Subject:       U.S.S. WAHOO - REPORT OF FOURTH WAR PATROL.

               (Period from February 23 to April 6, 1943)
 

               PROLOGUE:

               Arrived PEARL on February 7, 1943 from THIRD War
               Patrol.

               Commenced refit by tender, relief crew and ships force.
Shifted 4" gun from aft to forward and mounted a third 20mm gun on the
former 4" gun foundation.  Completed refit on February 15, 1943.

               Readiness for sea February 17, 1943.  Conducted
training February 17 to 19 inclusive.  Dry-docked at SuBase PEARL
February 21, 1943 for emergency repairs to No 5 torpedo tube shutter.
Cleared and painted bottom.  Undocked ship February 22, 1943.

     1.        NARRATIVE:

February 23:   1300VW; Underway from Pearl for patrol area via MIDWAY.
With surface escort until dark.

February 23-27:Enroute MIDWAY encountering generally rough weather
with mostly head seas.  Conducted daily dives and training.  Sighted
several friendly planes enroute.

February 27:   0600Y; Picked up air escort on 30 mile circle bearing
east from MIDWAY.

               0830Y; Moored starboard side to the port side of U.S.S.
Tarpon, at SuBase MIDWAY.
               1430Y; Departed MIDWAY for patrol areas having taken on
16,000 gallons fuel oil and 2,500 gallons fresh water.

               Crossed International Date Line.

February 27 to
March 11:      Enroute to patrol areas conducting daily training
dives, fire control drills and battle surface drills.  Had the unique
experience of making passage from Pearl to inside of the CHINA SEA
without sighting a plane and consequently made to entire trip on the
surface.  The seas were generally rough and from ahead.  Had to slow
to one engine speed several times, because of excess fuel consumption
per mile.

               During the first torpedo control drill after leaving
MIDWAY, the gyro-setting indicator regulators were found to fail
intermittently.  For ten days Lieutenant R. H. HENDERSON, spent
practically every moment when off watch in tracing out these troubles,
finally locating them in loose connections and in improperly adjusted
overload relay micro-switch.  Through his untiring efforts the
equipment was placed in proper operating condition prior to entering
the area.  He is deserving of the highest praise.  It is gratifying to
have a torpedo officer of his calibre aboard.

March 11:      0110I; Entered assigned area.

               0610I; Commenced submerged patrol in assigned area and
along the NAGASAKI - FORMOSA shipping route.  Seas were flat calm.

March 12:      During the night sighted many lighted sampans which
were always in pairs.
               0555I; Dived in the SHIMONOSEKI - FORMOSA trade routes,
hoping the "Beauty" the U.S.S. SUNFISH hit would limp through today.
It was perfect approach weather.

               Our plan of operation is to spend a day in each of
their known shipping routes while we work our way up north where we
hope to locate the route where the heavy traffic from the Yellow Sea
flows into the Inland Sea via SHIMONOSEKI.
               1342I; Sighted masts.  Conducted approach only to
identify two steam driven sampans about 500 tons each.

               1728I; Sighted small (60 foot) motor sampan.

               Sighted numerous lighted sampans during the night and
kept clear.

March 13:      0600I; Dived with MAOA TO light, just off the Southwest
coast of SAISHU TO, bearing 358dT. distant 6 miles where the SHANGHAI
- SHIMONOSEKI traffic could pass.  Also some Yellow Sea traffic could
round this corner.

               0700I; Sighted another small motor sampan.

               0814I; Sighted smoke.  Commenced approach which lasted
almost five hours.  The closest we could get was about 8,000 yards.
Finally abandoned the approach.  A peculiar mirage prevailed.  As far
as we could tell it was a small Inter-Island type steamer.  It was
either acting as a smoking decoy and patrol boat or it was trawling.
We nick-named it "SMOKY MARU".

