted to the Vice Chief of Naval Operations. Following is a summary of the cards:

CARD NO: | CORDINATES: | POSITION: | CHARACTER OF DENSITY LAYER
|||
1        |  30         |  12-21   | Isothermial to 120 ft.  6° drop from
2        |  27/45      |  123-25  |  130 ft. to 240 ft.
3        |  29/45      |  123-28  |  2° drop to 240 ft.
4        |  30/45      |  124-22  | Isothermial to 80 ft.  6° drop from
5        |  30/45      |  124-22  |  180 ft. to 120 ft.  5° drop from
6        |  20/45      |  123-32  | Isothermial to 110 ft.  5° drop from
7        |  20/45      |  123-32  |  110 ft. to 130 ft.

(P) HEALTH, FOOD, AND HABITABILITY

There was no sickness of any kind, not even a cold. Food and habitability were excellent.

-42-

ENCLOSURE (A)
```

— page 227 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS312)
SS/312/A16-3                Report of 4th War Patrol
Serial (U.)

— page 228 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS412)
SS412/216-3                 Report of 4th War Patrol.
Serial (01)

— page 229 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-412)
SS 112/A16-3
Serial (O)

Report of 4th War Patrol.

DATE        LOCATION         FREQ.   PWR.   PULSE   STRENGTH   REMARKS
            LATITUDE        LONGITUDE
4/28       125-06.8 N      97      750    15      Strong      Sweeping slowly.
            23-20.0 N      40      Moderate   Steady on.
            123-20.8 E      75      500    40      Moderate    Steady on.
            128-26.0 N      15      1000   10      Saturated   Koyod, Aircraft on
            32-20.0 N      5       500    8       Moderate    Slow sweep.
            32-26.2 N      7       500    8       Weak        Sweeping, double pulse.

4/29       125-24.9 E      99      50     Moderate   Sweeping.
            126-47.9 N      75      500    35      Strong      Steady.
            126-27.9 N      152     Weak
            126-28.0 N      103     500    30      Weak        Swagging.
            126-30.0 N      74      500    50      Moderate    Slow sweep.
            126-31.0 N      5       Weak        Swagging.
            123-01.0 E      160     500    15      Moderate    Slow sweep.
            135-06.0 E      10      Weak        Sweeping, double pulse.
            132-55.5 N      170     10      Weak        Swagging.

            12-29.1 N      78      500    25      Strong      Sweeping slowly.
            23-06.1 N      14      500    25      Weak        Swooping.

7/30       12-29.1 N      280     Weak        Swooping slowly.
            23-27.1 N      12      Weak        Swooping slowly.
            34-02.0 N      159     500    10      Strong      Swooping.
            34-02.0 N      159     500    10      Strong      Swooping.
            12-29.1 N      500    Saturated   Steady.  Remained Saturated.
            12-29.1 N      500    Strong      Swooping.

5/7        12-20.0 N      77      500    50      Moderate    Steady.
            12-50.8 N      97      500    35      Weak        Swagging.

            31-30.0 N
```

— page 230 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-12)
SS/12/A16-3
Serial (04) Report of 4th War Patrol

DATE        LOCATION        FREQ.  PRF  PULSE  STRENGTH  REMARKS
            WIDT
5/8         125-30.8 N     160    500  125    Weak      Sweeping.
5/9         129-06.9 N     160    500  1      Weak      Sweeping.
5/10        121-29.2 N     118    1500 10     Weak      Sweeping.
5/11        129-27.0 N     118    500  25     Moderate   Sweeping.
5/12        129-29.0 N     118    500  25     Moderate   Sweeping.
5/13        129-30.1 N     118    60   35     Saturated  Probaby SD
5/14        131-25.7 N     118    60   35     Saturated  Probaby SD
5/13        129-23.4 N     157    1000 8      Saturated  Plane contact on SD
5/14        133-29.3 N     157    1000 8      Saturated  Plane contact on SD
5/14        130-29.2 N     97     750  40     Moderate   Swooping
5/15        130-28.1 N     80     500  20     Weak      Sweeping
5/16        130-28.2 N     80     500  20     Weak      Sweeping
5/17        30-36.0 N      118    60   25     Saturated  Layed. Identified as SD.

