U.S.S. GROUPER (SS-214) — war patrol report SS-214_GROUPER.pdf

— page 1 —
START OF REEL
[HANDWRITTEN: H-108]
JOB NO. [HANDWRITTEN: ARL 144-76]

1.0
1.1
1.25

4.5  2.8  2.5
5.0  3.2  2.2
     3.6  2.0
     1.8
     1.4  1.6

OPERATOR [HANDWRITTEN: Brodis]
DATE [HANDWRITTEN: 8-27-75]

THIS MICROFILM IS
THE PROPERTY OF
THE UNITED STATES
GOVERNMENT

[STAMP: DEPARTMENT OF DEFENSE]
[STAMP: UNITED STATES OF AMERICA]

MICROFILMED BY
NPPSO-NAVAL DISTRICT WASHINGTON
MICROFILM SECTION

REEL TARGET, START & END
NAVEXOS 3968

— page 4 —
[STAMP: CONFIDENTIAL]
[STAMP: DECLASSIFIED]

U.S.S. GROUPER REPORT OF FIRST WAR PATROL
PERIOD FROM JUNE 4, 1942 TO JULY 30, 1942

1. NARRATIVE

June 4, 1942
0331 (Yoke) Dived expecting to sight the enemy at any moment.

0716 (Yoke) Received message from CTF Seven giving position of
            enemy carriers and main body and ordering task group
            7.1 less CACHALOT, CUTTLEFISH and FLYING FISH to go
            after them. Our position looked good so we remained
            submerged taking a course to intercept at 6 knots.

0726 (Yoke) Manned battle stations.

0731 (Yoke) Sighted a number of planes on the horizon bearing
            210° T. The distance was too great to tell much
            about them but they appeared to be taking off from
            a carrier.

0751 (Yoke) We were machine gunned and then bombed while running
            at 55 feet with 12 feet of periscope exposed in order
            to sight enemy carriers. I could see numerous splashes
            all around the ship and the last few bombs were quite
            heavy. Increased depth to 140 feet.

0807 (Yoke) Bombed again. Very close. Changed course.

0818 (Yoke) Heard a large number of explosions at a greater dis-
            tance believed, at the time, to be our own planes
            bombing the enemy carriers.

0830 (Yoke) Came up to periscope depth.

0832 (Yoke) Sighted anti-aircraft bursts from three ships, over the
            horizon, bearing 255° T to 263° T. No explosions could
            be heard.

0839 (Yoke) Sighted a large number of various type planes scattered
            throughout the sky between bearings 255° T and 263° T.
            numerous dog fights appeared to be going on in and out
            of the light clouds. Changed course to close the fir-
            ing ships.

0855 (Yoke) Sighted a large number of planes, not in formation,
            bearing 216° T. Some appeared to be bombers but no
            time was wasted with a periscope exposure to merely
            identify planes as the Japs were too good at spotting

-1-
ENCLOSURE (A)

— page 7 —
CONFIDENTIAL
Subject: _ _U.S.S. GROOPER - Report of First War Patrol_ _ _ _
1118 (Yoke) Sighted PBY headed for Midway and decided enemy must
not be in vicinity or there would be some fighters
after the PBY. Surfaced and proceeded at 19 knots.

1207 (Yoke) Sighted two fighters diving out of the clouds above
and astern of us. Dived to 200 feet.

1245 (Yoke) Heard echo ranging and came to periscope depth. Sight-
ed friendly task force making high speed range 7000
yards.

1325 (Yoke) Own forces clear. Surfaced and proceeded at 19 knots.

1347 (Yoke) Sighted 7 heavy or medium bombers coming out of the
clouds overhead. Dived. Ship seemed to hang at 160
feet and the diving officer flooded more water into
auxiliary thinking air pockets in the main ballast tanks,
that would give our position away if vented, were hold-
ing the ship up. Negative had already been blown. At
this time both torpedo rooms and the air manifold stati-
reported sea pressure gauges approaching 200 lbs. At the
same time the needles of the deep reading depth gauges
in the control room swung around and hit the pegs. The
diving officer reported we were below 500 feet. All
tanks were blown. All sea pressure gauges were well
beyond the 200 lb., calibration. Came up at full
speed with about a 300 up angle until bow buoyancy
could be vented and the air to the forward group of
tanks secured. The depth charge switch was in and kept
the overload relays from kicking out. Leveled off at
230 feet and surfaced slowly. No planes in sight. The
best estimate of maximum depth reached is 600 feet aft,
where sea pressure gauges in the after torpedo room and
maneuvering room hit the stops at about 260 lbs. Pro-
ceeded at 15 knots, inspecting for damage. A number of
electrical cables had been pushed in a couple of inches,
the cast iron plugs in the water manifolds for the
generator coolers had been flying around the engine room
like machine gun bullets, large quantities of water had
been taken in through the stern tubes and everyone had
a few more grey hairs. No other serious damage noted.

1455 (Yoke) Made test dive to 200 feet to check cable leaks that had
been tightened.

1536 (Yoke) Surfaced and proceeded on assigned mission at 19 knots.

1848 (Yoke) Arrived on station. Sighted four friendly submarines.

-4- ENCLOSURE (A)

— page 9 —
CONFIDENTIAL
Subject: _ _ _ U.S.S. GROUPER = Report of First War Patrol. _ _ _ _ _ _

June 12, 1942
1700 (Yoko) Underway for patrol area in accordance with CTF Seven
          082200.

June 15, 1942
0920 (Mike) In position 575 miles bearing 040° T from Wake sighted
          plane and dived. One lookout only sighted the plane
          and described it as a single engine, mid-wing, monoplane.

1020 (Mike) Surfaced and proceeded along assigned route.

June 18, 1942
0949 (Love) In position 260 miles bearing 022°T from Marcus sighted
          plane coming out of the bright sun, distance about one
          mile, altitude 300 feet. There were a few scattered
          clouds and a fringe of heavy clouds all around the hori-
          zon. Lookouts were on the alert and stationed as foll-
          ows: O.O.D., R.M., and C.O., forward lookouts; 2 port
          and 2 starboard lookouts on high lookout platform;
          horizon lookouts; torpedo platform; J.O.O.D. aft. The
          plane was sighted by the J.O.O.D. I sounded the diving
          alarm a couple of seconds after the J.O.O.D. shouted
          "In position". The first bomb exploded as the run-
          ning power hatch was being closed, depth gauge reading
          25 feet. Two more bombs exploded very shortly there-
          after. Dived to 200 feet. All compartments reported
          the bombs exploded very close to them. The after tor-
          pedo room heard fragments hit the hull. One light bulb
          was broken in the after torpedo room. All the pots and
          pans in the galley came tumbling down with the second
          bomb explosion adding considerably to the confusion.
          Remained at 200 feet until dark steering various courses
          in case fuel oil tanks had been hit and we were leaving
          a slick.

1948 (King) Surfaced and inspected for damage. None apparent.

June 19, 1942
0400 (King) Dived. Decision having been made to make the remainder
          of passage to patrol area submerged during daylight
          hours for the following reasons:
          (1) Proximity of enemy air bases (300 miles) and due to
              the presumption that all enemy air patrols from out-
              lying bases have been lengthened and increased since
              the Battle of Midway in expectation of a probable
              raid or as a result of the lesson learned there.
          (2) Present route should be an excellent hunting ground
              as it crosses all lines of communication from the
              Empire to the South.
          (3) Time on station will be cut down only about 3 days.

-6-
ENCLOSURE (A)

— page 10 —
CONFIDENTIAL
Subject: U.S.S. GROUPER - Report of First War Patrol. - - - - -
(4) Enemy knows course and remainder of route is
    through normal search areas.
(5) Radar out of commission.
(6) Present weather is ideal for detection by aircraft
    due to presence of low scattered clouds, bright
    sunlight and glassy sea.
(7) One man, a CPO, has cracked under the strain of
    bombing and depth charging so far. If we are going
    to deliver any telling blows to the enemy further
    loss of morale, that might result from an unnecess-
    ary bombing attack, cannot be risked for an addition-
    al three days in the area.

June 20, 1942
2040 (King) In position 29-02 N 150-20 E sighted dark object in the
    water about 10° on port bow distance 2000 yards. Object
    outlined by phosphorous, was crossing from port to star-
    board and gave every appearance of a submarine conning
    tower about to break water. Prepared two stern tubes
    while changing to firing course. On closer observation
    object made out to be a whale. Resumed course along
    assigned route.

June 23, 1942
0400 (King) In position 28-57 N 143-00 E sighted two dark objects
    on the horizon astern distance about 8000 yards. Chang-
    ed course to place objects that appeared to be two DDs
    in column, directly astern. Increased speed to 19 knots.
    Range appeared to decrease.
0420 (King) Divcd and changed course for stern tube shot. Objects
    were not sighted again and nothing was heard on the
    sound gear. There was sufficient light to see very well
    from the periscope as dawn was breaking in the east. If
    the objects sighted were destroyers they had changed
    course. If not they were very deceiving clouds.

June 25, 1942
1007 (Int) O.O.D. sighted large empty tanker astern crossing from
    port to starboard range about 4000 yards. At this time
    we were running alternate deep with observations once
    an hour enroute to area, placing entirely too much
    faith in the sound equipment. From this time on we ran
    at periscope depth when weather permitted and made more
    frequent observations when forced to run alternate deep.

-7-
ENCLOSURE (A)

— page 11 —
CONFIDENTIAL
Subject: _ _ _ U.S.S. GROUPER - Report of First War Patrol. _ _ _ _ _ _ _

1017 (Int) Fired three torpedoes from stern tubes. No explosion
heard in conning tower although a light cloud of smoke
appeared along the ship's water line making me think
the torpedoes were running under and not exploding.
Revised range and speed estimate and decreased depth
setting.

1020 (Int) Fired last torpedo in after tubes. Noted a large im-
pulse bubble astern, pulled down periscope and started
a high speed turn to bring bow tubes to bear. Sound man
reported a hot straight run, torpedo hit making a loud
explosion which was accompanied by a number of explosion
of lesser intensity. I thought, and so did the entire
fire control party, that we were being bombed again. No
time had been available to search for an air screen and
none had been made. I ordered 140 feet without looking
at the target. Realizing this was a mistake I ordered
periscope depth.

1027 (Int) Coming up past 120 feet there were two more muffled ex-
plosions. These were either bombs or boilers. Depth
was again increased in case planes were present knowing
the enemy ship could not get far after the explosion
that resulted from the last hit. Reloaded after tubes.
Both torpedo rooms and maneuvering room reported two ex-
plosions after the first three torpedoes were fired.

1050 (Int) Came up to periscope depth and made a thorough search.
Nothing could be sighted. Weather was clear, sea glass
calm and bright sun light.
The ship was definitely identified by both the Commander
Officer and the Executive Officer as the TOMIN MARU No.
(19,600 tons) shown on plate 19 in "Recognition of Japan-
ese Merchantmen". The only other possibility being the
HISSIN HARU shown on plate 95. The views presented
being exactly the same as seen through the periscope
when the ship crossed astern of us. The range for the
first 3 shots was badly underestimated due to the size
of the ship. Echo ranging could not be used as ship was
directly astern of us and we can not get ranges through
our own wake. Enemy was flying DML.
Increased depth to 140 feet and retired on course 1800T
at 2 knots as enemy had sufficient time to get off a
radio message before last hit and planes could be expect-
ed in the vicinity shortly.

June 26, 1942
0201 (Int) Entered assigned area.

-8- ENCLOSURE (A)

— page 21 —
CONFIDENTIAL
6. DESCRIPTION OF ALL AIRCRAFT SIGHTED

Contact: Date : Time : Position : Course : Description :
No. : : : : : :

— page 22 —
CONFIDENTIAL
6. DESCRIPTION OF ALL AIRCRAFT SIGHTED (CONT'D).
Contact: | Date | Time | Position | Course | Description :
No. | | | | |
---|---|---|---|---|---
26 | :6/4/42 | :0856(Y) | :150 miles bear- | :Diving | :Type "O"
| | | :ing 325° T from | :down per- | :Fighter.
| | | :Midway. | :iscope |
| | | | :window |
| | | | :with mach- |
| | | | :ine gun |
| | | | :& cannon |
| | | | :firing. |
---|---|---|---|---|---
27 | :6/5/42 | :0845(Y) | :90 miles bearing | :SE head- | :Undetermined
| | | :315° from Midway. | :ed for | :type, descrip-
| | | | :us. | :tions vary.
| | | | | :Dropped bomb
| | | | | :or depth char-
| | | | | :ge on us.
---|---|---|---|---|---
28 | :6/5/42 | :1118(Y) | :80 miles bearing | :SE | :USNavy PBY.
| | | | :315° T from Mid- | |
| | | | :way. | |
---|---|---|---|---|---
29 | :6/5/42 | :1207(Y) | :65 miles bearing | :SE | :Two fighters
| | | | :315° T from Mid- | | :diving out of
| | | | :way | | :clouds. Believ-
| | | | | | :ed to be frien-
| | | | | | :dly.
---|---|---|---|---|---
30 | :6/5/42 | :1347(Y) | :60 miles bearing | :NW | :7 -
| | | | :315° T from Mid- | | :US ARMY B-17s
| | | | :way. | |
---|---|---|---|---|---
31 | :6/6/42 | :0700(Y) | :115 miles bearing | :NW | :3 -
| | | | :307° T from Mid- | | :US NAVY PBYs
| | | | :way. | |
---|---|---|---|---|---
32 | :6/6/42 | :0840(Y) | :145 miles bearing | :NW | :US NAVY PBY
| | | | :307° T from Mid- | |
| | | | :way | |
---|---|---|---|---|---
33 | :6/6/42 | :1230(Y) | :190 miles bearing | :SE | :3 -
| | | | :307° T from Mid- | | :US NAVY PBYs
| | | | :way | |
---|---|---|---|---|---
34 | :6/14/42 | :0555(M) | :27-26 N | :W | :US ARMY B-17
| | | | :178-56E | |
---|---|---|---|---|---
35 | :6/14/42 | :0900(M) | :27-30N | :E | :US ARMY B-17
| | | | :178-00E | | :Lookout states:
---|---|---|---|---|---
36 | :6/15/42 | :0920(M) | :175 miles bear- | :E | :single engine
| | | | :ing 040° T from | | :mid-wing mono-
| | | | :Wake. | | :plane.
---|---|---|---|---|---
37 | :6/18/42 | :0949(L) | :260 miles bearing | :W | :Mitsubishi
| | | | :022° T from | | :Dairai 108.
| | | | :Marcus. | |
---|---|---|---|---|---
| | | | | |
- 19 - ENCLOSURE (A)

— page 24 —
CON FIDENTIAL
Subject: _ _ _ U.S.S. GROOPER _ Report of First _ War_Patrol.
8. ENEMY A/S MEASURES

(a) No propeller noises were heard on the sound equipment during
the depth charge attacks on June 4 except one DD that passed
directly overhead was heard to speed up, cross over and then
slow down. Sound heads could not be trained for considerable
periods due to necessity of building up hydraulic pressure and we
might have missed a number of noises during these periods. On
several occasions the hydraulic plant was started while the charges
were exploding in hopes that it would not be heard but each attempt
brought on more charges.

(b) During some of the silent periods on 4 June we were quite sure
the enemy was dragging something through the water to locate us as
strange noises could be heard in the superstructure particularly
above the conning tower.

(c) I am quite sure the enemy DD's either drop or throw their
depth charges while making slow speed.

(d) No echo ranging was heard during the attack on 4 June.

(e) Depth charge settings appear to be about 150 feet.

(f) Coordination of planes and destroyers appeared to be excellent
at Midway.

(g) Marcus maintains some sort of an air patrol, whether A/S is un-
known. Bombs and not depth charges were dropped at Marcus. The
aim was only fair but I would not give them another chance.

(h) The propeller noise heard during the attack on July 6, 1942 was
not one of our torpedoes. The sound man picked them up while
tracking our torpedoes out. Our torpedoes were running hot,
straight and normal when the other propellers were picked up coming
back along the tracks and separated but a few degrees from them.
Both sound men state the noise was exactly like that produced by
one of our PT boats. I think it was too rough for a PT boat. The
only search I made by periscope was a low power and none too
thorough, but I think that I would have picked up a destroyer. The
enemy ship was not noted to be carrying anything resembling a PT
boat and in any event she was going too fast to launch one. It is
possible the enemy plane launched a torpedo aimed back along the
tracks of our torpedoes and in this case the chances of a hit were
excellent and was probably prevented by our going deep. However,
no properly timed explosion was noted and I am under the impression
that all enemy torpedoes explode at the end of the run.

(i) The bombs or depth charges dropped on July 6, 1942 were much
heavier and much closer than anything experienced to date.

(j) During the depth charge attacks on 4 June the only evasive tac-
tics that could be used were to turn away from where we thought the
charges were exploding.

- 21 -

— page 25 —
CONFIDENTIAL

Subject: _ _ _ U.S.S. GROUPER - Report of First War Patrol. _ _ _

9. MAJOR DEFECTS EXPERIENCED

(a) A leak developed in No. 3 air bank located in No. 4 H.B. tank
while in the French Frigate Shoal area. This leak was bad enough
to slowly blow the ballast tank and necessitated running with the
vents open. It is the largest bank on board and was not blown
down as the H.P. air capacity is none too great with all banks in
commission. At Midway the tank was opened and the leak found to
be a defective blow down valve.

(b) After one week in the French Frigate Shoal area both periscopes
became badly fogged. They were very poor in low power and unusable
in high power except for a few seconds when first raised. They
cleared when shifted to the Midway area and then fogged badly again
in the China Sea clearing again in the area east of the NANSEI SHO.
Both periscopes were checked and recharged by tender personnel the
day prior to departure on patrol. Outer windows were cleaned with
alcohol every night which seemed to improve their condition some-
what. Whether the fogging is due to lack of pressure or dirty water
is undetermined at the present time.

(c) A bearing was wiped and the crankshaft scored on No. 1 air cond-
itioning machine. This casualty was the result of improper procedure
in securing and starting the machine. Temporary repairs were made.

(d) All main ballast differential pressure gauges were thrown out
of adjustment as much as 40 lbs by the depth charge attack on 4 June.

(e) All depth gauges are sluggish, sticky and out of adjustment as
a result of the depth charge attack on 4 June.

(f) The joint where the magnetic compass binnacle tube enters the
conning tower leaks badly at 250 feet. This is a result of the
deep dive made on 5 June.

(g) The radar mast was found to be grounded internally after the
deep dive on 5 June.

(h) All electrical cables passing through the pressure hull were
pushed in an inch or two, by the deep dive on 5 June, causing some
very bad leaks.

(i) It was necessary to stop for about two hours one night, in the
bright moonlight, while north of the Bonin Islands to repack the
starboard's stern tube which had started leaking excessively while
submerged.

(j) All main engine exhaust valves leaked at one time or another.
Working them on their seats from the topside followed by a short
run at full power stopped the leaks temporarily.

- 22 -

— page 26 —
CONFIDENTIAL
Subject: _ _ _ U.S.S. GROUPER - Report of First War Patrol. _ _ _
9. MAJOR DEFECTS EXPERIENCED

(k) Without exception all valves on the ship leak and were a con-
stant source of trouble. Air manifold valves were ground in several
times, trim manifold valves were ground in twice and V.C. stop
valves were ground in almost every night. The material used in all
composition valve discs appears to be of inferior quality. All
sea valves leak to some extent.

(l) Bow plane shafting packing glands leaked excessively at any
depth greater than 140 feet. Both were repacked prior to the
start of the patrol. The only means found to keep them tight was
to pack them with torpedo tail packing compound inserted with an
air grease gun. This was extremely dangerous as the high pressure
might crack the gland but a hand gun would not stop the leak.

(m) The trim pump is of little use and extremely noisy at deep sub-
mergence. It can not be used during depth charge attacks when con-
siderable water is taken aboard from various leaks that must be
compensated for by pumping or blowing if depth control is to be
maintained at slow speed.

(n) Main motors are extremely noisy.

(o) Both I.C. motor generators have become extremely noisy and
must be overhauled or replaced.

(p) The magnetic compass binnacle fogs every dive and cannot be
used for several hours after submerging and several hours after
surfacing due to the temperature difference on the surface and sub-
merged. Attempts to dry it out with hot air were not very success-
ful.

(q) Bow and stern plane shafting is extremely noisy in both power
and hand operation due to poor fitting universal joints and must
be completely overhauled.

(r) The bow plane tilting magnetic shifting clutch collar developed
a squeak that came in on the sound equipment in the form of extre-
mely loud modulated frequency echo ranging. All sorts of steps
were taken to stop the noise without results. To inspect the collar
required complete removal of the large gear casing which was too
dangerous while on patrol in enemy waters. As a last resort we
drilled a hole in the casing, on which we had no blueprints, and
filled it with hot running torpedo oil stopping the squeak.

(s) Most of the paint on the tapered part of No. 2 periscope was
found to be missing after the bombing at Midway and again after
the bombing in the China Sea leaving a very bright metal surface
exposed.

- 23 -

— page 27 —
CONFIDENTIAL
Subject: - - - U.S.S. GROUPER - Report of First War Patrol. - - -

9. MAJOR DEFECTS EXPERIENCED
(t) The hull ventilation supply flapper valve is inoperative due
probably to spray or moisture corroding the shaft.

(u) The pitometer log (rotary blance type) went out completely
with one of the first depth charges dropped at Midway, the
seal bellows breaking. A spare pump was installed. All hose con-
nections were broken and adjustments thrown out by the deep dive
on 5 June.

(v) Sound heads would not stay down at any depth below 100 feet.
This was due to worn fibre rollers on the locking device. Consider-
ation was given to replacing these rollers with metal ones but we
were afraid damage to the roller path might result.

(w) One torpedo after body was flooded on 4 June. This resulted in
a flooded gyro with bad bearings. The torpedo was reserved for a
"circular". One exploder was flooded and replaced with a spare.

10. RADIO RECEPTION

(a) Unable to copy HPI primary FOX on D1 loop below 50 feet in
French Frigate Shoal area. Came in quite clear at 55 feet although
signal faded out for about 15 minutes at sunrise.

(b) Unable to copy HPI primary FOX on D2 loop below 55 feet in
Midway area. Signal faded out about two hours before sunset. From
that time until surfacing HPI could not be copied on either the
DQ loop or the periscope antennae.

(c) HPI submarine schedule could be copied on either high or low
frequency throughout the patrol while on the surface. High frequ-
ency was a little better while in the East China Sea.

(d) Last consecutive serial sent "OPHELIA"

Last consecutive serial received "REGULUS"

- 24 -

— page 33 —
FB5-81/A16-3 COMMANDER SUBMARINE DIVISION EIGHTY-ONE (Ss)
Serial (027)

CONFIDENTIAL

Care of Fleet Post Office
San Francisco, California,
July 26, 1942.

From: The Commander Submarine Division EIGHTY ONE.
To : The Commander Submarines, PACIFIC FLEET

Subject: U.S.S. GROUPER (SS214) - First War Patrol;
Report of.

Reference: (a) Comsubpac conf. ltr. 8-42.

1. From reading this report it is believed that
many golden opportunities to inflict heavy damage on the
enemy were missed, in that the Commanding Officer chose in
many instances to use evasive tactics rather than aggressive
tactics. It is indeed unfortunate that an unseasoned ship,
so far as combat is concerned, should get its first baptism
of fire in an engagement of the magnitude of the battle of
Midway. It is felt that this initial introduction to combat,
together with the inadvertent deep dive of the U.S.S. GROUPER
colored the decisions of the Commanding Officer throughout
the patrol.

W.H. DOWNS

Copies to:
Comsubron 8
CO USS GROUPER

ENCLOSURE (B)

— page 34 —
REVIEWED, RETAIN CLASSIFICATION
BY [HANDWRITTEN: 91C] DATE [HANDWRITTEN: AUG 65]
[STAMP: REVIEWED]
43340

FF12-10/A16-3(5) SUBMARINES, PACIFIC FLEET W1

Serial 0884 Care of Fleet Post Office,
[STAMP: DECLASSIFIED] San Francisco, California,
August 3, 1942.
COMSUBPAC PATROL REPORT NO. 52
U.S.S. GROUPER - FIRST WAR PATROL

CONFIDENTIAL

From: The Commander Submarines, Pacific Fleet. [STAMP: FILED]
To : Submarines, Pacific Fleet.

Subject: U.S.S. GROUPER (SS214) - Report of First War
Patrol.

Enclosure: (A) Copy of subject report.
(B) Copy of Comsubdiv 81 Conf ltr FB5-81/
A16-3 Serial 027 of July 26, 1942.

1. It is regretted that the attack on the two
burning carriers sighted in the morning of June 4, 1942,
was not pressed home. Definite information of the tor-
pedoing and sinking of two carriers that morning would
have been most welcome.

2. It hardly seems conceivable that over 100
depth charges were dropped on the GROUPER on the morning
of June 4, 1942, and another 60 or 70 in the afternoon.
Some of these explosions may have been due to bombing
attacks on the carriers and others may have been internal
explosions on the stricken carriers.

3. Sighting tests of submerged submarines con-
ducted prior to the war, indicated that submarines painted
black could not be seen when at a keel depth greater than
120 feet, even by the most experienced observers.

4. Comments on the deep dive to an estimated
depth of 600 feet will be made in separate correspondence.

5. It seems probable that both ships reported
as hit by three torpedoes sank but there is no definite
proof that such was the case and it is known from [STAMP: RECEIVED]
[HANDWRITTEN: S-C FILES]
experience that tankers in the light condition are hard to [HANDWRITTEN: Room 2455]
[STAMP: DESTROYED] sink. The GROUPER is therefore credited with inflicting
the following damage on the enemy: [STAMP: AUG 19 1942]

[STAMP: DESTROYED] ROUTE TO:- [HANDWRITTEN: 10-10-11]
DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
Op File No. (SC) [HANDWRITTEN: A16-3(23)/SS214]
BY [HANDWRITTEN: OP09B9C] DATE [HANDWRITTEN: 5/26/72] [HANDWRITTEN: Finished-Nunn-File]
Doc. No. [HANDWRITTEN: ---]
- 1 [STAMP: DECLASSIFIED] Copy No. [HANDWRITTEN: 1] of [HANDWRITTEN: 5]
OWN [HANDWRITTEN: 1194]
[HANDWRITTEN: 42141]

— page 35 —
W1

FF12-10/A16-3(5) SUBMARINES, PACIFIC FLEET
Serial 0884 Care of Fleet Post Office,
San Francisco, California,
August 3, 1942.

COMSUBPAC PATROL REPORT NO. 52
U.S.S. GROUPER - FIRST WAR PATROL

CONFIDENTIAL
Subject: U.S.S. GROUPER (SS214) - Report of First War
Patrol.

— page 36 —
[STAMP: DECLASSIFIED]
[STAMP: CONFIDENTIAL]
Subject: U.S.S. GROUPER - Report of Second War Patrol. [HANDWRITTEN: (9)]
Period: From 28 August 1942, to 20 October, 1942.

Prologue

# Arrived Pearl Harbor July 30, 1942 from First War Patrol.
Commenced refit on July 31, 1942, by submarine base, navy yard,
and tender repair forces. Controlling job was installation and
boring of new bearings for # 1 periscope by navy yard. Readiness
for sea on 23 August, 1942. Not depermed or wiped; training per-
iod 24-26 August, 1942.

Second War Patrol was conducted in areas _ and _, Task
Force SEVEN operation order 75-42.

# Submitted in accordance with subpacflt. Conf.
Ltr. 12-42, received October 20, 1942.

1. NARRATIVE. (times INT unless indicated otherwise).

28 August Underway from Submarine Base, Pearl Harbor, for
0900 W assigned area, via MIDWAY, escorted by U.S.S. LITCH-
FIELD. Calibrated RDF. Escort dropped three (3)
familiarization depth charges, distances 275, 300,
350 yards. Escort released at nightfall.

1 September Arrived MIDWAY. Surface and air escorts. Topped off
0800 W fuel and water. U.S.S. FULTON replaced gasket on
flange in negative tank blow line located in #2 main
ballast tank. Departed MIDWAY with surface and air
escort at 1600 W. Escort released at nightfall.

15 September Arrived in area twelve (12) 4 days after departure
0220 from MIDWAY. Trip uneventful. Fired .50 cal.
machine gun and 10 rounds ammunition with the 3" at
homemade target on 4 September. Outside of the
structural test shots this is first time gun had been
fired. Results good. Sighted eight (8) fishermens
lights during trip, none of which interfered with our
progress. On 9 September 305 miles from CHICHIJIMA
in the Bonan group had radar contact at eight (8)
miles. Dove and ran submerged during daylight from
then on. Sky overcast. Do not believe we were
sighted. Crew was extensively trained each day during
entire passage.

- 1 - ENCLOSURE (B)

— page 47 —
[HANDWRITTEN: 1ST COPY]

FF12-10/A16-3(5) SUBMARINE FORCE, PACIFIC FLEET
Serial 01252

CONFIDENTIAL
[STAMP: DECLASSIFIED]
COMSUBPAC PATROL REPORT NO. 84
U.S.S. GROUPER - SECOND WAR PATROL.

From:
To :
Subject:

Enclosure:

1.
patrol was covered in a thorough manner. The percentage of
torpedo hits obtained on the patrol is not impressive, but an
increase with experience and training is expected.

2.
officer to delay attacking until sea, weather and visibility
conditions are favorable. In general, the immediate and direct
attack is favored, but the commanding officer on the spot must
judge the attack which offers the greatest prospect of success.

3.
concurs with the remarks of Commander Submarine Division Eighty-
One in his discussion of the various attacks. On the attack on
October 1, the patrol report offers insufficient evidence to
warrant a decision that the 7,000-ton Lyons Class freighter sank.
However, as a Japanese radio broadcast announced that the Lisbon
Maru (same class as Lyons Maru) was sunk by a submarine in the
East China Sea on October first, the GROUPER is credited with
the sinking.

4.
the GROUPER are to be congratulated on having inflicted the fol-
lowing damage on the enemy:

[STAMP: RECEIVED FILES]
[STAMP: NOV 26 1942]
[HANDWRITTEN: RUDIE LU- HE3]
[HANDWRITTEN: (US File No. SD) A16-3(5)]
[HANDWRITTEN: Inv. No. 3-5]
[HANDWRITTEN: RN- 43995]

Rs
Care of Fleet Post Office,
San Francisco, California,
November 2, 1942

The Commander Submarine Force, Pacific Fleet.
Submarine Force, Pacific Fleet.
U.S.S. GROUPER (SS214) - Report of Second
War Patrol.
(A) Copy of Comsubdiv 81 Conf ltr FB5-81/
A16-3/(SS214) Serial 043 of October 21,
1942.
(B) Copy of Subject War Patrol.

The area assigned the GROUPER on her second war

A tendency is noted on the part of the commanding

The Commander Submarine Force, Pacific Fleet,

The Commanding Officer, officers and crew of

SUNK

1 Freighter - 5,000 tons
1 Freighter - 7,000tons (Lisbon Maru)
Total ..... [HANDWRITTEN: 12,000 tons]

DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: OP-09B9C] DATE [HANDWRITTEN: 5/26/72]
[STAMP: DECLASSIFIED]

— page 48 —
11 01736

5-81/ COMMANDER SUBMARINE DIVISION EIGHTY-ONE.
A16-3/(SS214)
(043)
Care of Fleet Post Office,
San-Francisco, California,
October 21, 1942.

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

From: The Commander Submarine Division EIGHTY ONE.
To : The Commander Submarine Force, Pacific Fleet.

Subject: U.S.S. GROUPER (SS214) - Second War Patrol;
Report of.

Reference: (a) Comsubfor Conf. ltr. #12-42.
(b) Comsubfor Patrol Report #48.

1. The second war patrol of the GROUPER, which was
the first war patrol for the present commanding officer, was
well conducted. The area assigned was covered thoroughly,
especial emphasis being paid to the two generally known traffic
lanes through it. It is particularly gratifying to note that
the success of this patrol has instilled confidence in the
personnel and increased the morale.

2. The commanding officer has been directed to
submit a "prologue" together with additional information re-
quired by reference (a) in order to make his report conform
with the latest instructions.

3. The following remarks relative to the GROUPER's
torpedo attacks are submitted in accordance with reference (b):

ATTACK NO. 1

Surface, night, one torpedo fired, no hits. This attack
probably failed due to an under estimate of range and the large
track angle employed.

ATTACK NO. 2

Daylight, periscope depth, three torpedoes fired, no hits.
In discussing this attack with the commanding officer it appears
that the range was possibly under estimated and that the target
sighted the torpedoes and maneuvered to avoid. The commanding
officer states that the three minute period, as reported in the
narrative, was an estimated time and had the range been in error,
even slightly, the target could have turned prior to the tor-
pedoes crossing the target's track. Therefore, the probable
causes for the failure of this attack are due to excessive range
and the target maneuvering to avoid.

- 1 - ENCLOSURE (A)
[HANDWRITTEN: 3]

— page 49 —
FB-81/
A16-3/(SS214)
(043)

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

Subject:

ATTACK NO. 3

Surface, night, one torpedo fired, one hit. 5000 ton
cargo vessel sunk.

ATTACK NO. 4

Daylight, periscope depth, six torpedoes fired, two hits.
First three torpedoes fired where at a range of 3200 yards, which
is considered excessive. The fourth torpedo fired was heard to
hit in two minutes and ten seconds. Shortly thereafter observa-
tion showed that the target had stopped. No explanation is
apparent why the fifth torpedo did not hit as it was fired at a
range of 1000 yards and with a favorable track angle - the target
being stopped. The sixth torpedo evidently hit. Target was not
observed sinking but twenty two minutes after firing last torpedo
target had disappeared from location where she had been stopped
for two hours previously.

ATTACK NO. 5

Daylight, periscope depth, four torpedoes fired, one probable
hit. The first three torpedoes fired were from a range of 1500
yards and a track angle of 105 degrees. No explosions were
heard. Immediately thereafter the fourth torpedo was fired and
at that time dense white smoke was observed coming from the
target covering about 1/3 of her length.

4.
the GROUPER are to be congratulated on this patrol.

Copy to:
Comsubron 8
CO GROUPER

COMMANDER SUBMARINE DIVISION EIGHTY-ONE

October 21, 1942.

U.S.S. GROUPER (SS214) - Second War Patrol;
Report of.

W. M. DOWNES.

- 2 -

ENCLOSURE (A)
[HANDWRITTEN: X]

— page 50 —
[HANDWRITTEN: 1ST COPY]

U. S. S. GROUPER (SS214)

Report of Third War Patrol [HANDWRITTEN: [12 NOV - 31 DEC 42]]
C-O [HANDWRITTEN: SECRET] [HANDWRITTEN: DECLASSIFIED] A-L

[STAMP: DECLASSIFIED]

[HANDWRITTEN: 45350]

DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: DP-0909C] DATE [HANDWRITTEN: 5/30/72]
[STAMP: DECLASSIFIED]

— page 51 —
SECRET
[STAMP: CONFIDENTIAL]
Subject: U.S.S. GROUPER - Report of Third War Patrol.
Period: From November 12, 1942 to December 31, 1942.

Prologue

Arrived MIDWAY on 21 October, 1942 from
Second War Patrol. Commenced refit on 22 Octo-
ber, by submarine base personnel. Controlling
job was installation of SJ Radar. Readiness
for sea on 12 November, 1942. Not depermed or
wiped; no training period.

1.
NARRATIVE. (times KING unless indicated otherwise).

12 November Underway from MIDWAY with escort. Made test
0700 M dive for tightness. Released escort at 1130 M.

22 November Arrived in area 9(-) days after departure
from MIDWAY. Made entire trip on surface except
for trim-training dive each morning at daybreak.
On 17 November, had radar contact at 8 miles.
Dove and ran submerged forty minutes. Otherwise
trip uneventful. Conducted first three days of
patrol in Northeast section of area.

25 November Received dispatch about traffic from RABAUL to
SHORTLANDS so moved to Southwest portion of area
as most likely sector for interception.

27 November Sighted four vessels to southward distant
about 10,000 yards, heading 160°, speed 10
knots, angle on bow about 150 degrees. They
were outside of area. Closed to 5,000 yards.
Any closer approach would have meant positive
detection. Vessels were all small. Appeared to
be two destroyers, one patrol boat and a very
doubtful submarine. Visibility was such that
this attack could only be made submerged. The
type of targets coupled with the fact that we
would have to go forty or fifty miles out of
area justified no further action. A contact re-
port was made prior to decoding CTF 42 despatch
#262232 of November, that stated such reports
were not in order.

29 November Surfaced to charge anticipating possible
1000 early contact from despatch information.

[HANDWRITTEN: 45350] -1-

— page 64 —
TF42/A16-3
Serial 00159

[STAMP: CONFIDENTIAL]

TASK FORCE FORTY-TWO                                                              1 02078
                                                                                   Pk
                                                              Care of Fleet Post Office,
                                                              San Francisco, California,
                                                              January 1, 1943.

From:        The Commander Task Force FORTY-TWO.
To :         The Commander in Chief, United States Fleet.
Via :        The Commander South Pacific Force.

Subject:     U.S.S. GROUPER (SS214), Third War Patrol
             Comments on.

Enclosure:   (A) Copy of subject patrol report.

             1. Enclosure (A) is forwarded herewith.

             2. The GROUPER completed her third war patrol on
             December 31, 1942, having spent 49 days at sea and 34 days in
             patrol area.

             3. Nine contacts were made of which only two were
             developed into attacks. These two attacks were directed against
             four ships in two convoys. Due to lack of positive evidence,
             the GROUPER is credited only with sinking one AK of the HOKKAI
             MARU class of 8360 tons and possible damage to an AK (unidenti-
             fied) of 4000 tons.

             4. The GROUPER returned in excellent material con-
             dition. The current refit will be accomplished by the FULTON.

                                                              [SIGNATURE: James Fife, Jr.]
                                                              JAMES FIFE, Jr.

DISTRIBUTION:
VCNO, Cinclant,
Cincpac, Comsowespac,
Comsublant, Comsubpac,
Comsubsowespac, CSS 8 & 10,
Each SS TF42, (Not to be taken to sea, BURN),
CTF42 Patrol Summary File,
[HANDWRITTEN: 45350] CTF42 War Diary File,
[STAMP: FILMED] Comsubdiv 81, CO GROUPER File.
[STAMP: CONFIDENTIAL]

— page 65 —
[STAMP: CONFIDENTIAL]
[STAMP: Reg. No. [HANDWRITTEN: 126]]
[STAMP: B.S. No. [HANDWRITTEN: 1] 02078]

COMSOPAC FILE

A16-3/(11)
Serial 00187
[STAMP: CONFIDENTIAL]

                                        SOUTH PACIFIC FORCE
                                OF THE UNITED STATES PACIFIC FLEET
                                HEADQUARTERS OF THE COMMANDER

                                                                ab
                                                        JAN 15 1943

                        1st Endorsement on
                        ComTaskFor 42 Secret
                        Ltr.A16-3 Serial 00159
                        of January 1, 1943.

From:           The Commander South Pacific Area and South
                Pacific Force.
To :            The Commander-in-Chief, United States Fleet.

Subject:        U.S.S. GROUPER (SS214), Third War Patrol -
                comments on.

        1.      Forwarded. In retrospect, the Commanding
Officer probably regrets not having attacked the destroyer
whose trail he crossed the nights of 20, 21 and 22 December.
Knowing the destroyer's patrol line, the submarine could
have been waiting for him the night of December 23.

        2.      The report does not state whether the stowa-
way was commended or court-martialed.

                                                [SIGNATURE: W.F. Halsey]
                                                W. F. HALSEY

Copy to:
        VCNO
        Cincpac
        Cinclant
        Comsowespac
        Comsubpac
        Comsublant
        Comsubsowespac
        Comsubron 8
        Comsubdiv 81
        CTF 42
        C.O., GROUPER

[HANDWRITTEN: 45350]
[STAMP: FILMED]

                                                [STAMP: CLASSIFICATION THIS CORRESPONDENCE]
                                                [STAMP: CHANGED TO CONFIDENTIAL]
                                                [STAMP: AUTHORITY F-02]
                                                [STAMP: DATE JAN 31 1943]

                                                                [STAMP: COMMANDER IN CHIEF]
                                                                [STAMP: U.S. FLEET]
                                                                [STAMP: RECEIVED]
                                                                [STAMP: 1943 JAN 31 13 07]

— page 66 —
[STAMP: DECLASSIFIED]
CONFIDENTIAL
Subject: U.S.S. GROUPER - Report of Fourth War Patrol.
Period: From 21 January 1943 to 18 March 1943.

[HANDWRITTEN: 1ST COPY]

Prologue
Arrived Brisbane, Australia, on 31 December, 1942,
from third war patrol. Commenced refit on 1 January
1943, by repair department U.S.S. FULTON, relief crew and
ship's force. Completion of refit was delayed eight
hours by SJ radar work. Wiped and measured 20 January
1943; sound test not conducted; no training period
allotted; no torpedoes fired for training; ready for sea
21 January 1943. This unit will conduct unrestricted
warfare against enemy shipping.

1. NARRATIVE. (All times given in this
minus eleven time).

21 January 1655 Underway. 2055 dropped the pilot; met HMAS
RAMUNGA; 2345 passed point VAN.
Noon position - alongside fulton.
Miles steamed - 92.5
Gals.fuel used- 940

22 January 0002 made trim dive and two night approaches. During
morning conducted sound exercises 5D and 6D with the DD.
Noon - made deep submergence test dive. P.M. - practice
approaches and training exercises with the DD. 1705
RAMUNGA departed. 1727 passed point CAT.
Noon position - 26-37.0 S 154-59.0 E
Miles steamed - 216.3
Gals.fuel used- 2435.

23 January Enroute area. Made test dive and deep submergence.
Battle surface and fired all caliber guns. Fired three
training rounds with 3" gun at night. 2330 passed point
SKY.
Noon position - 22-43.3 S 156-26.0 E
Miles steamed - 354.7
Gals.fuel used- 5105

24 January Continued enroute area.
Noon position - 17-37.4 S 157-15.0 E
Miles steamed - 369.1
Gals.fuel used- 5745

25 January Continued enroute area. 2145 passed point BLUE.
2340 entered area "B"(s).
Noon position - 12-32.5 S 157-37.0 E.
Miles steamed - 333.7
Gals.fuel used- 5480

[STAMP: 47615 FILMED]
DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: OP-09B9C] DATE [HANDWRITTEN: 5/26/72]
1

— page 81 —
CONFIDENTIAL
Subject: U.S.S. GROUPER - Report of Fourth War Patrol.

7. DETAILS OF TORPEDO ATTACKS.

| Attack | 1 (a) | 1 (b) |
|---|---|---|
| Date | 28 Jan. | 28 Jan. |
| Location | 7-37 S. | 7-37 S. |
| | 156-47 E. | 156-47 E. |
| Torpedoes Fired | 3 | 1 |
| Hits | 0 | 0 |
| Type Target | HAKODATE MARU (5300T) | HAKODATE MARU (5300T) |
| Range | 1100 | 1100 |
| Periscope Depth | Yes | Yes |
| Estimated draft (target) | 20 | 20 |
| Torpedo Depth Setting | 6' | 6' |
| Stern Shot | Yes | Yes |
| Track Angle | 130 | 0 |
| Gyro Angle | 180 | 180 |
| Estimated Speed (target) | 12 | 12 |
| Firing interval | 8 sec. | -- |
| Spread | 3-0-3 | -- |

8. ENEMY A/S MEASURES.

Depth Charge Attack #1
During approach of 28 January, escort (patrol boat #44)
echo ranged constantly. It patrolled about 1000 yards on the bow of
the leading ship, usually taking the side toward which the next zig
would be made. We fired on the second and last ship of the convoy.
Went deep after firing the fourth torpedo down its throat from a
stern tube. The first of a series of 11 depth charges was dropped
about five minutes later. The rest followed singly over a period of
one hour. Echo ranging was not used during this period. We prac-
ticed normal evasive tactics changing course frequently. Sound con-
ditions were fair to good. None of the charges were "very close".

Depth Charge Attack #2
During approach of 31 January, the escort (DD) echo
ranged constantly. It patrolled at least 3000 yards ahead of the
single AK it was escorting. What appeared to be a small boat was be-
tween DD and AK. We were about 7000 yards from the track when closely
bombed by a plane. The DD just prior to the bombing had turned to-
ward us as if cognizant of our presence, probably dope from the plane.
We went deep and depth charging began in about 10 minutes. A combina-
tion of echo ranging and listening was used on the attacks. A total of
18 charges were dropped in the next hour. None of the charges were
"very close". We practiced normal evasive tactics, changing course
frequently.

16
[HANDWRITTEN: /6]

— page 83 —
FC5-8/A16-3
Serial 023
CONFIDENTIAL
1st ENDORSEMENT to
CO GROUPER 4th War
Patrol Report

From: The Commander Submarine Squadron EIGHT.
To : The Commander Task Force SEVENTY-TWO.
Subject: U.S.S. GROUPER (SS214), Fourth War Patrol;
comment on.

1. The GROUPER spent fifty-six days at sea during
her fourth war patrol, of which forty-six days were in com-
batant zones. The patrol was terminated on orders from the
Task Force Commander.

2. An excellent example of the price of delaying
action is illustrated by the outcome of the twenty-four
destroyer contact made on February 4, 1943. The GROUPER al-
lowed twenty destroyers to pass at firing range in order to
select a target in the rear guard of four destroyers. When
almost at the firing point an allied bombing attack was
launched which resulted in the targets making a radical
change of course and evading the attack altogether. All
chance of damage to the enemy was missed.