               1640I; (FIRST ATTACK).  The same SMOKY MARU headed
directly for us.  Went to battle stations and made approach.  At 1704I
fired one torpedo from a stern tube at 1,000 ton ship, range 1,000
yards, 90d port track, speed 12 knots.  Missed, a few feet ahead of
target.  After our long chase this morning and being anxious to shoot
something, we let him have just one.  He was the type of target worth
one torpedo if you sink him, but not worth two torpedoes under any
conditions.

               The torpedo was set to run at five feet.  The sea was
light (condition 2), however it is believed the torpedo ran shallow.
It was seen to porpoise just ahead of the target.  It is possible the
target did not sight it, because afterwards he held a steady course
and speed.  Miss was due to error in estimating mast-head height.  We
guessed 75 feet.  Actually it was about 55 feet.  This was determined
by timing the run of the torpedo when it broached just ahead of the
target.  Target similar to U.S.S. GUDGEONS sketch of the "Q" ship but
without any guns.  His turn count gave him 10 turns per knot.  Other
boats in this area will no doubt sight this type of ship in the
future.

               1815I;  Just as the target was going over the horizon
another SMOKY MARU came out to relieve the watch.  We avoided.

               Sighted many lighted sampans during the night.

March 14:      0600I; Dived with KAKYO TO light bearing 000dT. distant
3 miles, in position to intercept some of the Yellow Sea traffic which
rounds the corner for SHIMONOSEKI especially traffic from TSINGTAO.

               0645I; Sighted another SMOKY MARU.  He acted as if he
was patrolling.  He was towing nothing, yet his speed was five knots
or less on various courses.  The sea was flat calm.  The temperature
had dropped from 68d to 48d over night.

               0804I; SMOKY MARU, after making a wide circle, speeded
up to 10 knots.  Sighted smoke.  Commenced approach.  During the
approach had as many as five SMOKY MARUs in sight.  It certainly
looked as if they were acting as decoys drying to sucker us away from
a good sized target that might be smoking.

               1015I; Abandoned approach after establishing all
targets as too small for torpedo fire.  Some of these vessels remained
in sight during the entire day.

               Sighted many lighted sampans during the night.

March 15:      0600I; Dived with HEMPUN TO bearing 355dT. distant 11
miles.
               This was believed to be the route taken by a large
volume of the Yellow Sea traffic to JAPAN.  Visibility had slightly
decreased with a light haze.

               1414I; Sighted small patrol or gun boat range about
8,000 yards.  When we swung ship to approach course, we lost him in
the haze and were unable to regain contact.
               Sighted many lighted sampans during the evening.

March 16:      0150I; Radar contact 10,000 yards.

               0200I; Radar contact 3,200 yards and immediately
sighted vessel resembling a destroyer with a very sharp angle on the
bow and with moon in back of us.  Dived and pointed own ship towards
target for a possible "down the throat" defensive shot.  Lost sight of
the target when the range was about 1,400 yards.  The target was not a
destroyer, but another SMOKY MARU.

               0320I; Surfaced when SJ radar failed to pick up
anything.

               0600I; Dived with CHU TO light bearing 138dT.  distant
11 miles.

               0620I; Sighted another SMOKY MARU.  He was making
radical and frequent zigs at 7 knots speed.

               This MAIKOTSU SUIDO  is definitely not a good place for
submarine attacks.  It is shallow, with islands and shoals everywhere.
However, we considered it worth while to reconnoiter to see where this
Yellow Sea traffic is located.  We call this channel "Sampan Alley".

               Sighted several lighted sampans during the night.

               1940I; Upon surfacing set course North and when we
crossed the path of the ships sighted by the U.S.S. HADDOCK we changed
course and followed this track heading us for the proximity of
SHANTUNG PROMONTORY.

               Our SJ radar went out of commission during the night.
We have no technician aboard, but Lieutenant C.C. Jackson II and our
leading radioman have been relieved of all duties, while concentrating
on this valuable instrument.

MARCH 17:      Did not dive this morning.  Visibility was excellent
and sea calm.  Had some difficulty in dodging all of the junks and
trawlers to prevent being sighted.

               0800N; Dived on what we thought was a plane contact.
After talking it over, considered contact was very likely a flight of
three geese.  Stayed submerged while a few junks got out of sight.