(V) REMARKS
Because of the constant patrolling of our own aircraft, we found it necessary to use the SD on 2-3 minute chokes at night during the entire patrol. Apparently much of our aircraft radar is above the range of their I.F.R., and sight of the SD contacts on friendly planes at night were rendered without being able to detect their radar. Since it was necessary to use the SD at night, we decided that we might as well use it all day also. This permitted us to patrol on the surface in the daytime without interruption, and as all our contacts were made on the surface in the daytime, we feel sure that the Japs have no efficient SD detectors during our operation in the YELLOW Sea area. We noted that most of our submarine which we encountered at night also were using their SD's. A new aircraft detector radar and an improved A.R.R. with automatic scanning and extending search band to 3,000 MCS is now becoming a matter of urgency.

ENCLSOURE (A)
-46-
```

— page 231 —
```
CONFIDENTIAL
S5142/46-3
U.S.S. THOMPSON (SS-412)
Serial (0)

Report of 4th War Patrol.

Enemy aircraft activity was notably weak and ineffective off the Bismarck as compared to two months ago. Only occasional enemy day patrols were observed and their high radar patrols have declined almost to nothing; in fact, only three enemy radar equipped planes were encountered during the entire patrol, two of these being between PULAU SIRIH and PULAU GUNTOR and south of NOFSU. There were no signs of aircraft being used on anti-submarine patrols in the YELLOW SEA area.

Our own aircraft presented the gravest mental hazard of the patrol. They never showed us the slightest consideration in the matter of recognition and avoidance. On every day of contact with friendly planes showing IFF, we used the ABK. In addition, in daytime we turned broadside to them, and on one occasion at night fired recognition rockets. We feel that the planes correctly identified us in all cases, or could have correctly identified us at a range of 5 miles. Yet in every case where we were certain they contacted us, they circled close to hear for us. We did not see a range of 5 miles in all cases except four. In the first two cases we were taken unawares and the planes passed directly over us at night. The third case was at night on the surface off SIRIH ISLAND. This occasion occurred just a few days after a message was received saying that planes in the YELLOW SEA area would remain outside of 5 miles until mutual identification was established, I decided to make a test case about this one-being on Lifeguard Station at the time, I didn't want to die anyway. When we closed to 2 miles, fired a recognition rocket, the plane passed over us at about 5 feet altitude, opened to two miles, banked, and started in again. At this point we missed and we heard the limiting range on the SD with the mast went down. A few minutes later we surfaced with the plane at ten miles. When he began to close again, we fired another rocket. At five miles I sent a plain language voice message in the same frequency for him to go away and leave us alone. He immediately turned away and left us, having wasted 15 minutes of his time and ours. The fourth instance was on a Lifeguard Station in the daytime 150 miles south of NOFSU. A LIBERATOR was contacted at 10 miles. He closed to 6 miles, where he made one circle and then headed for us. We were in a position where we had 2 miles and wanted under. No doubt he was aware that there was a friendly gesture by flying over us in this fashion, but we can't separate out this from the basis of our orders or the fact that he was going to be a means of telling when a plane has identified us as friendly, therefore, any clear view being obvious us, it becomes an unfriendly act. Heretofore it has been little trouble to fire on friendly plane contacts, but now, with numerous plane patrols in all the
-47-
ENCLOSURE (A)
```

— page 232 —
```
CONFIDENTIAL
U.S.S. THRESHER (SS342)
SS312/A16-3
Serial (04)

Report of 4th War Patrol.