3. The material condition of the GROUPER in general
was excellent. Radar failures were encountered which might
have been repaired had personnel persisted in their efforts.
It must be realized that both the SJ and SD radars are newly
developed mechanisms and have not as yet progressed in design
to a state of ruggedness comparable with most of our machin-
ery aboard ship. Both, therefore, require constant care for
proper operation. Every instrument which gives an advantage
over the enemy must be utilized to the utmost. Some sub-
marines have by constant upkeep maintained these instruments
in an excellent operating condition throughout their patrol.

Pk
c/o Fleet Post Office,
San Francisco, Calif.
March 21, 1943.

[SIGNATURE: W.M. Downes]
W.M. DOWNES.

— page 84 —
TF72/A16-3/Pk
Serial 0122
C-O-N-F-I-D-E-N-T-I-A-L

2nd ENDORSEMENT to
CO GROUPER 4th War
Patrol Report

From: The Commander Task Force SEVENTY-TWO.
To : The Commander in Chief, UNITED STATES FLEET.
Via : The Commander, SOUTH PACIFIC FORCE.

Subject: U.S.S. GROUPER (SS214), Fourth War Patrol;
comments on.

1. GROUPER's Fourth War Patrol covered a period of
fifty-six days. She left Brisbane on January 21, 1943, and
arrived in her initially assigned patrol area east of VELLA
LAVELLA ISLAND on the 27th. In the afternoon of the 28th
she attacked the rear ship of a two-freighter escorted con-
voy bound for VELLA GULF from SHORTLANDS, firing three tor-
pedoes at a range of 1100 yards with a favorable track
angle. This initial spread missed, probably because of
over-estimate of target's speed. A fourth torpedo, fired
after the target turned to ram, also missed. On the after-
noon of February 1st, she sighted a group of six destroyers
but was unable to close to attack position. On the 4th, in
the early afternoon, she found herself in ideal position in
the middle of a formation of twenty-four destroyers. She
was about to attack the last destroyer of the formation just
at the moment allied aircraft happened to commence bombing
the formation. Her target turned away and GROUPER did not
fire. She then chased a destroyer which had been damaged
and slowed by the air attack but saw it taken in tow by
another destroyer before she closed it. On February 10th,
she rescued an army aviator from RENG! ISLAND. On the 12th
she proceeded north of NEW IRELAND and MANUS to her new
station off MEWAK where she arrived on the 20th. She
developed no attack opportunities enroute nor during thir-
teen days on her new station although two convoys were
sighted off MEWAK. She moved to MADANG March 5th and after
six more uneventful days started her return to Brisbane via
VITIAZ STRAIT on the 11th, arriving the 18th. Four tor-
pedoes fired. No hits.

2. (a) The attack on the two ship convoy headed
for VELLA GULF on 28 January from favorable position should
have resulted in destruction of one of the targets. Fail-

- 1 -
TASK FORCE SEVENTY-TWO,
Care of Fleet Post Office,
San Francisco, California.

March 22, 1943.

— page 86 —
[HANDWRITTEN: 346]
TF72/A16-3/Pk
Serial 0122
C-O-N-F-I-D-E-N-T-I-A-L
Subject: U.S.S. GROUPER (SS214), Fourth War Patrol;
           comments on.

TASK FORCE SEVENTY-TWO,
Care of Fleet Post Office,
San Francisco, California.
March 22, 1943.

and slowed by a bomb hit but taken in tow during GROUPER's
approach.

     3. The rescue on February 10, 1943, of First Lieut-
enant Lawrence R. McKulla, U.S. Army Air Corps, who had been
stranded for several days on RENG I ISLAND, was accomplished
with commendable skill and efficiency.

     4. GROUPER obtained valuable information with re-
gard to enemy shore radar installations. By means of her
detector equipment she found installations at the following
locations:

          RABAUL (One fixed, two rotating),
          WEWAK (One fixed, one rotating),
          GATUKAI (One rotating),
          FAISI (One fixed),
          BUKA (One fixed),
          AITAPE (One fixed),
          BOGIA (One fixed),
          MADANG (One fixed),
          CAPE CRETIN (One fixed) (existence doubtful).

     GROUPER also noted one ship-borne radar north of
KAVIENG on February 18.

     5. No damage was inflicted on the enemy by GROUPER
during this patrol.

[SIGNATURE: James Fife]
JAMES FIFE.

DISTRIBUTION:
Cominch (Advance copy),           ComsubsoWespac,
VCNO,                             CSS 6 & 8,
Cincant,                          CSD 81 & 82,
Cincpac,                          All SS TF 72 (Not to be taken
Comsowespac,                      to sea - BRN)
Comsublant,                       CTF-72 War Diaries and Patrol
Comsubpac,                        Summary File.
OinC S/M School, NL Conn.(2)      CTF-72 Boat File.
CO GROUPER (File),

— page 87 —
[HANDWRITTEN: Reg. No. 5057]
[HANDWRITTEN: R.S. No. 4-01048]

COMSOPAC FILE
A16-3/(11)
Serial 0579

SOUTH PACIFIC FORCE
OF THE UNITED STATES PACIFIC FLEET ab
HEADQUARTERS OF THE COMMANDER
APR
6 1943

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

3rd Endorsement on
C.O. U.S.S. GROUPER
Conf. Report of 4th
War Patrol, Period
21 Jan. to 18 March,
1943.

From: The Commander South Pacific Area and South
Pacific Force.
To : The Commander-in-Chief, United States Fleet.

Subject: U.S.S. GROUPER (SS214), Fourth War Patrol;
comments on.

1. Forwarded. GROUPER's collection of informa-
tion concerning enemy shore radar installations and rescue
of the stranded U.S. Army aviator were commendable but the
patrol was otherwise disappointing.

2. The comments in the forwarding endorsements
contain much which can be read with benefit by submarine
officers who have not had these experiences.

[SIGNATURE: W. F. Halsey]
W. F. HALSEY

Copy to:
VCNO
Cincpac
Cinclant
Comsowespac
Comsubpac
Comsublant
Comsubsowespac
CTF 72
Comsubron 8
Comsubdiv 81
CO USS GROUPER
[HANDWRITTEN: 47615]
[STAMP: FILMED]

[STAMP: COMMANDER IN CHIEF
U. S. FLEET
RECEIVED
1943 APR 16
11
16]

— page 88 —
[HANDWRITTEN: 1ST COPY]
6 01747

[STAMP: DECLASSIFIED]
CONFIDENTIAL

U.S.S. GROUTER
REPORT OF FIFTH WAR PATROL

FROM: April 12, 1943 TO: May 29, 1943.

NOT TO BE TAKEN TO SEA BY SUBMARINES - BURN

DECLASSIFIED ART. 0445, OPNAVINST 5510.1C
BY OP-09B9C DATE [HANDWRITTEN: 5/26/72]
DECLASSIFIED

[HANDWRITTEN: 50834]
[STAMP: FILMED]

— page 90 —
CONFIDENTIAL
Subject: U.S.S. GROUPER - Report of Fifth War Patrol.
Period: From April 12, 1943 to May 20, 1943.

Grouper arrived Brisbane from fourth war patrol
on March 18, 1943, and underwent a regular two
week refit followed by a one week readiness for
sea period and three day training period. In-
structions for current patrol were to conduct un-
restricted warfare against the enemy in the
Bismarck-Solomons-New Guinea area in operating
areas to be assigned by despatch at a later date.

NARRATIVE. (All times KING).

April 12
1108 Departed Brisbane.
1735 Passed point VAN and commenced scheduled training
exercises with escort.

April 13
Continued training exercises with escort during
forenoon and afternoon.
1200 Made test dive to deep submergence.
1650 Passed company with escort. Sighted freighter on
Easterly course.
2100 Sighted large empty tanker on Southerly course.

April 14 Held drills and training dives forenoon and after-
noon.

April 15 Held drills and training dives. Received in-
structions for rendezvous with TUNA off ADELE IS.

April 16 Commenced submerged daylight running.
2015 Sighted aircraft flare South of OSSEL ISLAND
followed by another North of it.
2030 Sighted TUNA bearing 280°T, distance 4 miles.
2100 Transferred McCabe, F. J., SC3c, #253 82 75, USN,
to TUNA FFT CSD-81 for duty and medical treatment.
Due to sea conditions, small amount of fuel avail-
able in TUNA and evidence of air and radar acti-
vity decided against fueling.

April 18 Received despatch assigning GROUPER area West of
145 E and South of 1-00 N with routing instructions.

April 19 Passed between GREEN and BUKA ISLANDS during the
night.

April 20 Commenced continuous periscope patrol during sub-
merged running.

April 27 Patroling 30-60 miles West of NUVULU ISLAND wait-
ing for weather to clear before proceeding to NEWAK.

[HANDWRITTEN: 50834]
1

— page 98 —
CONFIDENTIAL
Subject: U.S.S. GROUPER - Report of Fifth War Patrol.

NOON POSITION | MILES STEAMED | GALLONS FUEL USED
April 12 | 27-24 S 153-09 E | 128.9 | 1230
April 13 | 25-14 S 155-04 E | 227.9 | 2625
April 14 | 21-20 S 154-49 E | 302.3 | 3350
April 15 | 16-24 S 155-12 E | 307.9 | 4060
April 16 | 11-47 S 154-54 E | 203.6 | 2800
April 17 | 9-21 S 154-25 E | 197.7 | 1960
April 18 | 6-23 S 154-10 E | 217.3 | 2495
April 19 | 3-20 S 154-03 E | 205.4 | 2170
April 20 | 0-46 S 153-07 E | 187.3 | 1760
April 21 | 1-09 N 152-00 E | 165.0 | 1145
April 22 | 1-23 N 150-20 E | 147.8 | 745
April 23 | 1-34 N 148-27 E | 151.7 | 955
April 24 | 1-10 N 146-10 E | 155.0 | 975
April 25 | 0-46 N 143-58 E | 140.7 | 930
April 26 | 0-11 S 142-31 E | 131.6 | 755
April 27 | 1-46 S 142-32 E | 122.8 | 730
April 28 | 2-03 S 142-33.5 E | 134.7 | 630
April 29 | 2-59 S 143-39 E | 119.4 | 700
April 30 | 2-06 S 142-51 E | 120.3 | 810
May 1 | 0-10 S 143-01 E | 126.6 | 730
May 2 | 0-41 N 143-08 E | 154.6 | 1435
May 3 | 0-45 N 140-29 E | 153.1 | 1265
May 4 | 0-42 N 140-10 E | 132.7 | 700
May 5 | 0-38 N 139-37 E | 143.4 | 715
May 6 | 0-36 N 142-04 E | 147.5 | 675
May 7 | 0-21 N 143-56 E | 115.5 | 685
May 8 | 0-21 N 144-00 E | 112.8 | 680
May 9 | 0-34 S 142-46 E | 116.6 | 680
May 10 | 1-50 S 141-20 E | 103.6 | 680
May 11 | 2-20 S 142-22 E | 114.8 | 695
May 12 | 3-05.5 S 143-26 E | 115.0 | 375
May 13 | 2-19.5 S 143-52 E | 102.3 | 1510
May 14 | 1-12 N 144-34 E | 154.6 | 2025
May 15 | 1-13 S 144-51.5 E | 117.8 | 730
May 16 | 2-32 S 143-40 E | 107.4 | 585
May 17 | 2-17.5 S 143-11.5 E | 100.4 | 605
May 18 | 2-32 S 142-59 E | 102.1 | 570
May 19 | 2-32 S 144-26 E | 114.1 | 745
May 20 | 2-22 S 143-43 E | 133.6 | 1310
May 21 | 3-20 S 145-38 E | 173.6 | 2405
May 22 | 5-25 S 147-23 E | 167.6 | 2385
May 23 | 7-00.5 S 149-22 E | 130.6 | 2070
May 24 | 8-15 S 152-48 E | 187.3 | 3470
May 25 | 9-47 S 155-29 E | 178.7 | 2615
May 26 | 13-20S 156-10 E | 197.0 | 3245
May 27 | 17-46 S 155-30 E | 302.1 | 6805
May 28 | 23-32 S 154-40 E | 319.9 | 7390
May 29 | 27-15 S 153-15 E | 167.1 | 3385

APPENDIX (A)

— page 99 —
FC5-8/A16-3
Serial 062
CONFIDENTIAL
FIRST ENDORSEMENT to
CO GROOPER Report of
Fifth War Patrol.

SUBMARINE SQUADRON EIGHT
Fleet Post Office
San Francisco, California
May 31, 1943

From: Commander Submarine Squadron EIGHT.
To: Commander Task Force SEVENTY-TWO.
Subject: U.S.S. GROOPER (SS214), Fifth War Patrol;
Comments on.

1. GROOPER'S fifth war patrol was of forty-seven
days duration, of which twenty-four were spent on station.
This patrol was characterized by very few contacts and no
attacks. Of the two possible attack opportunities on tor-
pedo targets, the first, on a southbound convoy on the night
of May 12, failed when GROOPER was detected by the escorts
at long range and forced to employ evasive tactics, while
the convoy turned away. It is possible, if not probable,
that GROOPER was detected at 1925, while still on the sur-
face, as indicated by the first radical change of course by
the convoy. The second attack opportunity occurred later
during the same night, when a destroyer, probably one of
the escorts of the convoy sighted earlier, approached at
high speed. Poor depth control prevented observation for
a critical period of four minutes after GROOPER dived.
When the target was next observed it was in too unfavorable
a position to attack, and passed very close ahead. GROOPER'S
commanding officer conducted these approaches in an aggress-
ive manner and it is unfortunate they did not culminate into
attacks.

2. The inadvertent submergence during the night
of May 12, illustrates the necessity for the highest degree
of alertness at diving stations when running awash or
flooded down.

3. While it is possible that Japanese escorts
encountered during this patrol were equipped with radar,
such is not conclusive as GROOPER may have been detected
in each instance by visual sighting.

4. The material condition of the GROOPER is
very good, considering the period that has elapsed since
her commissioning. FULTON will accomplish the regular
refit during which the bridge structure will be altered
and an additional 20 MM gun installed forward.

— page 100 —
FC5-8/A16-3
Serial 062
CONFIDENTIAL                                          June 3, 1943

Subject:      U.S.S. GROUPEK (SS214), Fifth Patrol report,
              Comments on.

— page 101 —
FF12-15(72)/A16-3/Pk
Serial 0201
CONFIDENTIAL
2nd ENDORSEMENT to
CO GROUPER Fifth
War Patrol Report

From: The Commander Task Force SEVENTY-TWO.
To : The Commander in Chief, UNITED STATES FLEET.
Via : The Commander, SEVENTH FLEET.

Subject: U.S.S. GROUPER (SS214); Report of Fifth War
Patrol - comments on.

1. GROUPER left Brisbane 12 April on her fifth
war patrol. On the night of the 16th she transferred an
enlisted man at sea to a submarine returning from patrol.
Immediate medical treatment was necessary. April 27th
found the GROUPER patrolling West of WUVULU Island. April
29 she was operating just north of Wewak in generally poor
visibility. May 1st she commenced patrolling the Wewak -
Rabaul - Pelew convoy routes. On the morning of 3 May an
approach on a target was terminated when GROUPER identified
it as a subchaser. Lack of targets caused her to move
south on 10 May to cover area just north of IRINU. GROUP-
ER submerged and evaded a patrol boat sighted at close range
on May 11th. Early on the night of the 12th she sighted a
convoy of four large and three small ships. She gained
position on the surface and then submerged for a radar per-
iscope approach but was immediately detected at long range.
Escorts closed and forced GROUPER to pursue evasive tac-
tics. She later surfaced and unsuccessfully attempted to
regain contact. A destroyer was sighted the same night.
GROUPER submerged for a periscope approach but enemy detec-
tion came in fast, dropped three depth charges and then
headed away at high speed. Destroyer made high speed at-
tacks from sectors of low visibility outside sight and
sound range each time sub surfaced. GROUPER finally stay-
ed submerged and found nothing in sight at daybreak. She
sighted a subchaser May 18th. On May 20th GROUPER was
ordered to proceed to base via VITIAZ Strait and arrived
Brisbane 29 May after forty-seven days on patrol. No tor-
pedoes expended.

2. The GROUPER had but one contact with an enemy
convoy. The attack appears well conceived. Unfortunately
the escort group, by sight or radar, detected at long range
and forced GROUPER to assume the defensive. Subsequently
she pursued the convoy on the surface but failed further
contact.

- 1 -
TASK FORCE SEVENTY-TWO,
Care of Fleet Post Office,
San Francisco, California,

May 31, 1943.

— page 103 —
A16-3
Serial 01045
CONFIDENTIAL
CONFIDENTIAL

THIRD ENDORSEMENT to
CO GROUPER Report of
Fifth War Patrol.

From:
To :

Subject:

1. UNITED STATES FLEET
COMMANDER SEVENTH FLEET

[STAMP: Reg. No. [HANDWRITTEN: 4279]
L.L. No. [HANDWRITTEN: 6 01747]]

8 JUN 1943

The Commander, SEVENTH FLEET.
The Commander in Chief, UNITED STATES FLEET.

U.S.S. GROUPER (SS214); Report of Fifth War
Patrol - Report on.

Forwarded.

[SIGNATURE: J. Cary Jones]
J. CARY JONES,
Chief of Staff.

Copy to:
Vice OPNAV (with copy of report)

[STAMP: COMMANDER IN CHIEF
U.S. FLEET
RECEIVED
JUN 25 17 45
[UNCLEAR: 1943]]

— page 104 —
SS214/A16-3                               U.S.S. GROUPER (SS214)
Serial 012                                                               ss
[STAMP: DECLASSIFIED]
From:                                        Care of Fleet Post Office,
To :                                         San Francisco, California.
Via :                                        August 3, 1943.

Subject:                                     The Commanding Officer.
                                             Commander in Chief, United States Fleet.
                                             Commander Task Force, SEVENTY-TWO.

                                             U.S.S. GROUPER, Report of War Patrol
                                             number six.

Enclosure:                                   (A) Subject Report.

1.                                           Enclosure (A), covering the sixth war patrol
of this vessel conducted in the New Guinea - Bismarck -
Solomon area during the period of 19 June to 3 August, 1943.

                                             [SIGNATURE: H. P. HOTTEL.]
                                             H. P. HOTTEL.

[HANDWRITTEN: 1ST COPY]

[STAMP: DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C]
BY [HANDWRITTEN: OP-09B2C] DATE [HANDWRITTEN: 5/26/72]
[STAMP: DECLASSIFIED]

54237 [STAMP: FILMED]

— page 118 —
(F) SHIP CONTACTS:
NO. DATE TIME | LAT LONG | TYPE | INITIAL RANGE | EST CSE SPEED | HOW CONTACTED | REMARKS
||------||||
1. June 25 2300 | 7-10S 154-08E | Not seen | 7000 yds 270°T | * 180° 15 kts | SJ Night | Believed to be own SS returning Brisbane
2. July 10 0600 | 01-30N 151-00E | Armed Trawler | 10000 yds 090°T | Lying to | Periscope all day | No change in position
3. July 13 0824 | 00-02S 145-00E | 3 ASAKA MARU 1 OLYMPIA MARU 1 Armed Trawler 1 Subchaser | 12-13 mi 280°T | 125° 10 kts | Surface Day | Convoy appeared 15 mi southwest of estimated track.
4. July 15 1919 | 00-56N 150-52E | 1 KAIKAWA MARU 1 NISSIYO MARU 1 DD | 16000 yds 026°T | 191° 17 kts | Surface night | Radical zig-zagging
5. July 19 0943 | 00-35N 149-26E | 1 ATATU MARU 2 KAMOGAWA MARU 2 TB | 18000 yds 012°T | 200° 14 kts | Periscope day | Apparently hit in stern but gained con- trol of damage.
6. July 28 0850 | 06-02S 153-57E | 3 ASAGIRI class DD | 9000 yds 225°T | 23 kts | Sound | Unable to close range.

(13)

SHIP | SPEED | R.P.M.
-----|-------|-------
* DD | 23 | 200
ASAKA | 10 | 75
KAIKAWA | 17 | 190
NISSIYO | 17 | 95
DD | 14 | 100
TB | 14 | 137
ASAGIRI | 23 | 170
KAMOGAWA | 17 | 260

— page 119 —
(G) AIRCRAFT CONTACTS
NO. DATE | TIME | LAT | LONG | TYPE | INITIAL RANGE | EST CSE SPEED | HOW CONTACTED | REMARKS
1. June 24 | 1415 | 10-01S | 157-04E | 2 engine bomber | 5-6 mi. | Southerly 150 kts | Periscope Day | SD RADAR contact simultaneously
2. June 27 | 1319 | 02-45S | 150-28E | Unident-ified | 8 mi | Southerly 150 kts | Periscope Day | Observed through Periscope
3. July 2 | 0932 | 04-03N | 153-22E | Small Float Plane | 8 mi | Westerly 120 kts | Sight Day | Observed through Periscope
4. July 3 | 1345 | 03-55N | 153-17E | Large Float Plane | 6-8 mi. | Northerly 150 kts | Sight Day |
5. July 4 | 1143 | 04-00N | 152-25E | 1 Large 10-12 small | 8-10 mi | Southerly 150 kts | Sight Day |
6. July 5 | 0954 | 02-58N | 152-45E | 1 "NELL" 4 "ZEKES" | 8 mi | Southerly 150 kts | SD Radar Day |
7. July 7 | 1044 | 01-29N | 152-10E | Not seen | 8 mi | SD Radar Day | SD Radar Day |
8. July 7 | 1238 | 01-28N | 152-09E | Not seen | 8 mi | SD Radar Day | SD Radar Day |
9. July 9 | 1042 | 00-24N | 151-48E | 1 "NELL" | 8 mi | Southerly 150 kts | SD Radar Day |
10. July 9 | 1114 | 00-24N | 151-49E | 1 "MAVIS" | 8 mi | Southerly 150 kts | SD Radar Day |
11. July 14 | 1242 | 01-45S | 148-29E | 2 engine bomber | 6 mi | A/S patrol 150 kts | Sight Day |
7

— page 120 —
(G) AIRCRAFT CONTACTS (CONT'D)
NO. DATE TIME LAT LONG TYPE INITIAL EST CSE HOW REMARKS
                                        RANGE SPEED CONTACTED
12. July 13 1313 to 01-44S 148-29E 2 land Various A/S Screen Periscope Ranging ahead and
          1603                      2 float         for convoy         on both beams of
                                                                         convoy
13. July 15 0913 00-20S 150-01E Unident- 12 mi Southerly Sight
                                        ified         150 kts    Day
14. July 15 1245 00-20S 150-43E Small 10 mi Southerly Sight SD Radar at 12 mi.
                                        land          200 kts    Day
(14a)
15. July 18 1045 00-34N 151-50E 2 "LAVIS" 15 mi Southerly Sight
                                                      150 kts    Day
16. July 19 0749 00-34N 149-20E 1 "DAVE" 5 mi Northerly Sight On way to screen
                                                      150 kts    Day        convoy.
17. July 30 0620 00-56S 156-42E 1 "B-25" 3.5 mi 180° Sight Two very close
                                                      200 kts    Day        depth bombs.

— page 125 —
CONFIDENTIAL
TORPEDO ATTACK NO.1

FIRE CONTROL AND
TORPEDO DATA
TUBES FIRED | No.1 | No.2 | No.3 | No.4 | No.5 | No.6
TRACK ANGLE | 96°S | 98°R | 95°S | 68°S | 71°S | 67°S
GYRO ANGLE | 12°R | 14°R | 12°R | 16°L | 11°L | 15°L
DEPTH SET | 18ft | 18ft | 18ft | 18ft | 18ft | 18ft
POWER | HIGH | HIGH | HIGH | HIGH | HIGH | HIGH
HIT OR MISS | MISS | MISS | MISS | MISS | MISS | MISS
ERRATIC | YES | NO | NO | NO | NO | NO
MARK TORPEDO | 14-1-A | 14-3-A | 14-3-A | 14-1-A | 14-3-A | 14-3-A
SERIAL NO. | 19291 | 20249 | 20192 | 19175 | 41863 | 42060
MARK EXPLODER | 6 | 6 | 6 | 6 | 6 | 6
SERIAL NO. | 2514 | 3877 | 10526 | 3879 | 4400 | 14806
ACTUATION SET | MAGNETIC | MAGNETIC | MAGNETIC | MAGNETIC | MAGNETIC | MAGNETIC
ACTUATION ACTUAL | EXPLODED | - | - | - | - | -
MARK WARHEAD | 16 | 16 | 16 | 16 | 16 | 16
SERIAL NO. | 784 | 4516 | 5693 | 5639 | 5600 | 5694
EXPLOSIVE | - | - | -TORPEX- | - | - | -
FIRING INTERVAL | - | 16s | 11s | 0° | 16s | 10s
TYPE SPREAD | 0° | 2°R | 2°L | - | 2°R | 2°L
SEA CONDITIONS | - | - | -SMOOTH- | - | - | -
OVERHAUL ACTIVITY | - | - | -U.S.S. FULTON | - | - | -
REMARKS | - | - | -SEE PAGES 17 - 18 | - | - | -

(19)

— page 127 —
CONFIDENTIAL
FIRE CONTROL AND TORPEDO DATA

                                TORPEDO ATTACK NO. 2.

                                No.1       No.2       No.3       No.4
TUBES FIRED
TRACK ANGLE                     83°Stbd    85°Stbd    91°Stbd    89°Stbd
GYRO ANGLE                      45°L       43°L       37°L       40°L
DEPTH SET                       20ft       20ft       20ft       20ft
POWER                           HIGH       HIGH       HIGH       HIGH
HIT OR MISS                     MISS       MISS       MISS       MISS
ERRATIC                         NO         NO         NO         NO
MARK TORPEDO                    14-3-A     14-3-A     14-3-A     14-3-A
SERIAL NO.                      20072      41856      20062      41687
MARK EXPLODER                   6          6          6          6
SERIAL NO.                      14858      10758      14707      9753
ACTUATION SET                   MAGNETIC   MAGNETIC   MAGNETIC   MAGNETIC
ACTUATION ACTUAL                EXPLODED   AT-        -END       -OF RUN
MARK WARHEAD                    16         16         16         16
SERIAL NO.                      5597       4003       4412       4850
EXPLOSIVE                       T.N.T.     T.N.T.     T.N.T.     T.N.T.
FIRING INTERVAL                 -          8s         12s        6s
TYPE SPREAD                     1°R        1°L        3°R        3°L
SEA CONDITIONS                  -          -          -          -
OVERHAUL ACTIVITY               -          -          -          -
REMARKS                         -          -          -          -

(21)

— page 128 —
FC5-8/A16-3
Serial 0107

CONFIDENTIAL

FIRST ENDORSEMENT to
CO GROUPER Report of
Sixth War Patrol.

From:
To :
Subject:

1.
forty-six days, twenty seven-days of which were spent in the combat zone.

2.
GROUPER was, in general, excellent. Minor damage had been received due to
depth charging.

3.
ed by the FULTON. It is contemplated to give additional time to training at
the end of the refit period. SUBMARINE SQUADRON EIGHT
Fleet Post Office
San Francisco, California
3 August 1943

Commander Submarine Squadron EIGHT.
Commander Task Force SEVENTY-TWO.

U.S.S. GROUPER (SS214) Sixth War Patrol;
Comments on.

The GROUPER'S sixth war patrol covered a period of

Upon return from patrol, the material condition of the

The ship will be given a regular standard refit, conduct-

W. M. DOWNES.

— page 129 —
[HANDWRITTEN: 9] 0693
FF12-15(72)/A16-3/Pk
TASK FORCE SEVENTY-TWO,
Care of Fleet Post Office,
Serial 0257 San Francisco, California,

CONFIDENTIAL 7 August 1943.

2nd ENDORSEMENT to
CO GROUFER Report
of Sixth War Patrol

From: The Commander Task Force SEVENTY-TWO.
To : The Commander in Chief, UNITED STATES FLEET.
Via : (1) The Commander, THIRD FLEET.

Subject: U.S.S. GROUFER (SS214) - Sixth War Patrol;
comments on.

1. GROUFER left Brisbane 19 June 1943, on her Sixth
War Patrol. The evening of 25 June she made radar contact
with an unidentified ship Latitude 7°-10' S., Longitude 154°-
08' E., but sight contact was not made. An armed trawler was
sighted morning 10 July in Latitude 1°-30' N., Longitude
151° E. The morning of 13 July she sighted a convoy of four
freighters and two escorts on southeasterly course near the
Equator and Longitude 145° E. Her first attack on the convoy
was repulsed when she was detected and depth charged by an
escort, but she later surfaced and gained position ahead for
night submerged attack, firing three torpedoes at each of the
two leading ships, all of which missed. One of these torpedoes
made a circular run and exploded over GROUFER, causing no
damage. GROUFER again took position ahead for attack, but was
forced to dive by enemy plane, and the convoy zigged away pass-
ing out of range. She sighted a seaplane tender and tanker
early evening 15 July in Latitude 0°-56' N., Longitude 150°-52'
E., heading south under escort. The following morning she
made a submerged attack on the seaplane tender and fired four
torpedoes, all of which missed. The morning of 19 July she
was forced to dive by an enemy plane which dropped two depth
charges, causing no damage. Two hours later a southbound
convoy of two freighters and two escorts was sighted Latitude
0°-35' N., Longitude 149°-26' E. While making approach
GROUFER heard ALBACORE'S torpedoes hit and watcher her being
depth charged. The convoy divided, one ship damaged. GROUFER
continued her approach but was detected by escorts and depth
charged, receiving minor damage, and was unable to attack or
to make any further contact with convoy. She departed area
for Brisbane on 26 July. On the morning of 28 July she sight-
ed three northbound destroyers, which she was unable to close,
in Latitude 6°-02' S., Longitude 153°-57' E. She arrived
Brisbane 3 August after forty-five days on patrol.

- 1 -

— page 130 —
FF12-15(72)/A16-3/Pk
Serial 0257
CONFIDENTIAL
Subject: U.S.S. GROUFER (SS214) - Sixth War Patrol;
  comments on.

TASK FORCE SEVENTY-TWO,
Care of Fleet Post Office 0693
San Francisco, California,

7 August 1943.

2. While enroute to Brisbane, GROUFER was attacked
by a friendly plane in the early morning of 30 July in vic-
inity Latitude 11° S., Longitude 156°-44' E. The plane was
first sighted coming out of rain squalls astern at low alti-
tude, distance about 3½ miles. GROUFER fired the proper
emergency identification flare and submerged, but received
two close depth charges from the plane. She was within
thirty miles of her predicted dawn position at the time of
the attack and all air commands concerned had been notified
of this predicted position. She received minor damage which
can be repaired locally and without delaying her readiness
for next patrol. Commander THIRD FLEET has taken corrective
measures to reduce possibilities of further incidents of
this nature.

3. This was GROUFER's third successive war patrol
wherein she inflicted no damage on the enemy. Her present
commanding officer has conducted her last two patrols in
thoroughly aggressive manner, and in this last patrol he
was especially energetic and persistent in searching and
chasing, and in obtaining favorable positions from which to
commence submerged approaches. The approaches, however,
though logically and vigorously pressed, in no case culmin-
ated in a successful attack. GROUFER was detected before
reaching satisfactory firing position, or the target zigged
out of range, or another submarine attacked and dispersed
the targets, so that on only two occasions were torpedoes
fired, and on each of these attacks all torpedoes missed.
Special training will be given GROUFER prior to next patrol.

4. Not considered "successful patrol" for award of
Submarine Combat Insignia.

[SIGNATURE: JAMES FIFE.]

DISTRIBUTION:
Cominch (Advance copy - 2)
VCNO
VOPNAV (Op-23c)
Com 1st Flt
Com 2nd Flt
Com 7th Flt (2)
Comsubs 1st Flt
Comsubs 7th Flt
OinC, S/M Sch., NL Conn (2)

CSS 6, 8
CSD 81, 82
CTF 72/War Patrol Summary and
  Boat Files
Flt Radio Unit, MELBOURNE
All SS TF-72 (Not to be taken
  to sea - BURN)
CO GROUFER (File).

— page 131 —
[STAMP: Reg. No. 13253]
[STAMP: R.S. No. 9 0693]

COMSOPAC FILE

A16-3/(11)
Serial 01505

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

SOUTH PACIFIC FORCE
OF THE UNITED STATES PACIFIC FLEET
HEADQUARTERS OF THE COMMANDER
[HANDWRITTEN: 9-0359]

ab

[HANDWRITTEN: 31 AUG 1943]

3rd Endorsement on
CO USS GROUPER Report
of sixth War Patrol.

From: The Commander South Pacific.
To : The Commander-in-Chief, United States Fleet.

Subject: U.S.S. GROUPER (SS 214), Report of Sixth
War Patrol - comments on.

1. Forwarded.

2. The bombing of the U.S.S. GROUPER on 30 July,
1943 is now known to have been a result of incorrect brief-
ing of pilots on effective submarine - air recogni-
tion signals. The Commander Aircraft, Solomons erroneously in-
terpreted the impending change in submarine emergency ident-
ification signals.

[SIGNATURE: W.F. Halsey]
W. F. Halsey.

[STAMP: COMMANDER IN CHIEF]
[STAMP: U.S. FLEET]
[STAMP: RECEIVED]
[STAMP: 1943 SEP 9 14 13]

Copy to: VCNO
Cincpac
Cinclant
Comsowespac
Comsubpac
Comsublant
Comsubsowespac
CTF 72
Comsubron 6
Comsubron 8
Comsubdiv 81
Comsubdiv 82
CO USS GROUPER

— page 132 —
[HANDWRITTEN: 1ST COPY]
SS

(U)
SS214/A16-3
Serial 014

U.S.S. GROUPER (SS214)
Care of Fleet Post Office,
San Francisco, California.,
October 11, 1943.

DECLASSIFIED IAL
From: Commanding Officer, U.S.S. GROUPER.
To : Commander in Chief, United States Fleet.
Via : (1) Commander Submarine Force, Pacific Fleet.

Subject: U.S.S. GROUPER. Report of War Patrol number
seven.

Enclosure: (A) Subject Report.
(B) Track Chart.
(C) Navigational - Time plots of attacks (3).
(D) Sketch map of special mission landing
area.

(1) Enclosure (A), covering the 7th war patrol
of this vessel conducted in the New Guinea-Bismarck-
Solomons-Truk area and passage to Pearl Harbor during the
period August 25 to October 11, 1943 and Enclosures (B),
(C), and (D) are forwarded herewith. Area assignments
within the above area and the special mission undertaken
were in accordance with despatch orders received from
time to time during the period.

[SIGNATURE: M. P. Hottel]
M. P. HOTTEL.

DECLASSIFIED ART 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: OP-09B] DATE [HANDWRITTEN: 5/26/72]

DECLASSIFIED

[HANDWRITTEN: 57657]

— page 133 —
SKETCH MAP OF SPECIAL MISSION LANDING AREA

[HANDWRITTEN: STREAM]

[HANDWRITTEN: 500]
[HANDWRITTEN: 400]
[HANDWRITTEN: 300]
[HANDWRITTEN: 200]
[HANDWRITTEN: 100]

[HANDWRITTEN: 300]
[HANDWRITTEN: 310]
[HANDWRITTEN: 320]
[HANDWRITTEN: 330]
[HANDWRITTEN: 340]
[HANDWRITTEN: 350]
[HANDWRITTEN: 360]
[HANDWRITTEN: 010]
[HANDWRITTEN: 020]
[HANDWRITTEN: 030]
[HANDWRITTEN: 040]
[HANDWRITTEN: 050]
[HANDWRITTEN: 060]
[HANDWRITTEN: 070]
[HANDWRITTEN: 080]
[HANDWRITTEN: 090]
[HANDWRITTEN: 100]
[HANDWRITTEN: 110]
[HANDWRITTEN: 120]
[HANDWRITTEN: 130]
[HANDWRITTEN: 140]
[HANDWRITTEN: 150]
[HANDWRITTEN: 160]
[HANDWRITTEN: 170]
[HANDWRITTEN: 180]
[HANDWRITTEN: 190]
[HANDWRITTEN: 200]
[HANDWRITTEN: 210]
[HANDWRITTEN: 220]
[HANDWRITTEN: 230]
[HANDWRITTEN: 240]
[HANDWRITTEN: 250]
[HANDWRITTEN: 260]
[HANDWRITTEN: 270]
[HANDWRITTEN: 280]
[HANDWRITTEN: 290]

[HANDWRITTEN: HEAVY WOODS]

[HANDWRITTEN: 305°T]
[HANDWRITTEN: 312°T]
[HANDWRITTEN: 321°T]

[HANDWRITTEN: 2000 YDS]
[HANDWRITTEN: 1000 YDS]
[HANDWRITTEN: 500]
[HANDWRITTEN: 0]

[HANDWRITTEN: 193°T]

Positions obtained by bearings on fire and
Radar Ranges and are approximate. Line Tangent
to Cape and next headland North limits safe
approach. Best position is on this line with
a fire bearing 312°T.
TME

— page 135 —
CONFIDENTIAL

U.S.S. GROUPER, Report of War Patrol number seven.

(A) PROLOGUE

Arrived Brisbane August 3, 1943 and underwent normal
two week's refit and one week's readiness for sea period
including two day dry docking. Departed Brisbane August
25, 1943 and conducted sound test and gun firing in Moreton
Bay. Took departure from Cape Moreton Light at 1818 August
25, 1943. Conducted training exercises with PC 476 until
1700 August 26, 1943. Set course according to routing in
CTF-72 Op Plan S53-43 at 16 kts.

(B) NARRATIVE (All times "King" except where noted).

29 August.
0539 Trim dive, remained submerged.
0916 Picked up pinging to westward.
0918 Sighted COUCAL bearing 313°T, distance 10 miles,
La. 11-30S, Lo. 152-20E. Held two practice appro-
aches.
1314 Passed through Jomard Entrance.
1448 Alongside COUCAL, fueling.
1700 Completed fueling, held one practice approach.
1802 Set course to clear Deboyne Islands.

30 August.
Commenced submerged running during daylight.

1 September.
Passed between Green Island and Cape Henpan with-
out incident during night.

2 September.
0912 Sighted B-24 on course 325°T, distance 12 miles,
La. 1-37S, Lo. 155-10E.
1226 Sighted B-24 on course 145°T, distance 10 miles,
La. 1-32S, Lo. 155-06E.

3 September.
1150 Sighted B-24 on course 325°T, distance 8 miles,
La. 021N, Lo. 153-33E.
2000 Set course for assigned area south-west of Truk.

6 September.
0605 Sighted Tol Island of Truk Group bearing 020°T,
distance 36 miles.

(1) ENCLOSURE (A)

— page 136 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(B) NARRATIVE (CONT'D)

6 September (Cont'd)
0940 Sighted one PETE bearing 135°T on course 045°T,
     distance 5 miles.
1915 Observed searchlights, apparently in vicinity of
     Torres Island or Piannu Pass.

10 September.
1628 During daily fire control drill sighted vessel
     bearing 242°T, distant 12000 yards, La. 5-05N,
     Lo. 143-55E., on easterly course and apparently
     unescorted. Commenced deliberate and unhurried
     approach. Identified target as Naval Auxilliary
     Motor vessel of KAMOGAWA MARU type with 4" or 5"
     guns mounted forward and aft, and painted war
     color. Target was zigzagging with moderate zigs
     on base course of about 075°T with alternate left
     and right zigs. Increased speed as necessary to
     keep true bearing constant. When range had de-
     creased to about 4000 yards target made two
     successive zigs to starboard for the first time.
     The second zig occurred too late to turn for bow
     shot so the stern tubes were set up. The range
     was greater than had been anticipated due to this
     second zig. Frequent and unhurried observations
     were made and plot and T.D.C. carefully compared
     and checked as were silhouette and masthead height.
     It was decided not to shoot on this attack but to
     surface and chase if the target failed to zig to-
     ward us. However at 1701 target zigged left giving
     us a 90° angle on bow for careful course check so
     four torpedoes were fired with a run of 3000 yards
     since sea conditions, track angle of 120°, and
     lack of escort gave fair promise of success.
     Just after the check bearing between shots No. 2 and
     No. 3 was taken, the splash of a bomb was observed
     close on the starboard quarter followed by the
     explosion. Since only one bomb was dropped, and
     since the float planes usually carry two, depth was
     increased to 125 feet upon completion of firing.
     Two minutes and twenty-two seconds after firing
     the last torpedo, a heavy solid explosion was heard
     which was definetly not a depth charge or bomb.

(2) ENCLOSURE (A)

— page 137 —
CONFIDENTIAL

U.S.S. GROUPER, Report of War Patrol number seven.
(B) NARRATIVE (Cont'd)

10 September (Cont'd)
     An eight degree spread had inadvertantly been
applied and it is believed that the target
maneuvered to avoid and was hit by the right hand
torpedo which normally would have passed well
astern.

1708-27 One torpedo exploded at end of run.
1730 Observed target at 8000 yards on northeasterly
     course. Guns were trained out and diesel ex-
     haust was very black. There had been no change
     in speed of propellers as long as sound contact
     could be maintained. There was no obvious indi-
     cation of damage. Went to 100 feet to open out
     and reload for surface chase since we were unable
     to locate plane.
1755 Observed masts in general direction of target.
1806 Identified ship as tanker of TOA MARU class
     bearing 014°T, 15000 yards, with destroyer escort.
     Considerable signaling by destroyer who was well
     back on target's quarter. Commenced approach.
     This was another deliberate and unhurried approach
     as escort, who was pinging when first observed,
     did not bother us until after firing and zig-zags
     of target were very moderate. At 3500 yards the
     angle on the bow was zero. Escort had apparently
     changed courses to about 090° and stopped, leaving
     us well clear. Target was silhouetted against the
     after glow in the west and accurate ranges could
     be obtained. Attempted echo ranging but without
     success due to casualty to sound gear. Waited to
     fire until check could be obtained on 90° angle on
     bow at which time range by stadimeter was 1600 yards
     using 60 feet for stack height and 1950 yards using
     length and telemeter. Used 1800 on T.D.C.
1845 Fired six torpedoes. Spread was again applied
     incorrectly but at least 3 hits should have re-
     sulted. Assuming fully loaded tanker torpedoes
     were set to run at 25 feet. A later rehash in-
     dicates that had the draft been 10 feet less the
     ranges would have coincided and it is believed
     that at least 3 torpedoes ran under the tanker
     without exploding.

(3) ENCLOSURE (A)

— page 138 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.---
(B) NARRATIVE (CONT'D)

10 September (Cont'd).
     As in the previous attack only one torpedo exploded
     at end of run, indicating failure of the magnetic
     element.
     Just prior to firing escort was observed on star
     board beam with sharp angle on bow about 2000 yards
     away making turns for 22 knots at which time he
     was lost in poor visibility in that area. Since
     he could not be located subsequent to firing, went
     deep.
1851 Two patterns of four or five depth charges each
     at short interval. Destroyer conducted stop and
     start search until about 1900 when he faded out on
     bearing 190°T.
1918 Periscope depth, unable to see. Reloaded.
2011 Distant explosions - apparently from the northeast
     in the direction of the first target.
2025 Surfaced and commenced chase of tanker on 190°T.

11 September.
1139 Sighted unidentified vessel on southerly course.
     La. 3-28N., Lo. 150-49E. Commenced approach.
1316 Identified ship as MANILA MARU, 9436 tons, hospital
     ship, on course 190°T, 14 kts. Discontinued chase
     and headed for area.

12 September.
2342 Underway for new area south of Equator between
     150° and 155°E.

14 September.
1214 Submerged on SD Radar contact, plane unobserved.
     La. 1-50N, Lo. 150-04E.

17 September.
0248 Submerged on sight contact of plane bearing 280°T,
     on easterly course, distance 5 miles, La. 0-37S,
     Lo. 151-26E.

18 September.
1041 Sighted 2 engine land plane bearing 358°T, distance
     8 miles, on southerly course, La. 1-02S, Lo. 152-21E.

(4) ENCLOSURE (A)

— page 139 —
CONFIDENTIAL
U.S.S. GROUPEER, Report of War Patrol number seven.
(B) NARRATIVE (CONT'D)

19 September.
0719 Sighted one MAVIS bearing 120°T, distance 6 miles,
     on north-westerly course. La. 0-24S, Lo.152-31E.
1141 Sighted unidentified plane bearing 010°T, distance
     10 miles, on easterly course. La. 00-24S, Lo.152-
     45E.