               1000H; Surfaced.

               1055H; Dived.  Too many trawlers and junks were in
sight to dodge all of them.  This area appeared to be a shipping route
too.  A half dozen trawlers remained close to us the remainder of the
day.

               1835H; Surfaced.

               Many lighted sampans sighted during the night.
 

March 18:      0455H Dived with SHANTUNG PROMONTORY light bearing 231d
distant 19 miles.  The weather started out hazy and finally ended up
with a thick fog.  Remained submerged while we worked on SJ radar.
Took a few soundings.  Weather cleared up at the end of the day.
Radar is back in commission.  Congratulations to Lieutenant C.C.
JACKSON II and J.P. BUCKLEY, RM1c.

               Upon surfacing set course for ROUND ISLAND light off
the entrance to DAIREN.  We are bound and determined to find some
traffic.

March 19:      0422H; (SECOND ATTACK).  Sighted freighter.  Went to
full power and gained position ahead, tracking with radar.

               0455H; Dived when light enough to see through
periscope.

               0515H; Fired one torpex torpedo at medium sized
freighter identified as KANKA MARU, 4,065 tons, range 750 yards, 120d
port track, speed 9 knots.  Hit.  After part of ship disintegrated and
the forward part sank in two minutes, and 26 seconds.  These Torpex
heads carry a awful wallop.

               0520H; Surfaced to see if anyone survived that blow.
Lots of debris and a row boat were observed but no one left to tell on
us.

               0530H; Sighted another ship.

               0535H; Dived.  Ship turned out to be a junk.  So
commenced submerged patrol off DAIREN.

               0755H; (THIRD ATTACK).  Sighted freighter with large
angle on the starboard bow.  Commenced high speed approach.  We had to
run over seven (7) miles.

               0916H; Fired two Torpex torpedoes at what appeared to
be a new freighter or naval auxiliary in ballast with guns forward and
aft; similar to the TOTTORI MARU 5,973 tons, 125d starboard track,
speed 9 knots, range 1,800 yards.  First torpedo hit under his
foremast with a terrific blast, but his bow remained intact, however,
we could see a tremendous hole up his side.  Second torpedo hit him
amidships, but it was a dud,  The co-approach officer saw a small
plume and both sound operators heard the thud of the dud.

               0921H; Checked the set up and fired another torpedo.
The target maneuvered and avoided.

               0926H; Fired fourth torpedo right up his rump.  Again
the target maneuvered and avoided.  Target fired at periscope.  We
certainly hated to see this one go over the hill.  The water is so
shallow around here, we cannot afford to tangle with a concentration
of patrols.  That dud cost us one fine ship plus two other precious
torpedoes and a chance to shoot at more targets at this spot.

               0930H; Continued submerged patrol heading away from the
scene of the morning engagements.

               Except for one day of fog, the weather has been
perfect.  Tonight we are patrolling along the route our two victims
came in on yesterday.  It leads to a light off the KOREAN COAST and
just South of CHINNAMPO.  We shall patrol off of this light tomorrow.

               No small fishing boats sighted to-night - the first
time "no-see"!!

March 20:      0310H; Sighted ship.  Commenced approach.

               0440H; Dived.

               0515H; Broke off the approach when target turned out to
be a small patrol or trawler.  The visibility was so good that this
small craft was sighted at an unusually long range.

               Sighted several smoking ships well inshore and over the
horizon.  We are going over there to-night and patrol off CHOSAN MAN
Point tomorrow.  The traffic to CHINNAMPO, a large port, must pass
that point, so we hope to have some luck.

March 21:      The currents encountered around this port were really
strange, but conformed with those shown on the chart.
 

               0510H;  (FOURTH ATTACK).  O.O.D. picked up ship with a
range about 7,000 yards and angle on the bow 30d starboard.  Commenced
approach immediately.  At second observation ship had changed course
60d to his right putting us on his port bow so we swung ship again and
closed at high speed.