The present scene, it is beginning to become quite a nuisance. The best constructive suggestion that I can make is to indoctrinate the aviators to keep at least 5 miles from the submarines. Then when one does close, we will know that he does not recognize us, at least the present uncertainty which confronts us will be eliminated.

During this patrol we ran into some of the phenomenal radar performance which has been encountered in this area previously. For a period of about a week in the YELLOW sea we experienced calm seas, light breezes, and warm weather. During this time we made contact on a vessel, sailing Jan 12, 20,000 yards and tracked it out as far as 19,000 yards. On another occasion we experienced strong SJ interference from the SPRINGER and exchanged communications with him at about 100 miles. We made initial contact on a BR DR at 37,000 yards and commenced lobe switching at 34,000 yards. Small fishing junks were contacted at from 7,000 to 11,000 yards range. The SJ even tracked the wakes of four torpedoes running at four feet, and the operator announced the hit on the target before it was seen or heard otherwise.

-48-
ENCLOSURE (A)
```

— page 233 —
```
SUBMARINE DIVISION TWO EIGHTY ONE
PF5-261/A16-3
Cere of Fleet Post Office,
San Francisco, California.
27 May 1945.
C-O-N-F-I-D-E-N-T-I-A-L

FIRST ENDORSEMENT to:
COMSUBMARCOM: Comdr. Ltr.
SSAL/124-3 Serial (04)
Dated 25 March 1945.

From: The Commander Submarine Division TWO EIGHTY ONE.
To: The Commander-In-Chief, United States Pacific Fleet.
Via: (1) The Commander Submarine Squadron TWENTY NINTH.
      (2) The Commander Submarine Force, Pacific Fleet.
      (3) The Commander-In-Chief, United States Pacific Fleet.

Subject: U.S.S. THRESHER - Report of War Patrol Number FOUR.

1. The fourth war patrol of THRESHER was conducted in the China and Yellow Sea as a member of a coordinated attack group; Commanding Officer, GRIFFIN, Group Commander. Since the patrol commenced and ended at an advanced base at Wenchow, thirty-three days overall. Twenty days were spent in the assigned area, seven days in submerged patrol. The patrol was terminated on order of Commander Submarine Forces when THRESHER had expended all torpedoes but one.

2. The group acted in cooperation rather than coordination, as is customary in this area. Free interchange of information and mutual support led to impressive damage to the enemy.

3. At dawn on 24 April, 1945, THRESHER made sight contact with one enemy ship, later identified as a transport, escorted by the destroyer CUSHING on the surface. While it was determined that the enemy was not using sonar, it was decided to conduct an attack using a submerged approach. THRESHER made 90° before entering range, (about 2000 yards). From which she obtained sufficient data to evaluate the enemy's course. The enemy was observed to be traveling at the most favorable speed for the attack.

4. The enemy was about to commence a turn to the right for the third torpedo run. Counter attack by the escort lasted for about fifteen minutes, during which time all the torpedoes on the target were fired.

5. During passage depth, noted one and one half hours after the attack, the enemy was observed to be in a sinking condition. The Division Commander has no doubt that this was an obviously valuable enemy transport sunk.
-1-
```

— page 234 —
```
SUBMARINE DIVISION TWO EIGHTY ONE

TB5-281/A16-3
Serial: (023)

G-O-T-T-I-E-R-I-T-I-L

Subject: U.S.S. TRELANG - Report of War Patrol Number FOUR.