20 September.
1219 Sighted one ADAM on course 037°T, distance 5 miles
     La.0-02N, Lo. 150-26E.
1502 Sighted smoke bearing 017°T, and two float planes
     apparently well ahead of target. Came to collision
     course in order to delay attack until nearly sun-
     down when chances of detection by planes in glassy
     sea would be decreased. It was also hoped that
     planes would leave before we reached firing position.
     Held constant bearing until shortly before firing
     when we increased speed to cross ahead of target.
     Both planes passed overhead to southward.
1600 Commenced approach on "five ship convoy" consisting
     of 6000 ton AK with deck load of planes, one mine-
     layer of KANOME class and three subchasers for
     escort, and an additional plane screening close in.
     Target was on steady course of 190°T for at least
     two hours and the only difficult part of the ap-
     proach was avoiding the screens which were patrolling
     stations on each bow and quarter of the target.
     Held collision course until we were ahead of star-
     board bow screen. Ran up periscope and sighted
     float plane in direction of target about 50 feet off
     the water headed directly for the eyepiece. Ran
     down periscope and started to order increase in
     depth when the realization dawned that he was saying
     goodbye to his friends. Ran up periscope and watch-
     ed plane pass about 100 yards away headed south and
     climbing. Continued approach crossing ahead of
     target and cutting inside of the bow screen, intend-
     ing to turn 180° and fire bow tubes from 1000 yards.
     This proved impractical as port bow screen was
     about 300 yards away when turn should have been
     made, and it was thought that high speed necessary
     for turn would be detected, so crossed astern of
     screen and a 17-12-22 fired four torpedoes
     at range of 1800 yards

(5) ENCLOSURE (A)

— page 140 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(B) NARRATIVE (CONT'D)

20 September (Cont'd)
Upon completion of firing went deep as port quarter
escort was about 800 yards away and headed directly
for us.
1714 One minute and eight seconds after firing last torpedo,
heard one hit.
1717 Three torpedoes exploded at end of run. Escorts
started a deliberate and careful search.
1731 Escorts made first drop, on apparently false contact,
of an attack which lasted half an hour. Although
the escorts passed over us several times during
their attack none of the depth charges was anywhere
near us.
1915 Lost contact.
2007 Surfaced in extremely poor visibility.

24 September.
0849 Sighted unidentified plane bearing 005°T, distance
10 miles, on northwesterly course. La. 3-14S,
Lo. 155-29E.
1148 Sighted B-24 bearing 289°T on southeasterly course,
distance 8 miles, La. 3-15S, Lo. 155-24E.
1808 Surfaced and set courses to accomplish special
mission assigned by CTF-72. Passed between Cape
Henpan and Green Island without incident during
the night.

25 September.
0745 Sighted unidentified land plane bearing 100°T,
distance 10 miles, on southerly course, La. 4-59S,
Lo. 154-17E.
1230 Sighted small oiler of GOSEI MARU class accompanied
by two trawlers and one sub-chaser, bearing 048°T,
range 10000 yards. Commenced approach. Unable to
close range to firing position. Base course of
target 290°T, speed 10 knots. La. 5-09S, Lo. 154-10E.
1356 Resumed course and speed.

27 September.
0059 Sighted land bearing 256°T. Set course for dawn
position.
0427 Submerged.
1806 Surfaced and closed land to 1000 yards.

(6) ENCLOSURE (A)

— page 141 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven:--
(B) NARRATIVE (CONT'D)

27 September (Cont'd)
1825 U.S. Naval Liaison Officer and Australian Imperial
      Forces Major in command of party came aboard.
1835 Party of 17 whites and 29 natives came aboard from
      two artillery lighters with six seven-man rubber
      boats and 3000 pounds of freight and equipment.
1937 Embarkation completed and gear stowed. Rubber
      boats were too large for hatch and were secured
      in superstructure. Shelter space aft of conning
      tower is recommended as more accessible for this
      purpose. Lieutenant A. H. Mac Lean, A.I.F.,
      suffered strained back and rupture during embark-
      ation and was not landed with the rest of the party,
      but was transported to Pearl Harbor for return to
      Australia at the request of his C.O.
1938 Underway for designated landing point.

28 September.
0443 Submerged for the day and ran in towards land at
      2/3 speed.
      To be successful the landing had to be completed
      by midnight or shortly thereafter in order to allow
      for removal of traces and dispersal of party. The
      general lack of organization dispalyed during
      embarkation and the general uselessness of the
      natives aboard ship indicated that an expeditious
      landing must be handled by GROUPER personnel. It
      was discovered that only one of the landing party
      had ever been in a rubber boat and only twelve
      paddles had been furnished for the six boats
      (although outboard-motor rigs were provided, but
      no motors).
      Weather indications promised a rough embarkation
      and a hard pull to the beach against the expected
      land breeze. The pay-load per boat was calculated
      at 800 pounds in addition to two paddlers. All
      personnel and freight was divided accordingly, and
      that assigned to each trip was laid out and detail-
      ed before hand. Due to shortage of paddles, only
      four boats were used at first, until the supply
      was augmented by natives paddling when all six boats
      were utilized. When the land breeze failed to
      materialize and was replaced by several violent
      thunder squalls, the landing party agreed to send
      extra paddlers back with empty boats.

(7)                                                 ENCLOSURE (A)

— page 142 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(B) NARRATIVE (CONT'D)

28 September (Cont'd)
     This proved unnecessary as the shore party had
     collected native paddlers who assisted the
     GROUPER boat crews. Using four paddlers cut
     down the pay-load but speeded up the trips con-
     siderably and prevented boats from being blown
     too far off their course during the occasional
     violent puffs of wind. A ship's party was de-
     tailed to handle boats and freight, and all
     preparations were completed prior to arrival at
     the disembarkation point. One load was taken
     ashore by native canoe, but rough water made the
     use of this frail craft almost impossible along-
     side the submarine, and it was used thereafter
     only to return the native paddlers after their
     final trip.
1828 Surfaced, and shortly thereafter sighted a light
     between rain squalls dead ahead. Shifted rubber
     boats to shelter space so that they would be
     available when trimmed down. By this time the
     light was identified as a large fire, and from
     the distance (about 15 miles) at about the right
     altitude. Stood in directly for the light at
     16 knots instead of following the original plan
     of rounding the Cape close-to in order to find
     the bay. The CO of the party had brought an aerial
     photo of the locality but it had no scale and no
     record of altitude, and was of little use. None
     of our own charts gave any indication of the bay
     whatever, the best one merely showing a dotted-in
     coast line. The excellent navigation of Lt. Mason
     which hit this difficult land fall on the button
     under adverse weather conditions contributed more
     than any other factor to the successful accomplish-
     ment of this mission.
     When 2500 yards from the shore by radar, headed
     up and put the fire on the proper bearing and gave
     the pre-arranged signal which was promptly answered.
     Trimmed down as far as possible forward, manned the
     lead, and stood in slowly to 1000 yards from the
     shore, while the boats were being inflated and
     made ready.

(8) ENCLOSURE (A)

— page 143 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(B) NARRATIVE (CONT'D)

28 September (Cont'd)
2003 Sighted a plane which passed over us at a fairly
     low altitude, circled, and disappeared to north-
     ward.
2008 A member of the shore party came aboard in a native
     canoe to assist, and delivered confidential reports
     for transportation.
2010 First boat loaded and away. This boat capsized on
     landing due to one of the natives jumping out at
     the wrong time, but there were no casulties and
     no loss of gear. The other boats followed in fairly
     rapid succession. The four-foot waves made loading
     difficult and the gusty wind hindered paddling.
     We had approached as closely as possible, fixing
     on a position where the tangent of the Cape and the
     next headland to the north intersected the approach
     bearing on the fire. An on-shore set was encounter-
     ed which varied somewhat as we were blown about by
     the squalls. A fair swell was present which served
     to make the reefs prominent. Brilliant and almost
     continious lightning made the visibility excellent
     except during the occasional heavy downpours. Due
     to the set and variable winds, constant maneuvering
     was necessary to maintain position. No difficulty
     was encountered in this until the fire went out.,
     after which position was maintained by radar ranges
     on shore alone.
2015 Embarked Captain, A. L. Post., U.S.A.A.F., from
     native canoe for transportation to Pearl Harbor.
2310 Lookout reported vessel rounding the Cape. Observed
     by lightning flashes, it appeared to be a small
     tug or large launch. Alerted gun crews and pre-
     pared to destroy it if we were discovered. Contin-
     ued disembarkation. Tracked vessel by radar as it
     continued on steady course up the coast, passing
     3000 yards abeam.

29 September.
0102 Last trip left ship.
0216 Last trip returned. Flooded down awash and floated
     boats aboard.

(9) ENCLOSURE (A)

— page 144 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(B) NARRATIVE (Cont'd)

29 September (Cont'd)
     0235 All secured topside. Headed east at high speed.
          Attempted to transmit but transmitter failed and
          was not repaired until after we had submerged for
          the day.
          This area would be excellent for operations of
          this type during the northwest season. There is
          a steep-to beach with a minimum of 12 feet right up
          to it (Information from natives of village).
          Landing craft of almost any type could approach it.
          The accompanying sketch, while approximate, is
          the summation of all local information obtained
          plus that which we determined ourselves, and may
          be of assistance in future operations. Names
          and locations have been omitted for security pur-
          poses.
          The assorted freight caused the most difficulty,
          the battery charger being especially awkward. It
          is recommended that heavy freight of this type
          be flown-in in the future and that submarine trans-
          portation be limited to personnel and their equipment,
          or that power boats be provided.
          The spirit of cooperation and the willingness to
          undertake the hard work involved shown by the crew
          was very gratifying to the Commanding Officer.

30 September.
     0114 Sighted Green Island and passed between Green
          Island and Feni Island without incident.

1 October.
     1505 Sighted B-24 bearing 308°T, distance 12 miles,
          on south-easterly course. La. 2-30S, Lo. 153-19E.
     1800 Set course for Pearl Harbor in accordance with
          routing instructions.

2 October.
     0946(L) Submerged on sight contact of B-24 bearing 210°T,
          distance 10 miles, on north-easterly course,
          La. 1-49S, Lo. 157-18E.

                                        (10)     ENCLOSURE (A)

— page 145 —
CONFIDENTIAL
U.S.S. GROOPER, Report of War Patrol number seven. --
(B) NARRATIVE (CONT'D)

2 October (Cont'd).
1016(L) Surfaced.
1356(L) Submerged on sight contact of B-24 bearing
     265°T, distance 8 miles, on easterly course.
     La. 1-49S, Lo. 157-18E.
1412(L) Surfaced.

3 October.
1050(L) SD Radar contact at 18 miles, closed to 17 miles,
     then opened to 18 miles, and disappeared. Re-
     mained on surface.
1216(L) Submerged on SD Radar contact, plane unobserved.
     La. 0-23S, Lo. 164-03E.
1239(L) Surfaced.
1306(L) Submerged on sight contact of large unidentified
     land plane on westerly course. La. 0-21S, Lo.
     164-10E.
1326(L) Surfaced.

5 October.
1200(M) Passed under operational control of ComTask-
     Force-17 with task unit designation of 17-3.3.

7 October.
1246(X) SD Radar contact, 6 miles, on PBY. Exchanged
     recognition signals. Plane circled ship and
     departed on northeasterly course. La. 14-06N,
     Lo. 173-25E.

8 October.
1045(X) Sighted Johnston Island, distance 12 miles, bear-
     ing 054°T. Set course to pass to southward. In
     contact at various times with 3 PBY's and 2 SPD's.
1200(X) Sighted STINGRAY departing Johnston Island.
     Sighted small merchant vessel entering Johnston
     escorted by YP boat.
1230(X) Set course 067°T for Pearl Harbor. Sighted and
     exchanged recognition signals with numerous
     friendly planes enroute.

(11) ENCLOSURE (A)

— page 146 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven,
(B) NARRATIVE (CONT'D)

11 October.
0314 Sighted Task Force of 6 ships bearing 314°T,
       distance 13000 yards.
0640 Sighted escort and exchanged recognition signals,
       Proceeded to Pearl.

(11A) ENCLOSURE (A)

— page 147 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(C) WEATHER
    No Remarks.
(D) TIDAL INFORMATION
    No Remarks
(E) NAVIGATIONAL AIDS
    No Remarks.
(F) SHIP CONTACTS
    See Ship Contact Form (Page 21)
(G) AIRCRAFT CONTACTS
    See Aircraft Contact Form (Pages 22, 23 & 24)
(H) ATTACK DATA
    (See attached torpedo and gun attack report forms).
(I) MINES
    No Remarks.
(J) ANTI-SUBMARINE MEASURES AND EVASION TACTICS
    Air screen for 6000 ton AK convoy consisted of
    single close in screen and two other planes which
    searched a wide area 5 to 10 miles ahead of the
    target.
(K) MAJOR DEFECTS AND DAMAGE
    No Remarks.
(L) RADIO
    No Remarks.

(12) ENCLOSURE (A)

— page 148 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.

(M) RADAR
The SJ Radar gave excellent results, to extent
of picking up small cargo barge or PC boat at a
range of 4000 yards, a native canoe at 600 yards,
and schools of fish up to 1000 yards. This is
the first patrol the SJ Radar has given satis-
factory results, and this is first patrol since
its installation that we have had no nights
contacts.

(N) SOUND GEAR AND SOUND CONDITIONS
During second attack on Sept 10, 1943 a single
ping range was attempted. The Q.B. started a con-
tinuous signal when the "equipment" button was
pressed. Later investigation revealed that the
"line" switch on the fathometer was on. A guard
has been put on this switch to prevent such a
casualty again.
Sound conditions were generally good.

(O) DENSITY LAYERS
DATE      LAT   LONG   SURFACE TEMP.   LAYER TEMP   CHANGE
26 Aug    25S   155E         73             72        240'
28 Aug    12S   152E         81             80         80'
31 Aug     4S   155E         87             85        240'
9 Sept     5N   150E         88             84        210'
19 Sept    0N   151E         87             88        100'
28 Sept    5S   152E         87             86        200'

(P) HEALTH, FOOD, AND HABITABILITY
The health of the crew was generally excellent,
the food was adequate, and the habitability was
comfortable.

(13) ENCLOSURE (A)

— page 149 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.

(Q) PERSONNEL
     No remarks.

(R) MILES STEAMED - FUEL USED
     Brisbane to area:-                 1904 Mi.          21415 Gal.
     In area:-                          4139 Mi.          33730 Gal.
     Area to Pearl Harbor:-             3175 Mi.          48050 Gal.

(S) DURATION
     Days enroute to area:-             8
     Days in area:-                     30
     Days enroute to Pearl Harbor:-     11
     Days submerged:-                   31

(T) FACTOR OF ENDURANCE REMAINING
     Torpedoes      Fuel        Provisions      Personnel
     No. 10         2500 Gal.   15 days.        10 days.

(U) REMARKS
     INACTIVATING OF MARK 6 EXPLODER MECHANISM
     If a certain exploder mechanism will function at a
     depth of 20 feet below the keel of a given target, there
     appears to be no reason why this same exploder will not
     function 20 feet from the side of the same target. The
     loci of functioning points of this exploder will vary
     with geographical location and heading of target, but
     will probably remain at some distance from the hull.
     The loci of functioning points for different exploders
     for this same target will also vary due to the relative
     wide range of sensitivity of the individual exploder
     mechanisms but in all cases where the exploder will
     fire magnetically, will probably remain at some distance
     from the hull.
                                (14)          ENCLOSURE (A)

— page 150 —
CONFIDENTIAL
U.S.S. GROUPER, Report of War Patrol number seven.
(U) REMARKS (CONT'D)

INACTIVATING OF MARK 6 EXPLODER MECHANISM (CONT'D)

The large proportion of ships hit which are listed
as "damaged" rather than sunk is the best proof that
such "near misses" occur. Ships which should ordin-
ily be blown to pieces by one or more "observed hits"
often continue merrily on their way. The only reason-
able cause for this is the "near misses" which through
a periscope would appear as hits, and would correspond
in time to actual hits. The damage inflicted by
these "near misses", as shown by subsequent observations
of the target, and by information from enemy sources,
is negligible.
Theories have been advanced of some sort of device
used by the Japs to cause premature explosions of
our torpedoes, but it would appear that nature had
provided them with a fairly effective means, and
that only a non-magnetic ship would insure contacts
hits with the magnetic element activated.
Inactivating of the mechanism would eliminate
the normal prematures which result from improper
adjustment, sticky depth engines, and other causes
which even the most painstaking work by overhaul
personnel cannot completely eliminate.
It would appear far better to sink the enemy
vessels encountered, with targets in certain areas
are so hard to find and attack, than to continue
spoiling good chances just to prove that a really
useless mechanism can be made to function a fair
proportion of the time.
Therefore, now that the depth performance of the
torpedoes appears to be under control, it is strongly
recommended that all magnetic exploders which are to
be set for contact hits in accordance with current
instructions be inactivated, regardless of geographi-
cal location, to eliminate the possibility of premature
firing through magnetic actuation by the target's
magnetic field prior to actual physical contact
with the target.

(14A) ENCLOSURE (A)

— page 151 —
CONFIDENTIAL

TORPEDO ATTACK REPORT FORM

U.S.S. GROUPER Torpedo Attack No.1. Patrol No. 7.
1630 September 10, 1943 Lat. 5-05N, Long. 149-55E.

TARGET DATA - DAMAGE INFLICTED
Description:- Covered in Narrative.
Ships Sunk:- None.
Ships Damaged:- One hit on KAMOGAWA MARU, results
unobserved.

Target Draft 26' Course 089° Speed 14 kts Range 2450 yds.

OWN SHIP DATA
Speed 2.0 kts Course 282° Depth 66' Angle 0.

FIRE CONTROL AND TORPEDO DATA
Type Attack:- Day periscope.

(15) ENCLOSURE (A)

— page 152 —
CONFIDENTIAL

TORPEDO DATA - ATTACK NO. 1.

Tubes Fired: | 7 | 8 | 9 | 10
Track Angle: | 118½ | 124 | 120 | 128
Gyro Angle: | 166 | 162½ | 165 | 158
Depth Set: | 20' | 20' | 20' | 20'
Power: | HIGH | HIGH | HIGH | HIGH
Hit or Miss: | MISS | MISS | HIT | MISS
Erratic: | NO | NO | NO | NO
Mark Torpedo: | 14-3A | 14-3A | 14-3A | 14-3A
Serial: | 22641 | 42042 | 20112 | 22644
Mark Exploder: | 6-1 | 6-1 | 6-1 | 6-1
Serial: | 10510 | 6316 | 11485 | 10376
Actuation Set: | MAGNETIC
Actuation Actual: | MAGNETIC
Mark Warhead: | 16 | 16 | 16 | 16
Serial: | 875 | 4045 | 1619 | 3846
Explosive: | TORPEX | TORPEX | TORPEX | TORPEX
Firing Interval: | 0 | 8 | 8 | 10
Type Spread: | DIVERGENT
Sea Conditions: | MODERATE SEA, MODERATE SWELL.
Overhaul Activity: | U.S.S. FULTON.

(16) ENCLOSURE (A)

— page 153 —
CONFIDENTIAL

TORPEDO ATTACK REPORT FORM

U.S.S. GROUPER Torpedo Attack No. 2 Patrol No. 7.
1810 September 10, 1943 Lat. 5-08N, Long. 149-50E.

TARGET DATA - DAMAGE INFLICTED

Description:- Covered in Narrative.
Ships Sunk:- None.
Ships Damaged:- None.
Target Draft 29½ Course 230°T Speed 16 kts Range 1800 yds.

OWN SHIP DATA

Speed 2.0 kts Course 282°T Depth 65' Angle 0.

FIRE CONTROL AND TORPEDO DATA

Type Attack: Day periscope.

(17) ENCLOSURE (A)

— page 154 —
CONFIDENTIAL

TORPEDO DATA - ATTACK NO.2.

|             | 1     | 2     | 3     | 4     | 5     | 6     |
| :| :---- | :---- | :---- | :---- | :---- | :---- |
| Tubes Fired:| 116   | 122   | 118½  | 138   | 119   | 134   |
| Track Angle:| 13½   | 7½    | 10½   | 2     | 10    | 356   |
| Gyro Angle: | 25'   | 25'   | 25'   | 25'   | 25'   | 25'   |
| Depth Set:  | HIGH  | HIGH  | HIGH  | HIGH  | HIGH  | HIGH  |
| Power:      | MISS  | MISS  | MISS  | MISS  | MISS  | MISS  |
| Hit or Miss:| NO    | NO    | NO    | NO    | NO    | NO    |
| ERRATIC:    | 14-3A | 14-3A | 14-3A | 14-3A | 14-3A | 14-3A |
| Mark Torpedo:| 24756 | 24542 | 22305 | 24573 | 24078 | 20163 |
| Serial No:  | 6-1   | 6-1   | 6-1   | 6-1   | 6-1   | 6-1   |
| Mark Exploder:| 14654 | 5024  | 9383  | 10462 | 4823  | 4350  |
| Serial No:  |       |       |       |       |       |       |
| Actuation Set:| MAGNETIC                                      |
| Actuation Actual:| NONE                                        |
| Mark WarHead:| 16    | 16    | 16    | 16    | 16    | 16    |
| Serial No.  | 3731  | 3594  | 824   | 5504  | 1624  | 3867  |
| Explosive:  | TORPEX                                        |
| Firing Interval:| 0     | 8     | 8     | 6     | 7     | 8     |

Type Spread: DIVERGENT
Sea Conditions: MODERATE SEA, MODERATE SWELL.
Overhaul Activity: U.S.S. FULTON.

(18) ENCLOSURE (A)

— page 155 —
CONFIDENTIAL
TORPEDO ATTACK REPORT FORM
U.S.S. GROOPER. Torpedo Attack No. 3. Patrol No. 7.
1600 September 20, 1943 Lat. 0-02N, Long. 150-29E.

TARGET DATA - DAMAGE INFLICTED
Description:- Covered in Narrative.
Ships Sunk:- None.
Ships Damaged:- One hit on 6000 ton AK, results un-
observed.
Target Draft 25! Course 190°T Speed 10 kts Range 1950 yds.

OWN SHIP DATA
Speed 2.0 kts Course 090°T Depth 66! Angle 0

FIRE CONTROL AND TORPEDO DATA
Type Attack: Day periscope.

(19) ENCLOSURE (A)

— page 156 —
CONFIDENTIAL

TORPEDO DATA - ATTACK NO. 3.

Tubes Fired: | 7 | 8 | 9 | 10
Track Angle: | 85° | 86 | 92 | 87
Gyro Angle: | 195° | 195 | 189 | 194
Depth Set: | 12' | 12' | 12' | 12'
Power: | HIGH | HIGH | HIGH | HIGH
Hit or Miss: | MISS | MISS | MISS | HIT
Erratic: | NO | NO | NO | NO
Mark Torpedo: | 14-3A | 14-3A | 14-1A | 14-3A
Serial: | 24878 | 20076 | 19106 | 23348
Mark Exploder: | 6-1 | 6-1 | 6-1 | 6-1
Serial: | 5896 | 5732 | 9491 | 5170
Actuation Set: | MAGNETIC
Actuation Actual: | MAGNETIC
Mark Warhead: | 16 | 16 | 16 | 16
Serial: | 5835 | 6043 | 5959 | 6085
Explosive: | TORPEX
Firing Interval: | 0 | 9 | 7 | 7
Type Spread: | DIVERGENT
Sea Conditions: | CALM SEA.
Overhaul Activity: | U.S.S. FULTON.

(20) ENCLOSURE (A)

— page 157 —
CONFIDENTIAL

SHIP CONTACT REPORT FORM U.S.S. GROUPER

| NO. | TIME | DATE | LAT | LONG | TYPE | INITIAL RANGE | COURSE | SPEED | HOW CONTACTED | REMARKS |
|---|
| 1. | 1623 | 10 Sept | 5-05N | 149-55E | KANOGAWA MARU | 10,000 yds | 075°T | 14 kts | Periscope | Hospital Ship |
| 2. | 1809 | 10 Sept | 5-05N | 149-50E | TOA HARU 1 DD | 12,000 yds | 195°T | 16 kts | Periscope | |
| 3. | 1139 | 11 Sept | 3-28N | 150-49E | MANILA MARU | 18,000 yds | 196°T | 14 kts | Surface day | |
| 4. | 1600 | 20 Sept | 0-02N | 150-29E | 6,000 ton AK 1 Mine Layer 3 SC | 20,000 yds | 10 kts | 190°T | Periscope | Deck Load of 3 Planes or seaplanes |
| 5. | 1220 | 25 Sept | 5-08S | 154-10E | 1 GOSEI MARU 1 SC 2 Trawlers | 10,000 yds | 10 kts | 290°T | Periscope | |
| 6. | 2310 | 28 Sept | | | Cargo Barge or PC | 5,000 yds | 020°T | | Surface Night | |

(21)
ENCLOSURE (A)

— page 158 —
CONFIDENTIAL
AIRCRAFT CONTACT REPORT FORM
U.S.S. GROUPER

NO. | TIME | LAT | TYPE | INITIAL | EST. CSE | HOW | REMARKS
| DATE | LONG | | RANGE | SPEED | CONTACTED |
1. | 0917 | 1-37S | B-24 | 12 Mi. | 325°T | Periscope |
| 2 Sept | 155-10E | | | | 180 kts | |
2. | 1226 | 1-36S | B-24 | 10 Mi. | 145°T | Periscope |
| 2 Sept | 155-07E | | | | 180 kts | |
3. | 1150 | 0-21N | B-24 | 10 Mi. | 320°T | Periscope | Truk air
| 3 Sept | 153-33E | | | | 180 kts | | search
4. | 0940 | 6-50N | PETE | 5 Mi. | 095°T | Periscope |
| 6 Sept | 151-21E | | | | 180 kts | |
5. | 1755 | 5-05N | Float | 8 Mi | Various | Periscope | Air screen
| 10 Sept | 149-55E | Plane | | | 120 kts | | for KANOGWA
| | | | | | | | Maru
6. | 1215 | 1-50N | Unidentified | 6 Mi | --- | SD Radar |
| 14 Sept | 150-04E | | | | | |
7. | 0248 | 0-37N | Unidentified | 5 Mi | Easterly | Surface | Plane Un-
| 17 Sept | 151-26E | | | | 150 kts | | observed
8. | 1041 | 1-02S | 2 Engine | 6 Mi. | 160°T | Periscope |
| 18 Sept | 152-21E | land plane | | | 200 kts | |
9. | 0719 | 0-24S | MAVIS | 5 Mi | 330°T | Periscope |
| 19 Sept | 152-32E | | | | 180 kts | |
10. | 1141 | 0-24S | Unidentified | 10 Mi. | Easterly | Periscope |
| 19 Sept | 152-45E | | | | 200 kts | |

(22)
ENCLOSURE (A)

— page 159 —
CONFIDENTIAL
NO. TIME DATE LAT. LONG. TYPE INITIAL RANGE EST. CSE. HOW REMARKS
                                                                SPEED CONTACTED
                                        AIRCRAFT CONTACT REPORT FORM
                                                                U.S.S. GROUPER

11. 1219 0-02N ADAM 6 Mi. 035°T Periscope Convoy Screen
    20 Sept 150-26E                                 150 kts

12. 1600 0-02N Single 10 Mi. Various Periscope Convoy Screen
    20 Sept 150-29E Engine 120 kts
                       Float Plane

13. 1600 0-02N ADAM 10 Mi. Various Periscope
    20 Sept 150-29E 120 kts

14. 0849 3-14S Unidenti- 12 Mi. North- Periscope
    24 Sept 155-29E fied land westerly
                       plane 200kts

15. 1148 3-19S B-24 10Mi South- Periscope
    24 Sept 155-26E easterly
                       180 kts

16. 0745 4-59S Unidenti- 10 Mi. South- Periscope
    25 Sept 154-17E fied easterly
                       180 kts

17. 2025 Unidenti- 6 Mi. Surface
    28 Sept fied

18. 1505 2-30S B-24 10 Mi. 120°T Periscope
    1 Oct 153-1 180 kts

19. 0946 1-49S B-24 10 Mi. 045°T Surface
    2 Oct 157-18E 180 kts

(23) ENCLOSURE (A)

— page 160 —
CONFIDENTIAL
AIRCRAFT CONTACT REPORT FORM
U.S.S. GROUPER

| NO. | TIME | LAT | TYPE | INITIAL | EST.CSE | HOW | REMARKS |
|     | DATE | LONG |      | RANGE   | SPEED   | CONTACTED |         |
|-----|------|------|------|||||
| 20. | 1326 | 1-40S | B-24 | 8 Mi.   | 085°T   | Surface   |         |
| **  | 2 Oct | 158-09E |      |         | 180 kts |           |         |
| 21. | 1216 | 0-23S | Unidenti- | 12 Mi.  |         | SD Radar  |         |
|     | 3 Oct | 164-03E | fied |         |         |           |         |
| 22. | 1306 | 0-21S | Unidenti- | 6 Mi.   | 270°T   | Surface   |         |
|     | 3 Oct | 164-10E | fied |         | 180 kts |           |         |
| 23. | 1246 | 14-06N | PBY  |         | 045     | SD Radar  |         |
|     | 7 Oct | 173-25E |      |         | 120 kts.|           |         |
| **  | 1050 | 0-20S | Unidenti- | 18 Mi.  |         | SD Radar  |         |
| 20(A)| 3 Oct | 164-15E | fied |         |         |           |         |

(24) ENCLOSURE (A)

— page 161 —
FF12-10/A16-3(8)/(16) SUBMARINE FORCE, PACIFIC FLEET
Serial 01482
CONFIDENTIAL
                                                                1d
                                                Care of Fleet Post Office,
                                                San Francisco, California,
                                                16 October 1943.

THIRD ENDORSEMENT
GROUPER Report of
Seventh War Patrol.

COMSUBSPAC PATROL REPORT NO. 286
U.S.S. GROUPER - SEVENTH WAR PATROL.

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

Subject: U.S.S. GROUPER (SS214) - Report of Seventh War Patrol,
         (25 August to 11 October 1943).

1. The GROUPER's seventh war patrol was conducted in areas under
the operational control of Commander Task Force Seventy-Two and enroute Pearl
Harbor.

2. Three attacks were aggressively made, two of which resulted in
damage to the enemy. In each attack enemy anti-submarine measures prohibited
the GROUPER from observing results.

3. The GROUPER's special mission was successfully completed.

4. This patrol is considered successful for Combat Insignia Award.

5. The Commander Submarine Force, Pacific Fleet, congratulates the
Commanding Officer, officers, and crew for the damage inflicted on the enemy
and for the successful accomplishment of its special mission. The GROUPER is
credited with inflicting the following damage to the enemy:

DAMAGED

1 - Passenger-Freighter (KAMOGAWA MARU class) - 6,440 tons
1 - Passenger-Freighter (unknown class) - 6,000 tons
                                                TOTAL: 12,440 tons

NOTE: The above damage was inflicted in the operational areas of Commander
Task Force Seventy-Two who is requested to assume credit accordingly.

                                                C. A. LOCKWOOD, Jr.

Distribution and authentication
on following page.
                                                - 1 -

— page 163 —
[HANDWRITTEN: 1ST COPY]

DECLASSIFIED

U.S.S. GROUPER (SS214)

Care of Fleet Post Office,
San Francisco, California.

From : Commanding Officer, U.S.S. GROUPER
To : Commander in Chief, United States Fleet.
Via : Commander Submarine Division One Hundred
and One.
Commander Submarine Squadron Ten.

Subject: U.S.S. GROUPER, Report of War Patrol number
eight.

Enclosure: (A) Subject report.
(B) Track chart of areas.

1. Enclosure (A) covering the eighth war patrol
of this vessel conducted in northern LUZON STRAIT and off
the east and west coasts of southern FORMOSA during the
period of 1 March, 1944 to 28 April, is forwarded herewith.

F. H. WAHLIG.

DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: OP-09B9C] DATE [HANDWRITTEN: 5/26/72]

DECLASSIFIED

[HANDWRITTEN: - 77549]

— page 164 —
CONFIDENTIAL

UNITED STATES PACIFIC FLEET
SUBMARINE FORCE

REPORT OF WAR PATROL NO. [UNCLEAR: number]

— page 165 —
(A) PROLOGUE

       Upon completion of the seventh war patrol GROUPER arrived
at the Submarine Base, Pearl Harbor, on October 11, 1943.
On October 13, GROUPER departed Pearl for the San Francisco
area. On October 19, GROUPER arrived at HUNTER'S POINT NAVAL
DRYDOCKS where a major overhaul was commenced on the same date.
On November 12, Lieutenant Commander F.H. WAHLIG, U.S. Navy,
relieved Commander M.P. HOTTEL, U.S. Navy, as commanding
officer. The major overhaul, in which all alterations and
improvements approved and applicable were accomplished, was
completed on December 29. On January 1, 1944, GROUPER de-
parted the San Francisco area enroute to Pearl Harbor.
GROUPER arrived at the Submarine Base, Pearl Harbor, on
January 7, and was assigned to Submarine Squadron Four for
administrative purposes. From January 7 to 14, inclusive,
the Submarine Base completed voyage repairs. At this time a
P.P.I.was installed and the 3-inch gun replaced with a 4-inch
gun. On January 15, a training period was begun under the
supervision of Commander Submarine Division Eighty-One as
training officer. On January 16, while a training exercise
was being conducted, the conning tower, control room and pump
room were flooded. The resulting damage was extensive. Re-
placement and repair of damaged equipment and material was
undertaken by the Submarine Base and completed on February 15.
During this time the bridge was altered to reduce silhouette
and a D.R.T. table instal ed. On February 19, a training
period was begun again under the supervision of Commander
Submarine Division Eighty-One as training officer. Screened
targets were made available for both day and night exercises.
The employment of multiple targets at night gave opportunity
for the fire control and tracking organizations and the radar
operators to obtain much needed training for night approaches.
Training was completed on February 25. During February 26 to
29, inclusive, GROUPER was depermed, a sound test made, and
readiness for sea was completed.

(B) NARRATIVE (All times ITEM unless otherwise indicated)

1 March

1300(VW) Underway from Submarine Base, Pearl Harbor, on Eighth
       War Patrol, enroute to patrol area via Midway.

2 to 5 March

       Rough weather encountered from 2 to 4 March inclusive
       made it necessary to slow to six knots to avoid liabilit
       of damage from the seas or from taking in water. Daily
       drills were conducted, but GROUPER did not submerge on
       3 or 4 March.

(1)                                                ENCLOSURE (A)

— page 166 —
6 March
1010(Y) Moored alongside pier at the Submarine Base,
Midway. Fueled to capacity and took on battery and
fresh water.
Departure from Midway was delayed twenty-four
hours while the Submarine Base made repairs to the
cooling water fittings of No. 2 and No. 4 main engines.

7 March
1700(M) Underway from Submarine Base, Midway. Upon leaving
the channel rough seas and high winds from the west
were encountered. These conditions persisted for the
next five days, during which time the best speed that
could be maintained was about six knots.

12 March
The wind and sea had moderated and normal two-engine
speed was again possible. Training dives and fire control
drills daily were resumed.

18 March
1650(L) Sighted two patrol planes, identified as EMILY,
on easterly course, bearing 340T, distant about 8
miles. No indication on SD radar. Submerged.
1735(L) Surfaced.

19 March
1430(L) Flooded the terminal block of No. 3 main gene-
rator when a plug in the salt water cooling system
burst.
1545(L) Commenced patrol on course south, west of northern
Mariannas.
1600(L) Submerged to facilitate making repairs to No. 3
main generator.
1955(L) Surfaced. Repairs to No. 3 main generator completed.

20 March
Conducted surface patrol across SAIPAN-EMPIRE route.
1155(L) SD radar contact at 10 miles, closing, no airplane
sighted. Submerged.
1319(L) Surfaced.
1325(L) Sighted a two engine bomber on westerly course,
bearing 150T, distant about 7 miles. No indication
on SD radar. Submerged.

(2) ENCLOSURE (A)

— page 167 —
1530(L) Surfaced.

21 March
1215(L) SD radar contact at 12 miles, closing fast.
Submerged.
1340(L) Surfaced.
1532(L) SD radar contact at 20 miles, which opened and
disappeared at 24 miles.
2000(L) Proceeded enroute to final patrol area.

25 March
1155(K) SD radar contact at 10 miles closing. No airplane
sighted. Submerged.
1455(K) Surfaced.

29 March
0626 Submerged.
1400 Surfaced.
2100 Entered BASHI CHANNEL.
2200 Completed passage of BASHI CHANNEL.

30 March
Conducted surface patrol west of BATAN ISLANDS.
0815 Sighted six airplanes, identified as ZEKES, on
course south, bearing 230T, distant about 6 miles.
No indication on SD radar. Submerged.
0855 Surfaced.
2000 Set course 285T to cross LUZON STRAIT.

31 March
0935 SD radar contact at 16 miles, which closed to 14
miles and disappeared.
1005 SD radar contact at 6 miles. No airplane sighted.
Submerged.
1350 Surfaced.
1540 Sighted small craft bearing 300T, distant about
8 miles (Ship contact No. 1). Submerged to close and
identify it.
1950 Identified craft previously sighted as a fishing
sampan. This sampan and those sighted subsequently
during the patrol appeared to be of one type which
is described in PART (F).
2055 Surfaced. Several lights were visible bearing
about 155T, the direction in which the fishing boat
should have been at the time. Set course 295T to
cross TAKAO-HONG KONG route.

(3) ENCLOSURE (A)

— page 168 —
1-4 April
                                        Conducted submerged patrol by day across the
                                        TAKAO-HONG KONG route and along it by night.

2 April
                                        During the day the condition of the sea increased
                                        making depth control difficult to maintain and the
                                        probability of accurate torpedo run doubtful. A
                                        strong wind blew steadily from the east and the sky
                                        was covered with a heavy overcast.

3 April
0625 Submerged. By this time the sea had become so
     rough that periscope depth could not be steadily main-
     tained and accurate torpedo performance could not be
     expected.
1934 Surfaced. The weather and sea had not changed.

4 April
0015 The GROUPER was riding dry and comfortably when
     a large wave suddenly rose over the ship. No water
     was taken down the conning tower but a small amount
     of water entered the supply ventilation system, where
     it caused complete disintegration of the supply
     blower impeller. From this time on the problem of
     obtaining adequate ventilation was constantly with us.
0638 Submerged. As the sea conditions and weather app-
     eared to be moderating at,
1446 Surfaced.
                                        The last navigational position had been obtained
                                        on the morning of 2 April. The best information in-
                                        dicated our actual position to be well to the west-
                                        ward of our estimated position. A course of 095T
                                        was set to return to the TAKAO-HONG KONG route.

5 April
                                        Conducted surface patrol across TAKAO-HONG KONG
                                        route and southern approaches to PESCADORES CHANNEL.

6 April
                                        Proceeded on surface along route south from TAKAO
                                        and PESCADORES CHANNEL. Sighted sampans on three occ-
                                        asions during day. (Ship contacts Nos. 2, 3, and 4).
                                        In all of these and the following sampan contacts, the
                                        GROUPER maneuvered to avoid being sighted by them.

                                        (14)                                ENCLOSURE (A)

— page 169 —
7 April
Conducted surface patrol across routes from the
south to TAKAO and PESCADORES CHANNEL. Sighted several
sampans. (Ship contacts Nos. 5 to 10, inclusive).

8 April
1723 Sighted black smoke bearing 055T and headed
toward it. Commenced tracking of the smoke which
was intermittent and found that it was from a ship
that was apparently circling at a slow speed.
Shortly after this we became involved with a fishing
net that extended for miles in a line from 150T to 300T.
1843 Cleared net and continued to close the smoke.
1919 Sighted a small ship (Ship contact No. 11) which
had a tripod mast forward and a single stack from which
black smoke belched at intervals of about ten minutes.
It was evidently circling, alternately steaming ahead
at slow speed and stopping.
1924 Obtained a radar range of the ship at 15750 yards.
Because darkness was fast approaching maneuvered to
place the target toward the moon.
2210 The ship was clearly visible against the moon-
light at a range of 3600 yards. From the appearance
as seen previously and at this time it was identified
as similar to that shown on page 171 of ONI-14. Decided
that our best action was to keep clear and course
north was set. The position of the ship was Lat.
20-39N. Long. 120-02E. It was tracked on course
225T at a speed of from 0 to 6 knots. It was first
thought that this ship might have been operating with
the fishing boats, as the sampans were believed to be,
but upon sighting it, we became suspicious that its
purpose was otherwise.

9 April
Proceeded on the surface easterly toward BASHI
CHANNEL.
0028 SJ radar contact obtained at 21000 yards, bearing
108T. Only one pip was seen. Set course 108T to
investigate.
0125 Sighted a dark object, evidently a ship, bearing
105T, distant about 4 miles, and away from the moon.
(Ship contact No. 12. Commenced tracking it and
determined it to be lying-to in position Lat. 20-55N.
Long. 120-14E.

(5) ENCLOSURE (A)

— page 170 —
0143 At this time a white streak in the water which app-
       eared much like a wake was seen about 100 yards ahead
       and we maneuvered radically. As we passed through this
       streak it could be seen extending in a line toward and
       away from the bearing of the ship. A few minutes later
       an instantaneous flash of light on the ship was seen.
       As the situation seemed unfavorable to us, decided to
       get clear and perhaps get down moon. At this time the
       ship apparently moved on, also, for it was soon lost
       from sight. The unusual feature of this occurence
       is that only one radar pip was obtained, even after the
       ship was closed to less than 8000 yards, although the
       equipment was operating satisfactorily.
            Plotting of this ship showed that it could have been
       the same one that was sighted on the evening of 8 April,
       if that ship had made a speed of 6 knots on course 035T.
            Sighted two sampans, (Ship contacts Nos. 13 and 14).
0615 Submerged.
1425 Surfaced.
1635 Sighted airplane, identified as ZEKE, on easterly
       course, distant about one mile and a half. Submerged.
       This plane must have approached us from out of the
       sun.
1833 Surfaced.
1905 Sighted a flight of 13 two-engine bombers on
       northwesterly course, bearing 120T, distant about 8
       miles. No indication on SD radar. Submerged.
1950 Surfaced.
2150 Set course 270T.

10 April
0423 Sighted light of sampan bearing 300T, distant
       about 5 miles, and shortly thereafter two others
       close to it. (Ship contact No. 15)
0538 Lat. 21-02N - Long. 119-00E. Sighted smoke and
       immediately thereafter ships bearing 280T, distant
       about 10 miles. (Ship contact No. 16). In the in-
       creasing light saw four merchant ships. Commenced radar
       tracking and maneuvers to obtain position ahead of them.
0715 An airplane was sighted on a nearly steady bearing
       in the direction of the convoy and at a distance of
       about 7 miles. At this time tracking showed the convoy
       to be steady on base course 030T at a speed of 3 knots.
       Submerged and came to normal approach course. The
       range at that time was estimated to be 22000 yards and
       the distance to the track 2000 yards.
0826 Sighted nearest ship bearing 256T at an estimated
       range of 14000 yards. No escort was seen.

(6)
ENCLOSURE (A)

— page 171 —
It was evident that the convoy had changed base course
to about north. Ran along with it at standard speed for
forty minutes hoping that the convoy would change course
for TAKAO or PESCADORES CHANNEL.
1130 A light rain squall was seen to be approaching and
as the visibility decreased, decided to surface in this
opportunity and start an end around. The target was
then bearing 300T at an estimated range of 17000 yards.
1135 Surfaced and started end around at full speed, ex-
pecting the convoy would change course to right for
PESCADORES CHANNEL since it was obvious that they were not
going to TAKAO. The intermittent light rain squalls
continued as the wind and sea increased.
1330 Commenced tracking the convoy with radar on the after
ship of the nearest flank which was bearing 253T,
distant 23000 yards. The ship was chosen because it
was smoking constantly and therefore easily identified
for the radar. Tracking gave a base course of 000T,
and a speed of about 7 to 7.5 knots. The seas evidently
were slowing the convoy as well as us. This course
was headed for FORMOSA BANKS and it appeared doubtful
that they would change it to head for PESCADORES
CHANNEL. If the former was the case, there were left
some 27 miles in which to head them off before they
would get to the shallow water of the BANKS. The
weather was rapidly becoming worse and heavy rain
squalls were approaching from the northeast. With the
decreasing visibility, we gradually kept closing the
convoy track.
1400 Lost sight and radar contact.
1420 A heavy rain squall came over. This was the opp-
ortunity for which we had hoped. Changed course to
270T and took the chance that the rain squall would
hide us until we reached the convoy track.
1435 With the possibility of the rain squall passing
at any moment and leaving us on the surface ahead of
the convoy at an estimated range of 8000 yards and 1800
yards from the convoy track, submerged. It was still
raining but the rain was lessening.
1445 Sound bearings were obtained and indicated that we
were farther from the convoy track than estimated.
Came to normal approach course at speed of 6 knots.
The sea was very rough and depth control was difficult
to maintain. At 1459 slowed for periscope observation.
1501 Sighted convoy at an estimated range of 12000 yards.
This and subsequent observations showed that the convoy
had changed base course left to about 330T, probably
at 1400, and that it would be impossible to close even
the second ship of the nearest flank.

(7) ENCLOSURE (A)

— page 172 —
Held on in hopes that they still would change course
to the right for PESCADORES CHANNEL, which would put
us in a firing position. When last seen they were on
the same base course and had passed over FORMOSA BANK
at Lat. 22-40N. Long. 118-34E. The convoy was in two
columns, two ships in each, with one escort, heard but
not seen, leading the left column and one destroyer
escort, KAIKAZE class, closing the right column.
Three ships were seen well enough to attempt identi-
fication: Right column, first ship, LISBON MARU class,
second ship, similar to DAISAN OGURA MARU; left column,
second ship, similar to EIYO MARU.
1600 Broke off approach and proceeded south.
1945 Surfaced and set southerly course.

11 April

Conducted surface patrol across southern approaches
to TAKAO and PESCADORES CHANNEL.
1645 Sighted two airplanes, identified as ZEKES, on
southerly course, distant 5 miles. No indication on
SD radar.
1734 Submerged.
2248 Sighted a green flare bearing 290T.
2300 Changed course to investigate possible source of
flare. Found nothing.
2354 Changed course to north.