               0700H; Fired three torpedoes at large freighter
identified as SEIWA MARU 7,210 tons, range 1,600 yards, 117 port
track, speed 11 knots.  Third torpedo hit him amidships and he went
down by the bow attaining a vertical angle and was out of sight in
four minutes.  We counted 33 survivors in the water (temperature of
water and air 40d F).  There was debris for the survivors to cling to.
Considered they could last but a couple of hours.  Took several
pictures.

               This was a torpex head and the really blow a ship to
pieces and the sound is terrific to us.  Twice a wash basin has been
knocked off the bulkhead in the forward torpedo room.

               0930H; (FIFTH ATTACK).  O.O.D. sighted ship range
13,000 and angle on the bow 5d starboard.  Maneuvered for a stern
shot.

               0958H; Fired a spread of three torpedoes at large
freighter identified as NITU MARU, 6,543 tons, 87d starboard track
speed 10 knots range 800 yards.  Two torpex torpedoes hit, one under
his bridge and the other under the mainmast.

               This ship went down vertically by the bow and was out
of sight in three minutes 10 seconds.  Had the water been deeper he
would have sunk faster, because the bow was resting on the bottom as
it sank.  Two junks were nearby and they appeared to be heading to
pick up survivors.  Ordered battle surface to destroy the junks.

               1037H; Surfaced and found junks fleeing away instead of
heading for the survivors.  We chased them, but when we were within
two miles of the beach and nearing shoal waster we broke off the
chase.  Also we were just outside of a large port and we did not want
to invite trouble, so we headed back for the survivors.  Decided to
hunt for anything worth salvaging and pick up a survivor.

               We found four survivors.  Two on the bottom of one
overturned boat, one on the bottom of another over-turned boat and a
fourth floating by in a life jacket.

               We attempted to pick up at least one of them.  They
seemed to ignore us entirely.  After a few minutes of this
indifference we said to hell with them and went after something worth
salvaging.  Picked up a couple of House Flags which we cannot
identify.  One large life ring with S.S. NITU MARU - TARUNI painted on
it and a large book which appears to be a Merchant Marine Manual.

               1138H;  Departed this area at full power and then
commenced a surface patrol heading for SHANTUNG PROMONTORY at two-
third speed.

March 22:      Patrolling off SHANTUNG PROMONTORY.  Weather has
freshened up with seas and wind from the northwest and horizon
slightly hazy.

               0700H;  Made trim dive and inspected main motor that
was noisy.  Found loose brush and repaired it.

               0815H; Surfaced and continued surface patrol now
heading for a point off LAOTIEHSHAN PROMONTORY which is just around
the corner from PORT ARTHUR.  We believe we can contact some
CHINWANGTAO traffic here.

               1400H;  Dived upon sighting two power sampans.

               1435H;  Surfaced when they appeared to be trawling, and
continued on towards our new patrol area.

               There is, no doubt, a lot of shipping in this area, but
one must find it to sink it.  We believe we are heading for a good
spot.

               There is never much water in this "wading pond" known
as the Yellow Sea.  We have to be careful with our angle on dives to
keep from plowing into the bottom.  Aircraft and patrols have been
scarce, because we are in virgin territory, however, she "ain't"
virgin now and we are expecting trouble soon.  We hope to get at least
four more ships and then expend our gun ammunition on our way home.

               We have sighted lots of fishing junks, sampans,
trawlers, etc., but only a few cargo carrying junks.

March 23:      0043H;  Sighted  small ship with sharp angle on the bow
and dove.  Commenced approach, lost our target in haze.

               0305H;  Surfaced and continued toward our patrol
station.

               LAOTIGHSHAN [sic] CHANNEL can be also called "Sampan
Alley".  We were literally surrounded by them.  Strongly believe the
ship we just dived for was a junk, because after surfacing we saw a
junk that looked like our target.

               0410H;  (SIXTH ATTACK).  Sighted small freighter and
commenced approach tracking by radar.  Checked his course and speed
and attained position ahead.

               0430H;  Dived continuing approach.