— page 235 —
```
SUBMARINE DIVISION TWO EIGHTY-ONE

TBS/281/A16-3
Care of Fleet Post Office,
San Francisco, California,
27 May 1915.

Serial: (022)
C-O-H-E-L-P-E-T-I-T-I-V-I-I-I

Subject: U.S.S. TRITON - Report of War Patrol Number FOUR.

1. An excellent firing position was reached (average track angle 107°, small EYE guides, since 1900), and the enemy was attacked with four torpedoes, two of which hit and completely demolished him. (For pub date #5).

2. The subsequent two weeks were spent on life guard duty. Except for the confused situation which developed as the war progressed, there was small for service on no services were affected. Enroute to base, in the vicinity of the Marianas, TRITON detected and investigated with massive results all signals which led to characteristics of Japanese ship-borne radar.

10. Unusual radar performance in the Yellow Sea, comparable to that described by TRITON, has been noted by several submarines recently.

11. TRITON comments on the sea manners exhibited by friendly craft we will taken, as our control of the air over all water contiguous to Japan increases a clean cut understanding; and already, reliable means of identification becomes imperative; otherwise the efficiency of the services will suffer.

12. On her return to base TRITON was clean, shipshape and in very good material condition. Rafts will be accomplished in this standard time.

13. The commanding officers, officers and crew of TRITON are congratulated on a smart, well-conducted and effective patrol.

L. W. [HANDWRITTEN: signature]
```

— page 236 —
```
PC5-22/Aid-3
SUBMARINE SQUADRON TWENTY-EIGHT
Serial No. 0143.
SS/22/43 Serial (04)
Dated 25 March 1945.

From:     The Commander Submarine Squadron TWENTY-EIGHT.
To:       (1) The Commander-in-Chief, United States Fleet.
          (2) The Commander Submarine Force, Pacific Fleet.
          (3) The Commander-in-Chief, United States Pacific Fleet.

Subject:  U.S.S. THRESHER - Report of her Patrol Number FOUR.

1.  The Squadron Commander heartily congratulates the commanding officer,
officers and crew on the successful completion of THRESHER'S fourth war patrol and
on the extensive damage inflicted on the enemy.

2.  It is recommended that THRESHER be credited with the following:

                       SUNK
1  AP (SW)                     4600 Tons  Torp. Attack #1
1  AK Liner (Ex) Similar to Argun Maru  6666 Tons  Torp. Attack #2
1  ED or DE (KN)               900 Tons   Torp. Attack #5
                               Total Sunk  12166 Tons

                       DAMAGED
1  Wooden Junk (X)             100 Tons
                               Total Sunk and Damaged  12266 Tons

[HANDWRITTEN: J. E. Miller]
```

— page 237 —
```
F12-10(A)/A6-318
SUBMARINE FORCE, PACIFIC FLEET
Serial 01424
CONFIDENTIAL

FROM COMMANDER to
The Report of
Fourth War Patrol.

SUBJECT: SUBMARINE PATROL REPORT NO. 772
U.S.S. TANG - ROUTINE 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. TANG (SS-306) - Report of Fourth War Patrol
(20 April to 22 May 1945).

1. The fourth war patrol of the TANG, under the command of
Commander A. R. Emmet, U.S. Navy, was conducted in the Yellow Sea-South China
Sea area. The TANG along with the U.S.S. Searaven and U.S.S. Pargo formed
a coordinated attack group with the commanding officer of the SEARAVEN as group
commander.

2. This well planned and expertly conducted patrol resulted in five
torpedo attacks and one gun attack. One large freight-transporter, two medium
freight-transports, and one anti-submarine vessel, probably a DE or DD, were
sunk; and one wooden junk was damaged by the gun attack.

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

The Commander Submarine Force, Pacific Fleet, congratulates the
outstanding officer, officers, and crew of the TANG for this aggressive and
fully successful patrol. The TANG is credited with having inflicted the
following damage upon the enemy during this patrol:

|  TYPE                     |  TONS          |  ATTACKS        |
||||
|  1 - VM                  |  4,000 tons    |  (Attack No. 1) |
|  1 - AI (ARMED HEAVY Type) (SG) |  6,700 tons    |  (Attacks No. 2, 3, and 4) |
|  1 - DD or DE (SU)      |  920 tons      |  (Attack No. 5) |
|                          |                |                 |
|  TOTAL SUNK              |  11,600 tons   |                 |
|                          |                |                 |
|  1 - MIS (Wooden Junk) (SG) |  100 tons    |  (Gun Attack No. 1) |
|                          |                |                 |
|  TOTAL SUNK & DAMAGED    |  11,700 tons   |                 |

Distribution & Authentication
next page.
```