12 April

0032 Changed course to 060T to parallel TAKAO-HONG KONG
route.
0130 Sighted a white light bearing 040T, distant about
8 miles.
0140 Sighted a green flare bearing 030T, which might
have been a rocket.
0221 Sighted a white light bearing 045T, distant about
7 miles.
Decided to circle around this area to see if there
was any significance to what we had seen, but nothing
came of it.
0506 Set course south.
Sighted two sampans. (Ship contacts Nos. 17 and 18).
1525 SD radar contact at 10 miles which closed fast. No
plane sighted. Submerged.
1823 Surfaced and set course for BASHI CHANNEL.

13 April

0600 Completed passage of BASHI CHANNEL, set course for
EMPIRE-MANILA route.

(3) ENCLOSURE (A)

— page 173 —
7

0723 Sighted sampan, (Ship contact No. 19).
1100 Commenced surface patrol along EMPIRE-MANILA route.

14 April.
0600 Set course to clear area.

15 April
1900 Departed area for Majuro in accordance with routing
     instructions.

21 April
1800(L)Made rendezvous with U.S.S. TALBOR and received
     prisoner-of-war and mail for transportation to Majuro.

28 April
1030(M) Arrived Majuro and commenced refit.

(C) WEATHER

     The weather was generally clear with steady winds from the
northeast as described in the Sailing Directions for LUZON
STRAITS, SOUTHERN FORMOSA, and BATAN ISLANDS. Occasional
rainy periods with heavy overcast accompanied a shift in the
wind, such as occurred on 10 April. One period of stormy
weather commencing on 2 April lasted three days. During this
time the wind was force 5 or 6 and the seas rose to condition
6 at times. The sky was completely overcast but no rain fell.

(D) TIDAL INFORMATION

     In general the currents correspond to those indicated on
the Current Chart for Northwestern Pacific Ocean, for LUZON
STRAIT, and adjacent waters. However the northerly set be-
tween 119E and 120E is generally stronger. On April 5 it was
observed to be 1.8 kts setting 340T at 22N, and on 6 April it
was noted to be 1.1 kts setting 010T at 20-30N.

     Currents around the BATAN ISLANDS are accurately indicated
on Chart 2641.

(E) NAVIGATIONAL AIDS

     None observed.

(9) ENCLOSURE (A)

— page 174 —
(F) SHIP CONTACTS
NO | TIME | LAT(N) | TYPE | INITIAL | EST CSE | HOW | REMARKS
   | DATE | LONG(E) |      | RANGE   | SPEED   | CONTACTED |
---|||||||
1  | 1540   | 20-45    | Sampan | 8 mi    | Lying-to  | Lookout     |
   | 31 Mar | 110-11   |        |         |           |             |
2  | 0630   | 20-59    | Sampan | 8 mi    | Lying-to  | Submerged   |
   | 6 April| 119-28   |        |         |           | Periscope   |
3  | 1250   | 21-00    | Sampan | 8 mi    | Lying-to  | Surface     |
   | 6 April| 119-50   |        |         |           | Periscope   |
4  | 1500   | 20-43    | Sampan | 8 mi    | Lying-to  | Surface     |
   | 6 April| 119-48   |        |         |           | Periscope   |
5  | 0715   | 20-37    | Sampan | 6 mi    | Lying-to  | Submerged   |
   | 7 April| 119-06   |        |         |           | Periscope   |
6  | 1119   | 20-46    | Sampan | 8 mi    | Lying-to  | Lookout     |
   | 7 April| 118-57   |        |         |           |             |
7  | 0705   | 20-48    | Sampan | 8 mi    | Lying-to  | Surface     |
   | 8 April| 119-21   |        |         |           | Periscope   |
8  | 0915   | 20-40    | Sampan | 8 mi    | Lying-to  | Surface     |
   | 8 April| 119-25   |        |         |           | Periscope   |
9  | 1236   | 20-35    | Sampan | 8 mi    | Lying-to  | Surface     |
   | 8 April| 119-43   |        |         |           | Periscope   |
10 | 1350   | 20-33    | Sampan | 8 mi    | Lying-to  | Surface     |
   | 8 April| 119-54   |        |         |           | Periscope   |
11 | 1700   | 20-21.5  | AM-13  | 20 mi   | Various   | Lookout     |
   | 8 April| 119-55   | Class  |         | 6 kts     | Sighted smoke |
12 | 0028   | 21-01    | Contact| 10.5 mi | Unknown   | SJ          | Only one
   | 9 April| 119-58   | No. 11 |         |           |             | pip ob-
   |        |          | SS ??  |         |           |             | tained.
13 | 0525   | 21-08    | Sampan | 5 mi    | Lying-to  | Lookout     |
   | 9 April| 120-35   |        |         |           |             |
14 | 0610   | 21-03    | Sampan | 4 mi    | Lying-to  | Lookout     |
   | 9 April| 120-33   |        |         |           |             |
15 | 0423   | 21-04    | 3      | 5 mi    | Lying-to  | Lookout     |
   | 10 April| 119-10   | Sampans|         |           |             |

(10)
ENCLOSURE (A)

— page 175 —
(F) SHIP CONTACTS (CONT'D)

NO TIME | LAT(N) | TYPE | INITIAL | EST CSE | HOW | REMARKS
DATE | LONG(E) | | RANGE | SPEED | CONTACTED |

16 0538 | 21-03 | * | 12 mi | 030 | Lookout
10 April | 118-49 | | | 7½ kts |
17 0320 | 21-45 | Sampan | 5 mi | Southerly | Surface
12 April | 119-12 | | | | Periscope
18 1235 | 21-25 | Sampan | 5 mi | Lying-to | Surface
12 April | 119-13 | | | | Periscope
19 0733 | 21-27 | Sampan | 6 mi | Lying-to | Surface
13 April | 122-05 | | | | Periscope

* EIYO MARU, LIMA MARU, DAI SAN OGURA MARU, 1 unidentified MARU,
1 KAMIKAZE DD, 1 escort not seen.

These sampans were estimated to be about 70 feet long
with a clipper type bow and an overhanging stern. A deck
house extending about one-third of the length was erected aft.
Forward a mast was stepped carrying a boom which reached nearly
to the forward end of the superstructure. They were apparently
powered by a gasoline engine and only one was seen under sail.
At night they showed an all-around white light from the mast-
head and some also had 2 or 3 white lights along the boom.
No radio antennae were noticed. Many large schools of fish
were passed adjacent to these sampans and it was at first
thought that they were engaged solely in fishing. Later it
was considered that these sampans or some of them may have been
patrolling or serving as navigational aids. Some of these
sampans sighted were undoubtedly the same as those sighted at
previous times, but since they all looked alike, there was no
way of identifying one from another.

Most of the time was devoted to patrol of those parts of
the area where the best information available indicated that
convoys were routed and where previous contacts had been made.
Other routing may have been used for convoys moving during the
time of our patrol. It is possible that the presence of the
GROUPER in the area was known and shipping diverted around us.

(11) ENCLOSURE (A)

— page 176 —
(G) AIRCRAFT CONTACTS
NO | TIME | LAT(N) | TYPE | INITIAL | EST CSE | HOW | REMARKS
   | DATE | LONG(E) |      | RANGE   | SPEED   | CONTACTED |
---|------||------||||
1  | 1645 | 21-42   | 2    | 8 mi    | Easterly| Sight     | Dove. No SD
   | 18 Mar | 149-48  | EMILY|         | 120 kts |           | indication
2  | 1155 | 20-53   | --   | 15 mi   | --      | SD        | Dove
   | 20 Mar | 144-22  |      |         |         |           | Not seen
3  | 1330 | 20-53   | 2 engine | 6 mi    | 240     | Sight     | Dove. No SD
   | 20 Mar | 144-25  | Bomber |         | 150 kts |           | indication
4  | 1215 | 20-58   | --   | 12 mi   | --      | SD        | Dove
   | 21 Mar | 143-43  |      |         |         |           | Not seen
5  | 1532 | 20-55   | --   | 20 mi   | --      | SD        | Not seen
   | 21 Mar | 143-28  |      |         |         |           |
6  | 1155 | 21-53   | --   | 15 mi   | --      | SD        | Dove. No SD
   | 25 Mar | 131-50  |      |         |         |           | indication
7  | 0815 | 20-16   | 6 small| 8 mi    | Northerly| Sight     | Dove.
   | 30 Mar | 121-00  | Float|         | 150 kts |           |
8  | 0935 | 20-33   | --   | 16 mi   | --      | SD        | Not seen
   | 31 Mar | 119-57  |      |         |         |           |
9  | 1005 | 20-34   | --   | 16 mi   | --      | SD        | Not seen
   | 31 Mar | 119-57  |      |         |         |           |
10 | 1635 | 20-58   | 1    | 2 mi    | 090     | Sight     | Dove. No SD
   | 9 April| 120-32  | ZEKE |         | 150 kts |           | indication
11 | 1905 | 20-55   | 18 two en-| 8 mi    | 330     | Sight     | Dove. No SD
   | 9 April| 120-37  | gine Bombers|         | 200 kts |           | indication
12 | 0715 | 21-26   | 1    | 12 mi   | Various | Sight     | Convoy
   | 10 April| 119-05  | ZEKE |         | 120 kts |           | air screen
13 | 1645 | 21-20   | 2    | 5 mi    | Southerly| Sight     | Dove. No SD
   | 11 April| 120-03  | ZEKES|         | 150 kts |           | indication
14 | 1525 | 21-13   | --   | 13 mi   | --      | SD        | Dove. "
   | 12 April| 119-33  |      |         |         |           |

(12)                                                      ENCLOSURE (A)

— page 177 —
(H) ATTACK DATA
No remarks.

(I) MINES
No remarks.

(J) ANTI-SUBMARINE MEASURES AND EVASION TACTICS

The area between Lat. 20-30 to 21 north and Long. 119 to
121 east was scattered with sampans. It was considered advisable
to avoid being sighted by them, in event they had means of re-
porting our presence, and such action was taken on every contact
with one of them. The ship encountered on the evening of 8
April was undoubtedly patrolling. Perhaps our presence in that
vicinity on the previous day had been observed and reported.
It is also likely that it was also there for a rendezvous. For
a time this possibility was accepted and it was decided to stand
by for a while and await developments. Finally we were convinced
that he was patrolling only, and we went on. If the contact at
0149 of 9 April was not the same ship, it may have been another
patrol or perhaps a submarine. The scarcity of airplane activity
encountered in the area, especially when for 10 days we were
within a radius of 150 miles from TAKAO, is considered to be
most unusual. The airplane which was seen over the convoy on
10 April could not have remained with it long. During the sub-
sequent chase of the convoy an air escort was expected to arrive
at any time, but the weather may have kept the airplanes away
then.

The escorts of the convoy were pinging constantly on the
long range scale as they approached and passed.

In our tracking of the convoy on 10 April it appears that
in the morning the convoy base course was changed radically at
about the time when we ceased taking radar ranges, and in the
afternoon when the rain obliterated the radar. These circum-
stances may have been only coincidental. It is probable that
the convoy made a prescribed change of course at both times
or at the first time and changed because of the rain squall the
second time.

(13) ENCLOSURE (A)

— page 178 —
(K) MAJOR DEFECTS AND DAMAGE

1. GROUPER was delayed 24 hours at Midway during the
manufacture of new castings for No. 2 and No. 4 main engine
cooling water systems. The nipples in the fresh water side at
the point where the recirculating lines tap into the attached
engine pump had carried away enroute to Midway. Wooden plugs
were inserted to keep the engines in commission until repairs
could be made.

2. On March 19, a one-half inch pipe plug in the air
cooler circulating water line for No. 3 main generator burst
and salt water flooded the generator terminals. This shorted
out the terminals and burned out the terminal block. The drip
proof covers were insufficient protection. Although the ship's
force managed repairs which had the generator back in commission
in six hours, a new terminal block is required.

3. On March 27, the high voltage during a battery
charge burned out the solenoid for the bow plane tilting motor
clutch. Someone had inadvertently left the bow plane selector
switch in the control room on "TILT". Since no spares were
available, the tilting motor clutch was lashed in the power
position. Ship's force installed a positive contact switch in
the bow plane rigging-out indicator to prevent the tilting motor
circuit from being energized before bow planes were fully rigged
out.

4. On March 29, the flinger ring on the attached salt
water pump of No. 2 main engine wore away causing the pump
bearing to freeze. The pump was removed and a spare installed.
Engine hours at time of casualty were 3685.

5. On April 4, took water into the main induction from
heavy seas. The water entering the hull induction caused
disintegration of the ship's ventilation supply blower impeller.
No spares were available and no repairs were feasible.

6. On April 22, a casualty occurred to No. 3 unit of
No. 1 main engine. Upon inspection it was found that the
cylinder liner was cracked and the first compression piston
ring broken in half. Repairs were made immediately by the
ship's force. Engine hours at the time of the casualty were
918.2.

(14)
ENCLOSURE (A)

— page 179 —
(K) MAJOR DEFECTS AND DAMAGE (CONT'D)

7. On April 22, it was noticed that the hydraulic plant
was charging very sluggishly. The strainer was cleaned but this
had no effect. On April 23 the pilot valve plunger was in-
spected but no cause for the sluggish operation of the plant was
found there. The ship's force has been unable to determine the
fault which causes the pilot valve plunger and consequently the
automatic by-pass valve to operate improperly. For the re-
mainder of the patrol the plant was kept secured with the hand
by-pass valve open and on the diving alarm the plant was started.

8. At some time prior to the patrol the high pressure
air system had accumulated brass chips. These chips eventually
found their way to the high pressure air manifolds where they
caused injury to the seats of the following valves: bow buoy-
ancy blow, safety blow and the stops in the 600-lb main ballast
blow system. Each of these valves was ground in on three occ-
asions during the patrol. During the refit all high pressure
air manifolds and valves will be examined for injury and an
attempt made to clear the debris from the system.

(L) RADIO

Radio receiving conditions were good at all times and
other than from the SD radar, no interference was noticed. A
few Japanese stations were heard near our frequencies, but no
deliberate "jamming" was encountered. Reception of NPM Haiku
was generally best on 14730 kcs and 9090 kcs. It was possible
to pick up short wave broadcasts on the REO from all parts of
the world.
From 2205 to 2233 GCT on April 20, an attempt was made to
send an urgent message for C.T.F. 17 on 8470 kcs. There was
interference around that frequency which should not have pre-
vented our transmission from getting through but may have
caused our failure to receive an answer. The message was
broadcast twice on 8470 kcs and then as prescribed in Task
Force Seventeen Supplement.

(M) RADAR

SD-4 RADAR The performance of the equipment was uniformly ex-
cellent throughout the patrol. On March 18, when about 450
miles from MARCUS ISLAND, an interference resembling F-MCW
"jamming" was observed which lasted for about ten minutes.

(15) ENCLOSURE (A)

— page 180 —
(11) RADAR (CONT'D)

SD-4 RADAR. On April.5 an airplane was detected at 32 miles and
the detection of airplanes from 13 to 25 miles was usual. It is
recommended that this installation be calibrated for a higher
frequency as at present its frequency is at the lowest point of
its range.

SJ-1 RADAR. On the night of 29-30 March when off the BATAN
ISLANDS the operation of this radar was thoroughly checked and
found to be satisfactory. Ranges on land were obtained to the
limit of the range scale. On April 9 the "pip" at 21000 yards
on what was evidently a small ship was a phenomenon that per-
haps can be explained only by the presence of clouds of the
same bearing. No explanation can be offered for failure to
obtain contact with this object when the range was closed to
about 8000 yards. On April 10 well defined "pips" were obtained
on the ships in the convoy up to 21000 yards. There was later
found reason to have doubt of the accuracy of these ranges, but
any error which may have existed was such that the actual ranges
were greater than those indicated, to the extent of 3000 to
4000 yards. On the evening of April 11 contact with land de-
finitely proved that the range unit was indicating ranges less
than the actual. Later that night no precision sweep and "step"
were observed in the "A" scope. Investigation disclosed that
the leads connecting parts R-505 and R-572 were broken. When
these leads were repaired, the precision sweep and "step" were
restored. Subsequent checking of ranges on land with distances
by navigational fix indicated that the range error had been
eliminated. It is believed that this range error was caused
by the failure of part R-572.

(N) SOUND GEAR AND SOUND CONDITIONS

Sound conditions were generally good in LUZON STRAIT and
off the coast of FORMOSA. On the contact with enemy ships on
11 April, the JP gave good bearings at 12000 yards. JK and QB
were unable to hear screws, but received clearly audible echo-
ranging on 19 kcs.

The fathometer was used twice just south of FORMOSA BANKS
and gave good results with a single ping each time.

(16) ENCLOSURE (A)

— page 181 —
(O) DENSITY LAYERS
TIME (GCT) | LAT(N) | TEMPERATURE AT
DATE | LONG(E) | 65' | 100' | 150' | 200' | 250' | 300'
0200 | 21-43 | 71 | 70 | 70 | 70 | |
18 March | 149-51 | | | | | |
0030 | 21-02 | 71 | 70 | 70 | 70 | |
20 March | 144-15 | | | | | |
0112 | 20-59 | 73 | 73 | 73 | | |
21 March | 143-43 | | | | | |
0100 | 21-30 | 73 | 73 | 73 | | |
22 March | 140-00 | | | | | |
0600 | 22-14 | 67 | 67 | 67 | 67 | 67 | 67
22 March | 135-33 | | | | | |
0200 | 21-53 | 70 | 70 | 70 | 70 | 70 | 70
25 March | 131-50 | | | | | |
0420 | 21-36 | 71 | 71 | 71 | 71 | 71 | 71
27 March | 129-14 | | | | | |
0714 | 21-41 | 69 | 69 | 68 | 67 | 67 | 66
28 March | 124-46 | | | | | |
2130 | 22-00 | 67 | 67 | | | |
29 March | 122-51 | | | | | |
2330 | 20-06 | 74 | 74 | 74 | | |
30 March | 121-18 | | | | | |
0645 | 20-43 | 74 | 74 | 73 | | |
31 March | 119-19 | | | | | |
2215 | 21-24 | 72 | 72 | 72 | 70 | 68 | 66
1 April | 118-36 | | | | | |
2115 | 21-55 | 72 | 72 | 72 | 71 | 71 | 71
2 April | 119-14 | | | | | |
2055 | 21-11 | 74 | 74 | | | |
3 April | 119-00 | | | | | |

(17) ENCLOSURE (A)

— page 182 —
(O) DENSITY LAYERS (CONT'D)

TIME (GCT) | LAT(N) | TEMPERATURE AT:
DATE       | LONG(E) | 65' | 100' | 150' | 200' | 250' | 300'
||-----|------|------|------|------|------
2115       | 20-37  | 72  | 72   |      |      |      |
4 April    | 118-33 |     |      |      |      |      |
||-----|------|------|------|------|------
2142       | 20-37  | 74½ | 74½  | 74   |      |      |
7 April    | 119-05 |     |      |      |      |      |
||-----|------|------|------|------|------
2050       | 21-03  | 76  | 74½  | 74½  |      |      |
9 April    | 120-35 |     |      |      |      |      |
||-----|------|------|------|------|------
2045       | 21-03  | 75  | 75   |      |      |      |
10 April   | 119-03 |     |      |      |      |      |
||-----|------|------|------|------|------
0745       | 20-03  | 75  | 73   | 72   | 72   | 72   |
11 April   | 120-19 |     |      |      |      |      |
||-----|------|------|------|------|------
0643       | 21-07  | 76  | 76   | 75   |      |      |
12 April   | 119-39 |     |      |      |      |      |
||-----|------|------|------|------|------
0800       | 22-01  | 72  | 71   | 70   |      |      |
13 April   | 123-11 |     |      |      |      |      |

(P) HEALTH, FOOD, AND HABITABILITY

The health of the crew was generally good throughout the
patrol. Treatment was administered for:
    Numerous head colds.
    8 cases of cellulitis.
    6 cases of fungus infection.
    1 case of seasickness.
    1 case of undetermined head injury.

The single case of seasickness was chronic and the patient
was transferred at Midway. The case of undetermined head in-
jury was a reoccurrence from an old wound. This man was also
transferred at Midway.

The food was satisfactory.

Until the casualty to the supply blower on 4 April, the
habitability was excellent. From then on the ventilation never
seemed adequate.

(18)
ENCLOSURE (A)

— page 183 —
(Q) PERSONNEL
(a) Number of men on board during patrol                               69
(b) Number of men qualified at start of patrol                           51
(c) Number of men qualified at end of patrol                             61
(d) Number of unqualified men making their first patrol                  16
(e) Number of men advanced in rating during patrol                       22

(R) MILES STEAMED - FUEL USED
Midway to areas           2658 mi           31690 gals
In areas                  4837 mi           41245 gals
Area to Majuro            4258 mi           40525 gals

(S) DURATION
Days enroute to areas                                                    13
Days in areas                                                            27
Days enroute to Majuro                                                   13
Days submerged                                                            4

(T) FACTORS OF ENDURANCE REMAINING
TORPEDOES           FUEL           PROVISIONS           PERSONNEL FACTOR
24                  44000 gals     20 days              20 days
Limiting factor this patrol: Operation order.

(U) REMARKS
Mark 18 torpedoes. Eight Mk 18 torpedoes in excellent con-
dition were received from the Submarine Base and placed aft.
The maintenance and routine work required by these torpedoes
imposed no more difficulty than that required for Mk 14 tor-
pedoes. No casualties nor defects have been found in these
torpedoes.

The various units concerned of the Submarine Base E & R
department, especially those that accomplished the electrical
work, should be commended for the completely satisfactory resto-
ration of the equipment damaged in the flooding of the conning
tower, control room and pump room. No defects nor casualties
have occurred in any of this equipment and the general material
condition of all of it is excellent.

(19)                                                      ENCLOSURE (A)

— page 184 —
(U) REMARKS (CONT'D)

In the period from January 16 to February 15 the GROUPER
endeavored to make maximum use of the training facilities
provided by the Training Command. The benefits from the in-
struction which the personnel received can not be fully estimated
but the commanding officer and officers are unanimous in the
opinion that in every case the efficiency and ability of the
individual were improved. Those schools which are considered
to be especially of value are the Radar Maintenance, the Radar
Operators and Sound Operators. These comments in regards to
the training program are offered:
1. In the Radar Maintenance School submarine personnel
should be given more instruction in the operation and main-
tenance of the lofthan range unit and in general "trouble-
shooting" on the SJ radar.
2. Radar personnel who attend the Radar Maintenance
School and who have not been to the Radar Operators School
should be sent to operators school upon completion of the
maintenance course.
3. The Sound Operation School provides excellent training
for all personnel who stand sound watches.
4. Submarines could benefit by the transfer of personnel
to relief crews for one patrol so that they could attend the
longer courses of instruction, if such personnel were returned
to the submarine from which they came upon completion of the
instruction.
5. It is considered that short, intensive courses of
instruction in the maintenance of the pitometer log and the
gyrocompass would be of value.

(20) ENCLOSURE (A)

— page 185 —
FB5-101/A16-3
Serial 022
CONFIDENTIAL
FIRST ENDORSEMENT to
CO GROUPER ltr. SS214
/A16-3 of 27 April
1944.

SUBMARINE DIVISION 101
Care of Fleet Post Office,
San Francisco, California,
27 April 1944.

From: The Commander Submarine Division 101,
To : The Commander-in-Chief, U. S. Fleet.
Via : (1) The Commander Submarine Squadron Ten,
(2) The Commander Submarine Force, Pacific Fleet.
(3) The Commander-in-Chief, U. S. Pacific Fleet.

Subject: U.S.S. GROUPER (SS214) Eighth War Patrol - Comments on.

1. GROUPER Eighth War Patrol was conducted from 1 March
to 27 April 1944, princi pally in the waters just south of FORMOSA.
About 27 days were spent in patrol areas.

2. Although areas were diligently searched, there were
only three contacts and no attacks were made.
First Contact: (8 April) - This night contact appeared
to be a 500 ton vessel resembling a mine layer. The Commanding Offi-
cer decided that the target could not be hit with a torpedo on account
of its shallow draft, hence very properly kept clear. Sea conditions
were favorable for torpedo performance. The thought is therefore sug-
gested that Mark 18 torpedoes set to 5 or 6 feet depth might do the
job under such conditions. (Twenty-three torpedoes, selected at random,
and fired in smooth water with depth setting of 5 feet, averaged a run-
ning depth of 3.3 feet.)
Second Contact: (9 April) - This vessel resembled a
patrol vessel and could possibly have been the same one as in previous
contact. It was sighted after following up a single 21,000 yd. radar
pip. Failure of the SJ to get additional pips at closer ranges can-
not be explained.
Third Contact: (10 April) - GROUPER dived about sunrise
to attack a convoy of 2 AOs, 2 AKs and 2 escorts. When a zig away
made the torpedo run too great, the submarine surfaced, made an end
around, and dived only to again have the convoy zig away and start
crossing the FORMOSA BANKS. GROUPER did not follow because the full
moon made a submerged attack necessary and the water was too shallow
for diving. It is possible that this convoy was aware of submarine's
presence.

3. A normal refit will be given alongside the SPERRY.

[SIGNATURE: J. G. HENSEL]
J. G. HENSEL.

Copy to:
CO GROUPER.

— page 186 —
FC5-10/A16-3
Serial 088
CONFIDENTIAL
SECOND ENDORSEMENT TO
CO GROUPER ltr. SS214/
A16-3 of 27 April 1944.

SUBMARINE SQUADRON TEN
Care of Fleet Post Office,
San Francisco, California,
28 April 1944.

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

Subject: U.S.S. GROUPER (SS214) - Report of Eighth War Patrol -
Comments on.

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

2. The lack of contacts despite good area coverage, the
scarcity of enemy air patrols, and reports of other recent patrols
in this general area indicate that the Nips may have "pulled in
their horns" temporarily as a result of our strikes.

[SIGNATURE: C. F. Erck]
C. F. ERCK.

Copy to:
Comsubdiv. 101.
CO GROUPER.

— page 187 —
FF12-10/A16-3(15)/(16)
Serial 0862

CONFIDENTIAL

THIRD ENDORSEMENT to
GROUPER Report of
Eighth War Patrol.

COMSUBSPAC PATROL REPORT NO. 413
U.S.S. GROUPER - EIGHTH WAR PATROL.

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

Subject: U.S.S. GROUPER (SS214) - Report of Eighth War Patrol.
(1 March to 28 April 1944).

1. The eighth war patrol of the GROUPER was the first for
the new Commanding Officer, as such. The patrol was conducted in an
area off the southeast and southwest Coast of Formosa.

2. Only two contacts worthy of torpedo fire were made.
The attack on the convoy on 10 April was frustrated first, because of
air anti-submarine patrol over the convoy; and later because of bad
weather. No attacks were made.

3. This patrol is designated as not successful for Combat
Insignia Award.

Distribution and authentication
on following page.

- 1 - SUBMARINE FORCE, PACIFIC FLEET.
hch
Care of Fleet Post Office,
San Francisco, California,
6 May 1944

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

J. H. BROWN, Jr.

— page 188 —
SUBMARINE FORCE, PACIFIC FLEET hch
FF12-10/A16-3(15)/(16)
Care of Fleet Post Office,
San Francisco, California,
Serial 0862 6 May 1944

CONFIDENTIAL

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

COMSUBSPAC PATROL REPORT NO. 413
U.S.S. GROUPER - EIGHTH WAR PATROL.

Subject: U.S.S. GROUPER (SS214) - Report of Eighth War Patrol.
(1 March to 28 April 1944).

— page 189 —
[STAMP: DECLASSIFIED]
Serial: 04

U.S.S. GROUPER (SS214)

Fleet Post Office,
San Francisco, California.
[HANDWRITTEN: 1ST COPY]

From: The Commanding Officer.
To: The Commander-in-Chief, U.S. FLEET.
Via: (1) Commander Submarine Division FORTY-TWO.
(2) Commander Submarine Squadron FOUR.
(3) Commander Submarine Force, PACIFIC FLEET.
(4) Commander-in-Chief, U.S. PACIFIC FLEET.

Subject: U.S.S. GROUPER - Report of War Patrol
Number NINE.

Enclosures: (A) Subject Report.
(B) Track Chart of Patrol (For ComSubsPac).

1. Enclosures (A) and (B) covering the ninth War
Patrol of this vessel conducted in waters adjacent to the Jap-
anese Empire, east of KYUSHU and south of SHIKOKU and HONSHU,
during the period from 22 May to 6 July 1944, are forwarded
herewith.

F. H. WAHLIG.

[STAMP: DECLASSIFIED]

[STAMP: DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C]
[HANDWRITTEN: BY OP-09B DATE 5/20/72]

[HANDWRITTEN: 82084]

— page 190 —
CONFIDENTIAL
(A) PROLOGUE.

The eighth war patrol was completed on 28 April,1944,
when the GROUPER moored alongside the U.S.S. SPERRY at Majuro
Atoll, Marshall Islands. On 29 April a normal refit was
commenced by the repair forces of the SPERRY and Submarine
Division 101. During the refit period the officers and crew
of the GROUPER lived at the recently established submarine
rest camp on Kyrne Island. Officers and men enjoyed their
stay there and all benefited by the complete and convenient
facilities which the new camp provided for their relaxation
and recreation. On 12 May the officers and crew returned
on board and 13 May to 15 May were used in post repair tests
and preparations for sea. In the interim since 28 April
five officers were detached and six officers reported for
duty. From 16 May to 19 May, inclusive, the GROUPER oper-
ated for training under the supervision of Commander
Submarine Division 101, an additional day of training being
given because of the extensive change of officer personnel.
On 20 May and 21 May GROUPER completed preparations for the
ninth war patrol.

(B) NARRATIVE. All times are (I) except as indicated.

22 May

1312(L) Underway from alongside U.S.S. SPERRY at Majuro
Atoll for ninth war patrol.
1353(L) Departed Majuro in company with U.S.S. SWORD-
FISH and U.S.S. WEAVER (escort)
1719(L) Submerged for trim.
1742(L) Surfaced.

23 May

0500(L) U.S.S. WEAVER proceeded independently, escort
duty completed.
0930(L) U.S.S. SWORDFISH proceeded independently.
1630(L) Submerged for training.
1730(L) Surfaced.

24 May to 30 May, inclusive.

Enroute to area. Conducted daily training
dives, drills and battle problems.

29 May

2300 Commenced removal of interior of SD antenna
mast. The SD radar had not been operating
satisfactorily for two days.

30 May

0215 Completed repair of SD antenna mast.

(1)

— page 191 —
CONFIDENTIAL
31 May

1030    Submerged for training.
1114    Surfaced.
1500    Arrived in area.
2215    Sighted SOFU GAN (LOT'S WIFE) bearing 261
        true, distant about 12 miles.
2248    Commenced patrol of TOKYO-SAIPAN route.
2345    Made SJ radar contact on TORI SHIMA bearing
        358 true, distant 30 miles.

1 June
0805    SD radar contact on airplane at 13 miles
        which closed rapidly. Submerged.
1010    Surfaced.
1145    Sighted submarine on surface which was subse-
        quently identified to be the U.S.S. KINGFISH.
1220    SD radar contact on airplane at 16 miles
        which closed to 10 miles. Submerged.
1403    Surfaced.

2 June
0805    Submerged.
1120    Surfaced.

3 June
0155    Sound watch reported echo-ranging consisting
        of three distinct pings at 340 relative.
0200    SJ radar contact bearing 084 relative at 2000
        yards. Maneuvered to avoid and the contact was
        lost. Nothing was sighted.
0422    Submerged.
1907    Surfaced.

4 June
0421    Submerged to patrol route south from BUNGO
        SUIDO.
1952    Surfaced.
2345    SJ radar contact on land bearing 255 true,
        distant 70000 yards. Considered this to be the
        land south of ARIAKE WAN.

6 June
0015    When TOI MISAKI light was estimated to be
        bearing 315 true, distant about 17 miles and
        not visible, changed course to open from land.
0432    Submerged to patrol BUNGO SUIDO-PALAU route.
1925    Surfaced.

(2)

— page 192 —
CONFIDENTIAL
7 June
0427 Submerged to patrol intersection of VAN DIEMEN-
TOKYO route and route 150 true from BUNGO SUIDO.
1950 Surfaced and proceeded to close coast of KYUSHU.

8 June
0421 Submerged.
0900 Changed course to east to open from land.
Visibility was estimated to be about 6000 yards
because of light fog. Position was doubtful and
currents were not known.
1350 Sighted airplane, OSCAR or ZEKE, heading
toward us bearing 350 relative, about 2 miles away.
Went to 140 feet.
1410 Returned to periscope depth.
2005 Surfaced and commenced to close coast.

9 June
0220 Sighted HOSOSHIMA light bearing 310 true,
distant about 11 miles.
0330 Sighted SHIMANOURA SHIMA light bearing 320
true, distant about 12 miles. Because of the at-
mosphere it appeared more red than white and
flashing rather than steady, but after consider-
able observation it was seen to be a fixed white
light.
0400 Submerged to patrol 100 fathom curve along
coast of KYUSHU.
0620 Visibility considered to be 4000-5000 yards
because of fog. Position estimated to be about 7
miles southeast of FUKA SHIMA. Changed course to
cross BUNGO SUIDO with allowance for maximum
northerly current.
0930 Sighted sampan on course 320 true, bearing
260 true, distant 4000 yards.
1700 Visibility began to clear.
2000 Surfaced.

10 June
0434 Submerged to patrol across VAN DIEMEN-TOKYO
route.
1950 Surfaced.

11 June
0429 Submerged.
0700 Sighted MAVIS on southwest course.
1137 Sighted MAVIS on northeast course. This was
probably the same plane returning.
1905 Surfaced.

(3)

— page 193 —
CONFIDENTIAL
12 June

0429             Submerged.
0742             Sighted MAVIS on southwest course.
1035             Sighted MAVIS on northeast course. Probably
                 the same plane returning.
1955             Surfaced.
2236             Interference appeared on SJ radar in a sector
                 from 320 to 010 true. This interference was
                 thought to be emanating from a source having the
                 same frequency as our SJ.

13 June

0014             Interference disappeared from SJ radar.
0423             Submerged to patrol across VAN DIEM-TOKYO
route.
0608             Sighted RUFE on northeast course.
0643             Sighted RUFE on northeast course.
0649             JP sound operator reported propeller bearing
                 325 true. The range at this time was later
                 determined to be 16000 yards.
0651             Sighted BETTY on northeast course.
0655             Sighted hospital ship on course 055 true,
                 speed 10 knots, bearing 329 true, distant about
                 12000 yards. This ship was definitely identified
                 to be the HIKAVA MARU. The airplanes sighted
                 just prior to sighting the hospital ship may
                 not have been escorts, but from their presence
                 we expected shipping to be soon in coming along.
1045             Sighted MAVIS on northeast course.
1055             Sighted BETTY on northeast course.
1329             Sighted RUFE on northwest course.
1622             Sighted RUFE on northeast course.
1711             Sighted PETE on southeast course.
1811             Sighted RUFE on northwest course.
2020             Surfaced and proceeded northeast along the
                 track of the HIKAVA MARU for the airplane activity
                 of the afternoon seemed to indicate that shipping
                 was due along this route.

14 June

0100             Sighted KUBOTO SAKI light bearing 315 true,
                 distant 23 miles.
0400             Submerged.
                 At several times during day sighted float type
                 seaplanes which appeared to be flying around the
                 same point close to the shore. Their maneuvers
                 which were observed for an hour or more in each
                 case, indicated that they were neither patrolling
                 nor escorting.
2018             Surfaced.

(4)

— page 194 —
CONFIDENTIAL
15 June
0130         Sighted steady white light assumed to be
             SUSAKI light.
0350         Submerged.
             During morning sighted several twin float sea-
             planes flying close to land just as were those
             sighted yesterday. The visibility in the direc-
             tion of land was poor because of a haze which
             obscured the coast along the water.
1313         Sighted radio towers on SHIONO MISAKI as we
             passed about 4 miles from it. Nothing else could
             be definitely identified.
2017         Surfaced.
2222         Sighted lights of fishing sampans bearing 45
             and 90 relative and SJ had a contact bearing 70
             relative at 2000 yards. Maneuvered to avoid and
             clear vicinity of these vessels.

16 June
0402         Submerged.
0637         Sighted NAVIS on westerly course.
1954         Surfaced. A light rain was falling.

17 June
0228         Sighted a white light bearing 310 true which
             was lost in the poor visibility. Presumed this
             light to be on a fishing sampan.
0407         Submerged.
0509         Sighted a sampan, which was evidently patrol-
             ling, bearing 160 true, distant about 3000 yards.
             At the time he was hove to but shortly thereafter
             he proceeded on course 320 true and was soon lost
             from sight in the rain. This was very probably
             the sampan whose light was sighted previously at
             0228.
             After the morning deep dive it was reported
             that no. 10 tube was leaking through the outer
             door.
1950         Surfaced. The weather cleared about two
             hours afterwards.
             The torpedo was withdrawn from no. 10 tube
             and it was seen that the outer door was leaking
             around its upper part. After several unsuccessful
             attempts to stop this leak, no. 10 tube was
             secured and the torpedo was placed in an extra
             rack in the room.

18 June
0403         Submerged.
2010         Surfaced.

(5)

— page 195 —
CONFIDENTIAL
2255                Hove to. Ensign Boose, using the shallow water
                    diving outfit, went over the side to endeavor to
                    determine the source of the leak to no. 10 tube.
                    He twice got to the shutter of the tube but each
                    time the motion of the ship prevented him from
                    remaining there long enough to inspect the door.
                    Since nothing could be done in this manner it was
                    decided to make an attempt from inside the tube.
                    After Ensign Boose had entered the tube an air
                    pressure was built up in the torpedo room. Under
                    this pressure, no. 10 tube was opened sufficiently
                    to permit Ensign Boose to feel along that part of
                    the door which was leaking. He found no gasket
                    there. No. 10 tube was secured for the duration
                    of the patrol.
0050                Proceeded toward SHIONO MISAKI.

19 June
0402                Submerged.
1622                Sighted a MAVIS on northeast course.
2010                Surfaced and proceeded to close the land to
                    westward.

20 June
0348                Submerged.
1201                Changed course to parallel coast line. It
                    was estimated that we were about 8 miles off shore.
                    Rain had commenced about 0430 and since then the
                    visibility had not been more than 3000 yards.
1312                Sighted a sampan bearing 160 true, distant
                    about 3000 yards, which was on a converging course.
1325                At a range of 1000 yards the sampan headed
                    toward us. Went to 120 feet and ran silent.
1435                Returned to periscope depth. All clear.
                    Considered that the sampan did not know of our
                    presence and that his change of course toward
                    us was coincidental.
2000                Surfaced.
2218                Rain ceased and weather began to clear.

21 June
0040                Sighted a flashing white light which was
                    taken to be KO SHIMA light.
0123                Sighted a flashing white light which was
                    taken to be DAIO SAKI light.
0325                Submerged to patrol along 100 fathom curve
                    east of DAIO SAKI.
1525                Sighted a sampan bearing 320 true, distant
                    about 6000 yards.
2025                Surfaced.

(6)

— page 196 —
CONFIDENTIAL
2344
Interference appeared on SJ radar. This inter-
ference, as that previously encountered, was con-
sidered to be from a source having the same fre-
quency as our SJ. It was seen each time the antenna
swept through a sector of 5 degrees each side of
284 true and on occasion it would persist through
an entire sweep. This interference lasted through-
out the night and its true bearing did not change
as we went south.

22 June
0332 Submerged to patrol southwest of the IZU SHOTO.
0755 Sighted a sampan bearing 016 true, distant
6000 yards.
0845 Sampan turned toward us and when it was dis-
tant about 2000 yards we went to 150 feet and
ran silent. Both JP and JK sound heard the
sampan pass over us.
1005 Returned to periscope depth. All clear.
1415 Heard first of five successive distant under-
water explosions which did not sound like either
depth charges or bombs.
2020 Surfaced.
2100 Interference appeared on the SJ radar which
was similar in every respect to that which occurred
last night.

23 June
0330 Submerged to patrol southwest of the IZU SHOTO.
0530 Heard first of a number of successive
explosions which were similar to those heard
yesterday.
1406 Sighted BETTY on southwest course which passed
about 2 miles from us.
1530 Sighted masts of two ships bearing 277 true,
distant about 16000 yards. After making high
speed for a considerable time it was determined
that we would not close these ships which were on
course 030 true at a speed of 8 knots. What was
originally two ships eventually became ten as they
all passed by. The following were seen: One
escort leading and then two other small ships of
which only the tops of the masts and stacks could
be seen; next came two freighters, believed to be
of the MIHUKI MARU (or ARAKI MARU) class; on the
near quarter of these was a trawler type escort
and on their far quarter was what was probably
another escort; following just behind the freighters
were three small engine aft ships, either
freighters or oilers, which were estimated to be
of 1800 tons. The near freighter had a gun
mounted aft on a platform. Echo-ranging was heard
from at least one escort.
1730 Last ship of convoy passed out of sight.

(7)

— page 197 —
CONFIDENTIAL
1935 Surfaced.
The current during the day was 3.8 knots
setting 088 true. Considering this, it was
concluded that the ships had taken a course to
pass between KOZU SHIMA and MIYAKE SHIMA. Started
up this passage at 17 knots. Keeping the first
twelve miles we were continually dodging sampans,
the lights of which were seen first about broad
on one bow and then broad on the other, for a
total of eight altogether.
2217 The SJ radar went out of commission just as
a strong pip was obtained at 280 relative, dis-
tant 4500 yards. The casualty was only a fuse
which was soon replaced. This pip and one on a
sampan at 2700 yards were the only radar ship
contacts made during the passage.
2243 Miyake Shima was seen burning normally.
SJ radar contact on convoy at 15000 yards
bearing 320 relative.
2355 Tracking of this convoy gave them a speed of
8 knots and the following successive courses, 045,
020, and 000, indicating that they were keeping
close to the western islands of the IZU SHOTO.
They were not zig-zagging.
It was decided that the attack should not be
delayed longer for if the convoy kept changing
course to the left it would take a long time to
obtain a position ahead, and we were rapidly
closing the entrance to SAGAMI NADA. Also our
position at the time was favorable for an attack
with the least probability of becoming involved
in this conglomeration of ships.

24 June
0000 Commenced closing for attack with the largest
radar pip as target. When the range to this ship
was about 5000 yards all ten ships could be seen
on the PPI scope in 8000 yard scale. It was
evident from this that the selected target was
one of the freighters and that the other was in
line with the first and about 2000 yards farther
away. We had hoped that both of them would be
in column so that we could make an attack on
each. The visibility was hazy and it was not
until we were about 3200 yards from the target
that we could see it at all. Two of the smaller
ships, presumably escorts, passed ahead of us
at about 1800 yards. When the freighter was
sighted, its TBT and radar bearings coincided.

(3)

— page 198 —
CONFIDENTIAL
0029 With a torpedo run of 2800 yards commenced fir-
ing nos. 1,2 and 3 tubes at the freighter. As soon
thereafter as a set-up was obtained, commenced fir-
ing nos. 4,5 and 6 tubes at the next larger ship,
except the other freighter, which was about 600
yards astern of the first target. The wakes of all
torpedoes were distinctly visible. The first tor-
pedo was seen to hit the freighter just under the
after mast and the second torpedo was seen to hit
it forward of the bridge. Jets of flame broke out
along the length of the ship and black smoke rose
to about 150 feet above it. The flames disappeared
and this ship appeared to be breaking up.
No results were seen from the other torpedoes.
They may have gone underneath their target.
Just as no. 4 tube was fired an escort bearing
340 relative was seen to turn toward us. As the
same time we could see and the PPI observers in-
formed us that two of the escorts that had gone by
were also coming toward us. After no. 6 tube had
been fired the GROUPER swung left. The escort
that had come at us from the port bow passed about
500 yards to starboard as we turned to clear the
convoy and leave it astern.
0033 The escort on our port quarter at 1200 yards
fired a shell and about 30 seconds later fired
another from what was thought to be a 3-inch gun.
As seen on the PPI, one shell landed 10 degrees
relative and 800 yards ahead, and another 40
degrees relative about 900 yards ahead.
A cloud of smoke could be seen about 200 feet
in the air above where the freighter had been but
no ship was visible nor could this ship be found
on the PPI scope.
0034 Commenced firing nos. 7,8 and 9 tubes at a
target which appeared to be the same size as the
second target, both by sight and the PPI.
One minute and thirteen seconds after firing
no. 7 tube an explosion was heard. One minute and
forty-one seconds and one minute and forty seconds
after firing nos. 8 and 9 tubes, respectively,
explosions were heard. It was about this time
that the escort which had first fired at us dis-
appeared from sight and the PPI screen. Shortly
after the last torpedo explosion, a dull red light
was seen on our port quarter in the direction of
the ship at which we had just fired. This light
seemed to be a flame when observed through binoc-
ulars.
The possibility exists that no. 7 torpedo hit
the escort which had been at 1200 yards and on our
port quarter, no. 8 torpedo hit the ship at which
we were firing and no. 9 torpedo hit one of the
other escorts. All torpedoes were set at six feet

(9)

— page 199 —
CONFIDENTIAL
and the Mk. 18 torpedoes may have run at about
4 feet depth.
0035 The escort on our starboard quarter at 1400
yards turned on a greenish all-around light and
shortly thereafter commenced firing at us with
a 3-inch gun. This escort and one other were
chasing us. They were astern, distant 1400 and
1700 yards. The range began to open from them
as our speed increased to 13½ knots. These two
and five more ships, a total of seven, were all
that could be seen on the PPI. The leading chaser
continued firing at us at about 30 second inter-
vals. Nothing of these shots were seen except
the flash of firing.
The visibility which had been considered unfav-
orable at the time of firing was no doubt an
advantage to us now.
0039 Heard four successive explosions which could
be felt through the ship.
0043 Last shell was fired by leading chaser at a
range of 2800 yards, making a total of 14 fired
by this escort.
0044 Leading chaser commenced signalling to a
ship astern of him.
0055 Changed course 30 degrees to right. The only
escort which was chasing us then drew off on our
port quarter, apparently he had not observed our
course change.
As we departed the area a dull red glow was
seen on the horizon in that direction. This glow
which was assumed to come from a burning ship
was seen until 0217 when it was obscured by a
cloud.
0120 Lost chaser at 11500 yards bearing 200 rela-
tive.
0258 Submerged.
2010 Surfaced and proceeded toward MIKAI SHIMA.