               0443H;  Fired one TNT torpedo at medium sized collier,
identified as KATYOSAN MARU, 2,427 tons, range 1,000 yards, 88d port
track, speed 8 knots.  Hit collier just under the bridge.  The ship
was immediately enveloped in a screen of coal dust.  She settled fast
and slowed down.

               0457H;  Surfaced to head for our patrol point,.  It was
now the crack of dawn and we had about ten miles to go.  The collier
we had hit thirteen minutes earlier was not in sight.

               0535H;  Dived when it was getting so light we believed
we might be sighted from the beach.  Since this collier appeared to be
about the same size as the one we sank the other day we had decided to
hit her with a TNT war head to see if we could obtain a comparison.
Our conclusion is that all TNT war-heads should be converted to
Torpex, because they cannot compare to Torpex.  Torpex has the
necessary force to sink ships.

               0923H;  Sighted a SMOKY MARU near PROMONTORY, about ten
miles away.  He was probably going to try and gain some face for the
"NIPS".

               1003H;  SMOKY MARU must have dropped a depth charge.
Something like a far-away depth charge was heard.

               1004H;  SMOKY MARU dropped second depth charge.

               1031H;  Third depth charge.

               1032H;  Fourth depth charge.

               1830H;  Surfaced and set course for a point a little to
the Northwest of ROUND ISLAND which is off DAIREN.  We feel the
shipping will avoid coming into DAIREN direct and will attempt "an end
run".

               Had to run the gauntlet again as we passed through
"Sampan Alley".

               They have secured the light on ROUND ISLAND, so we know
they are rerouting their traffic.
 

March 24:      0505H;  Sighted single float type airplane.

               0645H;  Sighted smoke and commenced approach.  If we
took the normal approach course, the target and WAHOO would end up
behind the breakwater at DAIREN.  Knew we could not close the target
sufficiently for an attack, but we closed at high speed just to check
his course and position.

               1330H;  Established the "NIPS" end run route and
commenced heading for it.  This freighter was between 4 and 5,000
tons.  She passed 16,000 yards ahead of us.  We hope to get a couple
of ships over on this route within the next day or so and before the
"Nips" learn of our presence.

               1924H;  (SEVENTH ATTACK).  Radar made contact at 10,000
yards bearing about 090dT.  This was considered fine radar and
operator performance as the contact was noticed on the same bearing
and just short of land contacts.

               This indicated to us that we had a ship and that we
were right on its track and we were about to stop their endrun play.
Commenced surface approach tracking by radar and maneuvered for a
stern shot.  It was quite dark.

               1949H;  Fired a spread of three torpedoes at a large
tanker with engines aft, identified as SYOYO MARU 7,499 tons, range
1,700 yards, track 80d starboard, speed 12 knots.  The first two
torpedoes had premature explosions at end of 18 second run.

               Third torpedo missed.

               1955H;  Fired fourth torpedo and it missed.

               2000H;  The tanker let go several 4 or 5 inch rounds at
a range of about 3,000 yards using the Nip's famous flashless powder.
One of the shells landed directly ahead us and burst with a loud bang.
We dived and tracked the target.

               Here again faulty torpedoes frustrated an attack,
wasted four valuable torpedoes that we have carried over 5,000 miles,
almost caused the WAHOO to be destroyed, and allowed the target the
time to open up on its radio and frustrate our newly discovered ,
fertile, shipping route.

               2014H;  (EIGHT ATTACK).  Surfaced after fourteen
minutes of ducking target's shots.  He was still shooting, but it must
have been at random as he had not seen us the past fourteen minutes.
Went ahead full power to get up ahead of this fellow quickly or we
would both end up in DAIREN HARBOR.

               2054H;  When were well ahead and had the target in the
middle of a rising moon we dived.

               2122H:  Fired a spread of three torpedoes at target
1,200 yards range, 90d starboard track, target speed 10 knots.  Second
torpedo with TNT head, hit him in the engine room.  He sand in 4
minutes 25 seconds going down by the stern.  The target was loaded to
the gills with fuel oil.