— page 238 —
```
FF712-10(A)/18-318
SUBMARINE FORCE, PACIFIC FLEET

Serial 01424
CONFIDENTIAL

THIRD REPORT to
THE Reports of
Fourth War Patrol.

COSTSUSALU PATROL REPORT NO. 772
U.S.S. TIRANTE (SS-420) - Report of Fourth War Patrol
(20 April to 22 May 1945).

Subject: U.S.S. TIRANTE (SS-420) - Report of Fourth War Patrol
(20 April to 22 May 1945).

DISTRIBUTION:
(Complete Reports)
Commch (7)
Cincpac (6)
JTFPOA (1)
JICPOA (1)
Comsubpac (1)
OinC (1)
Ombudsman (1)
S/N School, II (2)
CO, S/N Base, PH (1)
Comsopac (2)
Comsubserv (1)
ComSubFwd (Fwd Echelon) (2)
ComSubFwd (Rear School) (2)
Comsurg (1)
Comsubpac (40)
ComsubComd (2)
STAL, HI (3)
ComSubSpecSubord (3)
All Squadrons and Div.
Commanders, Pacific (2)
Submarines, Pacific (1)

[M. S. Garply]
[SIGNATURE: W. E. LULLET]
Asst. Flag Secretary.
```

— page 239 —
```
[STAMP: DECLASSIFIED]
U.S.S. TREPANG (SS-12)
SS1142/A16-2
[STAMP: DECLASSIFIED]
[STAMP: 0445, ORIGINATED]
[STAMP: 19 JULY 1945]

Serial (012)

From: The Commanding Officer.
To: The Commander-in-Chief, United States Fleet.

Via: (1) The Commander Submarine Division
      (2) The Commander Submarine Squadron 10.
      (3) The Commander Submarine Force, Pacific Fleet,
      (4) The Administration.
      (5) The Commander-in-Chief, U.S. Pacific Fleet.

Subject: U.S.S. TREPANG - Report of FIFTH War Patrol.

Enclosures:
(A) Subject Report.
(B) Track Charts (2).
(C) Photographic Film (under separate cover).

1. Enclosure (A) covering the FIFTH War Patrol of this vessel conducted in southern and eastern Empire waters during the period 15 June to 31 July 1945, is forwarded herewith.

[C. P. Ernst]
[SIGNATURE: A. R. PAUST]
```

— page 240 —
```
CONFIDENTIAL                U.S.S. TIRPITZ (SS-12)
SSAL2/A16-3
Serial (09)                Report of Fifth War Patrol.

(A) PROLOGUE:
Arrived GHAT from fourth war patrol on 22 May 1945. Completed
excellent refit by APOLLO and Submarine Division 281 on 6 June,
1945. Conducted post repair trials and training operations.
Departed on patrol 15 June, 1945 for Lifeguard Locale.

(B) NARRATIVE:
The below named officers and chief petty officers are on board
and have completed number of war patrols indicated including
TIRPITZ's Fifth:

NAME                      RANK & CLASSIFICATION       FILE OR    WAR
                         |                           |          |
EARLESON, John M.       Lieut. (j.g.), USNR.        185975     13
CARLSON, Elliott W.     Lt. (j.g.), USNR.           269951      5
PARKER, Philip D.      Lt. (j.g.), USNR.           269950      5
PAUST, Allen R.        Comdr., USNR.               77025       2
KOWAL, Robert P., Jr.  Ens., USNR.                  359715      2
HOUSTON, Charles F., Jr.  Lt. (j.g.), USNR.        359715      2
NAGLE, Charles B.      Lt. (j.g.), USNR.           136811      4
POINDEXTER, Joseph B., Jr.  Lt. (j.g.), USNR.     136811      4
PITTMAN, Martin H.     Lt. (j.g.), USNR.           185975      3
STURM, Robert W.       Lieut. (j.g.), USNR.        185975      3

GRIGGOS, Keith N.      CRT (A)(T)-6, USNR.         629 24 44   9
HARRINGTON, Melvin H.  CMDR (A)(T)-6, USNR.         275 63 79   5
LOCKLIN, William J.    CMDR (A)(T)-6, USNR.         562 72 75   5
OVERBY, Kenneth P.     CM (A)(T)-6, USNR.           562 72 75   5
TOWNS, Wilbur P.       CDR (A)(T)-6, USNR.          294 24 56   7
SAYRE, Louis J.        CM (A)(T)-6, USNR.           294 24 56   7

15 June
1500 (K)                Underway in company with REDFIN and DE escort in accordance
                       with OpOrder 129-45.

                       Conducted daily training dives, tracking, and emergency
                       drill enroute to area.

16 June
1200 (K)               Position: Lat. 16-43.8 N.
                       Long. 143-57.0 E.
```