25 June

0330 Submerged.
0501 Sighted DAVE on a westerly course which passed
about 4 miles from us.
1448 Sighted EMILY on northwesterly course which
passed about 6 miles from us.
1955 Surfaced and proceeded north to patrol off
KATSUURA WAN.

26 June

0230 Sighted the beam of a searchlight over the
horizon bearing 310 relative. This light was
taken to be on land in the vicinity of KATSUURA.

(10)

— page 200 —
CONFIDENTIAL
0317 Submerged and commenced patrol northeast along
     100 fathom curve.
0407 Sighted MAVIS on northeast course.
0415 Sighted MAVIS on southeast course.
     These airplanes were evidently starting out on
     routine patrols.
0658 Sighted the top of a ship bearing 016 true,
     distant 13000 yards. Commenced approach but
     ceased it when ship was identified to be a PG
     type of patrol vessel. The vessel was patrolling
     just along the 100 fathom curve.
0815 Lost sight of the patrol vessel in the
     closing visibility.
0910 Visibility closed to about 500 yards because
     of heavy rain. Changed course to open from land.
1313 Rain stopped and the visibility began to
     clear.
1559 Sighted two TESS on northeasterly courses.
1610 Sighted TESS on easterly course.
1620 Sighted TESS and NELL on westerly courses.
1655 Sighted NELL on westerly course.
1705 Sighted TESS on northeasterly course.
     From the airplane activity we were evidently
     on the line used by airplanes arriving in and
     leaving the TOKYO area.
1955 Surfaced and proceeded toward the IZU SHOTO.

27 June
0015 SJ radar had a contact bearing 335 relative,
     at 6500 yards. Commenced tracking and determined
     that the contact was a small craft on course 060,
     speed 6 knots. Maneuvered to pass around it.
0330 Submerged.
0731 Sighted a drag-line fishing boat on course 240
     true, bearing 082 true, distant about 6000 yards.
     Maneuvered to avoid it. This was believed to be
     the same craft that was contacted by radar at 0015.
1955 Surfaced.

28 June
0355 Submerged.
1940 Surfaced.

29 June
0400 Submerged. The bow planes failed to rig out
     by power and they were rigged out by hand. After
     being rigged out they could not be tilted in
     power. Attempts to restore the bow planes were
     continued unsuccessfully until 1315.
1330 Surfaced.
1845 Departed patrol area enroute to Midway.

     (11)

— page 201 —
CONFIDENTIAL
30 June to 6 July, inclusive.

Enroute to Midway. Made training dives and con-
ducted drills and battle problems.

6 July
0815(Y) Made rendezvous on Midway 30 mile circle with
plane escort.
1108(Y) Moored portside to pier S-1 at Midway. Took
on fuel and fresh provisions. Removed five Mk.
18 torpedoes from ship.
1600(Y) Underway enroute to Pearl Harbor.

6 to 9 July

Enroute to Pearl Harbor.

10 July
0608(VW) Made rendezvous with escort.
1100(VW) Moored at Submarine Base, Pearl Harbor.

(12)

— page 202 —
CONFIDENTIAL
(C) WEATHER

Enroute to the NANPO SHOTO the weather was normal. From
there to the west of KYUSHU and thence back along the coast of
HONSHU and down through the NANPO SHOTO the weather was con-
sidered unfavorable to submarine operations. The Asiatic
Pilot definitely states for this area, "in June the prevailing
winds are southerly and westerly and the weather is generally
fair; but the southerly winds are sometimes strong and east-
erly winds bring rain." From 1 June to 28 June the sky was
seven-tenths to completely overcast ninety percent of the
time, during the day with strato-cumulus clouds and at night
with cirro-stratus clouds. The atmosphere was hazy, especial-
ly around the horizon, and visibility was usually less than
10 miles. Often fogs which would persist from one to six
hours would close the visibility to 2000 or 3000 yards. Along
the coast of KYUSHU there was calm or light winds, usually
from the east. South of SHIKOKU the light wind blew from
the northeast. Along the south coast of HONSHU the winds
were usually light and from the east or northeast. On the
17th and 18th of June the wind blew from the northeast with
a force of 6 and it rained continuously for about eighteen
hours. On 26 and 27 June in the IZU SHOTO and NANPO SHOTO
area the wind blew from the southwest with a force of 4; the
sky was only about three-tenths overcast but the atmosphere
remained hazy.

(D) TIDAL INFORMATION

Because of the infrequency of definite navigational
positions the following information on currents must be con-
sidered only as estimates. In general the currents off the
coast of KYUSHU were considered to be as shown on the charts,
though on one day in the HYUGA NADA, when about 20 miles from
the coast, a westerly instead of a northerly set was found,
which was probably caused by the KUROSHIO. About 60 miles
from the south coast of SHIKOKU the KUROSHIO had a velocity
of one to two knots and it did not seem to be affected by
the wind. South of the line east and west through SHIONO
MISAKI and extending through an area thirty miles in width
parallel to that line, the current was found to have a velo-
city of 3.2 knots and varied in direction as follows, setting
about 055 true from near KUROTO SAKI to about twenty miles
west of SHIONO MISAKI, and setting about 078 from there to
about 20 miles east of SHIONO MISAKI. Within ten miles of
the shore the currents around SHIONO MISAKI had the dir-
ection as shown on the chart. In the KUMANO NADA a westerly
set was found within twenty miles of the shore. Between the
KUMANO NADA and the ENSHU NADA a westerly set was found which
was best estimated as 235 true at 1.2 knots. Sixty miles south
of SHIONO MISAKI to the vicinity of the IZU SHOTO the KUROSHIO
set about 075 true with a velocity of 2 knots. South of ZENI
SU the current was found to be setting about 080 true with a

(13)

— page 203 —
CONFIDENTIAL
velocity of 3.8 knots. Northeast of MIKAYE SHIMA and thence
toward INUBO SAKI the current set northeast at about 2 knots,
just as shown on the charts.

(E) NAVIGATIONAL AIDS

The following navigational lights were seen:
HOSOSHILO KO - normal characteristics.
SHIMONOURA SHIMA - normal characteristics.
KURO SAKI - normal characteristics.
SUSAKI (?) - normal characteristics.
DAIO SAKI - one second flash every fifteen
seconds.
KO SHIMA - only the white light was seen.
MIYAKE SHIMA - normal characteristics.

The following navigational lights were not
seen burning:
TOI MISAKI - from 17 miles. Visibility was
not good.
ICHIE SAKI - from 15 miles.
SHIONO MISAKI - from 14 miles.

As several commanding officers who have made patrols in
this area have remarked, SJ contact with land should be
maintained whenever it is possible to do so. The overcast
sky and hazy atmosphere rendered celo-navigation a matter
of infrequently getting two or three stars against an
indefinite horizon between evening and morning twilights.
A position plotting device, similar to the one described
in Radar Information Notes-No. 8, facilitated determining
radar positions and the use of this device, which can be
easily made on board, is recommended.

(F) SHIP CONTACTS. All times are (I).

| No. | TIME DATE | LAT. LONG. | TYPE(S) | INITIAL RANGE | EST. CSE. SPEED | HOW CONTACTED | REMARKS |
|---|---|---|---|---|---|---|---|
| 1. | 0655 6/13 | 32-42N 133-57E | HIKAWA MARU | 16000 | 055°T 10K | JP Sound | See Below |
| 2. | 1539 6/23 | 33-39N 138-39E | See Below | 16000 | 045°T 8K | P | |
| 3. | 2248 6/23 | 34-24N 139-25E | Same as (2) | 15000 | 045°T 8K | R | |
| 4. | 0658 6/26 | 35-10N 140-44R | Patrol Gunboat | 13000 | 240°T 10K | P | Passed at 6000 yards |
| 5. | 0015 6/27 | 33-42N 140-48E | Not Known. | 6500 | 060°T 6K | R | Avoided |
| 6. | 0731 6/27 | 33-00N 140-34E | Drag-line Fishing boat | 6000 | 240°T 6K | P | Avoided |

(14)

— page 204 —
CONFIDENTIAL
Contact No. 1 - The coming of the HIKAWA MARU was anticipated
because of the airplanes which preceded it. When first
sighted by periscope the range was 12000 yards. It passed
about 6000 yards from us. There was no doubt about the iden-
tification of this ship and it was correctly marked. A cage
structure, which resembled the antenna screen shown in
pictures of captured Japanese radar, was definitely seen to
be located abaft of the stack, about half-way to the after
end of the super-structure.

Contact No. 2 - This was a convoy consisting of one PG escort,
two small unidentified ships which may have been escorts,
two trawler type escorts, two freighters of SEIHUKU MARU
(or similar 3500 ton) class, and three engine-aft freighters
or oilers of about 1800 tons.

Contact No. 4 - A PG type of patrol craft having one gun for-
ward and one gun aft. It was estimated to be about 225 feet
long. As well as could be made out from about 8000 yards
this ship had what appeared to be a cage structure erected
above the after part of the bridge similar to that on the
HIKAWA MARU.

Contact No. 6 - This boat was believed to be the same craft
that was contacted by radar at 0015. It was evidently
patrolling on a line 060-240 true at six knots.

Sampans or their lights were seen in the following
areas: One near the entrance to the BUNGO SUIDO, three 25
miles, bearing 150 from SHIONO MISAKI, one about 60 miles
on the same bearing from the same point, one off IWAZAKI
WAN, one near the 100 fathom curve east of DAIO SAKI, one
about 10 miles east of ZENI SU and eight were encountered
during our passage between MIKAYE SHIMA and KOZU SHIMA. On
most of the days when we were close to land the visibility
was such that we could not have seen a sampan unless it
passed 6000 yards or less from us, so no definite statement
can be made concerning surface patrols except in the IZU
SHOTO. It has been reported that sampans have been numerous
in that area and they were on the night of our passage.
From information of this area we fully expected to
encounter surface patrols of a very effective type north of
MIKAYE SHIMA on the night of our attack but none were
contacted.
The currents are strong and unpredictable west of the
IZU SHOTO and for this reason the opinion is offered that
east and west bound traffic only is routed this way close
to IRO SAKI and that shipping to and from the north and
southeast is routed east and west of MIKAYE SHIMA. If the
latter traffic leaves SAGAMI NADA at dusk and arrives there
at dawn, patrols in between ZENI SU and INABA SHIMA
should get results.

(15)

— page 205 —
CONFIDENTIAL
(G) AIRCRAFT CONTACTS. All times are (I).

| No. | TIME DATE | LAT. LONG. | TYPE(S) | INITIAL RANGE | EST. CSE. SPEED | HOW CONTACTED | REMARKS |
|---|---|---|---|---|---|---|---|
| 1 | 0805 6/1 | 29-26N 140-51E | - | 18m | 157°T 150K | R | Closing Dived. |
| 2 | 1220 6/1 | 29-16N 140-55E | - | 20m | - | R | Dived at 11 miles. |
| 3 | 1350 6/8 | 32-09N 132-06E | ZEKE or OSCAR | 2m | 270°T 150K | P | Went to 160 ft. |
| 4 | 0700 6/11 | 31-57N 134-15E | MAVIS | 8m | SW 120K | P | On patrol |
| 5 | 1137 6/11 | 31-58N 134-18E | MAVIS | 8m | NE 120K | P | Same |
| 6 | 0742 6/12 | 31-52N 134-04E | MAVIS | 9m | SW 120K | P | Same |
| 7 | 1035 6/12 | 31-50N 134-04E | MAVIS | 4m | NE 120K | P | Same |
| 8 | 0608 6/13 | 32-35N 134-01E | RUFE | 6m | NE 200K | P | Escort for HIKAWA MARU |
| 9 | 0643 6/13 | 32-36N 134-01E | RUFE | 4m | NE 200K | P | Same |
| 10 | 0651 6/13 | 32-37N 134-01E | BETTY | 3m | NE 200K | P | Same |
| 11 | 1045 6/13 | 32-40N 133-58E | MAVIS | 7m | NE 130K | P | On patrol |
| 12 | 1055 6/13 | 32-40N 133-58E | BETTY | 5m | NE 200K | P | Same |
| 13 | 1329 6/13 | 32-42N 133-55E | RUFE | 6m | NW 200K | P | Same |
| 14 | 1622 6/13 | 32-43N 133-49E | RUFE | 6m | NE 200K | P | Same |
| 15 | 1711 6/13 | 32-41N 133-52E | PETE | 7m | SE 150K | P | Same |
| 16 | 1811 6/13 | 32-39N 133-54E | RUFE | 8m | NW 200K | P | Same |
| 17 | 0801 6/14 | 33-17N 135-27E | UN | 8m | NW-SE 120K | P | Same |
| 18 | 1000 6/14 | 33-16N 135-24E | UN | 6m | SE 120K | P | See Below |
| 19 | 1010 6/14 | 33-16N 135-24E | UN | 6m | E-W 120K | P | Same |
| 20 | 1505 6/14 | 33-12N 135-34E | UN | 5m | SW 120K | P | On patrol |
| 21 | 1555 6/14 | 33-12N 135-35E | PETE | 6m | NW 120K | P | Same |
| 22 | 0729 6/15 | 33-25N 135-28E | KAWAN 94 | 4m | NW-SE 120K | P | See Below |
| 23 | 1029 6/15 | 33-25N 136-35E | KAWAN 94 | 3m | NW 120K | P | Same |
| 24 | 0637 6/16 | 32-30N 136-17E | MAVIS | 8m | WEST 120K | P | On patrol. |

(16)
[HANDWRITTEN: .f)]

— page 206 —
CONFIDENTIAL
(G) AIRCRAFT CONTACTS (Cont).

No. | TIME | LAT. | LONG. | TYPE(S) | INITIAL | EST | HOW | REMARKS
| DATE | | | | RANGE | CSE | CONTACTED |
| | | | | | | SPEED | |
25 | 1622 | 33-39N | 136-58E | MAVIS | 5m | NE | P | On
| 6/19 | | | | | 120 | | patrol
26 | 1406 | 33-35N | 138-42E | BETTY | 5m | 210 | P | Same
| 6/23 | | | | | 250 | |
27 | 0501 | 33-57N | 139-27E | DAVE | 6m | 260 | P | Same
| 6/25 | | | | | 150 | |
28 | 1448 | 33-49N | 140-30E | EMILY | 7m | 340 | P | Same
| 6/25 | | | | | 150 | |
29 | 0407 | 34-57N | 140-35E | MAVIS | 8m | NE | P | Same
| 6/26 | | | | | 150 | |
30 | 0415 | 34-57N | 140-35E | MAVIS | 5m | SE | P | Same
| 6/26 | | | | | 150 | |
31 | 1554 | 34-57N | 140-58E | TESS | 5m | 025 | P | See
| 6/26 | | | | | 160 | | Below
32 | 1610 | 34-57N | 140-58E | TESS | 3m | 070 | P | Same
| 6/26 | | | | | 160 | |
33 | 1620 | 34-57N | 140-58E | TESS | 7m | 180 | P | Same
| 6/26 | | | | | 160 | |
34 | 1655 | 34-56N | 141-00E | NELL | 6m | 000 | P | Same
| 6/26 | | | | | 160 | |
35 | 1705 | 34-56N | 141-00E | TESS | 5m | 310 | P | Same
| 6/26 | | | | | 160 | |

Contacts 18, 19, 22 and 23 - When first sighted these
airplanes appeared to be escorting but after watching each
for about an hour it was apparent that they were flying back
and forth around the same point and taking off and landing
in the vicinity.

Contacts 31 to 35, inclusive - When these planes were
sighted we were probably at that point over which air traffic
is routed to and from the TOKYO area.

From the very numerous airplanes that were sighted it is
concluded that the enemy makes extensive use of aircraft for
anti-submarine patrol. Large patrol boats of the EMILY and
MAVIS types are used for submarine searches 200 or 300 miles
off the coast and small float type planes are used to patrol
from the coast out to about 60 miles.

(17)

— page 207 —
CONFIDENTIAL
(H) ATTACK DATA
U.S.S. GROUPER
TIME: 0029(I)

TORPEDO ATTACK No. 1
DATE: 24 June 1944

PATROL No. 9
LAT: 34-36N
LONG: 139-32E

TARGET DATA - DAMAGE INFLICTED

Description: The attack was made on a convoy consisting of
two freighters of EIHUKU class, one PC type escort, two
trawler type escorts, three small engine-aft ships and
two small unidentified ships. This convoy was first seen
at 1530(I) of the preceeding day. After a pursuit of about
seven hours radar contact was made at 2243(I) of the same
evening and radar tracking of the convoy was commenced.
The night was very dark and the atmosphere was hazy. The
near freighter, which was painted black, was not seen
distinctly until the range to it was 3200 yards, and the
other ships, which were painted grey, were most difficult
to see even at lesser ranges. The sea was calm. A sur-
face attack was made commencing at a range of 2700 yards
from the first target. Three torpedoes from forward were
fired at (1) a freighter of the EIHUKU MARU (or similar)
class, three more torpedoes from forward were fired at
(2) what was considered to be an 1800 ton engine-aft
ship which was 600 yards astern of the freighter, and
after turning away from the convoy, three torpedoes
from aft were fired at (3) another one of the 1800 ton
engine-aft ships. From the disposition of the convoy
at the time it seemed that it would be hardly possible
for a torpedo to get through it without hitting something.

Ships Sunk: (1) One EIHUKU MARU class freighter of 3500 tons.(EC).

Damage Determined by: The first and second torpedoes were
seen to hit this ship and two timed torpedo explosions
were heard. Jets of flame appeared along its length
and shortly thereafter the ship was seen to be breaking
up and sinking. Three minutes after the torpedoes hit
this ship it was gone from sight and the PPI screen.

Ships Damaged: (3) One small engine-aft ship of 1800 tons. (EU).

Damage Determined by: A torpedo explosion was heard one
minute and forty seconds after no. 8 torpedo was fired
at this ship. That appeared to be a flame was seen on
the bearing of this ship after the explosion. This
flame increased in size and during our departure from
the area of the attack a dull red glow was seen against
the sky.

(18)

— page 208 —
CONFIDENTIAL
Ships Possibly Sunk: (3) Two of types and sizes not known. (UN)

Damage Determined by: Torpedo explosions were heard one minute
and thirteen seconds and one minute and forty-one seconds
after firing nos. 7 and 9 tubes, respectively. It is pos-
sible that two other ships in the convoy may have been hit.
One may have been the escort which fired only two shots at
us. It is considered that the four explosions, which were
heard and felt at 0039 and which occurred nearly simul-
taneously, may have been depth charges on a sinking escort.
As we were withdrawing only seven ships were seen on the
PPI screen.

(1) Target Draft 8 Course 000 Speed 8 Range 2750(at firing)
(2) Target Draft 7 Course 000 Speed 8 Range 2760(at firing)
(3) Target Draft 7 Course 000 Speed 9 Range 1450(at firing)

Own Ship Data

(1) Speed 9 Course 290 Depth Surface Angle 0 (at firing)
(2) Speed 10 Course 290 Depth Surface Angle 0 (at firing)
(3) Speed 12 Course 100 Depth Surface Angle 0 (at firing)

Fire Control and Torpedo Data

Type Attack: This was a night attack using TBT bearings and
radar ranges after the target course and speed had been
determined by radar tracking. From the time at which the
range had closed to 5000 yards the PPI was used exclu-
sively in order to observe continuously the movements of
the entire convoy. Ranges were taken from the PPI
throughout the attack and bearings from the PPI were
used for the TDC until TBT bearings were obtained.

| | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|
| Tubes Fired | Track Angle | 109 | 110 | 109 | 100 | 100 | 101 | 117 | 120 | 119 |
| Gyro Angle | ½L | 1½R | ½L | ¾L | 7½L | 10L | 17R | 20R | 18R |
| Depth Set | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Power | High | High | High | High | High | High | High | High | High |
| Hit-Miss | Hit | Hit | Miss | Miss | Miss | Miss | Miss | Hit | Miss |
| Erratic | No | No | No | No | No | No | No | No | No |
| Mk. Torp. | 14-3A | 14-3A | 14-3A | 14-3A | 14-3A | 14-3A | 13 | 13 | 13 |
| Serial No. | 40229 | 26047 | 22678 | 22181 | 22671 | 40540 | 51455 | 54195 | 54094 |
| Mk. Expldr. | 6-4 | 6-4 | 6-4 | 6-4 | 6-4 | 6-4 | 4-2 | 4-2 | 4-2 |
| Serial No. | 737 | 12931 | 1565 | 5903 | 230 | 1007 | 16821 | 16978 | 16905 |
| Mk. Warhead | 16 | 16 | 16 | 16 | 16 | 16 | 18 | 18 | 18 |
| Serial No. | 2073 | 3122 | 12370 | 2346 | 2078 | 11778 | 735 | 677 | 787 |
| Explosive | Tpx | Tpx | Tpx | Tpx | Tpx | Tpx | Tpx | Tpx | Tpx |
| Firing Int. | - | 8 | 8 | - | 8 | 8 | - | 10 | 10 |
| Type Spread | 0 | 1½R | 1½L | 0 | 1½R | 1½L | 0 | 2R | 2L |
| Sea ConditionsCalm|
| Overhaul ActivityU.S.S. SPERRY|

(19)

— page 209 —
CONFIDENTIAL
Remarks: The reasons for misses in the second attack are
believed to have been because either the torpedoes ran
too deep for the target selected or the target may have
turned, for at the range of firing there was ample time
for the target to do so.
Explosions were heard which could have been the
results of nos. 7 and 9 torpedoes each hitting a small
ship.

(I) MINES. No information.

(J) ANTI-SUBMARINE MEASURES AND EVASION TACTICS

An account of all ships and surface craft is given in
section (F). There is no doubt that the sampans seen by
day and the drag-line fishing boat were patrols for they all
appeared to be well equipped with radio. The sampan off
HINAZAKI WAN was heading for us at about 1000 yards when we
went to 120 feet. It is believed that he did not know of our
presence and that he just happened to be heading our way.
The sea was too rough for a craft that size to be doing much
listening and the rain should have given him interference
on his sound gear. The sampan which was seen off ZUMI SU
was heard to pass directly over us after we had gone to 120
feet. It is thought that this was coincidental also. In
each case we ran silent beneath a sharp thermocline at
about 90 feet to avoid being detected. When lights of
sampans were sighted we maneuvered to avoid them. On the
night of 23 June we must have passed within 2000 yards of
some of these craft as we went between them. They should
have heard us even if they didn't see us.
After the attack on 24 June the escort which had closed
us to 1200 yards just as we completed our turn commenced
firing a 3-inch gun. He fired only two shells. The escort
that was closest in pursuit of us fired fourteen 3-inch
shells. We feared at the time that he would open up with a
20 mm. but perhaps he did not have one. Fortunately for us
the faster of the escorts which sustained the chase could
make no more than twelve knots. The only escape tactics
used after this attack were to put our stern to the nearer
chaser and make all possible speed. We tracked the chasers
by PPI and TDC as we withdrew. When it was considered that
we were far enough ahead of them so that they could not
follow our wake, we changed course thirty degrees.

(K) MAJOR DEFECTS AND DAMAGE

Conning tower upper hatch latch - On 29 May the safety
latch of the conning tower upper hatch sheared just above
the catch. Repair was made by acetylene welding. On 17
June the weld failed. A new latch was manufactured and
installed.

(20)

— page 210 —
CONFIDENTIAL
Hydraulic Plant By 2 June numerous leaks had developed in
the hydraulic plant. The leather valve disc in the automatic
by-pass valve had been renewed three times. It is believed
that the damage to the disc was because the valve cylinder had
not been surfaced prior to being installed. After the above
date the hydraulic plant was operated only when submerging or
surfacing. It will be necessary to (1) renew the automatic
by-pass valve and housing, (2) grind and re-seat the hand by-
pass valve, (3) check all other valves in the system for
leaks and (4) flush out the entire hydraulic system.

Bow Planes Frequent failures, which usually were quickly
remedied, occurred in the bow plane operation because of elec-
trical grounds in the bow plane rigging and tilting circuits.
During the morning dive on 29 June the bow planes would not
rig out by power and were rigged by hand. They then would not
tilt in power. Investigation of the casualty showed that a
broken contactor had shorted across the tilting circuits and
that the power clutch for tilting would not engage. Power
rigging was restored. To restore power tilting will be a
matter of repair during refit.

No. 10 torpedo tube door On 17 June no. 10 torpedo tube
was observed to be leaking through the outer door. An un-
successful effort to stop the leak was made by taking up on
the operating linkage of the door. After the tube door had
been opened for an attempt at external inspection and again
closed, an inspection was made from inside the tube. This
inspection was necessarily most indefinite but it indicated
that the gasket on no. 10 tube had been partially or completely
lost. The only reason for thinking that the gasket may be
still there is that the outer door leaked no more after it
had been opened than before. This tube had not been fired
outboard since leaving Majuro. The sight glasses and
pressure gauges were removed and the tube was secured for
the duration of the patrol.

Battery Ventilation Blowers On 26 June nos. 1 and 3 battery
exhaust ventilation blowers stopped running during a battery
charge. Each had a wiped after support bearing. Both these
blowers were secured and battery ventilation was controlled
by nos. 2 and 4 blowers and the ship's exhaust ventilation
blower.

No. 3 Main Engine On 1 July the cylinder liner of no. 11
unit of no. 3 main engine cracked. This was a re-conditioned
liner which had been installed during the last navy yard
overhaul. The failure is believed to have been caused by
metal fatigue. The liner was replaced and the engine was
in commission again eight hours after the casualty.

(21)

— page 211 —
CONFIDENTIAL
(L) RADIO

Throughout the patrol no radio casualties occurred and
radio reception was always good. What was considered to be
deliberate jamming by the enemy was heard at various times
on 9090 kc and 6380 kc. Signal strengths at night were
checked as follows:

(1) 5 June Lat. 31N Long. 132E.
        9090kc S4
        6380kc S4
        4525kc S1

(2) 19 June Lat. 33N Long. 137E
        9090kc S5 Signal drifted.
        6380kc S3 Signal was distorted.

(3) 21 June Lat. 34N Long. 138E
        9090kc S5
        6380kc S4
        4525kc S5
        1668kc S1

(M) RADAR

SD Radar On 27 May it was observed that the SD radar was
not transmitting properly. After a thorough check of the
equipment it was determined that the fault was in the
antenna mast. On 29 May the conductors were withdrawn
from the mast and it was found that the insulators between
the conductors had fallen out of place causing the con-
ductors to short circuit intermittently. The insulators
were replaced and the mast reassembled. No. 2 periscope
was used as a topping lift in the removal and installation
of the conductors. Previous to and after the casualty
this radar functioned normally. The SD was not used at
any time between the fifth and last day in the area.

SJ Radar On 23 May resistor R-44 in the PPI unit was found
open circuited and was replaced. On 30 May the motor-
generator speed regulator failed to function because of a
weak spring in the governor. The necessary repairs were
quickly effected. During the refit a complete overhaul
of the motor-generator set will be required and the power
supply cable should be renewed. The SJ radar mast will
require alignment at that time.
    On the nights of 3 and 9 June when the sea was flat
calm SJ radar was obtaining pips at ranges from 1500 to
3000 yards, usually on bearings between 70 and 290 rela-
tive but occasionally closer to the bow. In the visibil-
ity which existed we could have seen any surface craft
and such a profusion of periscopes could hardly be
expected. It is considered that these pips, which some-
times were of good size, were (1) from our own wake for
the GROUPER was zigging on a plan that used a one hundred
degree course change and (2) from those sources described
in Radar Information Notes No. 8.

— page 212 —
CONFIDENTIAL
(N) SOUND GEAR AND SOUND CONDITIONS.

It is considered that all sound gear functioned normally
throughout the patrol.
Records made by the Underwater Sound Laboratory of various
underwater sounds were received just prior to our departure
for this patrol. These records were used for instructing
the sound watch standers with good results.
Because of the few contacts during this patrol little
information was obtained on sound conditions. On 13 June,
in Lat. 32-42N Long. 133-57E, the screws of the HIKAKA MARU
were heard at 16000 yards by JP gear but they were not heard
by the JK at 6000 yards. On 22 June the sampan which passed
over us near ZEII SU was heard at 2400 yards. On 26 June
the gunboat seen off KATSUURA was not heard at 8000 yards.
Pinging was heard from an estimated distance of 3000 yards
when the convoy was seen on 23 June in Lat. 33-39N Long.
138-39E, but JP could not hear this convoy at all.

(O) DENSITY LAYERS

As it was expected for this time of year, there were
no positive density layers and negative layers were en-
countered on every submergence. The first of such layers
were sometimes found at 90 feet but usually nearer 200
feet. There were always additional negative layers under
the shallow ones. The greatest variations were observed
when close to the coast. In the KUROSHIO the temperatures
were considered to be generally consistent. The following
are some bathythermograph recordings taken:
Date | Position | Time | I | O | 50 | 100 | 150 | 200 | 250 | 300
June |
2 | 39-50N | 1015 | 77 | 76 | 76 | 75.5 | 74 | 73 | 71
  | 138-15E |
3 | 30-06N | 0620 | 66 | 66 [HANDWRITTEN: (SS)] | 64 | 60 | | |
  | 134-30E |
6 | 31-16N | 0455 | 72 | 72 | 71.5 | 70 | 60 | 67.5 | 65.5
  | 132-15E |
7 | 31-45N | 0515 | 64 | 64 | 64 | 58 | | |
  | 132-37E |
8 | 32-07N | 0520 | 73 | 73 | 73 | 73 | 70 | 67.5 |
  | 132-01E |
9 | 32-30N | 0510 | 74 | 74 | 73 | 70 | 66 | 63 |
  | 132-00E |
10 | 32-10N | 0505 | 73 | 73 | 66 | 64 | 60 | |
  | 133-16E |
11 | 31-52N | 0455 | 72 | 72 | 72 | 70 | 70 | |
  | 134-13E |
12 | 31-56N | 0450 | 71 | 71 | 70 | 69.5 | 68 | 67 |
  | 134-04E |
13 | 32-30N | 0630 | 71 | 71 | 70 | 69.5 | 69.5 | 67 |
  | 134-00E |

(23)

— page 213 —
CONFIDENTIAL
(O) DENSITY LAYERS (Cont)
                                                                Time
Date Position Zone I      0   50  100  150  200  250  300
June
14   33-14N     0525     74  74   73   73   72   71
     135-04E
15   33-17N     0500     74  74   72  67.5
     135-15E
16   32-34N     0430     74  74   73   68
     136-15E
18   32-42N     0435     72  71   71   70   69   68
     136-30E
19   33-20N     0432     72  72   70   69   68
     136-36E
20   33-32N     0425     74  74   74   72   67   65
     136-28E
21   34-15N     0345     68  69   64   60
     137-07E
22   33-33N     0335     68  72   71   67
     138-24E
24   34-18N     0330     70  73   73   73
     140-15E
25   34-00N     0340     74  74   73   72   70
     140-25E
26   34-55N     0325     75  75   74   73   69
     140-35E
27   34-25N     0345     74  74   69
     140-37E
28   33-08N     0335     72  72   72   69
     140-38E

(P) HEALTH, FOOD AND HABITABILITY

     The health of the entire personnel was excellent
throughout the patrol. The food was good. Habitability
was very good and the ship was comfortable throughout
the days of long submergence.

(Q) PERSONNEL

     The performance of duty of all officers and men
was most satisfactory at all times. The commanding officer
and officers and the men themselves consider that those
men who had opportunity to attend the various training
schools at Pearl derived much benefit from them that could
not be obtained in any other manner. In addition, these
schools have served to stimulate the interest of the men
in the further possibilities of the equipment which they
operate as well as convince them of its importance to the
ship as a whole.

                                                      (24)

— page 214 —
CONFIDENTIAL
(Q) PERSONNEL (Cont)

The following information on personnel is furnished:
(a) Number of men on board during patrol 70
(b) Number of men qualified at start of patrol 50
(c) Number of men qualified at end of patrol 59
(d) Number of men unqualified making their
    first patrol 8
(e) Number of men advanced in rating during
    patrol 11

(R) MILES STEAMED - FUEL USED

Majuro to area 2867 mi. 32335 gals.
In area 4343 mi. 32765 gals.
Area to Midway 2518 mi. 33330 gals.

(S) DURATION

Days enroute to area 9
Days in area 29
Days enroute to Midway 7
Days submerged 27

(T) FACTORS OF ENDURANCE REMAINING

Torpedos Fuel Provisions Personnel factor
15 51,000 gals. 10 days 10 days

Patrol was terminated by operation order.

(U) REMARKS

Mark 18 Torpedoes A routine was followed of charging each
torpedo at seven day intervals using a constant three
ampere rate. The average specific gravity drop between
charges was about 20 points. Open circuit voltages upon
completion of charges averaged 192 volts. Torpedo no. 54195
had no. 9 cell jumped out on the day prior to departure from
Majuro. The cell had shown a specific gravity of about
1100 immediately after a charge. This torpedo was fired
in the attack on June 24 and the best evidence indicated
that it ran normally.

On 13 June the HIKAWA MARU (AH) was tracked at 10½
knots for which a propellor rpm count of 110 was obtained.
This does not conform with the speed vs rpm data given
on page 61 of ONI 208-J (Revised) for this class of ships.

(25)

— page 215 —
COMMANDER SUBMARINE DIVISION EIGHTY-ONE

FB5-81/A16-3                                        Fleet Post Office,
                                                    San Francisco, Calif.,
Serial 020                                          11 July 1944.

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

FIRST ENDORSEMENT to:
USS GROUPER Report of
Ninth War Patrol.

From:           Commander Submarine Division EIGHTY-ONE.
To:             Commander-in-Chief, U. S. FLEET.
Via:            (1) Commander Submarine Squadron EIGHT.
                (2) Commander Submarine Force, PACIFIC FLEET.
                (3) Commander-in-Chief, U.S. PACIFIC FLEET.

Subject:        U.S.S. GROUPER - Report of Ninth War Patrol.
                (22 May to 10 July 1944.)

                1. This patrol was conducted in waters adjacent to
KYUSHU, SHIKOKU and HONSHU and covered a period of 49 days
of which 29 were spent in the assigned area. Area coverage
was good although it was hindered by overcast skies, foggy and
hazy atmosphere.

                2. Few surface ship contacts were made - one was a
properly marked hospital ship. On the afternoon of 23 June,
an 8 knot convoy was sighted on a northeasterly course
apparently bound for SAGAMI NADA. The convoy consisted of
three escorts, two 3,500 ton AKs, three 1,800 ton cargo vessels
or oilers and two small unidentified ships. The range could not
be closed sufficiently for attack, but on surfacing at dusk,
GROUPER chased the convoy through IZU SHOTO and delivered a
night surface attack early on the 24th near the entrance to
SAGAMI NADA. A 3,500 ton AK and one of the 1,800 ton vessels
were each attacked with 3 torpedoes, and 3 Mk XVIII torpedoes
from the stern tubes were fired at another of the 1,800 ton
ships. Two good hits were seen and heard in the 3,500 ton
freighter. The target was seen to be sinking and to disappear
from the radar screen. Another timed hit in the third target
was heard and appeared as a glow or flame in the direction of
this target. Two other timed torpedo explosions were heard,
but evidence upon which to credit damage unfortunately is lack-
ing. GROUPER was driven off by gunfire from the escorts and
was prevented from further attack by the proximity of an enemy
port.

                3. GROUPER arrived from patrol in very good material
condition and will be given a normal refit including docking.

— page 217 —
FC5-8/A16-3

C-O-N-F-I-D-E-N-T-I-A-L
Serial 073

SECOND ENDORSEMENT TO
GROUPER Ninth War Patrol.

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

Subject: U.S.S. GROUPER (SS214) - Ninth War Patrol -
         comment on.

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

2. During this patrol the area was covered in accord-
ance with existing instructions. These instructions allowed for a
number of periodic investigations of coastal shipping, each of
which was limited to a period of three days. Due to the strong
currents encountered in these waters and the unfavorable conditions
for celestial navigation, these periods did not allow the submarine
sufficient time to accurately determine its position and then
boldly approach the land. By a recent change these periods adjacent
to the coast have been extended.

3. The GROUPER will be given a regular standard refit
by the Submarine Base under the supervision of Submarine Squadron
FOUR.

4. The Commanding Officer, officers, and crew are
congratulated on the damage inflicted upon the enemy.

W. M. DOWNES.
COMMANDER SUBMARINE SQUADRON EIGHT
Care of Fleet Post Office,
San Francisco, California.
12 July 1944.

— page 218 —
FF12-10/A16-3(15)/(16)
Serial 01433
CONFIDENTIAL
THIRD ENDORSEMENT to
GROUPER Report of
Ninth War Patrol.

SUBMARINE FORCE, PACIFIC FLEET
hch
Care of Fleet Post Office,
San Francisco, California,
17 July 1944.

[STAMP: JUL 19 1944]

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

COMSUBSPAC PATROL REPORT NO. 474.
U.S.S. GROUPER - NINTH WAR PATROL.

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

Subject: U.S.S. GROUPER (SS214) - Report of Ninth War Patrol.
(22 May to 6 July 1944).

1. The ninth war patrol of the GROUPER was conducted in
areas south of the Empire.

2. Two contacts worthy of torpedoes were made. One of
these, a convoy, was aggressively attacked in the early morning hours
of 24 June. Insufficient evidence does not permit crediting of more
damage to this convoy, but it is probable that other ships were sunk
or damaged.

3. This patrol is designated as "Successful" for Combat
Insignia Award.

4. The Commander Submarine Force, Pacific Fleet, congratu-
lates the Commanding Officer, officers, and crew for inflicting the
following damage upon the enemy:

S U N K
1 - Freighter (EIHUKU MARU class) (EC) - 3,500 tons (Attack No. 1)

D A M A G E D
1 - Small Freighter (EU) - 2,000 tons (Attack No. 1)

C. A. LOCKWOOD, Jr.

Distribution and authentication
on following page.
- 1 -

— page 220 —
[HANDWRITTEN: 1ST COPY]

U.S.S. GROUPER (SS214)

SS214/A16-3
CONFIDENTIAL
[STAMP: DECLASSIFIED]
Serial 010

Care of Fleet Post Office,
San Francisco, California.

15 October 1944.

From:
To :
Via :

The Commanding Officer, USS GROUPER.
The Commander in Chief, United States Fleet.
(1) The Commander Submarine Division 222.
(2) The Commander Submarine Squadron 22.
(3) The Commander Submarine Force, Pacific Fleet.
(4) The Commander in Chief, U.S. Pacific Fleet.

Subject: U.S.S. GROUPER, Report of War Patrol, number Ten.

Enclosure: (A) Subject Report.
(B) Track Charts (3 - for Comsubpac only)

1. Enclosure (A) covering the tenth war patrol
of this vessel conducted (1) in the Palau area from 1 to 5
September, (2) for life-guard duty in that area during air
strikes from 6 to 11 September, (3) east of the Philippines
and southeast of the Nansei Shoto from 14 to 25 September,
and (4) LUZON STRAIT from 26 to 29 September, during the
period 14 August to 15 October, 1944, is forwarded herewith.

[SIGNATURE: F. H. Wahlig]
F. H. WAHLIG

[STAMP: DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C]
[HANDWRITTEN: BY OPROC DATE 5/28/72]
[STAMP: DECLASSIFIED]

[HANDWRITTEN: 92258]

— page 221 —
CONFIDENTIAL
(A) PROLOGUE
On July 11, 1944, GROUPER arrived at Pearl Harbor
having the ninth war patrol completed. GROUPER was assigned
to the Commander Submarine Squadron Four and the Commander
Submarine Division Forty-Two for administration and refit.
On July 12 a two week refit was commenced by the Submarine
Base T & R Department and Submarine Division Forty-Two. On
July 27 when GROUPER was operating for training a major
casualty occurred to the stern planes which required exten-
sive work to effect repairs. On August 7 GROUPER commenced
training under the supervision of Commander Submarine Divi-
sion Forty-Two. Training was completed on August 11.
GROUPER made ready for tenth war patrol on August 12 and 13.

(B) NARRATIVE (All times are ITEM except as indicated)

August 14
1330(VW) Underway from Submarine Base, Pearl Harbor,
for tenth war patrol.
1350(VW) Took departure for MAJURO ATOLL, proceeding
in company with U.S.S. GAR and escort, PC-1077.
2000(VW) Released escort.

August 15 - 22
Enroute to MAJURO. Conducted daily dives,
battle problems, school of the boat and exercises
with U.S.S. GAR.

August 23
1015(L) Made rendezvous with MAJURO escort, U.S.S.
CROUTER (DE11)
1412(L) Entered MAJURO channel.
1525(L) Moored alongside U.S.S. SPERRY.
Took on fuel to capacity and fresh water.
Repair forces of Submarine Squadron Ten accom-
plished several minor repairs.

August 24
0945(L) Underway from alongside U.S.S. SPERRY.
1050(L) Took departure for patrol area, proceeding
in company with U.S.S. GAR and escort, U.S.S.
CROUTER.
1431(L) Released escort.

(1)

— page 222 —
CONFIDENTIAL

August 25
1030(L) Parted from U.S.S. GAR.

August 25 - 30
Enroute area. Conducted daily dives, battle
problems and schools.

August 30
0820(K) Sighted a U.S. Army "Liberator" which passed
on a westerly course about 12 miles north of us.

August 31
1130 Arrived in patrol area southeast of PALAU
ISLANDS. Proceeded towards western side of Islands.
1430 Submerged.
1615 Surfaced.

September 1
0430 Arrived in patrol area west of PALAU ISLANDS
and commenced patrol of western approaches to them.
0532 Submerged.
1905 Surfaced.

September 2
0545 Submerged.
0725 Surfaced.
0840 Started SD radar.
0900 Airplane contact on SD radar at 18 miles which
opened and disappeared at 28 miles.
0918 Airplane contact on SD radar at 1 mile. Sub-
merged. This contact was later determined to have
been in the SD equipment itself.
0943 Surfaced. Set watch on radio frequency for
Army "Liberator" strike on PALAU ISLANDS.
Listened to int r-plant communications during
strike but heard no reports of results.

(2)

— page 223 —
CONFIDENTIAL
1210 . Started the SD radar again.
1225 Airplane contact on SD radar at 20 miles which
closed rapidly. Submerged. No airplane sighted.
1335 Surfaced.
After having had two airplane contacts within
20 minutes of each time of putting the SD radar in
use, it was decided to secure the SD radar while in
this area.

September 3
0530 Submerged.
0853 Surfaced.
0930 Set watch on radio frequency for Army "Liberator"
strike on PALAU ISLANDS.
Again only inter-plane communications were heard.
1259 Sighted a "Liberator" about 15 miles south
of us, heading for the Islands.
1400 Secured watch on "Liberator" frequency.

September 4
0000 Commenced closing BABELTHUAP ISLAND.
0406 Submerged.
0837 Proceeded southward parallel to reefs and about
8 miles from them.
1417 Commenced closing TOAGEL MLUNGUI channel.
1916 Surfaced and proceeded to westward.

September 5
0055 Commenced closing BABELTHUAP ISLAND.
0515 Submerged.
1105 Proceeded southward parallel to the reef and
about 3 miles from it.
1605 With the entrance to TOAGEL MLUNGUI channel
bearing 120 true, distant about 3 miles, sighted
smoke of a ship approaching the channel from inside
the reef.
1620 Made out the ship to be a small naval vessel
which appeared to be of a converted yacht or mine-
sweeping type. He was zigging radically at about 6
knots speed on a base course which was almost directly
towards our position. No echo-ranging was heard.
After looking this ship over carefully it was
concluded that he was clearing the way for ships that
would be departing later. Our position was considered

(3)

— page 224 —
CONFIDENTIAL

to be very desirable should the latter occur. It
was decided to avoid being detected if possible and
await developments.
1640 When the range was 3200 yards started deep to
let the ship pass over us. Shortly thereafter his
screw count went from 120 to 180 turns. We felt
sure that we had not been detected and that he was
1651 just increasing speed.
1740 Sound lost contact on screws.
1740 Started up to periscope depth.
At periscope depth sighted the tops of stack
and masts of the same ship bearing 250 true at about
8000 yards. He soon disappeared from sight on an
estimated course of 300 true.
Commenced continuous periscope watch on harbor
and channel. As darkness approached it was apparent
nothing was going to come out of there this evening.
1902 Surfaced and proceeded on course 300 true on
the chance of overtaking the vessel seen earlier
and perhaps engaging him with gunfire in the moon-
light before it became time to proceed to life-guard
station for the next day.
2300 Proceeded toward station for life-guard duty.