               It is interesting to note that when we tracked this
target at slow speeds we get one target speed and when we were making
high speeds, we obtained another target speed.  The slow speed
tracking is more accurate.  This is caused by pitometer log
inaccuracy.

               2134H;  Surfaced and headed south for another likely
spot off O TO Light.

March 25:      0157H:  (NINTH ATTACK).  Sighted ship.  He had a green
light burning constantly which appeared in every respect to be his
starboard sight light.  Three hours prior to this our SJ radar
training gear jammed and we were still trying to repair it when this
contact was made consequently had to conduct approach without radar.

               The moon was bright, so maneuvered for a favorable
position ahead.

               0355H;  Dived and commenced submerged approach.

               0436H;  Fired a spread of two torpedoes at a medium
sized freighter, later identified as the SINSEI MARU 2,556 tons, range
1,300 yards, 87d starboard track, speed 8 1/2 knots.  First torpedo
exploded prematurely at the end of 26 second run.  Second torpedo
exploded prematurely at the end of a 49 second run and about fifty
yards short of target.

               0444H;  (FIRST GUN ATTACK). Battle surfaced.  First 4
inch shot it target in after deck house at 3,800 yards range.  Closed
in on target and raked him with 20mm. and holed him with almost 90
rounds of 4 inch.  Target caught fire in several places.  Her life
boat was dangling from the forward davit.  Passed about twelve
survivors in the water all sort'a chattering.  The crew yelled to the
survivors, "So Solly, Please".

               0510H;  (SECOND GUN ATTACK).  Lookout reported ship on
the horizon.  Proceeded at flank speed to investigate, leaving first
freighter on fire and listing.  Upon closing found target to be a neat
little diesel driven freighter quite similar to HADACHI MARU, 1000
tons, but definitely a cargo ship.

               0535H;  Commenced firing on second freighter with 20mm.
and 4 inch.  He caught fire several times, but the fire was
extinguished by her crew or it went out on its own accord.  She
speeded up to about 13 knots and appeared to be trying to ram the
WAHOO.  We had no trouble in keeping clear.  A member of her crew was
in the foretop waving his arms - maybe he was conning ship.  A few
20mm. hits in his vicinity caused him to slide down a guy wire like a
monkey.

               Repeated gun fire soon had her blazing all over and
dead in the water.

               Quartermaster reported first freighter listing badly
during this engagement and before cease firing he reported first
freighter sinking rapidly, and finally she was seen to sink.

               0614H;  After expending 170 rounds of 4 inch and about
2,000 rounds of 20mm. on these two freighters, proceeded on our course
for our patrol point off O TO Light.

               Anyone who has not witnessed a submarine conduct a
battle surface with three 20mm. and four inch gun in the morning
twilight with a calm sea and in crisp clear weather, Just "ain't
lived."  It was truly spectacular.

               Our deck took a beating.  Practically every blast of
the 4 inch would give a hit on the target and a partial hit on the
WAHOO.  The wooden decking would tear and take off with each shot.

               0625H;  Watched freighter sink through No. 1 periscope.

               0640H;  Aircraft contact.  Dived.  This is bad for us,
because it spoils our new hunting ground.  The aircraft is bound to
have seen the freighter burning and then sink.  So remained submerged
conducting high periscope observations.

               1222H;  Sighted large passenger freighter with large
angle ont he bow with range about 16,000 yards.  Commenced high speed
approach.  Took observations at 8,000 yards generated range.  Our set-
up checked surprisingly well.  Continued high speed approach.  Took
another observation when generated range was 5,000 yards.  Target had
reversed course and the range was about 12,000 yards.  It was possible
the target sighted us, but we doubt it.  We believe he had an air
escort or an aircraft hovering our area warned him.  Anyway we lost
the best target we have seen this trip.

               1345H;  Sighted aircraft.  Something was evidently
cooking.  As our battery was low, we cleared the area on new course at
best speed.