— page 241 —
```
CONFIDENTIAL
U.S.S. THRESHER (SS412)
S3412/16-3
Serial: (09)

Report of Fifth War Patrol.

17 June
1200 (K) Position: Lat. 20-14.9' N.
              Long. 140-16.5' E.
1400           Parted company with REDFIN, who had a rendezvous to make with TORO.

18 June
1200 (K) Position: Lat. 24-55.3' N.
              Long. 139-47.8' E.

19 June
0700 (K) Received CSP's despatch ordering us to Lifeguard for fighter strike at this date. Will be two hours late arriving, but will be in the line of flight all this time so anticipate no trouble picking up our DIBO.
1115           Heard planes on 475 KCS. Planes are turning back due to bad weather. Strike cancelled.
1200 Position: Lat. 29-53.0' N.
              Long. 139-23.8' E.
2300           On station for B-29 strike. Numerous plane outcasts proceeding to and from station during next 5 hours.

20 June
0400 (K) Heard air cover for submarines north of us relocating those and dispersing for hours. Have conversed with TICHIGAN and his air cover without difficulty, but our own DIBO never showed up. Three planes passed close to us with the DIBO, but could not raise them on 475 KCS. I was unable having this trouble. Shorter times of air cover were available on that part of the planes, as they continued southward with no apparent trouble and there were no reports by radio concerning them.
0450           Set course towards TORT SIMI to obtain a fix position for 36 hours now.
0930           Sighted SOUTH CAR bearing 130° T., distance 18 miles.
1200 Position: Lat. 29-59.0' N.
              Long. 140-61.1' E.
```

— page 242 —
```
CONFIDENTIAL
U.S.S. TRANG (SS-412)
SS 412/A16-3
Serial (09)

Report of Fifth War Patrol

11:00
Sighted TORI SHIMA bearing 025° T.
2000
Surfaced. Radar contact on TORI SHIMA at 43,000 yards.
2140
Exchanged signals on SJ with SEA ROBIN.

21 June
0620 (X)
Received CSDP's orders to proceed to station east of KYOTO...
240 miles away. Bucking force 5 knots with 11 hours to
make it. Laying speed 10 1/2 knots and bridges with
taking the boxtime.

0930
Sighted SUMUSHI SHIMA bearing 060° T., distant 25 miles.
Position: Lat. 31-15.2 N.
         Long. 140-19.0 E.
1728
Received CSDP's cancellation of last orders--proceed back
to westward again. All hands relieved to put seas astern
for a change.

1830
Sighted AOGA SHIMA bearing 295° T., distant...
2100
Passed 22 miles south of AOGA SHIMA.
2110
Received CSDP's orders to take station off TRAKO SUIDO for
Lifeguard duty for B-29 strike on NAGATA. Have 180 miles
to go and 2 to 3 hours to build it. Could just...
heavy seas, but was worried about being found by
aircraft after daylight.

22 June
0200 (T)
Seas getting quieter--17 knots now.
0750
Sighted DAIO SAKI bearing 270° T., distant 30 mi...
0948
Submerged for first time in over 36 hours on Lifeguard
station 12 miles off Japanese coast. Commenced listening
on 475 KCs on SD mast at 50 foot.

1030
Heard conversation on radio and had several SD contacts.
Surfaced.

1040
Sighted three groups of B-29's on way home from NAGOYA.
In communication with BOXKITE cover.
```