September 6
0520 Arrived at life-guard station.
With PELELIU ISLAND, on which the main air-
field is situated, 11 miles away and ANGAUR ISLAND
14 miles away, it was hoped that our fighter
escort would soon arrive, for we were easily visible
from land.
0858 Having heard nothing on the radio which would
indicate that the rest of the striking force was
in the vicinity, and not feeling confident that we
alone had control of the situation while in such a
position, submerged and commenced closing PELELIU
ISLAND.
1400 Sighted striking force planes approaching
PELELIU.
1410 Surfaced.
1429 Four night-fighters took station over us.
1510 Commenced keeping station about 4 miles off
PELELIU ISLAND.
1600 Air strike was completed for the day and
escorts departed.
1610 Submerged and proceeded to westward on course
270 true.

(4)

— page 225 —
CONFIDENTIAL
1902 Surfaced.
1906 Changed course to 300 true to intersect
     possible departures from PALAU harbor.

September 7

0030 Proceeded toward position for life-guard duty.
0530 Arrived at life-guard station.
0611 Two night-fighters took station over us. Pro-
     ceeded toward BABELTHUAP ISLAND.
1635 Air strike was completed for the day and
     escort departed.
1649 Proceeded to westward.

September 8

0130 Proceeded toward life-guard station.
0535 Arrived at life-guard station. VHF radio had
     failed and was out of commission. For communications
     with escorting airplanes the APR-1 receiver was
     used for listening to VHF and our transmissions
     were sent on the primary carrier frequency. In
     this way satisfactory communications were established.
     Our escort was informed of the VHF failure which
     was thought to be an 832 tube.
0703 Two night-fighters took station over us.
0806 Commenced keeping station about 3½ miles
     west of PELELIU ISLAND.
1003 A LEXINGTON SB2c airplane came alongside and
     dropped an 832 tube for VHF.
1005 Commenced maneuvering to retrieve tube.
1012 Just as we were in position to pick up the
     tube a report was received that a burning airplane
     was approaching us.
1015 An SB2c sat down about 500 yards off the port
     bow. This plane sank in about 30 seconds after
     hitting the water.
1020 While all the squadron hovered over us to
     watch proceedings, took on board the two occupants
     of the airplane, which was from VB-19, USS LEXINGTON:

     Lieutenant William H. CRAVENS, USNR, File No.
     98388 - pilot.
     GRAY, Ira G., 617 34 63, ARM3c, USNR -
     radioman.

     Reported to escort that survivors were on
     board and apparently neither was seriously injured.

(5)

— page 226 —
CONFIDENTIAL

and that further report would be made as soon as
their exact condition was determined. Put both
below and pharmacist's mate went to work on them.
Lieutenant CRAVEN was suffering only from shock,
swallowing salt water and muscular soreness. GRAY
was brought on board unconscious because of sub-
mergence. He had a laceration of the right ankle and
slight abrasions of the leg. All indications were
that both would be in good shape in several days.
1025 Resumed recovery of tube for VHF.
1032 Recovered tube.
1100 Put new tube in VHF and discovered that it
was not what was the cause of the failure.
Received a message from escort asking if pilot
or radioman was injured and requesting receipt
for tube.
1153 Made report on condition of survivors and
receipted for tube.
Received report that there were three men in
a raft at a position 6 miles east of ANGAUR ISLAND.
Proceeded toward that point at four engine speed taking
course to pass between PELELIU and ANGAUR ISLANDS.
1155 Received report that an airplane was down 4
miles southwest of PELELIU ISLAND. Both escort
planes went off to investigate.
1239 Called for one of the escorts to come back
because I desired him to strafe gun position on
ANGAUR ISLAND which we would pass at about 4000
yards. The escort returned and strafed the gun
position as we passed. He must have known why he
was wanted.
1256 Recovered one survivor from torpedo bomber of
Squadron VT15, U.S.S. ESSEX, which was the second
airplane reported. There were no signs of other
personnel. A large gasoline slick was seen where
the airplane had sunk. Two of our bridge watch
had seen this airplane go down. It had been burn-
ing furiously then and it had exploded when it
hit the water. No one was seen to leave the
airplane before it crashed. The survivor was the
pilot,
Lieutenant Charles D. WEBB, USNR,
File No. 114842
1258 Lieutenant WEBB had second degree burns of the
face and right thumb. He had administered himself
very effective first aid. The pharmacist's mate
gave him routine treatment and confined him to bed.
Reported rescue of Lieutenant WEBB to escort.
Proceeded to position of raft. Requested
one escort to continue search for survivors from
Lieutenant WEBB's airplane.

(6)

— page 227 —
CONFIDENTIAL
1317
Recovered all the following personnel from a
torpedo bomber of Squadron VT15, U.S.S. ESSEX:
Lieutenant Walter E. HARPER, USNR, File No.
263860 - pilot.
DOLD, John F., 202 52 72, ARM2c, USN -
radioman.
BURKETT, George F., 268 89 40, AMM1c, USN -
gunner.

The above were sitting very comfortably in
their raft when we first saw them. They could
have looked no more comfortable or satisfied if
they were out there on a fishing trip. Reported
this rescue to our escort.

Numerous reports had been received of downed
airplanes. All these were plotted immediately
upon being received. It was apparent that many
of the reports were on the same airplanes from
different witnesses. That this would happen was
expected. For this reason we endeavored to get
all positions charted. At this time it was
determined that crashes had occurred at these
positions:
(1) 190-15 miles from reference
(2) 195-36 miles from reference
(3) 210-29 miles from reference
(4) 197-32 miles from reference

Recoveries had been made at positions (3) and
(4). We proceeded with one escort to position
(2) and sent the other escort to investigate
position (1). The escort reported nothing at
position (1) and we found nothing at position (2).
A report of one crash stated there were no survi-
vors and no position was given. The LEXINGTON
base asked if the following positions had been
investigated: 190-15 and 195-36. We reported that
we had done so and nothing had been sighted at
either of those positions and added that survivors
had been rescued at 210-29 and 197-32. The
LEXINGTON base receipted for our message. It was
assumed that positions (2) and (4) were the same
and that (1) was an error in reporting (3).
1333 Commenced return to station.
1530 Air strikes were completed for day and escorts
departed.
1545 Sent message over carrier frequency to ESSEX
and LEXINGTON reporting names of six rescued person-
nel. No receipt was obtained.

(7)

— page 228 —
CONFIDENTIAL
1600 Proceeded westward.
1906 Set course 330 true to cross approaches to
PALAU ISLANDS.

September 9

September 10

0045 Proceeded to life-guard station.
0545 Arrived at life-guard station.
0640 Since heavy rains prevented air strikes, com-
menced patrol across western approaches to PALAU
ISLANDS.

September 10

0530 Arrived at life-guard station and commenced
closing land.
1014 Air escorts took station over us.
A report had been heard earlier during morning
that a rubber life-raft with one occupant had be
seen in the harbor. This report was not addressed
to us but subsequently we had a report that the
survivor was inside harbor and that we could not
get to him and added that survivor was attempting
to work his way over reef.
1220 Heard report that two men in a life-raft were
attempting to work their way out across the reef
of PALAU harbor. Escort went to investigate and
reported two men on a rock in the harbor.
1228 Received message recommending we take position
on eastern side of Islands at bearing 150 and 20
miles from reference. Proceeded toward that
position at four engine speed.
1454 Arrived at new station.
1455 Requested escort to investigate PALAU harbor
for survivors.
1500 Escort reported no information for us.
1555 Requested escort to investigate harbor again.
1600 Escort reported no information.
1710 Sighted what appeared to be a white smoke
signal coming off water near beacon at entrance
to PALAU passage. Requested escort to investi-
gate.
1712 Escorts reported no information and departed.
Air strike completed for day.
1713 Proceeded toward position for next day.

(8)

— page 229 —
CONFIDENTIAL

September 11

0630 Arrived at life-guard station.
0738 Air escorts took station over us. Established
VHF communications.
0740 Received a report survivor in water 5 miles
due west of PELELIU ISLAND. Proceeded at four
engine speed.
0840 Picked up the following named survivor 2½
miles northwest of PELELIU ISLAND:

Abner HARRIS, 708 88 98, AR3c, USNR, VB13,
U.S.S. FRANKLIN.

He had bailed out of his plane, an SB2c,
and was uninjured. The name of the pilot, LIEUT.
KEOHD, was obtained from HARRIS. The escorts
were informed of the survivor and requested to
conduct search for the pilot. Several of the
planes of the squadron stayed to witness the
recovery and when the man was safely on deck a
report was received that the name of the man res-
cued was MORAN and to tell him he would have
company(?). Since the planes had assumed that it
was MORAN we had rescued there was a little diffi-
culty to overcome before finally getting through a
report on HARRIS.
0845 One of the FRANKLIN planes dropped a condensor
for our VHF radio for which we thanked him.
0850 Picked up condensor.
0900 Took station about 5 miles northwest of
PELELIU ISLAND.
1513 Escorts departed. Air strikes for the day
completed.
1643 Submerged.
1723 Surfaced.
1800 Proceeded to clear PALAU area as directed in
operation order.
Reported results of life-guard duty to the
Commander Submarine Force.

September 13

0638 Changed course to 305 true.
1237 Sighted an unidentified airplane on an easterly
course which went into a cloud on bearing 165 true,
distant about 7 miles.
1245 Sighted an unidentified airplane on a westerly
course bearing 175 true, distant about 8 miles.
Submerged. This may have been the same airplane

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1315 that was previously sighted.
1436 Came to periscope depth. Nothing was in sight.
     Surfaced.

                     September 14

0545 Interference obtained on the SJ radar,
     determined to be friendly.
0553 Changed course toward radar source.
0705 Sighted the periscope of a submarine on the
     surface.
0707 Exchanged recognition signals by SJ radar
     and commenced closing the submarine.
0729 Identified other submarine as the SEAHORSE
     with which GROUPER was to make rendezvous.
0750 Received on board mail from group commander
     which contained instructions for operations with
     coordinated submarine group.
0753 Departed from other submarine enroute to
     assigned patrol station.
1030 Arrived at assigned station about 500 miles
     east of LUZON. Commenced reconnaissance patrol on
     surface in compliance with instructions for patrol
     issued by group commander.

                     September 18

1200 In obedience to orders from the commander of
     the coordinated submarine group set course 350 true
     to proceed at 11 knots to change of patrol station.

                     September 19

1936 In obedience to modification of previous orders
     from commander submarine group set course 325 to
     proceed at 13 knots for special duty.

                     September 20

1424 Arrived at station and commenced patrol.
1520 Submerged.
1940 Surfaced.
1945 Set course 070 true to continue on to patrol
     station at 11 knots.

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CONFIDENTIAL

September 21

0555        Arrived at patrol station 170 miles southeast
            of SAKISHIMA GUNTO and commenced offensive re-
            connaissance patrol in compliance with instruc-
            tions for patrol issued by group commander.

September 22

1134        Sighted an unidentified airplane which passed
            to the south on an easterly course, distant about
            7 miles. Submerged.
1337        Surfaced.

September 23

0730        Sighted a BETTY which passed to the south on
            a westerly course, distant about 6 miles. Submerged.
1033        Surfaced.
1236        In obedience to orders from group commander
            proceeded to change patrol station on bearing 290
            true, distance 150 miles.

September 24

0900        Arrived at patrol station and continued
            patrolling as before.

September 25

0900        In obedience to orders from group commander
            proceeded independently to change of patrol station.

September 26

0614        Submerged at the eastern entrance to BASSHI
            CHANNEL on course 225 true.
0718        Sighted NELL on northeasterly course which
            passed to the southeast, distant about 10 miles.
2012        Surfaced. Y'AMI ISLAND was bearing 145 true,
            distant 14 miles.
2110        Radar indication on APR-1 of 150 megacycles.
            This signal, weak and intermittent at first, grad-
            ually became much stronger and more frequent. Commenced

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CONFIDENTIAL

looking for an airplane. The moon was a little
more than half full and five hours from setting.
2117 The same radar interference had been steady
and very strong for 30 seconds. Submerged.
2136 Heard an explosion, thought to be a bomb,
which was estimated to be several miles away.
2157 Both JP and JK sound operators reported light
fast screws which quickly faded out. The bearing
of these screws was 145 true.
2230 Surfaced. Set course 230 true at 11 knots.
No indications of radar shown by the APR-1.
2235 Sighted two lights bearing 030 true, distant
about 3 miles. Lights believed to be those shown
by sampans in these waters.
2353 Radar indications on APR-1 of 150 megacycles.
Signal was weak and infrequent.

September 27

The previous radar indications continued weak
and infrequently.
0205 The same radar indication became very strong
and constant. Submerged.
0320 Surfaced. No radar indications shown on APR-1.
The moon had set and the night was very dark and
clear.
0335 Radar indication of 150 megacycles on APR-1.
This signal was very strong and constant for about
20 seconds and was increasing rapidly in strength
as the APR-1 antenna went under as we submerged.
0835 Surfaced. Set course 270 true at 11 knots.
0910 Radar indication of 150 megacycles on APR-1.
This signal was strong and constant and quickly
increased to maximum on SPA screen.
0913 Submerged. No airplane sighted.
0923 Heard distant explosion.
0948 Surfaced.
1037 Radar indication at 92 megacycles on APR-1.
This indication persisted throughout the day.
The frequency of its appearance and its strength
was variable.
1305 Arrived in assigned patrol area southwest of
FORMOSA and commenced patrolling on north and
south courses in lane twenty miles wide.
1402 Sighted TESS on course north which passed
about 12 miles to the east.
1442 Sighted an unidentified airplane heading
toward us from the south, distant about 9 miles.
No radar indication on APR-1 except the previous
92 megacycles which was weak and intermittent. Sub-

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CONFIDENTIAL

1530 norgod.
1534 Surfaced.
         Lookout reported an airplane diving toward us
         from out of a cloud. Submerged. Believe this
         dive was on the house.
1651 Surfaced.

September 28

         The radar indication at 92 megacycles still
         showed at intervals on the APR-1. As the night
         progressed it became weaker until 0250, when from
         this time until about 0340 it was stronger and
         more frequent than it had been previously.
         Submerged.
0621 Sighted BETTY at three miles which appeared
0857 to be circling us. Started to 140 feet.
0920 At periscope depth no airplane was sighted.
0950 Sighted high peaks of FORMOSA.
1138 Sighted two BETTYS and a TOPSY flying together
         on course north. They passed to the east at
         about 5 miles.
1255 Surfaced.
1345 Radar indication at 150 megacycles on APR-1.
         Signal was strong and constant. Submerged. No
         airplane sighted.
1910 Surfaced.
1938 Radar indication of 150 megacycles on APR-1.
         Submerged. The night was very bright with a large
         moon and few clouds. No airplane was sighted.
2056 Surfaced.
2230 Proceeded to depart area via BALINTANG CHANNEL.

September 29

0150 Sighted hospital ship bearing 194 true,
         distant about 9 miles. This ship's course and
         speed were estimated to be 060 true and 12 knots.
         At the time BALINTANG ISLAND was bearing 090 true,
         distant 70 miles. Changed course to 090 true
         to avoid hospital ship and pass through BALINTANG
         CHANNEL.
0315 Hospital ship passed out of sight to westward.
0520 Cleared BALINTANG CHANNEL.
0600 Submerged.
1117 Sighted FRANCIS on course north which passed
         to the west at 8 miles.

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— page 234 —
CONFIDENTIAL
1315 Sighted NELL on a northerly course which passed
     to the east, distant about 8 miles.
2000 Surfaced.
     Set great circle course for western end of
     SAIPAN safety lane.

September 30 - October 6
Enroute to Saipan. On the morning of October 3
typhoon weather was encountered which lasted through
October 5, and heavy seas persisted in SAIPAN area
through October 6. GROUPER fortunately did not
encounter the center of this storm, but in heavy
seas made a maximum speed of seven knots possible
on October 4 and 5.

October 6
0530 Made rendezvous with SAIPAN escort, USS HERALD
     (AM101), and proceeded toward SAIPAN.
1205 Released escort.
1207 Entered channel.
1253 Moored alongside the U.S.S. FULTON.

October 6 - 7
Obtained fuel and provisions from U.S.S. FULTON.
The repair forces of FULTON and Submarine Squadron
Eight accomplished urgent voyage repairs.

October 8
0705 Underway from alongside U.S.S. FULTON.
0751 Departed entrance buoys SAIPAN channel, enroute
     to MAJURO, proceeding in company with escort, USS
     MOTIVE (AM102).
1343 Released escort.

October 8 - 15
Enroute from SAIPAN to MAJURO

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CONFIDENTIAL
October 15

0827(L) Made rendezvous with MAJURO escort, USS
CROUTER (DE11).
1230(L) Entered MAJURO channel.
1340(L) Moored alongside, U.S.S. H.W. GILMORE,
having completed a 16008 mile circuit of the
Central Pacific Ocean Forward Area.

(C) WEATHER

The weather in all areas was normal for the time of
year. The only adverse weather was the typhoon which was
encountered on October 4 in latitude 13 north, longitude
140. This caused heavy seas lasting through October 6.

(D) TIDAL INFORMATION

The currents observed in the PALAU area conformed to
the current data contained in JICPOA Bulletin no. 87-44.
In the western PACIFIC OCEAN and LUZON STRAIT the currents
were as described in the pilot charts and coast pilots for
those areas.

(E) NAVIGATIONAL AIDS

The navigational aids in the PALAU ISLANDS are ade-
quately described in JICPOA Bulletin No. 87-44. No other
navigational aids were sighted.

(F) SHIP CONTACTS

| No. | Time Dato | Lat. Long. | Type(s) | Initial Range | Est. Course Speed | How Cont-acted | Remarks |
|---|---|---|---|---|---|---|---|
| 1 | 1705(I) Sept.5 | 7-37N 134-32E | Small Naval | 12000 yd. | 310 6-8 | Periscope | Escort SC or AI |
| 2 | 0150(I) | 19-50N 121-26E | AH | 20000 yd. | 050 11 | | Correctly Sight Lighted and Marked |

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CONFIDENTIAL

(G) AIRCRAFT CONTACTS

CONTACT NUMBER | 1 | 2 | 3 | 4 | 5
S Date | 8-30 | 9-2 | 9-2 | 9-3 | 9-13
U Time (Zonc) | 0820K | 1000K | 1225K | 1359K | 1237I
B Position: Lat. (N) | 06-27 | 07-23 | 07-23 | 07-30 | 12-04
M Long (E) | 143-40 | 132-32 | 132-30 | 133-41 | 129-34
A Speed (knots) | 15 | 9 | 10 | 11 | 11
R Course (true) | 270 | 090 | 090 | 180 | 305
I Trim | Surf. | Surf. | Surf. | Surf. | Surf.
N Minutes Since Last
E SD Radar Search | 0 | 0 | 0 | --Not in Use--

— page 237 —
CONFIDENTIAL

(G) AIRCRAFT CONTACTS (Cont)

CONTACT NUMBER | 6      | 7      | 8      | 9      | 10
|||||
SUBMARINE      |        |        |        |        |
Date           | 9-13   | 9-22   | 9-23   | 9-26   | 9-26
Time(Zone)     | 1245I  | 1134I  | 0730I  | 0715I  | 2110I
Position: Lat. (N)| 12-04  | 22-35  | 22-49  | 24-09  | 21-02
Long. (E)      | 129-34 | 127-00 | 123-09 | 122-04 | 121-25
Speed (knots)  | 11     | 11     | 11     | 3      | 10.5
Course (true)  | 305    | 290    | 260    | 225    | 235
Trim           | Surf   | Surf   | Surf   | Sub    | Surf
Minutes Since Last| ---    | ---    | ---    | ---    | ---
SD Radar Search| ---    | ---    | ---    | ---    | ---
               | Not in use

AIRCRAFT       |        |        |        |        |
Number         | 1      | 1      | 1      | 1      | 1
Type           | Unid   | BETTY  | BETTY  | NELL   | Unid
Probable Mission| Pat.   | Pat.   | Pat.   | Pat.   | Pat.
How Contacted  | Sight  | Sight  | Sight  | Sight  | APR-1
Initial Range (miles)| 6      | 5      | 5      | 5      | 1
Elevation Angle| 1      | 3      | 3      | 2      | 1
Range & Relative|        |        |        |        |
Bearing of Plane|        |        |        |        |
When It Detected|        |        |        |        |
S/M:           | ND     | ND     | ND     | ND     | Unk.

CONDITIONS     |        |        |        |        |
Sea: (State (Beaufort)| 1      | 4      | 4      | 1      | 1
(Direction(Rel)| 240    | 200    | 100    | 150    | 160
Visibility (miles)| 15     | 15     | 10     | 15     | 5
Clouds: (Height in Ft.| 10000  | 10000  | 10000  | 12000  | 10000
(Percent Overcast| 8      | 8      | 5      | 5      | 3

MOONS          |        |        |        |        |
(Bearing (Rel) |        |        |        |        | 220
Moon: (Angle   |        |        |        |        | 40
(Percent Illum.|        |        |        |        | 60

Type of S/M Camouflage on this patrol - Light gray.

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CONFIDENTIAL
(G) AIRCRAFT CONTACTS (Cont)

CONTACT NUMBER | 11 | 12 | 13 | 14 | 15
S | Date | 9-27 | 9-27 | 9-27 | 9-27 | 9-27
U | Time (Zone) | 0205I | 0335I | 0913I | 1402I | 1442I
B | Position: Lat. (N) | 21-03 | 21-00 | 21-01 | 21-17 | 21-10
M | Long. (E) | 120-47 | 120-45 | 120-27 | 120-02 | 120-01
A | Speed (knots) | 11 | 11 | 11 | 10.5 | 10.5
R | Course (true) | 270 | 270 | 270 | 180 | 180
I | Trim | Surf | Surf | Surf | Surf | Surf
N | Minutes Since Last | - | - | - | - | -
E | SD Radar Search | - - - - -Not In Use- - - - -

A | Number | 1 | 1 | 1 | 1 | 1
I | Type | - | - | - | TESS | TESS
R | Probable Mission | Pat | Pat | Pat | Trans | Trans
C | How Contacted | APR-1 | APR-1 | APR-1 | Sight | Sight
R | Initial Range (miles) | - | - | - | 12 | 9
A | Elevation Angle | - | - | - | 3 | 4
F | Range & Relative
T | Bearing of Plane
  | When it Detected S/M | ND | ND | ND | ND | ND

C | Sea: (State (Beau- | 1 | 1 | 1 | 1 | 1
O | fort)
N | (Direction (Rel) | 160 | 160 | 160 | 160 | 160
D | Visibility (Miles) | - | - | 30 | 20 | 20
I |
T | Clouds: (Height in | 1500 | 1700 | 2000 | 10000 | 10000
I | Ft.
O | (Percent | 2 | 3 | 2 | 2 | 2
N | Overcast
S | Moon: (Bearing (Rel) | Set | Set | | |
  | (Angle | Dark | Dark | | |
  | (Percent
  | Illum.

Type of S/M Camouflage on this patrol - Light gray.

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— page 239 —
CONFIDENTIAL
(G) AIRCRAFT CONTACTS (Cont)
CONTACT NUMBER
| | 16 | 17 | 18 | 19 | 20 |
|---|---|---|---|---|---|---|
| S | Date | 9-27 | 9-28 | 9-28 | 9-29 | 9-29 |
| U | Time (Zone) | 1534I | 1346I | 1939I | 0857I | 1138I |
| B | Position: Lat.(N) | 21-06 | 20-45 | 20-49 | 20-59 | 20-59 |
| M | Long (E) | 120-00 | 120-04 | 120-25 | 120-05 | 120-04 |
| A | Speed (knots) | 10.5 | 11 | 11 | 2.5 | 2.5 |
| R | Course (true) | 180 | 180 | 150 | 000 | 180 |
| I | Trim | Surf | Surf | Surf | Sub | Sub |
| N | Minutes Since Last | | | | | |
| E | SD Radar Search | | Not In Use| A | Number | 1 | 1 | 1 | 1 | 3 |
| I | Type | Unid | - | - | BETTY | 2 BETTY |
| R | | | | | | 1 TOPSY |
| C | Probable Mission | Pat | Pat | Pat | Pat | Trans |
| R | How Contacted | Sight | APR-1 | APR-1 | Sight | Sight |
| A | Initial Range (miles) | 10 | - | - | 3 | 10 |
| F | Elevation Angle | 4 | - | - | 25 | 3 |
| T | Range & Relative | | | | | |
| | Bearing of Plane | ND | ND | ND | ND | ND |
| | When It Detected | | | | | |
| | S/M | C | (State (Beau- | | | | | |
| O | Sea: (fort) | 1 | 1 | 1 | 1 | 1 |
| N | (Direction(Rel) | 160 | 080 | 080 | 070 | 070 |
| D | Visibility (Miles) | 20 | 30 | 30 | 20 | 30 |
| I | (Height in | | | | | |
| T | Clouds: (Ft. | 10000 | 2000 | 2000 | 10000 | 10000 |
| I | (Percent | | | | | |
| O | Overcast | 2 | 6 | 7 | 4 | 4 |
| N | (Bearing(Rel) | | | | | |
| S | Moon: (Angle | | | | | |
| | (Percent | | | | | |
| | Illum. | | | | | |

Type of S/M Camouflage on this patrol - Light gray.

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— page 240 —
CONFIDENTIAL
(G) AIRCRAFT CONTACTS (Cont)

                                                              21             22
CONTACT NUMBER

S   Dato                                                      9-29           10-2
U   Time (Zone)                                               1117I          0920I
B   Position: Lat. (N)                                        20-07          19-25
M             Long (E)                                        122-31         133-59
            Speed (knots)                                     2.5            17
            Course (true)                                     090            100
            Trim                                              Sub            Surf
            Minutes Since Last
            SD Radar Search                                   Not in Use

A           Number                                            1              1
I           Type                                              FRANCIS        Unid
R           Probable Mission                                  Pat            Unk
C           How Contacted                                     Sight          Sight
R           Initial Range (miles)                             12             4
A           Elevation Angle                                   5              10
F           Range & Relative
T           Bearing of Plane
            When It Detected
            S/M                                               ND             ND

C           (State (Beau-
O   Sea:    fort)                                             1              3
N           (Direction (Rel)                                  120            090
D   Visibility (miles)                                        30             30
I           (Height in
T   Clouds: Ft.                                               8000           6000
I           (Percent
O           Overcast                                          4              7
N
S           (Bearing (Rel)
    Moon: (Angle
            (Percent
            Illum.

Type of S/M Camouflage on this patrol - Light gray.

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(H) ATTACK DATA

     No attacks made.

(I) MINES

     None encountered.

(J) ANTI-SUBMARINE MEASURES AND EVASIVE TACTICS.

     The only anti-submarine measures encountered were
enemy aircraft which were presumed to be on anti-submarine
patrol. In LUZON STRAIT the APR-1 receiver was employed
when on the surface to search for radar equipped enemy patrol
aircraft. When a radar indication became constant and
increasing in strength, GROUPER submerged. In this manner
the GROUPER probably avoided a bombing attack on the night
of September 26 by submerging for a radar indication at
2117, after which a bomb explosion was heard at 2136.

(K) MAJOR DEFECTS AND DAMAGE

     WRT Tank Overflow Valve. On about September 22 it was
determined that WRT tank overflow valve was leaking, per-
mitting water from WRT tank to flow into forward trim tank.
Investigation revealed that the gasket of the WRT tank
overflow valve had slipped out of place.
     No.9 Torpedo Tube Outer Door Gasket. On September 28
it was found that no. 9 torpedo tube was taking water through
a leak at the upper part of the outer door. At SAIPAN a
diver found the outer door gasket unseated and slightly
deformed. A new gasket was installed. On the previous
patrol of GROUPER a similar casualty occurred to the gasket
of the outer door of no. 10 torpedo tube. It is understood
that other submarines have experienced this same casualty.
An investigation should be made to determine and eliminate
the cause of this gasket failure.
     Main Storage Battery. On September 22 it was found
that tops of several cells in each battery had opened at
the edges and leakage of electrolyte had resulted. Both
batteries were thoroughly cleaned and the leaking cells
re-sealed. During the storm from October 4-6 again a number
of cell tops were opened, mostly in the outboard rows of
cells. Working under adverse conditions an attempt was
made to clean the batteries and re-seal the opened cells.
This attempt was not successful and when GROUPER arrived
alongside the FULTON, there were full grounds in both
batteries. While alongside the FULTON both batteries were
thoroughly cleaned, broken cell tops re-sealed, ventilation

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— page 242 —
CONFIDENTIAL
ducts cleaned and re-pariffined and the battery completely
inspected for grounds. Grounds were found which rendered
battery charging unsafe. GROUPER experienced similar trouble
to a less degree during the previous patrol. During the
past refit at the Submarine Base, P.H., loose wedging was
made secure and additional wedging placed in order to
prevent re-occurrence of the casualty. As this is a matter
of utmost consequence, the elimination for this defective
condition will be stressed during the coming refit.

(L) RADIO

Reception. Strength of reception on all frequencies
varied from S-1 to S-4. On occasion reception on 6380 kcs.
was better than on the other frequencies. Jamming by con-
tinuous transmissions from enemy sources usually occurred
during the HAWAII schedule and during early morning hours
on the foregoing frequencies.
Transmission. Attempts to deliver traffic during
daylight hours on October 3 and 4 were not successful. All
frequencies were tried, including higher harmonics of the
4235 series. In each case frequency calibrations had been
carefully checked and transmitter meters indicated that
the transmitter was functioning properly. After twilight
prompt delivery of traffic was effected. It is believed
that spray and salt accumulations caused loss of trans-
mission power at the antennae.
VHF. On September 6 the VHF motor generator lost its
residual magnetism. This magnetism was restored and the
motor generator was put in use again on September 9. The
ship's force had previously arranged a 28 volt supply from
the ship's power for use while the generator was out of
commission. On September 7 the VHF radio failed because
of a defective four section condensor. From then until
September 10, when the condensor made up by the ship's
force was installed in the VHF, the APR-1 receiver was used
for listening to airplane communications on VHF frequencies.
Transmissions to the airplanes was made by voice over the
TBL on the primary air frequency.
APR-1 Receiver. This receiver was used very success-
fully for listening to aircraft voice communications.

(M) RADAR

The SD radar was not used from the second day in the
PALAU area until the day prior to arrival of GROUPER at
SAIPAN. When in use its operation was satisfactory.
The SJ radar functioned very satisfactorily throughout
the entire patrol. A key which was installed in the trans-

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— page 243 —
CONFIDENTIAL
mitting current by the ship's force made communication
by SJ radar possible and on one occasion recognition was
effected with another submarine by this means. The SJ
keying arrangement as specified by Consubpac Conf. ltr.
FF12-10/S67-5/(20) Serial 01614 of August 4, 1944, will be
requested for the coming refit. The SJ radar was operated
only occasionally during the time spent in LUZON STRAIT.
The APR-1 and SPA were used to search for enemy
radar. At first indications were obtained on various
ship installations in the vicinity of this receiver.
These included the SJ and SD radars and ventilation fans.
In the case of the SJ and SD radars the frequencies of
the APR-1 response were determined so that they would
not be confused with enemy radar intercepts. It was also
found the SJ radar with high voltage off produced an APR-1
SPA indication at about 250 megacycles. This signal was
not of great intensity and had neither the appearance nor
sound of a radar signal. A similar effect at about 96
megacycles was produced by the SD radar with high voltage
off. The ventilation fans individually and collectively
produced various signals. In every instance of these
signals the pulse rate fluctuated and diminished with
decrease of SPA gain. After cataloguing these spurious
signals it was considered that search for enemy radar
signals could be made with definite results. When an
indication of enemy radar was received in the APR-1 and
SPA its frequency and pulse form were noted and search
was continued throughout the range of the APR-1 with a
pause at the indicated frequency for observation of the
of the intercepted signal. In each case when GROUPER
submerged for an APR-1 indication the SPA screen showed
for the intercepted signal (1) that the frequency of the
sweeps increased (2) that the strength of the signal
increased gradually (3) that the signal became constant
and strength increased rapidly. Distance and bearing of
the radar source were neither determined nor estimated.
To provide for some determination of the relative bearing
of radar intercepts the modification of the APR-1 antenna
as specified in Consubpac Conf. ltr. FF12-10/S67-5/(20)
Serial 01581 of 1 August, 1944, will be requested for the
coming refit. Data on interception of enemy radar trans-
missions is contained in section (U) of this report.

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— page 244 —
CONFIDENTIAL
(N) SOUND GEAR AND SOUND CONDITIONS

     The single ship contact on September 5 off the PALAU
ISLANDS indicated that sound conditions there were very
good for both sonic and supersonic listening. The light
fast screws heard on the night of September 26 in LUZON
STRAIT did not persist long enough to give an indication
of sound conditions there. It is considered that all sonic
and supersonic equipment functioned satisfactorily through-
out this patrol.

(O) DENSITY LAYERS

     Density layers were found in various areas as follows:

Date | Time GCT | Lat. (N) | Temperature for Depth
     |         | Long. (E) | 0 | 50 | 100 | 150 | 200 | 250 | 300
Aug. |         |           |   |    |     |     |     |     |
29   | 0705    | 6-09      | 79 | 34 | 34  | 34  | 33  | 32  |
     |         | 144-40    |   |    |     |     |     |     |
Sept.|         |           |   |    |     |     |     |     |
1    | 2015    | 7-20      | 80 | 82 | 82  | 82  | 82  |     |
     |         | 133-45    |   |    |     |     |     |     |
3    | 2040    | 8-06      | 83 | 83 | 83  | 83  | 83  | 82  | 81
     |         | 133-49    |   |    |     |     |     |     |
5    | 1915    | 7-47      | 83 | 83 | 82  | 82  | 82  | 81  |
     |         | 134-04    |   |    |     |     |     |     |
13   | 0330    | 12-07     | 84 | 84 | 83  | 82  | 82  | 81  |
     |         | 129-27    |   |    |     |     |     |     |
15   | 2040    | 13-21     | 83 | 83 | 83  | 82  |     |     |
     |         | 128-55    |   |    |     |     |     |     |
19   | 2055    | 15-25     | 83 | 83 | 82  |     |     |     |
     |         | 128-25    |   |    |     |     |     |     |
23   | 0055    | 22-46     | 82 | 82 | 82  | 82  | 80  |     |
     |         | 127-55    |   |    |     |     |     |     |
26   | 1905    | 21-29     | 80 | 80 | 79  | 79  | 79  | 78  |
     |         | 122-12    |   |    |     |     |     |     |
27   | 0035    | 21-00     | 81 | 80 | 80  | 79  |     |     |
     |         | 120-39    |   |    |     |     |     |     |
28   | 2115    | 20-50     | 82 | 81 | 80  | 79  | 71  |     |
     |         | 119-59    |   |    |     |     |     |     |

(P) HEALTH, FOOD AND HABITABILITY

     The health of officers and crew was excellent through-
out the patrol. There were no cases of skin infections.
That only six days were spent submerged and that the entire
crew was rotated through sun lookout watches may have had
some effect in this. Of the rescued aviation personnel only

(24)

— page 245 —
CONFIDENTIAL
three required medical care. The officer who had the
second degree burns of face and right thumb quickly and
completely recovered without complications or scars and
he was fit for duty after six days. The other officer and
the enlisted man who suffered minor injuries were fully
recovered after three days.
The food was excellent in every respect during the
entire patrol. The opportunities afforded to replenish
several items of stores during the stop-overs at MAJURO
and SAIPAN contributed materially to the maintenance of
a well-balanced and varied diet. The subsistence of the
seven additional aviation personnel imposed no extra demand
on the commissary. The ice cream machine proved itself
a most desirable item of submarine equipment.
The three officers and four enlisted men who were
rescued made a total of 12 officers and 76 men on board
throughout most of the patrol. Although normally the
accommodations are considered to be congested there seems
to be "always room for a few more", as the additional
personnel imposed no difficulties in providing for them.
The ship was always comfortable and well-ventilated.
During the past refit an additional air-conditioning
unit and booster blower had been installed in the
Control Room which made a marked improvement in the
habitability of the forward compartments.

(Q) PERSONNEL
The GROUPER employs a procedure for qualification
similar to that of the GROWLER, differing mainly only in
that all officers are assigned to lecture and instruction.
In addition to the qualification school each department
gives a course of instruction by lecture and demonstration
in the machinery, installations and equipment of the depart-
ment, including operation, maintenance, repair and watch
standing, for all ratings concerned. In this manner it is
intended not only to obtain better performance of both men
and equipment but to maintain and stimulate the interest
of personnel new and old to the improvement of the effi-
ciency of the entire ship.
Again the new personnel obtained prior to patrol proved
very satisfactory. These new men are willing and enthusias-
tic and with but few exceptions are rapidly assimilated into
the organization. In three patrols GROUPER has had nearly
an eighty per cent turnover of personnel without, in the
opinion of the commanding officer, detriment to the
efficiency of the personnel as a whole.
During the life-guard assignment the entire ship's
personnel showed an enthusiastic interest in the duty at
hand. The aviation personnel rescued had to be protected

(25)

— page 246 —
CONFIDENTIAL
from the well-intended but overwhelming solicitude of the
ship's company. Clothes, cigarettes and toilet articles,
etc., were provided in abundance to supply the needs of the
aviators. And always there were eager audiences seeking the
aviators to tell of their experiences.
The following information on personnel is furnished:

(a) Number of men on board during patrol                                72
(b) Number of men qualified at start of patrol                          45
(c) Number of men qualified at end of patrol                            55
(d) Number of men unqualified making their
    first patrol                                                        13
(e) Number of men advanced in rating during
    patrol                                                               3

(R) MILES STEAMED - FUEL USED

Pearl to Majuro                 2,676 mi    33,150 gal
Majuro to Palau area            2,522 mi    26,840 gal
In Palau areas                  2,120 mi    18,220 gal
Palau to Luzon Strait           3,529 mi    30,500 gal
In Luzon Strait                   538 mi     4,000 gal
Luzon Strait to Saipan          2,054 mi    27,430 gal
Saipan to Majuro                2,569 mi    39,500 gal

                                16,008 mi   179,640 gal

(S) DURATION

Days enroute Pearl to Palau area             16
Days in Palau area                           12
Days in other areas                          18
Days enroute Luzon Strait to Majuro          16
Days submerged                                6
                                             --
                                Total        62

(T) FACTORS OF ENDURANCE REMAINING

Torpedoes      Fuel      Provisions      Personnel factor
24             9000 gals   4 days          7 days

Limiting factor this patrol - Patrol terminated by
operation order.

(26)

— page 247 —
CONFIDENTIAL

(U) RADIO AND RADAR COUNTERMEASURES (REF. C. & D FORMS,
REVISED)

INTERCEPTION OF ENEMY RADAR TRANSMISSIONS

1. Ship or Station...USS.GROUPER

2. Area covered this mission (give dates).LUZON.STRAIT...
   September.26.to.28,.1944,.inclusive(Lat.21N,.Long.120-30E,
   approx)

3. Was enemy radar: Shipborne...Airborne.X.Landbased..Unknown
   (a) Describe enemy installation...Not.sighted

4. Intercept Equipment....APR-1.receiver

5. (a) Frequency.150.megacycles.......Dial Readings..150...
   (b) PRF...1000.per.secondHow Measured..SPA-1...
   (c) Pulse Width.10.microseconds...How Measured..SPA-1...
   (d) Sketch Pulse
      [Diagram of a pulse] and [Diagram of a pulse]
   (e) Was Lobe Switching Used...Rate...How determined...
      ...Not.indicated
   (f) Polarization of enemy signal
   (g) Sweep Rate...Variable

6. (a) Was radar used for surface or air search,GL,SLC,GCI,
      or AI....Submarine.Search
   (b) Evidence for this conclusion...Own.submarine....
      activities.in.this.area

7. Action of enemy radar, including distances and bearings
   at which he searched, tracked, faded, etc..Distances...
   and.bearings.of.radar.sources.not.determined..The.signal
   when.first.intercepted.was.usually.weak.and.sweeps.were
   infrequent..Sweeps.would.increase.in.frequency.and.signal
   strength.would.increase..Signals.ultimately.would.become
   fixed.and.strength.would.then.increase.rapidly

8. Narrative:
   September 26
   2110 First intercept indication.
   2117 Signal became fixed and strong.
        Submerged. No airplane sighted.
        Moon 60 per cent at 40 degrees
        elevation.
   2136 Explosion as of depth bomb, not close.
   2230 Surfaced. No intercept.
   2353 Radar intercept. Weak and infrequent.

(over)

(27)

— page 248 —
CONFIDENTIAL
September 27
0205 Radar intercept continued as before.
0320 Radar intercept fixed and strong. Sub-
0335 merged. No airplane sighted. No moon.
0835 Surfaced. No intercept.
0910 Radar intercept, fixed and strong. Sub-
0913 merged. No airplane sighted.
0928 Heard distant explosion.
0948 Surfaced. No intercept.

September 28
1345 Radar intercept, fixed and strong.
1910 Submerged. No airplane sighted.
1938 Surfaced. No intercept.
Submerged. No airplane sighted. Night
was bright with moonlight.
2056 Surfaced. No intercept.

(28)

— page 249 —
CONFIDENTIAL

INTERCEPTION OF ENEMY RADAR TRANSMISSIONS

1. Ship or Station.......USS.GROUPER

2. Area covered on this mission (give dates) LUZON STRAIT.
   September 27-28, 1944 (Lat.21N.Long.120-30E.approx.)....

3. Was enemy radar:Shipborne...Airborne...Landbased..Unknown X.
   (a) Describe enemy installation...Not given.

4. Intercept Equipment....APR-1 receiver.

5. (a) Frequency..92-93 megacycles...Dial Readings..92-93
   (b) PRF..1200 per second.......How Measured..SPA-1
   (c) Pulse Width..19 microseconds...How Measured..SPA-1.
   (d) Sketch Pulse
     _   _
    |_| |_|

   (e) Was Lobe Switching Used..Rate..How determined...
       Not indicated.
   (f) Polarization of enemy signal
   (g) Sweep Rate..Varied from 6 per minute to one in
       thirty minutes.

6. (a) Was radar used for surface or air search, GL,SLC,
       GCI, or AI....Submarine search.
   (b) Evidence for this conclusion....Own submarine
       activities in this area.

7. Action of enemy radar, including distances and bearings
   at which he searched, tracked, fired, etc. From the
   evidence is presumed this radar was shipborne. The
   variation in sweep rate is attributed to the relative
   movements of this submarine and the source which was
   considered to be a surface patrol craft. The distance
   of this patrol craft was assumed to have always been
   beyond the effective search range of the radar.

8. Narrative:

   September 27 1037 Radar intercept. Very weak. Con-
                       tinued intermittently until
                1442 Submerged for air (not radar source).
                1530 Surfaced. Radar intercept continued
                       as before.
   September 28       Radar intercept continued as before
                       until
                0250 Radar intercept became stronger and
                       more frequent.
                0340 Radar intercept became strongest and
                       continued about the same until
                0640 Submerged for patrol.

(29)

— page 250 —
CONFIDENTIAL
(V) REMARKS

Mark 18 Torpedoes. A full load of Mark 18-1 tor-
pedoes were carried. No difficulties were experienced
with them except for the usual disruption of both rooms
during the periods of charging. The short charging time
and lack of need for watering during an entire patrol
constitute a marked improvement in the electric torpedo.
It is hoped that further improvement will be made by pro-
viding a means of charging torpedoes without withdrawing
them from the tubes.

The commanding officer is greatly appreciative of
the prompt and effective responses rendered to the GROUPER
by the FRANKLIN and LEXINGTON in the matter of VHF radio.
The air escorts provided were not only of value for leading
the GROUPER to the downed aviators and widely extending
our search radius but they gave the assurance that out
life-guard duty could proceed without enemy molestation or
interruption.

The three officers and four enlisted men recovered
were soon assimilated into the GROUPER organization. The
officers were rotated during the day-time with the junior
officers of the deck on the bridge and at high periscope
watches. The three radiomen by taking over the watches
on the APR-1 receiver rendered the ship an invaluable
service. The aviation machinist's mate kept sun lookout
watches and in other ways made himself very useful on board.
All showed an active interest in the patrol and it is
regretted that we could not have produced some results to
reward them for their efforts in our behalf. In addition
the pilots' first hand accounts of the operations in which
they had participated served to acquaint us with phases
of this war of which we usually learn only the results.
They also imparted much desirable information concerning
enemy aircraft.

(30)

— page 251 —
SUBMARINE DIVISION TWO HUNDRED TWENTY TWO

FB5-222/A16-3
Serial: (034)
CONFIDENTIAL

FIRST ENDORSEMENT to
GROUPER Report of
Tenth War Patrol.

From:
To :
Via :

Subject:

1.
merged, and the GROUPER's Task assignments varied from offensive operations
and life guard duties in the PALAU area to joining a Coordinated Attack
Group around FORMOSA, under Captain Wilkins in the SEAHORSE.

2.
was good, as a 16,000 mile patrol would be. The GROUPER's rescue of avi-
ation personnel, close-in to the PALAU Islands, is another outstanding ex-
ample of the praiseworthy cooperation of our Submarine Commanding Officers
with Air Groups, and the results are gratifying, both to the submariners
who are accomplishing these rescue missions in the face of imminent counter
attack, as well as to the plane crews who are witnessing this all-out at-
tempt to assist them in every way.

3.
material difficulties, and the refit will be complet ed within the normal
period. The morale of the Officers and men; in spite of returning with
twenty-four torpedoes, the cleanliness of the ship; and attitude of the
Officers and men is commendable for such a long Patrol.