               1458H;  Sighted a new destroyer range about 8,000
yards, angle on the bow 15d port.  He searched with his Q.C.  Went to
150 feet, and rigged for depth charge.  As water was about 30 fathoms
deep, did not dare tackle this fellow with only two torpedoes aboard
which from late experience would likely be prematures.  It hurt our
pride to have to hide in our shell and crawl away.

               1655H;  Heard one distant explosion.  This could have
been either a bomb or depth charge.  The pinging had ceased after
getting very faint.  We figured our Dog Dog had no chance of finding
us then.  He may have picked up one of the two freighters sitting on
the bottom and depth charged it.

               1855H;  Surfaced and cleared present area on three
engines.

               1012H;  (THIRD GUN ATTACK).  Sighted trawler.

               1020H;  Opened up with 20mm. guns and 4 inch on a
diesel trawler of about 100 tons.  Holed him several times.  A few
fires started, but was so water-soaked they soon died out.  Threw
aboard some home made MOLOTOV cocktails concocted and manufactured by
the MIDWAY marines.  They didn't burn well, due probably to the water-
soaked wood.  This trawler had a nice radio antenna which he probably
opened up on.

               1050H;  Departed leaving the trawler in pretty much a
wrecked condition.  It was rough to board her.  Otherwise we could
have had fresh fish and also opened up some sea valves in her.

               During this engagement all three 20mm guns were jammed
at the same time.  These guns really do jam often.  Our cooling tubes
prevented several explosions like we had last trip.  The guns actually
boil all the water out of these tubes.  Other boats should get larger
tubes.

March 28:      Conducted surface patrol on SHIMONOSEKI - FORMOSA
shipping routes.  We have no had a good fix since night of the 25th.
Took occasional soundings throughout the day.

               1235H;  Dived on radar contact; did not sight the
plane.

               1338H;  Surfaced.  Visibility was poor all day.

               1800H;  (FOURTH GUN ATTACK).  Sighted two lighted
motor sampans (FISHI MARUS).

               1808H;  Opened up with two 20mm. guns on the two
sampans.

               1820H;  Secured 20mm. guns and crews after expending
about 500 rounds on each sampan.  They did not sink, but they have a
lot of holes in them and they are quite wrecked.  It was still to
rough to go aboard for a mess of fresh fish.  Our mouths watered at
such a possibility.

March 19:      0255H;  (TENTH ATTACK).  Sighted ship, and commenced
radar tracking.

               0400H;  Dived when we had gained a favorable position
ahead and it was light enough to see the target through the periscope.

               0416H;  Fired a spread of two torpedoes at fairly large
freighter identified as KIMISIMA MARU 5,193 tons, range 900 yards, 90d
port track, speed 8 1/2 knots.  First torpedo hit under his mainmast
which was our point of aim and completely disintegrated everything
abaft of his stack.  The forward section sand two minutes and thirty-
two seconds later.  The torpedo was set at 15 feet due to rough seas.
This was a Torpex head and it is believed was an influence explosion.
               The target made a lot of noise as she sunk and broke
up.  We all could hear it through the hull.
               The second torpedo was aimed at the foremast.  It
missed, because the first torpedo stopped the foremast in its
tracks!!!!!!!

               0426H;  Surfaced and headed for our base.  All
torpedoes expended.

               Made surface transit through COLNNETT STRAIT during
daylight.  We had a lot of small craft and a small freighter in sight,
all at the same time.  They did not bother us and we kept right on
going.

               0740I;  Departed out of area.

               0845I;  Dived on radar contact.  Did not sight the
plane.

               0935I;  Surfaced.

               1935I;  Good SJ radar contact at 9,200 yards.  Did no
investigate nor did we sight anything.

March 30:      1827I;  Good contact on the SJ radar at 9,800 yards.
Did not investigate nor did we sight anything.

               1910I;  An unusual swell washed over the bridge and
flooded the main induction.  Water entered the maneuvering room
through the auxiliary induction causing waster to partially flood the
main cubicle.  Several zero grounds were created which in turn started
many small fires making the control station untenable by a very
caustic smoke.  All main propulsion stopped and out of commission.
All forced ventilation stopped.