— page 243 —
```
CONFIDENTIAL          U.S.S. TREPANG (SS412)
SS412/146-3
Serial (09)
Report of Fifth War Patrol

1044
Straddled by 3 bombs, at 1,000 yards on port bow, 2 at 2,000 yards on starboard quarter. B-29 in flight of 7 just touched them—we decided later. By first thought was that a shore battery had opened up on us.

1046
Received distress message—5 survivors in life jackets with green dye 12 miles off KUK SALT, a distance of 17 miles from us, about 52 from SHELLED. Handed for reported position that was full speed.

Later amplifying reports identified those survivors as from a B-29 which had exploded in mid-air, another B-29 from the same formation gave a position 23 miles from land, the closest toward SITKA ALASKA and only 7 miles from land. Our B-29 cover (BOXIT 1) thoroughly scouted the area from the coast, down to 2 positions with negative results. While BOXIT conducted inshore search, TREPANG searched, 1 ½ miles off the coast, to the eastward. BOXIT said that the ship has considered options for searching for survivors. Patch was found a number of large splashes of brick and the water scattered through 8 miles across, neither of us could identify them.

1200
Position: Lat. 34°-02.1' N.
       Long: 137°-06.3' E.

1320
BOXIT ONE departed from station. Decided not to search any closer to the beach, as the slight chance of finding any survivors did not warrant the risk. BOXIT would certainly have found anything in the vicinity. No visible surface radar signals were noted. The B-29 was not visible any more with almost certainty, but, still, and from a previous cyzronious in this vicinity, we knew that the jets have a fairer turn in this vicinity.

1330
Dived.

2003
Surfaced. Headed towards INABA SHIMA to make a land-fall.

2100
Received CSDP orders to proceed to new station for flight. Struck for Tokyo tomorrow, 1000. Distance is 200 miles with 13 hours to make it. Want to be going speed— fortunately the seas are almost calm.

23 June
0730 (K)
Received dispatch ordering daily in strike until 1345.
```

— page 244 —
```
CONFIDENTIAL
U.S.S. TREPANG (SS412)
SS412/416-3
Serial: (09)

Very fortunate, for we were behind schedule.

0530
Passed between MIURA SHIMA and CHICHO WAN.

0553
Sighted aircraft at about 10 miles. Div'd to 100 ft. Saw depth charge and watched a BAP 2-engine plane pass about 4 miles ahead of us. Probably a transport enroute from TORI or CHICHI to TOKYO.

0608
Surfaced.

0707
SD contact at 11 miles. Div'd.

0746
Surfaced and headed northward 25 miles off NAMPO SHOTO.

0806
SD contact at 20 miles; shows IFF.

0810
Sighted a B-29 weather reconnaissance plane on way to TOKYO. Saw him heading home again 20 minutes later.

1040
Div'd 6 miles from Lifeguard station, while 18 25 miles from 5 SHIMA and YOTSU SAKI.

1200
Position: Lat. 34-23.1 N.
Long. 104-03.8 E.

1319
Surfaced on station.

1325
Communication with DUBOIS FOURTEEN at 15 miles. He closed us and began to circle us at 3 miles. Four MUSTANGS joined up a few minutes later. This outfit really KILLED its business and was a terrific improvement over which we received this last two patrols.

1400
J.O.O.D. saw a splash bearing 050° T., distance about 7 miles. Observed a periscope coming down in same position. Headed for position at 6 knots flank speed.

1445
DUBOIS reports survivor in raft and marked contact. To smoke fleet. Also that another one would kill it. Told him we will wait until we completed this recovery if possible.

1426
Picked up Second Lieutenant Lamar K. CUTHBERT, [HANDWRITTEN: 0206-7813], apparently in good health, but quite tired. Later examination revealed fracture of right collar bone.
```