Care of Fleet Post Office
San Francisco, California
16 October 1944

The Commander Submarine Division TWO HUNDRED TWENTY TWO.
The Commander in Chief, United States Fleet.
(1) The Commander Submarine Squadron TWENTY TWO.
(2) The Commander Submarine Force, Pacific Fleet.
(3) The Commander in Chief, U.S. Pacific Fleet.

U.S.S. GROUPER (SS124) - Report of Tenth War Patrol.

Only six days of this sixty-two day Patrol were spent sub-

There were no surface ship contacts, although area coverage

The GROUPER returned from this Patrol with no unusual

[SIGNATURE: G. R. Donaho]
G. R. DONAHO.

— page 252 —
FC5-22/A16-3
Serial: 055
C-O-N-F-I-D-E-N-T-I-A-L

SECOND ENDORSEMENT to
USS GROUPER Report of
Tenth War Patrol.

From:
To :
Via :

Subject:

1.
Division TWO HUNDRED TWENTY-TWO.

2.
congratulated on the efficient lifeguard services rendered during this
patrol.

Copy to:
CSD 222
CO GROUPER

SUBMARINE SQUADRON TWENTY-TWO
11/ck
Fleet Post Office,
San Francisco, California,
16 October 1944.

Commander Submarine Squadron TWENTY-TWO.
Commander in Chief, U.S. Fleet.
(1) Commander Submarine Force, Pacific Fleet.
(2) Commander in Chief, U.S. Pacific Fleet.

U.S.S. GROUPER (SS214) Tenth War Patrol - comments on.

Forwarded, concurring in the remarks of the Commander Submarine

The Commanding Officer, officers and crew of the GROUPER are

W.J. SUITS.

— page 253 —
FF12-10/A16-3(15)
Serial 02335

CONFIDENTIAL

THIRD ENDORSEMENT to
GROUPER Report of
Tenth War Patrol.

COMSUBSPAC PATROL REPORT NO. 554
U.S.S. GROUPER - TENTH WAR PATROL.

SUBMARINE FORCE, PACIFIC FLEET
mr
Care of Fleet Post Office,
San Francisco, California,
24 October 1944.
[HANDWRITTEN: 25 OCT 1944]
NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
ENTERING PATROL AREA.

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. GROUPER (SS214) - Report of Tenth War Patrol.
(14 August to 15 October 1944).

1. The tenth war patrol of the GROUPER was conducted in
the Palau Area, with a primary mission of lifeguard duty in that area
during air strikes from 6 to 11 September, and as a member of an at-
tack group under Captain C. W. Wilkins, U.S. Navy, in the U.S.S. SEA-
HORSE (SS304), in areas east of the Philippines, southeast of the
Nansei Shoto, and in Luzon Straits.

2. As a result of alert and daring execution of lifeguard
tactics and smart employment of air coverage, the GROUPER had the honor
of rescuing seven aviation personnel. Unfortunately, during the of-
fensive phase of the patrol no contacts worthy of torpedo fire were
made.

3. This patrol is designated as "Successful" for Combat
Insignia Award.

4. The Commander Submarine Force, Pacific Fleet, congra-
tulates the commanding officer, officers, and crew for this splendid
job of lifeguarding.

C. A. LOCKWOOD, Jr.

DISTRIBUTION:
(Complete Reports)
Cominch (7)
CNO (5)
Cincpac (6)
Intel.Cen.Pac.Ocean Areas (1)
Comservpac (1)
Cinclant (1)
Comsubslant (8)
S/M School, NL (2) All Squadron and Div. (2)
S/M Base, PH (1) Commanders, Pacific (2)
Comsopac (2) Substrainpac (1)
Comsowespac (1) All Submarines, Pacific
Comsubsowespac (2)
CTF 72 (2) [SIGNATURE: E. L. Hynes]
Comnorpac (1)
Comsubspac (40) E. L. HYNES, 2nd
SUBAD, MI (2) Flag Secretary.
ComsubspacSubordcom (3)

— page 254 —
[HANDWRITTEN: 1ST COPY]

U.S.S. GROUPER (SS214)

Care of Fleet Post Office
San Francisco, California.

SS214/A16-3
Serial: (014)
[STAMP: DECLASSIFIED]

1 January 1945

From: Commanding Officer, USS GROUPER
To : The Commander in Chief, United States Fleet
Via : (1) The Commander Submarine Division 202
(2) The Commander Submarine Squadron 20.
(3) The Commander Submarine Force, Pacific Fleet.
(4) The Commander in Chief, United States Pacific
Fleet.

Enclosure: (A) Subject report.
(B) Track charts (2) For Comsubpac only.

1. Enclosure (A) covering the eleventh war patrol
of this vessel conducted in the Nanpo Shoto and Empire areas
during the period 9 November, 1944 to 1 January, 1945, is
forwarded herewith.

[SIGNATURE: F. H. Wahlig]
F. H. WAHLIG

[STAMP: DECLASSIFIED]
DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: OP 09C] DATE [HANDWRITTEN: 5/20/22]

[HANDWRITTEN: 103667]

— page 255 —
CONFIDENTIAL
(A) PROLOGUE.

     On 15 October the tenth war patrol was completed
when GROUPER moored alongside the USS GILMORE at Majuro
Atoll. The GROUPER was assigned to Commander Submarine
Division 222 for administration and refit. On 16 October
a normal refit was commenced by the relief crew of Submarine
Division 222 and the repair forces of the HOWARD W. GILMORE.
On 29 October the refit was completed. Post repair inspec-
tions and trials were conducted from 30 October to 2 Novem-
ber, inclusive. On 3 November training was commenced under
the supervision of Commander Submarine Division 222. On 6
November training was completed. On 7 and 8 November the
GROUPER made ready for the eleventh war patrol.

(B) NARRATIVE: All times are Item except where otherwise
                   designated.

                               9 November

     Underway for eleventh war patrol.
0900(I) Took departure from Majuro Atoll, proceeding
0950(I) in company with escort, USS RAMSEY (DD16).
1300(I) Released escort.

                             9-15 November

     Enroute to patrol area; conducting daily dives
drills and battle problems.

                               16 November

     In obedience to orders proceeded to position
0010(L) assigned for lifeguard duty.

                               17 November

     Wind and seas had been increasing for several
days. Consequent rolling and pitching of ship had
opened cracks in the sealing compound of nearly
all cells and at numerous joints of the ventila-
tion ducts in both batteries. Ground resulting
from acid seepage had become 205 volts in the
after battery and 130 volts in the forward battery.

ENCLOSURE (A)                               -1-

— page 256 —
CONFIDENTIAL
18 November
0609 Seas continued to be very rough.
1733 Submerged to permit work in both battery tanks.
     Surfaced.
     As a result of the work done and a battery charge
     the grounds were reduced to below 130 volts on each
     battery.
     Commenced riding out seas in vicinity of life-
     guard station.

19 November
     Continued riding out seas near lifeguard station.

20-21 November
     Seas moderated during these two days. Patrolled
     on surface between lifeguard station and Sofu Gan,
     across possible routes from Empire to Bonin Islands.

22 November
     Battery grounds have again become over 130 volts
     in each battery.
0548 Submerged to permit work in both battery tanks.
1650 Surfaced.
     Work on batteries succeeded in reducing grounds
     to below limit for charging.

23 November
     Patrolled on surface eastward of Sofu Gan.

24 November
     Proceeded to lifeguard station No. 2 for an air
     strike on Tokio. Between 1430 and 1530 sighted
     Superfortresses returning from strike.
1952 Received report that a B-29 had gone down at
     latitude 29-35N, longitude 142-40E, at about 1536.
     Between 1530 and 1630 GROUPER had been within six
     miles of that position and had seen only one Super-
     fortress going south. Proceeded toward the
     position of the report.

ENCLOSURE (A)
-2-

— page 257 —
CONFIDENTIAL
2302 Arrived at the given position, fired three
V ry shells and commenced search. We had some
reason to believe that the report we had received was
in error because we had seen nothing at the given
position during daylight. We more than hoped that
it was because the chances that there were survivors
and that they could be found in the rough sea seemed
very remote.

25 November
0605 Received the good news that the B-29 which had
been reported down had reached its base. Ceased
search and proceeded westward.

26 November
Patrolled westward of Chichi Jima hoping to
pick up something driven out by an air strike on the
harbor that morning.
0550 Submerged.
1715 Surfaced and proceeded toward lifeguard station
No. 2.

27 November
At lifeguard station for an air strike on Tokio.
Between 1500 and 1630 sighted Superfortresses return-
ing to their base.
2100 Proceeded toward lifeguard station No. 3.

28 November
0605 Sighted a small craft which was assumed to be
a trawler distant about four miles bearing 322 true;
latitude 30-23N, longitude 141-37E. Shortly there-
after lost sight of the trawler in a rain squall.
0615 Submerged to close the trawler.
0940 Not having again sighted our object, surfaced.
There were light rain squalls all around.
1141 Sighted two trawlers, one bearing 320 true,
distant about four miles and the other bearing 345
true, distant about five miles. They were similar
in appearance and it was not possible to determine
which one had been sighted previously. Commenced
tracking.

ENCLOSURE (A)
-3-

— page 258 —
CONFIDENTIAL

1236         Having estimated that the course of the trawlers
             was 150 true and that their speed was 3½ knots, sub-
             merged to close their track. The sea was observed
             to be between four and five causing the trawlers to
             yaw as much as twenty degrees and requiring the
             GROOPER to make at least 60 rpm to maintain depth
             control.

1321         Sighted the leading trawler bearing 315 r la-
             tive, distant 2300 yards. Estimated it to be of about
             100 tons displacement in the brief glimpse obtained.
             Saw only the upper masts of the second trawler and
             from these considered it to be of the same size as
             the other. Decided that even with the sea condition
             the possibility of hitting it with a torpedo warranted
             an attack on the leading trawler. Continued tracking
             the target.
                  It was finally obtained that the target was on
             course 160 true at a speed of 3 to 3½ knots. Came
             to course 030 true. Position at time of attack
             latitude 30-22N, 142-02E.

1351         Fired no.1 torpedo on an 96 starboard track with
             1½ degrees left gyro angle, depth set zero, torpedo
             run 900 yards. Tracked the torpedo by sound tracking
             which indicated that the torpedo passed very close
             to the target bearing at the time coinciding with the
             torpedo run. An estimated target speed of 3½ knots
             was used for this firing.

1352         Fired no. 2 torpedo on a 105 starboard track with
             5 degrees left gyro angle, depth set zero, torpedo
             run 740 yards. Again sound tracked the torpedo on
             the target bearing at the time of intercept. Target
             speed was decreased to 3 knots for this shot.

1353         Fired no.3 torpedo on a 117 starboard track
             with 2 degrees right gyro angle, depth set zero,
             torpedo run 520 yards. This time also the sound and
             periscope bearings coincided. Again decreased target
             speed and used 2½ knots.
                  It is most likely that control errors, which in
             this case need have been only of small magnitude,
             caused the misses. The coincidence of sound and
             periscope bearings were not a definite indication that
             the torpedoes passed under the target because of the
             possible inaccuracies of the sound bearings and errors
             in the estimation of the torpedo runs. The waves
             precluded observing the torpedoes but the sound track-
             ing indicated that they held their course for the
             full run. Evidently none of them broached prior to
             passing the target but one or more must have done so
             afterwards, for at

ENCLOSURE (A)
• -4-

— page 259 —
CONFIDENTIAL
1356 Loading trawler had reversed course and was
     heading across our bow about 300 yards away. Its
     crew were at action stations and the deck gun, which
     looked about 40mm. size, and the gun atop the pilot
     house, possibly a 20mm, had been manned. Evidently
     no one on the trawler had seen the periscope for it
     proceeded past us.
1358 Heard a depth charge, not close.
1359 Heard a second depth charge not close. Neither
     trawler could be seen because of difficulty with
     depth control so we started to 200 feet.
1400 Changed course to 160 true and commenced reload.
1422 Heard a third depth charge at some distance.
1426 Heard a fourth depth charge, still farther away.
1500 Returned to periscope depth, nothing in sight.
1716 Surfaced and proceeded toward lifeguard station.

29 November

1650 Arrived at lifeguard station No. 3. Weather had
     become stormy and the sea had risen to four condition.

30 November - 2 December

     Remained in vicinity of lifeguard station.
     Winds were about force 9 and the seas had increased
     to five condition. Submerged to 120 feet during
     daylight hours. By the night of 1 December the
     motion of the ship had again opened cracks in
     scaling compound of many cells and in the joints of
     the ventilation ducts in both batteries. The battery
     grounds had become 180 volts forward. On 2 December
     reduced battery grounds below 130 volts. On the
     evening of 2 December proceeded toward lifeguard
     station No. 2.

3 December
[HANDWRITTEN: 8]
     Enroute lifeguard station No. 2.

4 December

     On lifeguard station No. 2 for air strike on
     Tokio. Between 1600 and 1700 heard reports from
     two planes which were evidently going down. Their
     positions were adjacent to other lifeguard stations.

ENCLOSURE (A)
-5-

— page 260 —
CONFIDENTIAL

When it was considered that we could depart our sta-
tion, proceeded toward latitude 31-50N, longitude
141-45E, anticipating orders to assist in the search
for survivors of a plane reported down at that position.
1330 Arrived at position but could not conduct a
search because of recall to lifeguard station.
2000 Having received notification that we were not
required to take lifeguard station turned back to
make search as previously planned.

5 December

0610 Commenced search.
1700 Having received orders to patrol area abandoned
search and started back to area.
2206 Sighted a ship bearing 095 true, distant 7000
yards. Latitude 30-55N, longitude 143-07E. Turned
to course 270 true. Ship was made out to be a patrol
craft and it was approaching us. There was a half
moon at eight degrees but heavy clouds rendered the
night dark. The SJ radar had been out of commission
since 2100.
2302 Lost sight of patrol craft.

6 December

0047 Changed course to 090 true to find patrol boat.
0130 SJ radar was put in operation.
0134 Sighted smoke bearing 010 true at 16000 yards.
Changed course to 180 true. Latitude 30-55N, longi-
tude 142-55E. Night had become very bright and
visibility was excellent.
0140 Changed course to 340 true.
0145 Obtained radar bearing of 010 true and range of
15700 yards on bearing of smoke. Commenced radar
tracking. This was a tremendous range at which to
pick up such a small ship by radar but it was not
logical to expect any other types of ships in this
vicinity.
0157 Determined there were two ships very close together.
0202 Tracked the patrol boats on course 255 true,
speed 10 knots. Commenced maneuvering to get ahead of
them on their track.
0240 Patrol boats changed course to 340 true, leaving
us on their quarter. Continued maneuvering to get
ahead of them.

ENCLOSURE (A)
-6-

— page 261 —
CONFIDENTIAL
0350 Patrol boats had takcn course 040 truc, again
     putting us on their quartcr. Thcir actions now
     indicatcd that thcy had knowlcdgc of our prcscnce.
     Wo had remaincd bctwccn 12000 and 14000 yards from
     thcm, for bcyond 14000 yards, thcy wcre too faint
     on SJ for tracking and insidc 12000 yards wc
     would cxpcct to bc sightcd. How thcy dctcctcd our
     prcscnce is not known; no radar was indicatcd by
     the APR rcccivcr, so it is prcsumcd that wc wcre
     sightcd.

0500 Patrol boats had takcn coursc 080 truc putting
     us astcrn of thcm at about 12000 yards. Sincc
     daylight was approaching and wc wcre accomplishing
     nothing, sct coursc 250 truc.
0536 Changcd coursc to 070 truc to go back and takc
     a look at what wc had bccn chasing through thc high
     pcriscopc.
0552 Confirmcd thc assumption that our objcc ts wcre
     two patrol boats, probably thc samc oncs that wc had
     sccn on 28 Novcmbcr. Thcir position at this timc
     was latitudc 31-00N, longitudc 142-40E, and thcy
     wcre still on coursc 080 truc.
0609 Sct coursc 260 truc.
0730 Changcd coursc to 180 truc.
0836 Sightcd a planc, idcntificd as NELL, on coursc
     270 truc, distant 9 milcs. Submc rgcd. This planc
     camc from thc bcaring on which thc patrol boats
     should hav c bccn at thc timc. Pcrhaps it had bccn
     callcd out to look for us. Changcd coursc to 090
     truc on thc possibility that thc trawlcr s might
     havc turncd south and thcn latcr would turn wcst.
1655 Surfaccd and procccdcd wcstward.

7 Dcccmbcr
Patrollcd on thc surfac c southcast of Sofu Gan.

8 Dcccmbcr
0537 Patrollcd northwcst of Chichi Jima.
1715 Submc rgcd.
     Surfaccd.

9 Dcccmbcr
Patrollcd on thc surfac c southwcst of Sofu Gan
along possiblc routc to Bonin Islands.

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CONFIDENTIAL

10 December

1221 Continued patrol along the same route.
1715 Sighted plane, identified as BETTY, on southerly
course, distant 5 miles, submerged.
Surfaced.

11 December

1055 Patrolled west of Bonin Islands.
1715 Sighted plane, identified as MAVIS, distant 8
miles, submerged.
Surfaced.

12 December

Enroute to lifeguard station No. 8 in Empire
area.

13 December

0730 Submerged.
1335 Surfaced at lifeguard station.
Between 1355 and 1448 sighted at least forty
Superfortresses enroute to Nagoya and between 1515
and 1545 sighted a number of them returning to their
base.
1512 Received message from a B-29 stating that a
parachute had been sighted bearing 120 true from
Daio Saki light, distant 110 miles.
1619 Assumed all our planes were clear of our life-
guard area and proceeded toward position given in
message received at 1512.
Sea conditions were unfavorable to search, the
wind was from 30 to 40 knots and sea was condition
five.
1900 In latitude 33-22N, longitude 138-06E, sighted
what was assumed to be a pyrotechnic burst, bearing
150 true, estimated distance 10 miles. This burst,
which was red in color, resembled no type of dis-
tress signal any of us had ever seen. It could be
best described as being similar to what is known in
amusement display pyrotechnics as a "flowerpot".
The spread of this burst covered over 2 degrees in
the horizontal and it persisted for about 20 seconds.
It was considered that the projector for such a

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— page 263 —
CONFIDENTIAL

2003 pyrotechnic could hardly be carried in a rubber raft
and certainly not as a hand device. Proceeded toward
bearing of burst.
Having arrived at the estimated point of the
burst fired three green Very rockets.
Commenced search in this area.

14 December

0055 Sighted what appeared to be a fluorescent light
bearing 065 true, distant about 4 miles. Proceeded
down this bearing.
0100 Sighted what appeared to be two blinking fluor-
escent lights nearly dead ahead, distant about 3
miles. These lights seemed to be on the water or
very close to it.
As these lights were approached it was seen
that they were an unusual phosphorescent or fluor-
escent effect emanating from the wave crests and a
number of them could be seen all around. As we
passed through this area an odor, similar to that of
palm oil as one officer described it, was noticed.
It also seemed that the sea in this area was like
that which would be produced by oil on the surface.
0111 Sighted a pyrotechnic burst similar to that seen
previously this night bearing 030 true distant about
8 miles. Proceeded toward it. Latitude 33-13N,
longitude 128-22E.
0115 Fired a green Very rocket.
0118 Fired a green Very rocket.
0140 Having arrived at the estimated position of
the course of the burst fired three green Very
rockets. Commenced search in this area.
It was difficult to find any explanation for
what we had seen. B-29 raids had been made at night
of which no notification had been given to lifeguard
submarines and the possibility of a B-29 in diffi-
culty could be considered. Later it was learned
that Tokio had been raided twice that night by Super-
fortresses. Perhaps the bursts that we had observed
were incendiary bombs. GROUPER had been guarding the
lifeguard frequency continuously since 18 November.
About 0500 received a message that a single
parachutist without a life belt had blown out of a
B-29 at position bearing 135 true from Daio Saki,
distant seventy-two miles. Although this was a
different position from that given previously it
was obviously of the same casualty.

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— page 264 —
CONFIDENTIAL

With a forty knot wind and a condition five sea
search was considered futile.
0615 Submerged.
1710 Surfaced. Weather and sea had improved.

15 December

Patrolled about 60 miles west of IZU SHOTO.
0612 Submerged.
1140 Sighted 3 planes, identified as BETTYS, on
course 230 true, which passed at about 6 miles.
1343 Sighted an unidentified plane on course 085
true, distant about 3 miles, which was lost from
sight in the rain.
1715 Surfaced.

16 December

Proceeded toward lifeguard station No. 8 for
0043 air strike on Nagoya only to learn after arriving
there that air strike had been delayed twenty-four
hours.
0624 Submerged and proceeded south.
1715 Surfaced.

17 December

Remained in vicinity of lifeguard station but
again the raid was postponed.
0624 Submerged.
1346 Sighted 2 planes, identified as Zekes, on course
180 true, which passed at about 6 miles.
1717 Surfaced.

18 December

0620 Submerged.
1215 Surfaced on lifeguard station.
1345 Sighted vapor tracks overhead of two planes
going south.
1350 Sighted one unidentified single engine plane very
high overhead going north.
1433 Sighted some Superfortresses on the way to their
base.
1500 Started south from life-guard station.
1655 Sighted a plane, identified as BETTY, on course
south, distant about 6 miles. Submerged.

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— page 265 —
CONFIDENTIAL

1810 Surfaced and continued south.
2300 Departed station and patrol area, onroute for
     Midway.

19 December

2000 Contact of three targets on SJ radar, bearing
     090 true distant 15000 yards. Latitude 32-23N,
     longitude 140-22E. Commenced tracking.
     During the tracking it was determined that
     there were at least five ships of which three were
     very small and probably escorts. The other two ships
     were estimated, from the size of their pips and the
     maximum radar range, to be small, as the enemy ships
     encountered in this area have usually been. Their
     estimated course and speed were 320 true and seven
     knots. There was no indication of a zig plan.
2054 First indication of radar interference which
     appeared to be originating from the bearing of one
     of the larger targets. This interference was of the
     same frequency as SJ radar and it was first considered
     that perhaps one of our submarines was tracking the
     convoy from the opposite flank. Later it was con-
     cluded that one of the larger ships in the convoy
     had the radar and frequently beamed it in our direc-
     tion. The sweep of this radar was irregular indi-
     cating it might have been hand operated.
2202 As GROOPER moved ahead on the port flank of the
     convoy the radar pattern showed that the formation
     was in a line of the true bearing of the larger ships
     with the three escorts nearer us.
     The night was very bright and clear though
     there was no moon. It was therefore decided to
     attempt a submerged attack by radar and periscope.
     With the range 11000 yards to the selected target
     and the distance to the track 4000 yards, submerged
     to radar depth and commenced approach. As soon as
     we became submerged echo-ranging was heard.
2211 Radar tracking showed that the convoy had changed
     course to its right to about 060 true. It was obvious
     that we could make no attack now. Submerged to 65
     feet and changed course to 050 true. The echo-ranging
     disclosed there were six pingers in the convoy, two
     apparently on the flank away from us and one which
     was trailing besides the three previously known.
     At radar depth no indications were obtained.
2338 Surfaced. No targets were visible on the SJ
     radar.
2341 Set course 090 true and sent contact reports on
     area frequency and to Comsubpac.

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— page 266 —
CONFIDENTIAL

20 December

0015 Set course 000 true at 15 knots.
0142 Radar contact at 16000 yards, bearing 000 true.
     Changed course to 030 true to try the port flank since
     we had been unsuccessful on the starboard one.
0148 Interference appeared on SJ radar. This inter-
     ference which was of a different pattern than that
     previously obtained continued to show at intervals.
0245 By this time the wind had risen to about forty
     knots and the sea to condition five. The boat speed
     GROUPER could make was about 11 knots and it was
     frequently taken down the conning tower
     hatch. Steady streams of water were coming into both
     engine room inductions and it was found necessary
     to shut the hull supply valve.
0251 With the two large ships abeam it was seen that
     there were two radars in the convoy, one at the pre-
     viously noticed same frequency as our SJ and one at
     a slightly lower frequency. Apparently there was
     one in each of the two larger ships. The second radar,
     like the first, appeared to be hand operated.
     The convoy was tracked to be on course north at
     a speed of five knots.
     By 0500 the sea had become at least condition
     six and our speed had been slowed to about seven knots.
     The seas were breaking over the bridge with such force
     that it was considered advisable to secure the look-
     outs to prevent having them injured or washed over-
     board.
0527 With the dawn morning was becoming very light.
     Our position at this time was estimated to be 20000
     yards ahead of the center of the convoy. Submerged.
     By 0600 it was concluded that it would not be
     possible to run at periscope depth. Went to 120
     feet at which depth echo-ranging seemed strongest.
0608 Heard echo-ranging bearing 210 and 130 true.
     Changed to 270 true.
     By 0730 it had been determined from the echo-
     ranging that the convoy had changed to some course
     between 270 and 300 true. Three escorts were evidently
     on the near flank. The other two flankers were heard
     faintly. No screws were heard at any time.
0831 Lost contact on echo-ranging. Changed course
     to 090 true.
1710 Surfaced.

ENCLOSURE (A)

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— page 267 —
CONFIDENTIAL

                                                                24 December

1415(K)         Sighted a structural buoy painted red and
                showing a quick flashing white light. The naviga-
                tor was unable to identify it. Latitude 32-50N,
                longitude 158-18E.
                Closed buoy and looked it over carefully.
                There were no markings on it, but there was little
                doubt that it was Japanese. It had a perch con-
                sisting of two verticle hoops at right angles to
                each other over the light.
1519(K)         Sank the buoy with the eighth shot from the
                four-inch gun.
2330(K)         The GROUPER's "Melody Maulers" rendered a
                half-hour variety song program over the ship's
                entertainment broadcast system. At midnight
                they led the singing of Christmas carols in which
                all hands joined.

                                                                28 December

0959(Y)         Made rendezvous with air escort from Midway.
1123(Y)         Entered Midway channel.
1140(Y)         Moored at berth S-2, Submarine Base, Midway.
1533(Y)         Underway.
1600(Y)         Took departure for Pearl.
1732(Y)         Air escort from Midway departed.

                                                                1 January

0645(VW)        Made rendezvous with escort, PC-602.
0933(VW)        Passed entrance buoys.
1028(VW)        Moored at Submarine Base, Pearl.

ENCLOSURE (A)                                                   -13-

— page 268 —
(C) WEATHER
In the area between latitudes 27 to 32 north and long-
itude 138 to 143 east the weather was probably normal for
this time of the year. The wind was usually from the west
around to the north with a force of from twelve to twenty
knots. The seas were generally from the direction of the
wind and were of condition two and three and occasionally
four. Rain squalls were frequent. On 18 and 19 November
the wind was from the northeast at 30 knots and the sea
was condition four and five. In the area from latitude 32
to 34 north and longitude 137 to 140 east the weather en-
countered between 30 November and 2 December and between 13
to 20 December was generally very stormy. The wind blew
usually from the northwest with a force of 30 to 40 knots.
Seas from the northwest were condition four to six. On
the night of 1 December in latitude 33 north, longitude
142 east, the wind changed through 360 degrees on two
occasions during each of which heavy rain fell.

(D) TIDAL INFORMATION
Currents observed in the Nanpo Shoto and Empire areas
conformed to existing data.

(E) NAVIGATIONAL AIDS
None Sighted.

(F) SHIP CONTACTS
| No. | Time Date | Lat.N Long.E | Type(s) | Initial Range | Est. True Course | Speed Kts | How Contacted | Remarks |
|---|---|---|---|---|---|---|---|---|
| 1 | 0605I | 30-23 | Armed | 8000 | 090 | 3 | Sight | See |
| | 28 Nov. | 141-37 | Trawler | Yds. | | | | below |
| 2 | 1141I | 30-23 | Armed | 10000 | 150 | 3 | Sight | See |
| | 28 Nov. | 141-37 | Trawler | Yds. | | | | below |
| 1 | 2206I | 30-52 | Patrol | 7000 | 270 | 11 | Sight | See |
| | 5 Dec. | 142-55 | Craft | Yds. | | | | below |
| 2 | 0134I | 30-51 | Patrol | 15700 | 255 | 10 | Sight | See |
| | 6 Dec. | 142-59 | Craft | Yds. | | | | below |
| 8 | 2000I | 32-23 | 2 ships | 15000 | 320 | 7 | Radar | |
| | 19 Dec. | 140-22 | 6 escorts | Yds. | | | | |

Of the two patrol craft sighted at 1141 on 28 Novem-
ber, one was evidently the same patrol craft that had been
seen previously at 0605. On the evening of 5 December it
was presumed that there was only one patrol vessel seen but
there may have been two of them. This contact evidently
was with one or both of the two vessels seen later at 0134,
on 6 December.

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— page 269 —
CONFIDENTIAL
(G) AIRCRAFT CONTACTS

CONTACT NUMBER
S Date                     1       2       3       4
U Time (Zone)              0836I   1220I   1055I   1140I
B Position: Lat. (N)       30-45   28-19   27-42   33-36
M Long. (E)                142-35  139-13  140-28  137-16
A Speed (knots)            10.5    10.5    10.5    3
R Course (true)            082     180     265     180
I Trim                     Surf    Surf    Surf    Sub
N Minutes Since Last
E SD Radar Search          - - - Not in Use

A Number                   1       1       1       3
I Type                     NELL    BETTY   HAVIS   BETTY
R Probable Mission         Search  Patrol  Patrol  Patrol
C How Contacted            Sight   Sight   Sight   Sight
R Initial Range (Miles)    9       5       15      6
A Elevation Angle          3       1       2       1
F Range & Relative
T Bearing of Plane
  When it Detected S/M

CONDITIONS
Sea: (State (Beau-         1       1       3       2
      fort)
    (Direction (Rel)       270     330     020     225
    Visibility (Miles)     25      25      25      10
Clouds: (Height in         Cu      Cu      Cu      Cu
      Ft.                  10000   8000    10000   5000
    (Percent
    Overcast               20      90      30      90
Moon: (Bearing (Rel)
    (Angle
    (Percent Illum.

Type of S/M Camouflage on this patrol - haze gray.

-15-

ENCLOSURE (A)

— page 270 —
CONFIDENTIAL
(G) AIRCRAFT CONTACTS (Cont)

CONTACT NUMBER | 5 | 6 | 7 | 8
---|---|---|---|---
Date | 12-15 | 12-17 | 12-18 | 12-18
Time (Zone) | 1343I | 1346I | 1350I | 1655I
Position: Lat. (N) | 33-35 | 33-34 | 33-26 | 33-26
           Long. (E) | 137-16.9 | 135-30 | 137-17 | 137-17
Speed (Knots) | 3 | | |
Course (true) | 180 | | |
Trim | Sub | | |
Minutes Since Last | Not in Use --- | | |
SD Radar Search | | | |

AIRCRAFT
Number | 1 | 2 | 1 | 1
Type | Unid. | Zeke | Unid. | BETTY
Probable Mission | Patrol | Search | Patrol | Patrol
How Contacted | Sight | Sight | Sight | Sight
Initial Range (Miles) | 5 | 6 | 6 | 6
Elevation Angle | 1 | 3 | 8 | 3
Range & Relative | | | 6 |
Bearing of Plane | | | 265 |
When it Detected S/M | | | |

Sea: (State (Beau- | 2 | 4 | 2 | 2
       fort) | | | |
     (Direction (Rel) | 225 | 350 | 340 | 340
Visibility (Miles) | 5 | 15 | 15 | 15

Clouds: (Height in | 4000 | 2000 | 2000 | 2000
         Ft. | | | |
        (Percent | Cu | Cu | Cu | Cu
         Overcast | | | |
        (Bearing (Rel) | | | |
Moon: (Angle | | | |
      (Percent Illum. | | | |

Type of S/M Camouflage on this patrol - haze gray.

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— page 271 —
CONFIDENTIAL
(H) ATTACK DATA

USS GROUPER TORPEDO ATTACK No. ONE PATROL No. ELEVEN
TIME: 1351(I) DATE: 28 Nov. 1944 LAT: 30-22N LONG: 142-02E

Description: Target was one of two 100 ton armed trawler
             type patrol vessels (MISC).

Ship(s) sunk: None
Ship(s) damaged
or probably sunk: None

Damage determined by: None

TARGET DATA

(1) Target Draft 4 Course 160 Speed 3.5 Range 900(at firing)
(2) Target Draft 4 Course 160 Speed 3.0 Range 740(at firing)
(3) Target Draft 4 Course 160 Speed 2.5 Range 520(at firing)

OWN SHIP DATA

(1) Speed 3.5 Course 077 Depth 64 feet Angle (at firing) 0
(2) Speed 3.5 Course 080 Depth 64 feet Angle (at firing) 0
(3) Speed 3.5 Course 085 Depth 64 feet Angle (at firing) 0

FIRE CONTROL AND TORPEDO DATA

Type attack: Submerged periscope attack made in condition
             four sea. All torpedoes were set at zero depth for
             shallow draft of the target.

             1         2         3
Tubes Fired  1         2         3
Track Angle  96S       105S      117S
Gyro Angle   349       355       002
Depth Set    Zero      Zero      Zero
Power        -         -         -
Hit or Miss  Miss      Miss      Miss
Erratic      No        No        No
Mark Torpedo 18-1      18-1      18-1
Serial No.   55047     54519     55116
Mark Exploder 8-5       8-5       8-5
Serial No.   8983      10086     8784
Mark Warhead 18-2      18-1      18-2
Serial No.   2854      2010      2603
Explosive    Torpex    Torpex    Torpex
Firing Interval -        1' 30"    2' 05"
Type Spread  None      None      None
Sea Conditions 4         4         4
Overhaul Activity        USS HOWARD W. GILMORE

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CONFIDENTIAL

Remarks: Sound tracking indicated that the torpedoes ran
          their true course throughout their runs. Waves pre-
          vented observation of depth performance. From the ac-
          tion of target after firing it was concluded that tor-
          pedoes did not broach until after they had passed it.
          Depth performance may have caused misses but it is
          probably that they resulted from errors in fire control.

(I) MINES

          None

(J) ANTI-SUBMARINE MEASURES AND EVASIVE TACTICS

          After the attack on the patrol vessel on 23 November
          four depth charges were dropped which were not close. The
          patrol vessels may have had listening devices but there
          was no indication that the GROUPER had been detected. No
          evasion tactics were used. Because of the speed of which
          the patrol vessels were capable it is assumed that the
          depth charges they dropped were of a delayed firing type.
          The convoy encountered on the night of 19 December showed
          two radars with frequencies close to that of our SJ. Of
          eight ships, six were considered to be of escort type, for
          six different echo-rangings were tracked. One signal
          frequency was at 18.2 kcs. and the others were all at 17.6
          kcs. Whether the GROUPER was detected by the radars or by
          radar detectors is not known. After each time the GROUPER
          submerged the convoy changed course radically. The GROUPER
          apparently was not detected submerged and no evasive tactics
          were employed.

(K) MAJOR DEFECTS AND DAMAGE

          1. Hydraulic plant. With all operating valves in the
          neutral position the accumulator charges at an average of
          every five minutes and with all operating valves in the
          power position the accumulator charges at least once a
          minute. Such operation is evidently caused by excessive
          wear of operating valves and pistons. As indicated by the
          amount of oil returned from them as compared with the other
          units, pistons in the following operating gears are worn
          excessively: Negative tank flood valve, safety tank flood
          valves, safety tank vent valve, and the main induction.
          2. Main Storage Battery: Difficulties with the main
          storage battery began on Nov. 9. On that date, the ground
          on the after battery totalled 210 volts. On Nov. 15, the
          ground on the forward battery totalled 110 volts. These
          grounds were attributed to cracks in sealing compound and
          leaks in the ventilation system, which permitted acid seepage

ENCLOSURE (A)                                     -18-

— page 273 —
CONFIDENTIAL

across the cell tops and voltmeter leads. The batteries
were cleaned thoroughly with fresh and soda water and dried
with air. The cracks in the sealing compound were sealed
with a hot iron and on some cells were coated with copal-
tite. The ventilation ducts were taped with rubber and
friction tape and coated with glyptol and copaltite in an
effort to reduce leakage.
     Each period of rough weather produced an aggravated
similar condition of the battery and made necessary almost
continuous work in the wells as described above. Approx-
imately 750 man hours were expended on the batteries in
order to keep grounds, which at times exceeded 180 volts,
within charging limits.
     In the work on the battery, it was found that only
a small proportion of the grounds were contained in the
ventilation system.
     Since this condition has been consistent throughout
the past three patrols, it can only be concluded that
neither the forward or after battery is properly wedged
nor braced, and movement of the cells occurs in rough
seas. This movement cracks open sealing compound, ventila-
tion ducts and rubber connectors and loosens terminal
posts.
     The original wedging and the bracing installed during
last overhaul are not standard with present practice.
It is considered that the only way the existing defect can
be eliminated is by complete re-wedging and re-bracing
of the both batteries in accordance with latest BuShips
plans.

(L) RADIO

     Radio reception on the new NPM frequencies was very
good at all times. 6085kc and 4515kc were best at night
and 9090kc was the best during daylight.

(M) RADAR

     The SJ functioned satisfactorily throughout the
patrol. The only casualty which occurred required the
replacement of the pulse network of the transmitter.
Because of this the SJ radar was out of commission for
about four hours of the night of 5-6 December.

(N) SOUND GEAR AND SOUND CONDITIONS

     During the training period at Majuro, the sensitivity
of the QC equipment was considered to be below that which
should be expected. The combined efforts of the repair
forces, relief crew and ship's force accomplished no
definite improvement prior to departure for patrol.

ENCLOSURE (A)
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— page 274 —
CONFIDENTIAL

(O) DENSITY LAYERS

     No record of density layers obtained because the thermal
element of the bathythermograph became inoperative on 12
November.

(P) HEALTH, FOOD AND HABITABILITY

     The health was good. A few cases of boils at the be-
ginning of the patrol were cleared up by the time of arri-
val on station.
     The food was excellent, being always of good quality,
well prepared and of pleasing variety. Sumptuous dinners
were served in celebration of Thanksgiving (both of them)
and Christmas.
     A total of seventy-five men were accommodated this
patrol without hardship to any individual.

(Q) PERSONNEL

     At the beginning of this patrol there were on board
twenty-nine unqualified men, of whom fifteen were making
their second patrol. Of these all were qualified as well
as four who were making their first war patrol.
     The industry and enthusiasm which these new men dis-
played, not only in their desire for qualification but also
in their eagerness to become competent in all their duties,
and their obvious ability are considered to be indicative
of the excellent type of recruits now available to submarines.

     Number of men on board during patrol                               75
     Number of men qualified at start of patrol                         46
     Number of men qualified at end of patrol                           65
     Number of unqualified men making their first patrol                14
     Number of men advanced in rating during patrol                     20

(R) MILES STEAMED - FUEL USED

     Majuro to area             2491 miles          31,715 gallons
     In area                    6179 miles          54,370 gallons
     Area to Midway             2439 miles          24,365 gallons
     Midway to Pearl            1375 miles          21,000 gallons

               Total            12484               131,450

(S) DURATION

     Days enroute to area        9
     Days in area               33
     Days enroute to base       13
     Days submerged             15

ENCLOSURE (A)                                       -20-

— page 275 —
FIDENTIAL
(T) FACTORS OF ENDURANCE REMAINING
          Torpedoes           Fuel           Provisions Personnel Factor
          21             33,012 gallons       7 days       10 days

(U) RADIO AND RADAR COUNTERMEASURES (REF. CM & D FORMS
    REVISED)
    Part U is contained on page 22.

(V) REMARKS
    Mark 18 torpedoes. Sixteen Mark 18 Mod. 1 torpedoes
    were carried this patrol. No difficulties were encoun-
    tered in the upkeep of them.

ENCLOSURE (A)
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— page 276 —
CONFIDENTIAL
(U) RADIO AND RADAR COUNTERMEASURES (REF. CM & D FORMS
    REVISED)

    INTERCEPTION OF ENEMY RADAR TRANSMISSIONS

1.  Ship or Station - U.S.S. GROUPER (SS214)

2.  Area covered on this mission (give dates) East of Hachi-
    Jima Island on the night of 19-20 December, 1944.

3.  Was enemy radar:Shipborne x Airborne Landbased Unknown.
    (a) Describe enemy installation - Encountered during
    darkness. Installation not sighted. From the dis-
    tinctive pulse patterns, it was concluded that there
    were two radars,

4.  Intercept Equipment - SJ Radar and APR-1.

5.  (a) Frequency - 300MC                     Dial Readings - - - -
    (b) PRF - 1500 per second                 How Measured - SPA & SJ Radar
    (c) Pulse Width - 4 micro-second          How Measured - SPA & SJ Radar
    (d) Sketch Pulse (As seen on SJ-a"A" Scope)

    [SKETCH OF PULSE WAVEFORM] [SKETCH OF PULSE WAVEFORM]
    Pulse No 1                       Pulse No 2
    (e) Was Lobe Switching Used--No--Rate ----- How determined
    (f) Polarization of enemy signal - - - -
    (g) Sweep Rate - Variable - probably hand rotated.

6.  (a) Was radar used for surface or air search, GL, SLC,
    GCI, or AI - Surface search.
    (b) Evidence for this conclusion.-

7.  Action of enemy radar, including distances and bearings
    at which he searched, tracked, faded, etc., - Radars
    were in a convoy of enemy ships which were tracked
    at a maximum range of 16000 yards. The interference
    was noted to cover an arc of 10 degrees on the S.J.
    (P.P.I.) scope. At 16000 yards the interference on
    the SJ set was weak and periodic.

8.  Narrative: -

    This convoy was encountered at 2000 on 19 December.
    The initial contact on a near escort was at a range of
    15000 yards. When the convoy was closed 2000 yards at 2054
    radar interference was noted. The convoy was composed of
    two small ships with six escorts. Observations indicated
    that the radars were located on what were apparently the
    escorted ships.

-22-

— page 277 —
SUBMARINE SQUADRON TWENTY

FC5-20/A16-3/A9

Serial: 0240

CONFIDENTIAL
FIRST ENDORSEMENT to
CO GROUPER Report of 11th
War Patrol, SS214/A16-3,
Ser. (014) of 1/1/44.

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. GROUPER (S 214) - Report of ELEVENTH War
 Patrol (9 November 1944 to 1 January 1945).

 1. The eleventh war patrol of GROUPER, comprising a
period of fifty-three days, thirty-two of which were spent on
lifeguard stations, was conducted in the NANPO SHOTO and EMPIRE
Areas. Area coverage was necessarily subordinated to the need
of meeting lifeguard demands, which constituted the GROUPER's
major mission. No downed aviators were observed and no rescues
effected.

 2. Five ship contacts were made, two on armed trawlers,
two on patrol craft and one on a convoy of two small unidentified
ships with six echo-ranging escorts; this latter contact, made at
night by radar and itself radar equipped, unfortunately could not
be closed to attack position, despite ten hours persistent effort,
because of heavy seas which finally limited submarine speed to
seven knots and precluded running at periscope depth.

 3. One torpedo attack was made:
Attack No. 1
 Three Mark 18-1 bow torpedoes were fired at an
armed trawler of about 100 tons at ranges from 900 down to 520
yards. Depth set zero. The three misses were probably due to
control errors which need not have been large to cause a miss on
so small a target.

 4. Refit period of the GROUPER will be extended as
necessary to permit a complete re-wedging of her batteries and
resealing of all cells as well as major renewals and repairs
throughout the hydraulic system.

 - 1 -

Care of Fleet Post Office,
San Francisco, California,
3 January 1945.

— page 278 —
SUBMARINE SQUADRON TWENTY

3 January 1945

FC5-20/A16-3/A9

Serial: 0240

CONFIDENTIAL

FIRST ENDORSEMENT to
CO GROUPER Report of 11th
War Patrol, SS214/A16-3,
Ser. (014) of 1/1/44.

Subject: U.S.S. GROUPER (SS214) - Report of ELEVENTH War
Patrol (9 November 1944 to 1 January 1945).

— page 279 —
F12-10/A16-3(15)
Serial 066
CONFIDENTIAL
SECOND ENDORSEMENT to
GROUPER Report of
Eleventh War Patrol.
COMSUBSPAC PATROL REPORT NO. 634.
U.S.S. GROUPER - ELEVENTH WAR PATROL.

SUBMARINE FORCE, PACIFIC FLEET
hch
Care of Fleet Post Office,
San Francisco, California,
7 January, 1945.
[STAMP: 13 JAN 1945]
NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
ENTERING PATROL AREA.

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. GROUPER (SS214) - Report of Eleventh War Patrol.
(9 November to 1 January 1945).

1. The eleventh war patrol of the GROUPER, under the com-
mand of Commander F.W. Wahlig, U.S. Navy, was conducted in the Nanpo
Shoto and Empire areas. The GROUPER performed lifeguard duties for
B-29 strikes as well as conducting an offensive patrol.

2. Unfortunately, during this long arduous patrol but few
contacts with small ships were made, and no opportunity to rescue down-
ed aviators presented itself. The one torpedo attack made on a small
trawler was unsuccessful.

3. Award of the Submarine Combat Insignia for this patrol
is not authorized.

DISTRIBUTION:
(Complete Reports)
Cominch (7) C. A. LOCKWOOD, Jr.
CNO (5)
Cincpac (6)
ICPOA (1)
Comservpac (1)
Cinclant (1)
Comsuoslant (8)
S/M School, NL (2)
CO, S/M Base, PH (1)
Comsopac (2)
Comsowespac (1)
Comsubsowespac (2)
CTG 71.9 (1)
Comnorpac (1)
Comsubspac (20)
SUBAD, NI (2)
ComsubspacSubordcom (3)
All Squadron & Division
Commanders, Pacific (2)
Substrainpac (2)
All Submarines, Pacific(1)
[SIGNATURE: E. L. Hynes]
E. L. HYNES, 2nd,
Flag Secretary.