— page 245 —
```
CONFIDENTIAL                U.S.S. TREPANG (SS-412).
SSHA/1/26-3
Serial (09)                     Report of Fifth War Patrol.

  1430  First Lieutenant Frank K. AYERS, U.S.A.F., Pilot No. 805-545,
crossed out an excellent jump just ahead of us. He crossed about 1,000 yards away, while he landed 1,000
yards on the port bow. Had him board in about 5 minutes from the time he jumped. This was his second experience
of this kind, having been picked up by a DD the first time.

  1500  Dived.

  1513  Dived.

  2043  Surfaced and proceeded to new Lifeguard station 60 miles
cuw. Transmitted TREPANG'S First giving dop on survivors.

24 June
  0005 (X)  Sight contact on unidentified plane crossing storm. Dived.
SD contact on way down at 2 miles.

  0136  Surfaced on Lifeguard Station for B-29 strike.

  0145  Communication with BOXITE, who circled us at 3 to 20 miles.
Had contact on a dozen or so planes during next hour.

  0150  Received cancellation of fighter strike scheduled for
later this morning.

  0330  BOXITE departed station - no business this time.

  0453  Dived.

  1200  Position: Lat.  34-27.0' N.
Long.  140-43.1' E.

  1251  Surfaced to air out boat.

  1313  Dived.

  2000  Surfaud in force 6 heads, heavy overcast. Get in touch
for station for fighter strike on TOKYO at 1000 tks.,
maximum spud into such & knots.

June 25
  0210 (X)  SJ contact on NEKURA SHIMA at 40 miles. Subs and Water
no bottom contact urge strike would be cancelled, do con-
tinned working way southerly to be ready to go towards
NAXPO SHOT. This was the only chance we would have to
```

— page 246 —
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CONFIDENTIAL
U.S.S. TAFANG (SS412)
Serial (09)
Report of Fifth War Patrol

. . . make our station off NAGOYA on time, as maximum speed is now 6 knots.

1000
Can just make our 1215 station if we turn and run at full speed with the seas—still no cancellation. Consulted with residual fighter pilots—they also felt certain strike would be cancelled. Decided to hold on until 1475/76 was definite.

1112
SD contact at 7 miles—shows IFF. Never sighted. Attempted communication on VHF—no response.

1200
Position: Lat. 33-29.8 N.
Long. 139-59.1 E.

1300
Received CSP's despatch postponing strike 24 hours.

1304
Dived.

2046
Surfaced. Set course for station off NAGOYA. Seas now only force 4.

2130
Passed between MIKURA SHIMA and HACHITO SHIMA.

June 26
0706 (K)
Submerged 10 miles south of Lifeguard station off ITAKO SUIDO.

0941
Surfaced on station. Numerous B-29's going in toward target. Minor shore line in sight.

1004
Sighted a FRANK at 5 miles. Decided he probably would not bother us as long as there were so many B-29's to play with. Our 2 BOATS with fighter cover are due any minute now.

1006
Dived as the FRANK banked and commenced a run on us. Watched him through periscope still in his dive as we passed 40 feet, about 1,000 yards away. Ducked periscope to save it from starting.

1012
Back to periscope depth. Saw 2 B-29's circling overhead. They must have driven off FRANK.

1015
Surfaced. In communication with our BOATS. Received report of survivors in a position 8 miles off the beach.
```