— page 280 —
[WATERMARK: Great Seal of the United States (faintly visible)]
[WATERMARK: 1942 (faintly visible below the seal)]

— page 281 —
[HANDWRITTEN: 1st copy]

U.S.S. GROUPER (SS214)
Care of Fleet Post Office,
San Francisco, California.

SS214/A16-3
Serial: (02)
[STAMP: DECLASSIFIED]
[STAMP: CONFIDENTIAL]
26 April 1945.

From: Commanding Officer, U.S.S. GROUPER.
To : The Commander in Chief, United States Fleet
Via : (1) The Commander in Chief, United States Pacific
Fleet.
(2) The Commander Submarine Force, United States
Pacific Fleet.
(3) The Commander Submarine Squadron FOUR.
(4) The Commander Submarine Division ONE-HUNDRED
THREE.

Subject: U.S.S. GROUPER, Report of War Patrol number twelve.

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

1. Enclosure (A) covering the twelfth war patrol of
this vessel in the East China and Yellow Seas during the
period 3 March to 26 April, 1945, is forwarded herewith.

[SIGNATURE: F. H. Wahlig]
F. H. WAHLIG

DECLASSIFIED-ART. 0445, OPNAVINST 5510.1C
BY [HANDWRITTEN: OP-09B2C] DATE [HANDWRITTEN: 5/30/72]
[STAMP: DECLASSIFIED]

[HANDWRITTEN: 120558]

— page 282 —
CONFIDENTIAL
TWELFTH WAR PATROL REPORT

(A) PROLOGUE

GROUPER arrived at the Submarine Base, Pearl
Harbor, on 1 January, having completed the eleventh
war patrol. GROUPER was assigned to Submarine Squadron
Twenty for administration and refit. On 2 January
an extended refit required for the re-wedging of both
batteries was commenced by the repair forces of the
U.S.S. PROTEUS and the relief crew of Submarine
Division 202. This refit was completed on 26 January.
Post repairs trials were conducted from 27 to 30
January. On 31 January a training period was begun
under the supervision of Captain E.S. Hutchinson,
U.S.N. On 4 February GROUPER was assigned to Sub-
marine Division 45 for administration. On 6 February
training was completed. On 7 and 8 February GROUPER
made ready for sea. On 9 February GROUPER departed
the Submarine Base, Pearl Harbor, for Saipan to await
patrol assignment. GROUPER arrived Saipan on 21
February and moored alongside U.S.S. FULTON. Voyage
repairs, of which the major items were air leaks in
bow buoyancy and main ballast tank blow valves and
a packing squeal in the starboard shaft, delayed the
readiness for sea of GROUPER until 2 March.

(B) NARRATIVE (All times are Item except where otherwise
indicated).

ON BOARD

Officers                                Previous War Patrols

Commander F. H. Wahlig, USN                       5
Lieut. Comdr. R. O'Neill, Jr., USN                1
Lieutenant B. Hinman, DE, USNR                    0
Lieutenant M.M. Davis, DE, USNR                   3
Lieutenant (jg) M.W. Hartle, DE, USNR             4
Lieutenant (jg) F. Gunn, E(L), USNR               0
Lieutenant (jg) W.B. Prigmore, USN                3
Lieutenant (jg) W.R. Boose, USN                   4
Lieutenant (jg) P.D. Astry, DE, USNR              3
Ensign B. A. Cameron, D(L), USNR                  0

Chief Petty Officers

BARNDT, H.W., Jr., CTi(PA)(SS), USN               0
COX, R.L., CMOMM(PA)(SS), USN                     3
FRITCHEY, T.A., CRT(AA)(T)(SS), USNR              4
PYLE, O.J., CEM(AA)(T)(SS), USN                   4
PYRDOL, D.J., CMOMM(T), USN                       0
STEFANI, R.C., CPHM(AA)(T)(SS), USN               3

ENCLOSURE (A)                                     -1-

— page 283 —
CONFIDENTIAL

3 March
1000 Underway from alongside U.S.S. FULTON, Tanapag
       Harbor, Saipan, for twelfth war patrol.
1038 Took departure from net entrance buoy and pro-
       ceeded in company with escort.
1730 Released escort.

4 March
1200 Position 14-25N, 143-30E
0710 Submerged for training.
0750 Surfaced.

5 March
1200 Position 19-02N, 137-26E
1123 Sighted periscope bearing 110 degrees relative
       distant 3000 yards. Maneuvered to avoid possible
       torpedoes. The periscope which appeared large in
       diameter was seen at intervals as GROUPS drew
       away from it. Lost sight of it at about 5000 yards
       just prior to which time it had been constantly and
       lengthily exposed.
1510 Submerged for training.
1635 Surfaced.

6 March
1200 Position 23-28N, 137-34E
1512 Submerged for training.
1603 Surfaced.
1618 Submerged for training.
1634 Surfaced.
2245 Submerged for training.
2321 Surfaced.

7 March
1200 Position 27-19N, 137-38E
1041 Submerged for training.
1230 Surfaced.

ENCLOSURE (A).
-2-

— page 284 —
CONFIDENTIAL

8 March
1200 Position 29-16N, 136-25E
0554 Submerged for training.
Since seas were condition four and winds were
of high velocity decided to remain submerged until
darkness.
1325 Surfaced.

9 March
1200 Position 29-18N, 135-13E
0620 Submerged to ride out high seas and winds which
have persisted since yesterday.
1320 Surfaced.

10 March
1200 Position 29-42N, 132-14E
0610 Submerged.
Remained submerged while the liner of no. 1
unit, no. 2 main engine, was replaced.
1844 Surfaced.

11 March
1200 Position 29-48N, 131-19E
0526 Submerged.
0739 Sighted Betty on course south, distant 6 miles.
1347 Sighted Betty on course south, distant 5 miles.
2025 Surfaced.
2125 Commenced transit of Tokara Kaikyo (Colnett
Strait).
2226 Heard explosion, considered very distant.
2230 Heard explosion, considered closer than first.
2233 Heard explosion, considered close by.
2240 Heard and slightly felt explosion, very close.
2247 Heard explosion, distant.
GROUPER was about 25 miles from the nearest
land when these explosions occurred. It was not
considered that their objective was GROUPER. Since
2115 there had been obtained the following radar
indications on the APR receiver - 223mc, 3000prf,

ENCLOSURE (A) -3-

— page 285 —
CONFIDENTIAL
c.
pulse and 233 mc. and 6000 prf, 3½ usec.
which, both at varying strengths. These continued
until about 2315.
2300 Sighted a white light in the direction of Yaku
Shima.
2310 Lost sight of light.
2312 Intercept on APR of 150 mc, 1000 prf, with 10
usec. pulse, considered to be air-borne radar. This
intercept varied in strength and at
became saturated, keyed off and on again and
then disappeared completely.

12 March

1200 Position 30-46N, 129-48E

0112 Completed passage of Tokara Kaikyo and proceeded
to conduct patrol with Task Group 17.22 in East
China and Yellow Seas.
0541 Submerged.
0940 Sighted Betty on course 200, distant 8 miles.
1935 Surfaced.
1943 Contact on SJ radar at 4400 yards which quickly
closed to 2300 yards, believed to be a plane. Sub-
merged.
2028 Surfaced.

13 March

1200 Position 32-09N, 126-16E

0615 Submerged.
1945 Surfaced.

14 March

1200 Position 32-12N, 125-59E

0553 Submerged.
1842 Surfaced.

15 March

1200 Position 32-36N, 125-11E

0603 Submerged.
1935 Surfaced.

ENCLOSURE (A)
-4-

— page 286 —
16 March
1200 Position 32-27N, 126-40E
0603 Submerged.
1945 Surfaced.

17 March
1200 Position 32-10N, 127-36E
0601 Submerged.
1955 Surfaced.
2303 Interference obtained on SJ radar which was
2306 identified as SJ radar.
     Exchanged recognition and identification with
     SADAVI proceeding on an opposite course.

18 March
1200 Position 31-03N, 129-34E
0515 Started through passage between Uji Gunto and
     Kusakaki Shima. Had indications of radar on the APR
     at 79, 97, 102, 143, 155, 159 and 165 megacycles
     with those at 97, 155, 159 and 165 steady and sat-
     urated. Since the distance to Kusakaki was only 5
     miles, it was considered that we were being tracked
     by one or more of these radars.
     Submerged.
0517 Arrived at life-guard station.
0957 Sighted two planes identified as Kate headed
1002 directly toward us from 3 miles. Lowered periscope.
     Heard explosion which sounded like that from a
     bomb.
1025 Raised periscope, no planes in sight.
1027 Heard second explosion similar to the previous
1030 one.
     The presence of these planes tended to confirm
     the opinion that our presence in this area was
     definitely known. It was decided to remain sub-
     merged to await arrival of air cover.
1239 Sighted three unidentified planes heading east,
     distant about 6 miles. Believing these to be friendly,
     at
1249 Surfaced. Radar indications on APR at 102 and
     159 megacycles showed steady and saturated. Distance
     to Kusakaki Shima was 16 miles. Heard life-guard
     communications but none requesting our services.

ENCLOSURE (A)
-5-

— page 287 —
CONFIDENTIAL

1302        Submerged.
1610        Surfaced.
            Radar indications on APR as on the previous
            surfacing.
1634        Submerged.
1945        Surfaced and proceeded south between Kusakaki
            Shima and Kuro Shima.
            The APR had all the radar indications that
            were present in the morning but only those at 97,
            155, and 159 megacycles seemed to be tracking us.
            These indications decreased in strength as the dis-
            tance to the land increased, and at about 20 miles
            the radars evidently resumed their sweeping.

                                19 March

            1200 Position   31-03N, 129-38E

0417        Passed between Kusakaki Shima and Kuro Shima.
            As those islands were approached all the radar
            indications were obtained as on the previous night.
            From observation of these indications on the APR
            an opinion was made that GROUPER was probably
            picked up by one or more of these radars at about
            18 miles.
0530        Submerged on station.
1126        Sighted two unidentified planes which passed
            at about five miles from our position. The peris-
            cope was lowered for five minutes and when raised
            no planes were in sight.
2003        Surfaced and proceeded south past Kusakaki
            Shima and Kuro Shima. Radar indications obtained
            were similar to those of the previous night.

                                20 March

            1200 Position   30-54N, 129-24E

0423        Passed between Kusakaki Shima and Kuro Shima
            with the APR loaded as before when in this position.
0522        Submerged.
1945        Surfaced and proceeded past Kusakaki Shima and
            Kuro Shima with the APR giving the same indications
            as on the preceding two nights.

                                21 March

            1200 Position   31-35.0N, 128-09.2E

0527        Submerged.
1936        Surfaced.

ENCLOSURE (A)                               -6-

— page 288 —
CONFIDENTIAL

                                                                22 March
                1200 Position   31-52N, 126-09E
0609            Submerged.
1938            Surfaced.

                                                                23 March
                1200 Position   30-23N, 124-45E
0542            Submerged.
1938            Surfaced.

                                                                24 March
                1200 Position   29-49N, 123-45E
0546            Submerged.
1955            Surfaced.

                                                                25 March
                1200 Position   30-54N, 124-44E
0544            Submerged.
1947            Surfaced.

                                                                26 March
                1200 Position   30-39N, 125-05E
0523            Submerged.
1950            Surfaced.

                                                                27 March
                1200 Position   31-02N, 125-25E
0443            Contact on SJ radar at 32000 yards. Turned
                toward and closed.
0520            Sighted lights of a ship dead ahead.
0526            Identified ship as the hospital ship TAKASAGO
                HAU, properly lighted and marked, on course 040
                true at 14 knots. Turned away. Position: 31-08N,
                125-36E.
0534            Submerged.
1613            Sighted three Zekes which from 3 miles turned
                and headed toward our position and passed over us.
1948            Surfaced.

ENCLOSURE (A)                                                   -7-

— page 289 —
CONFIDENTIAL

28 March

1200 Position 30-27N, 125-24E

0127 Sighted a white light distant about 6 miles.
     Commenced tracking of it, as it was evidently on
     some sort of ship or craft.
0147 Determined that the objective was at speed
     less than two knots and that it was possibly a wooden
     patrol or picket boat, or perhaps a fishing sampan,
     since no radar range could be obtained at an estim-
     ated distance of 8000 yards. Commenced closing it.
     Though there was a full moon, the existing haze had
     reduced the visibility.
0220 At 3600 yards radar range could not make it
     out other than a small craft with two masts, apparently
     lying to. Assuming it to be a picket or patrol boat
     because of its appearance and its position so far
     from the nearest land, at
0225 Opened fire with 40mm. After the fifth shot
     the light was extinguished.
0240 With range 1560 yards ceased firing, having
     expended 76 rounds of 40mm. ammunition. The objec-
     tive appeared to be down by the stern as the result
     of several hits.
0256 Since it was apparent that this craft had no
     armament and its occupants were seen to be making
     the usual gesture of surrender, proceeded to go
     alongside the sampan. Position: 30-55N, 125-26E.
     Closed the sampan to about 10 yards. The six
     occupants were definitely not Japanese and probably
     were Chinese. All of them were holding a fish in
     each hand and they were making a terrific din with
     their cries. The sampan, which was estimated at 50
     tons, had a large hole aft on the port side near
     the stern and the after mast was dismantled.
     Apparently none of the occupants had been harmed.
     There were no evidence of any radio nor of any
     propulsion other than sail. Because the occupants
     were believed to be Chinese no further action seemed
     warranted. The large hole aft coming down to nearly
     the water-line had destroyed most of the fish hold.
0300 Proceeded enroute to lifeguard station for
     Baker 29 raid on Shanghai.
0315 Received notification raid had been delayed.
0543 Submerged.
1955 Surfaced. Proceeded toward lifeguard station.

ENCLOSURE (A)
-8-

— page 290 —
CONFIDENTIAL

                                                                29 March

1200 Position 30-10N, 123-47E

0327        Received notification that air raid on
            Shanghai had taken place as originally scheduled
            and about five hours before this time. Manned
            lifeguard frequency.
0554        Submerged.
2005        Surfaced.

                                                                30 March

1200 Position 31-03N, 125-30E

0645        Submerged.
1955        Surfaced.

                                                                31 March

1200 Position 32-05N, 127-55E

0601        Submerged.
1948        Surfaced.

                                                                1 April

1200 Position 32-12N, 126-25E

0640        Submerged.
2001        Surfaced.

                                                                2 April

1200 Position 32-40N, 124-57E

0130        Interference obtained on SJ radar, identified
            as SJ radar. This interference continued inter-
            mittently until 0224 when recognition signals were
            exchanged with an unidentified submarine.
0243        SJ radar interference disappeared.
0544        Submerged. Bow planes failed to operate in
            electrical power.
1948        Surfaced. Bow planes restored to electrical
            operation.

ENCLOSURE (A)                                                   -9-

— page 291 —
CONFIDENTIAL

                                                                3 April
                1200 Position   34-54N, 123-45E
0535            Submerged. Seas were condition four and peri-
                scope depth could not be maintained. Set depth
                120 feet, coming up for periscope observation every
                hour.
1955            Surfaced.

                                                                4 April
                1200 Position   34-52N, 124-07E
0622            Submerged. Seas were again condition four.
                Set depth 120 feet, coming up for periscope obser-
                vation every hour.
1954            Surfaced.

                                                                5 April
                1200 Position   32-15N, 126-02E
0634            Submerged.
1938            Surfaced.
2325            Contact on SJ radar at 7000 yards which closed
                quickly, believed to be a plane. Submerged.
2330            Surfaced.

                                                                6 April
                1200 Position   31.17N, 128-31E
0604            Submerged.
1425            Sighted unidentified plane on course 270,
                distant 6 miles.
1950            Surfaced.
2114            Contact on SJ radar bearing 257 relative at
                22000 yards. Tracked contact which was apparently
                a large plane until at
2123            Submerged with the plane coming in fast.
                From the size of the radar pip assumed the
                contact was a friendly patrol plane. Expected it
                to pass clear of us since we were in a submarine zone.
2153            Surfaced.
2205            Contact on SJ radar at 16000 yards, closing
                fast. Evidently the same plane, which had crossed

ENCLOSURE (A)                                                   -10-

— page 292 —
C: FIDENTIAL
over us, was now coming back.
2206 Submerged.
Although it was thought that this plane was
friendly, with the possibility always existing that
it was not, it did not seem desirable to illuminate
for recognition. Since interference was showing
strong on the SJ radar "A" scope, sent recognition
by SJ radar keying.
2253 Surfaced.
Perhaps the recognition by SJ radar was
successful for the plane had departed our vicinity.
Commenced guarding aircraft frequency 4475 kc.
and VHF.

7 April

1200 Position 29-26N, 129-15E

0215 Contact on SJ radar at 25000 yards, which
disappeared immediately. The pip was similar to
that given by the plane earlier in the night.
Assumed friendly patrol plane.
0300 Contact on SJ radar at 14000 yards which was
lost immediately. Assumed to be friendly patrol
plane.
0334 Contact on SJ radar at 6000 yards. Strong
interference observed on "A" scope. Sent recog-
nition signal by keying SJ radar. Received correct
reply from plane by flashing light. Plane sighted
in the moonlight and identified as friendly patrol
plane.
0452 Contact on SJ radar at 16000 yards which opened
out and was lost at 23000 yards. Assumed friendly
plane.
0456 APR indication of enemy airplane radar which
became a saturated signal, at
0501 Submerged. This enemy plane probably had
one of our planes as his objective but since dawn
had begun considered it advisable to submerge.
During the night we were evidently directly
on the line used by friendly planes enroute to and
from their search for the Japanese task force
headed south that night.
0635 Surfaced and resumed guarding aircraft
frequencies.
0814 Sighted five planes identified as Val heading
directly toward us from the north, distant 3 miles.
Submerged.
0820 Put I.C. system out of commission to make repairs.
0903 Sighted four Hellcats headed north, distant
about two miles.
1143 I.C. system restored to service.

ENCLOSURE (A)
-11-

— page 293 —
CONFIDENTIAL
1145         Sighted a friendly air group headed north.
1225         Sighted a friendly air group headed north.
1235         Surfaced.
1305         Sighted 6 Hellcats and 6 Corsairs which circled
             us and then proceeded east.
1415         Commenced eastward transit of passage south of
             Akesuki Jima.
1540         Completed transit set course 070 true.
1742         Proceeded toward East China Sea to conduct
             search for aviators downed in attack on enemy forces.
2110         Commenced westward transit of passage south of
             Akesuki Jima.
2242         Completed transit, proceeded north toward posi-
             tion 30-47N, 128-30E.

                       8 April
1200 Position        31-14N, 128-21E

0258         Contact on SJ radar at 23000 yards, assumed
             to be friendly plane.
0302         Contact disappeared.
0604         Arrived at position 31-20N, 128-30E. Commenced
             searching area on course south.
0714         Received aircraft contact report that remnant
             of enemy task force were in position 31-12N, 128-10E,
             on course 000 true at speed 2 knots. Set course to
             proceed to intercept that force if possible to do so.
0948         Arrived at point 15 miles north of enemy
             estimated position and started to close to south.
0959         Sighted two Mariners bearing 205 true, distant
             12 miles.
1014         Mariners circled us. Sent message, "Have you
             any information for us", by VHF radio. Answered,
             "I have nothing for you. I am returning to vicinity
             I was searching".
             Because the planes had come from the south west
             it was assumed that they had been searching to the
             westward. GROUPER had covered courses eastward from
             the reported enemy position. It began to look like
             the enemy had gotten away. Perhaps the cruiser had
             sunk or had been sunk by the destroyers which had
             decided not to remain around after daylight.
1039         APR indication of enemy plane radar which came
             to saturation.
1040         Submerged.
1120         Sighted four unidentified planes on course
             south, distant 8 miles.

ENCLOSURE (A)
                       -12-

— page 294 —
[STAMP: CONFIDENTIAL]
CONFIDENTIAL
1122 Sighted four Corsairs and four Hellcats on
     course north distant 4 miles.
1130 Surfaced.
1135 Proceeded toward position 31-00N, 128-25E
     to conduct search for downed aviators, survivors,
     wreckage and anything else we might be fortunate
     enough to find.
1150 Sighted friendly submarine surfacing 2 miles
     distant.
1153 Exchanged signals with CREVALLE which headed
     to eastward.
1222 Sighted two Mariners distant 12 miles which
     came toward us. They passed close by us, circled
     and then proceeded on their way.
1305 Sighted a Mariner with four Hellcat escorts
     searching to southwest of us at about 10 miles.
     They approached, circled and proceeded on their
     search, which was apparently for survivors.
     Transmission overheard on aircraft frequencies
     indicated that planes had evidently investigated
     all the positions of survivors of which GROUPER
     had been informed.
1330 Arrived at 13-00N, 128-25E, headed south.
1445 Sighted two Mariners on course south bearing
     310 true, distant 10 miles. These planes and the
     group seen at 1305 were seen to be searching the
     area to the southwest of GROUPER.
1530 APR indication of enemy plane radar which came
     in twice again and went out completely at 1540.
2336 Commenced eastward transit of passage south
     of Akosuki Jima and took departure for Saipan.
[HANDWRITTEN: 8/4]

9 April

1200 Position 29-17N, 131-16E

0401 Contact on SJ radar at 20000 yards, assumed
     to be friendly patrol plane.
0403 With contact 6000 yards, fired recognition
     signal and submerged.
0432 Surfaced.
0528 Submerged.
1943 Surfaced.

10 April

1200 Position 29-17N, 136-02E

ENCLOSURE (A)
-13-

— page 295 —
CONFIDENTIAL
                                                                11 April
        1200 Position           24-23N, 137-19E
0955    Submerged.
1040    Surfaced.

                                                                12 April
        1200 Position           18-43N, 137-20E
1647    Submerged.
1708    Surfaced.

                                                                13 April
        1200 Position           15-21N, 141-38E

                                                                14 April
0605    Rendezvoused with Saipan escort.
1027    Arrived at net entrance, Saipan, and entered
        channel.
1057    Moored alongside U.S.S. FULTON, Tanapag Harbor.
        Took on fuel and water and unloaded torpedoes.

                                                                15 April
0940(K) Underway from alongside, U.S.S. FULTON.
1012(K) Passed through net and took departure for Pearl.
1017(K) Proceeding in company with the USS KINGFISH
        and escort.
1500(K) Released escort.

                                                                16 April
        1200(K) Position        17-08N, 148-37E

                                                                17 April
        1200(K) Position        18-12N, 153-34E

ENCLOSURE (A)
                                                                -14-

— page 296 —
CONFIDENTIAL

                                                                18 April
                1200(L) Position        21-09N, 157-45E

                                                                19 April
                1200(L) Position        22-07N, 162-41E

                                                                20 April
                1200(L) Position        22-15N, 157-56E
                1900(L)         USS KINGFISH departed to proceed ahead.

                                                                21 April
                1200(H) Position        21-57.3N, 172-32.2E

                                                                22 April
                1200(H) Position        21-38.8N, 177-43.9E
                Crossed 180th Meridian and repeated date

                                                                22 April
                1200(X) Position        21-36.0N, 176-44W

                                                                23 April
                1200(X) Position        21-20N, 171-33W

                                                                24 April
                1200(X) Position        21-05N, 166-51W

                                                                25 April
                1200(X) Position        20-55N, 162-10W

ENCLOSURE (A)
                                                                -15-

— page 297 —
CONFIDENTIAL

                                                                26 April

0432(VW)             Rendezvoused with Pearl escort.
1020(VW)             Passed entrance buoys, Pearl Harbor channel.
1115(VW)             Moored at Submarine Base, Pearl Harbor, twelfth
                     war patrol completed.

ENCLOSURE (A)                                       -16-

— page 298 —
CONFIDENTIAL

(C) WEATHER
Jacobs I
The weather in the East China and Yellow Seas
was in general as good as could be expected at this
time of the year. There was a light fog which per-
sisted for about six hours on the morning of 14 March.
In the western part of the East China Sea around lati-
tude 31-00 north there was fog from the late evening
of 28 March until early morning on 31 March during
which visibility was decreased to less than 2000
yards in the daytime and less than 1000 yards at night.
South of Quelpart Island on 2 April a fog limiting
the visibility to less than 1000 yards persisted
for about twenty-four hours. On 3 and 4 April in
the Yellow Sea when between latitudes 34-00N and
36-00N, winds were from 20 to 30 knots from 350 true
and seas were of condition four. In the East China
Sea skies were clear around the period of the full
moon on 28 March, otherwise the skies were usually
cloud covered or overcast in both the East China
and Yellow Seas.

(D) TIDAL INFORMATION
The only currents observed in both the East
China and Yellow Seas were found to conform with the
current data given in H.O. 123-B.

(E) NAVIGATIONAL AIDS
No navigational aids were sighted.

(F) SHIP CONTACTS
| No. | Time Date | Lat. Lon. | Type(s) | Initial Range | Est. Cse. Speed | How Con-tacted | Remarks |
|---|---|---|---|---|---|---|---|
| 1 | 0526I 27 March | 31-08N 125-36E | Hospital Ship | 28000 yards | 040 14 kts. | SJ radar | Properly marked |
| 2 | 0127(I) 28 March | 30-55N 125-26E | Fishing Sampan | 8000 yards | Lying to | Sighted light | |

(G) AIRCRAFT CONTACTS
Upon subsequent investigation of occurrences it
was determined that anti-submarine activities by enemy
aircraft may have been conducted on the night of 11-12
March in the vicinity of Colnett Strait when the
explosions were heard and on the night of 12-13 March
in the vicinity of Kusakaki Shima where GROUP R may
have been followed by planes for three periods of

ENCLOSURE (A)
-17-

— page 299 —
CONFIDENTIAL

nearly two hours each. If such was the case GROUPER
was in ignorance of these activities because of failure
to interpret the indications existing at the time.
Of sixteen probable indications of radar equipped
enemy planes, fourteen were at night and two during day.
For three of the night contacts and one of the day
contacts the GROUPER submerged. After our patrol planes
began operating in the area it seemed that the enemy
planes were seeking them out rather than submarines.
On the three occasions when GROUPER encountered friendly
patrol planes which turned on their IFF equipment,
indications of radar equipped enemy planes were obtained:
four minutes after the first occurrence, fifteen minutes
after the second and forty two minutes after the third,
GROUPER did not use any IFF equipment while in the area.
It is assumed that GROUPER was tracked by shore-
based radars on 18, 19 and 20 March and that the planes
seen on those days may have been on anti-submarine
missions.
Throughout the period there was much less enemy
airplane activity than was expected. The various oper-
ations directed against Kyushu and the Nansei Shoto
commencing on 18 March were probably the cause for this.

(H) ATTACK DATA

USS GROUPER GUN ATTACK No. 1 PATROL No. 12
Time 0225I Date 28 March Lat. 31-08N Long. 125-36E

TARGET DATA - DAMAGE INFLICTED

Sunk: None
Damaged: One sampan (MISC)-wooden hull about 60
feet in length, estimated 50 tons displacement.
Damage Determined By: Upon going alongside the sampan
it was seen that a large hole had been made on
the port side above the water line near the stern
and one mast had been dismantled.

DETAILS OF ACTION

Commenced firing at 2600 yards range with 40mm.
Fifth shot hit and target turned presenting only its
stern. Continued firing while closing the range and
maneuvering to get on beam of target again. At an
average range of 1940 yards fired 76 rounds of which
38 were high capacity and 38 were incendiary. Five

ENCLOSURE (A)
-18-

— page 300 —
CONFIDENTIAL
. . . hits, all of which must have been high capacity,
were observed. Even considering other causes for
this gunnery performance, the present 40mm. sights are
not very efficient. Action broke off because of
assumed friendly (Chinese) identity of occupants.

(I) MINES
No mines nor minelaying activities encountered.

(J) ANTI-SUBMARINE MEASURES
The only anti-submarine measures observed were
conducted by aircraft and are described in Section
(H).

(K) MAJOR DEFECTS AND DAMAGE

HULL AND MACHINERY

No. 1 air compressor - On 16 March the fourth stage
piston of no. 1 high pressure air compressor froze
in its cylinder. The piston was broken in removing
it from the cylinder at a point three-eighths
of an inch above the fillet at its base. Inspection
of the fracture showed that one-third of the area was
occupied by a blow-hole. A new section of piston was
turned out on the lathe from a length of steel stock
and secured into the second stage cylinder by a
threaded fit. The fourth-stage bull nose was secured
to the new section by one-quarter inch dowels set an
inch apart at right angles. After adjustments were
made the compressor operated satisfactorily and con-
tinued to do so throughout the patrol. This failure
was considered to be material.
No. 1 lubricating oil purifier - On 5 March the
forward engine room lubricating oil purifier was put
out of commission. Investigation disclosed that the
threaded sleeve of the lower bushing support for the
rotor had broken from its base. The base was put
in the lathe and a quarter-inch groove cut into the
base. A new sleeve was made and fitted into the
groove and retained there by screws from the under
side. The purifier was put back into operation and
performed satisfactorily throughout the run. This
failure is attributed to personnel who last overhauled
this purifier. It was apparently caused by a poorly
fitted bushing which permitted rotor wobble.
Auxiliary engine - On 6 April the auxiliary engine
would not start. Investigation disclosed that the

ENCLOSURE (A) -19-

— page 301 —
CONFIDENTIAL
coupling to generator was broken, putting this engine
out of commission for the duration of the patrol.
This casualty is attributed to carelessness of oper-
ating personnel.
Bow Planes - On 2 April the bow planes failed in
electrical operation. After considerable time spent
in searching for the cause of the failure it was
found to be in the contactor circuit through the
contact relay spring and knife-edge. Wear and
cumulative arcing had rendered this circuit no
longer positive. A pig-tail conductor was installed
across the spring and knife-edge.

(L) RADIO
Material - On the night of 7 April antenna loading was
seriously reduced because of moisture accumulation
in the antenna trunk. This condition was rectified in
about twelve hours by drying the trunk with a portable
electric dryer.
Performance - Reception of Fox schedules was good in
the East China and Yellow Seas except during the period
from 1930 to 2030(Item) daily when all frequencies
faded until they were sometimes unreadable. With 9090
kc. remaining the strongest. The 9090 kc. schedule
was always the most readable, except for a
two week period commencing about 10 March when it was
apparent that the transmitter tape was causing blurred
characters.

(II) RADAR
Material - The SJ radar antenna rotating gear box
installed is one of the first Mare Island multiple
speed designs. The gears are now worn excessively
and they are not only very noisy in operation but in
the hand position the gears slip out of engagement.
This installation will be replaced during the coming
overhaul.
Performance - The following data on SJ radar performance
was noted: During the heavy fog on the night of 2
April indications on Quelpart Island (6388 feet) were
obtained in excess of 200000 yards. This was the
first occurrence observed in which the effect of fog
on the performance of the radar was distinctly evident.
In clear atmosphere the TAKASAGO MARU gave nearly a
saturated indication at 38000 yards. Earlier patrol
planes gave nearly a saturated indication at 22000
yards and at this or slightly greater range they
were usually first detected. The maximum range at
which an enemy plane was detected was 16000 yards.

ENCLOSURE (A)
-20-

— page 302 —
CONFIDENTIAL
(H) SONAR GEAR AND SOUND CONDITIONS.

Material - On 21 March the JK-QC sound shaft began mak-
ing a groaning sound when trained. The cause of this
noise was determined to be from wear of the shaft
lower bearings. The noise was of such magnitude that
this shaft could be used only when surface cruising.
Performance - There were no occurrences from which sonar
gear performance or sound conditions could be observed.

(C) DENSITY LAYERS

No density layers were found in the East China
and Yellow Seas in the depths to which dives were
made because of the shallow water. In the East China
Sea the water temperature ranged from 64 degrees when
in the Kuroshio to 45 degrees when outside of that
stream. On several occasions the water temperature
varied as much as 12 degrees at a constant depth when
passing along or through the edges of the Kuroshio.
In the Yellow Sea the temperatures were found to be
constant at about 43 degrees. Where the Yellow Seas
and East China Seas mixed, near lat. 32-00N the
temperature of the water was usually variable at a
constant depth.

(P) HEALTH, FOOD AND HABITABILITY

The general health of the officers and crew was
excellent. Probably because of the cool temperatures
in the area, skin infections were few. There were
two cases of boils which were not serious.
The food was good, well prepared and a balanced
diet was provided.
Habitability was normal. In the cooler waters
condensation made both torpedo rooms very damp and
unpleasant.

(Q) PERSONNEL

(a) Number of men detached after previous patrol 22
(b) Number of men on board during patrol 76
(c) Number of men qualified at start of patrol 55
(d) Number of men qualified at end of patrol 67
(e) Number of unqualified men making their first
patrol 13

All the new men displayed enthusiasm for
submarine duty. All of them quickly became capable
of taking their places in the organization for which

ENCLOSURE (A)
-21-

— page 303 —
their previous good training is considered respon-
sible.
     The presence on board of a very expert lathe
operator was invaluable to GROUP R. The work of
this lathe operator restored to operation a high
pressure air compressor and a lubricating oil
purifier, casualties to both of which at the
beginning of patrol at first indicating that neither
would be further available.

(R) MILES STEAMED - FUEL USED

     Saipan to area           1797 miles          22910 gals.
     In area                  4670 miles          49655 gals.
     Area to Pearl                 miles          79400 gals.

(S) DURATION

     Days enroute to area          9
     Days in area                 28
     Days enroute to Saipan        6
     Days submerged               30

(T) FACTORS OF ENDURANCE REMAINING

     Torpedoes           Fuel           Provisions     Personnel Factor
     22                  gals.          10             10

     Limiting factor this patrol - terminated by
operation order.

ENCLOSURE (A)
                                   -22-

— page 304 —
CONFIDENTIAL
(U) COMMUNICATIONS, RADAR AND SONAR COUNTERMEASURES
Radar Countermeasures
(1) Intercept of enemy radar signals.

Intercepts of enemy radar signals in the
East China Seas were obtained by the APR-1 re-
ceiver only. Pulse rate and pulse widths were
measured by the SPN-1 equipment. The following
are considered to be intercepts of enemy land
based radars:

Date | Location | Freq. mc. | PRF | Width usec.
---|---|---|---|---
11 Mar. | Yaku Shima | 145 | 450 | 10
12,17,21 Mar. | Danjo Gunto | 98 | 750 | 45
6,8 April | " " | 155 | 300 | 20
18,19,20 Mar. | Kusakaki Shima | 75 | 300 | 50
| | 79 | 500 | 80
| | 97 | 750 | 40
| | 102 | 500 | 80
| | 148 | 500 | 10
| | 155 | 500 | 12
| | 159 | 500 | 14
| | 160 | 400 | 10
| | 165 | 500 | 12

It is possible that some of those radars
observed while in the vicinity of Kusakaki Shima
may have been located on Kyushu, Kuro Shima,
Koshiki Retto and Yaku Shima.

31 Mar. | Saishu To | 77 | 500 | 25
1,2,5 April | or Mara To | 77 | 200 | 45
| | 79 | 500 | 80
| | 83 | 300 | 30
| | 94 | 750 | 19
| | 86 | 750 | 22
| | 97 | 500 | 80 Sine
| | 103 | 300 | 65 wave
| | 148 | 500 | 7
| | 152 | 500 | 10
| | 157 | 500 | 12
| | 159 | 500 | 5-3 double
| | 160 | 500 | 8 pulse
| | 165 | 500 | 5
| | 198 | 500 | 5-7 double
| | 303 | 500 | 15 pulse

7,8 April | Near Akuseki | 97 | 500 | 12
| Jima | 155 | 500 | 10

ENCLOSURE (A)
-23-

— page 305 —
CONFIDENTIAL

All of the above intercepts were considered to
be from rotating sources. Only those at or near 97 mc.
observed in the Saishu To vicinity were timed at
regular sweep intervals. These intervals were from
3½ to 5 minutes.
It was observed that whenever our planes passed
in the vicinity of the radar locations there was in-
creased radar activity indicated on the APR receiver.
These additional intercepts were always in the 150
to 160 mc. band.
In periods when there was fog the phenomenon
occurred in which nearly all radar intercepts were
received at saturation though the nearest sources
were from one hundred miles to one hundred and twenty
miles away. In clear weather no intercepts were ob-
tained from these same sources at about seventy miles.

The following were considered to be intercepts of
enemy airborne radars encountered in the East China Sea:
Date             Freq.    PRF    Width
                 mc.             usec.
12 March         155      1000   15
                 153      750    5
                 210      1200   6½
18 March         162      1000   12
21 March         151      1000   12
25 March         153      1000   8
26 March         148      750    10
1 April          312      1250   15
2 April          165      850    5
6 April          150      1200   12
7 April          152      1200   12
8 April          152      1000   10
8 April          157      1000   12

From two cases where enemy radar equipped planes
were ranged on GROUPER radar it was concluded that the
enemy also varies signal strength and that the strength
of the intercepted signal is not a reliable indication
of the distance of the source.

The following intercepts were received which were
not classified:
Date         Location             Freq. PRF    Width
11 March     25 miles south       223 3000     5
11 March     of Yaku Shima        233 6000     3½

ENCLOSURE (A)
-24-

— page 306 —
CONFIDENTIAL
(2) Jamming, own and enemy.
None observed.

(3) Deception, own and enemy
None observed.

(4) No data.

Communications Countermeasures
(1) Intercept of enemy signals.
No intercepts of enemy signals were heard
except those considered to be jamming.

(2) Jamming, own and enemy.
Enemy signals were always present on the
wolf pack frequencies. Usually this jamming
seemed to be only random keying.
Enemy jamming was present on 4235 kc. and
8470 kc. almost always. This jamming consisted
of random keying, Vs, and continuous modulated
signals.

(3) Deception, own and enemy.
On March 27 when GROUPER was attempting to
transmit to NPH on 4235 kc. an enemy radio came
in with NPH call followed by several Q signals
and asked for signal strength. Later NPH veri-
fied that we had not previously been in commun-
ications with them.

Sonar Countermeasures
No enemy sonar observed.

ENCLOSURE (A)
-25-

— page 307 —
CONFIDENTIAL
(V) REMARKS

                                        The encounters with friendly patrol planes in the
area provided situations for which the present means of
recognition do not seem adequate, especially at night.
On the night contacts with these patrol planes they were
assumed to be friendly. First, because of the great
ranges at which they appeared on the SJ radar and second,
because of the lack of intercept on the APR receiver
of any known enemy radar signals. Yet neither of these
reasons for believing the planes to be friendly could
have been considered as positive identification. The
enemy has large planes and the possibility exists that
the enemy may have air-borne radar that is not within
the range of the present APR equipment. It cannot be
regarded as a desirable procedure to illuminate with
pyrotechnics or to use a light in order to establish the
submarine identity when such actions might only serve
to definitely disclose the submarine to an enemy plane.
Neither does it seem prudent to remain on the surface
while a plane closes steadily to less than 400 yards
when the plane and the submarine are not certain of the
others friendly identity. Soon after each time a friendly
plane used its IFF an enemy plane came into the vicinity.
While those enemy planes were probably searching for
the patrol planes it is not likely that they would ignore
a submarine contact. From these incidents it is conclu-
ded that the use of the present IFF equipment is good
neither for the planes nor the submarine. In the daytime
when visibility and lack of clouds permit the sighting
of a plane at a great distance prompt identification
may avoid submergence but the wisdom of remaining on the
surface becomes doubtful when a friendly plane with which
recognition has not been exchanged comes directly in to
less than 1000 yards. On the forenoon of 8 April a
friendly submarine was observed to submerge on two
occasions, apparently for SD indications on friendly
planes. In an area where enemy planes are frequently
encountered and often cause a submarine to submerge the
presence of friendly planes which cannot be identified
promptly as such impose an additional problem. If the
friendly planes are equipped with 10 cm. radar, perhaps
recognition between submarine and plane can be established
by the use of that radar. The use of sector approaches
by a plane when investigating a contact which may be a
friendly submarine might serve to show the submarine
that the plane is friendly.

ENCLOSURE (A)                                     -26-

— page 308 —
SUBMARINE DIVISION 103

FB5-103/A16-3                                        Care of Fleet Post Office,
                                                     San Francisco, California,
Serial 029                                           27 April 1945.

CONFIDENTIAL
FIRST ENDORSEMENT to
CO GROUPER'S Report of
Twelfth War Patrol.

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

Subject: U.S.S. GROUPER - Report of Twelfth War Patrol; Comments on.

      1. The Twelfth War Patrol of the U.S.S. GROUPER was conducted
in the East China and Yellow Seas between 3 March and 26 April 1945.
Twenty-eight days were spent in the area; thirty days submerged.

      2. This patrol was characterized by lack of suitable targets,
many plane contacts both enemy and friendly, life-guard duty performed
and search for reported enemy task force. The only attack made was a
gun attack on a fishing vessel with the 40mm. After the target had been
holed, the Grouper closed it and determined that its occupants were
Chinese fishermen. The vessel was therefore not molested further.

      3. The discussion of recognition between planes and submarines
under "Remarks" points out some of the difficulties. It is certainly a
problem not yet solved. The IFF, probably our best bet, is far from per-
fect.

      4. The U.S.S. Grouper returned clean and in fine material
condition considering the time since her last overhaul. She now goes
to Navy Yard Overhaul on the West Coast.

      5. The Division Commander congratulates the Commanding
Officer, Officers and Crew of the Grouper upon the completion of this
patrol in which, though almost without tangible results, tasks essential
to the war effort were accomplished and done in a thorough manner.

[SIGNATURE: K. S. Benson]

— page 309 —
SUBMARINE SQUADRON FOUR
Fleet Post Office
San Francisco, California

FC5-4/A16-3
Serial: 0331
C O N F I D E N T I A L

SECOND ENDORSEMENT to
USS GROOPER (SS214) - Re-
port of Twelfth War Patrol.

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

Subject: U.S.S. GROOPER (SS214) - Report of Twelfth War
         Patrol.

1. Forwarded, concurring in the remarks of the Ad-
ministrative Commander Submarine Division ONE HUNDRED THREE.

2. The Squadron Commander congratulates the Com-
manding Officer, officers, and crew of the U.S.S. GROOPER upon
completion of her Twelfth War Patrol.

3. It is regretted that no enemy targets presented
themselves for attack.

[SIGNATURE: W. V. O'Regan]
W. V. O'REGAN.
11/wft
30 April 1945.

— page 310 —
FF12-10(A)/A16-3(18)
Serial 01008
CONFIDENTIAL
THIRD ENDORSEMENT to
GROUPER Report of
Twelfth War Patrol.

SUBMARINE FORCE, PACIFIC FLEET
Care of Fleet Post Office,
San Francisco, California,
3 May, 1945.
NOTE: THIS REPORT WILL BE
DESTROYED PRIOR TO
ENTERING PATROL AREA.

[HANDWRITTEN: F4254 Ga]
5 02900

COMSUBSPAC PATROL REPORT NO. 740
U.S.S. GROUPER - TWELFTH 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. GROUPER (SS214) - Report of Twelfth War Patrol
(3 March to 26 April 1945).

1. The twelfth war patrol of the GROUPER, under the command of Commander
F. H. Wahlig, U.S. Navy was conducted in the East China and Yellow Seas areas. The
GROUPER, along with the U.S.S. GUARD FISH (SS217), the U.S.S. SEA DEVIL (SS400)
and the U.S.S. TENCH (SS417), formed a coordinated attack group, with the commanding
officer of the TENCH as group commander. In addition to offensive patrol, lifeguard
services were rendered.

2. Despite thorough and intelligent area coverage, only two contacts
were made. One was a properly marked hospital ship; the other, a sampan, which was
attacked by gun fire. Upon identifying the sampan as Chinese, the commanding officer
correctly ceased action; no occupants were harmed. It is regretted that no contact
worthy of torpedo fire, nor opportunities to effect rescue, were encountered. The
Force Commander wishes the GROUPER better luck next time.

3. Award of Submarine Combat Insignia for this patrol is not authorized.

MERRILI COMSTOCK.
[SIGNATURE: E. L. Hynes]
E. L. HYNES, 2nd,
Flag Secretary.

DISTRIBUTION:
(Complete Reports)
Cominch (7) | ComsubspacAdComd (20)
CNO (5) | SUBAD, MI (2)
Cincpac (6) | ComsubspecSubordcom (3)
JICPOA (1) | All Squadron and Div.
AdICPOA (1) | Commanders, Pacific (2)
Conservpac (1) | Substrainpac (2)
Cinclant (1) | All Submarines, Pacific (1)
Comsubslnt (8)
S/M School, NL (2)
CO, S/M Base, PH (1)
Comsopac (2)
Comsowespac (1)
Comsubsowespac (2)
CTG 71.9 (1)
Comnorpac (2)
Comsubspac (3)

[STAMP: EXTRA : ORIGINAL]
[STAMP: ORG. MICRO]
[STAMP: PHOTO-LAB OP-16]
[STAMP: RETURN TO F-4253]

— page 311 —
END OF REEL
JOB NO. [HANDWRITTEN: H108]

1.0
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||||| 2.0
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THIS MICROFILM IS
THE PROPERTY OF
THE UNITED STATES
GOVERNMENT

[STAMP: DEPARTMENT OF DEFENSE]
[STAMP: UNITED STATES OF AMERICA]

MICROFILMED BY
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