               Immediately opened all battery cut-out switches which
stopped the fires.  Idled one engine while we took a suction through
the after torpedo room hatch.  This cleared the maneuvering room of
smoke in a hurry, but we took quit a bit of water in the torpedo room.

               Commenced clearing up grounds in main control cubicle
and clearing main induction of water.

               The following parts wee burned up or damaged and will
have to be replaced during the next refit period:

               3 Generator rheostat clutch switches.
               1 Generator trip switch.
               2 Generator rheostat filed contactors.
               100 feet of wiring.

               2040I;  Went ahead standard speed on port shaft with
No. 2 main engine on propulsion.

March 31       0442I;  Went ahead standard speed on both shafts.  No.
1 engine available for propulsion.

               0833I;  Dived on plane contact.  It was flying very low
distance about 4 miles.  Radar did not pick it up.  Unfortunately we
were right on the route between TOKYO and the BONINS.  The sky was
heavily over-cast with a low ceiling.  This plane was probably
piloting down the chain of the Southern Islands.

               0912I;  Surfaced.

               1100I;  All main engines available for propulsion
except No. 3.

               1230K;  another plane contact, distance about 12 miles
by radar.  Did not sight it.  This plane was in the same groove as the
other one, this morning.  We did not dive.

April 2:       0910K;  Sighted sail on the horizon.  After closing it
a bit we could see a single sail and a long hull.  Believed this to be
a patrol disguising himself or economizing on fuel.  We were several
hundred miles east of the BONINS and no sail boat had any business in
these parts.  Position Latitude 31d - 30' N; Longitude 150d - 25' E.

April 6:       1030Y;  Arrived U.S. Submarine BASE, MIDWAY ISLAND.

               Had second unique experience of this patrol of
surfacing in middle of Yellow Sea, on March 25th and proceeding on
surface from that date until arrival at MIDWAY, with only short trim
dives, one submerged attack and two ducking for plane contacts.
 

     2.  WEATHER.
                 The weather was generally crisp and clear except when
southerly winds caused fog.

     3.  TIDAL INFORMATION.
                 The tides and currents conformed with the information
shown ont he charts and contained in sailing directions.

     4.  NAVIGATIONAL AIDS.
                 On entering the areas all Navigational lights shown
on chart which were encountered were burning with proper
characteristics.  However, ROUND ISLAND light was extinguished after
the third attack in that area, and it is presumed others were put out
also.  On March 29 KUSAKAKI SHIMA Light was burning, but in view of
the sinking twenty-six miles from it that morning it has probably been
doused.

     5.  ENEMY SHIPS SIGHTED:
 

Date     : Time  :  Position       :Course : Speed  :     Type
---------------------------------------------------------------------
3/14/43  : 1704I :Lat. 32-57 1/4 N : 404d  :12 knots:1-1,000 ton AK
         :       :Long.126-11 E    :       :        :
---------------------------------------------------------------------
3/15/43  : 1415I :Lat. 34-04 1/2 N : 270d  : High   :Small patrol or
         :       :Long.125-53 1/2 E:       :        :Gun boat
---------------------------------------------------------------------
3/19/43  : 0515H :Lat. 38-29 1/2 N : 305d  : 9 knots:1-4,065 Ton AK
         :       :Long.122-18 1/2 E:       :        :NANKA MARU
---------------------------------------------------------------------
3/19/43  : 0916H :Lat. 38-27 1/2 N : 295d  : 9 knots:1-AK or NAVAL AUX
         :       :Long.122 18 1/4 E:       :        :TOTTORI MARU
         :       :                 :       :        :5,973 tons
--------------------------------------------------------------------
3/21/43  : 0700H :Lat  38-10 1/2 N : 000d  :11 knots:1-AK 7,210 tons
         :       :long.124-33 E    :       :        :SEIWA MARU
--------------------------------------------------------------------
3/21/43  : 0958H :Lat. 38-04 1/2 N : 357d  :10 knots:1-AK 6,543 tons
         :       :Long.124-32 1/2 E:       :        :NITU MARU
--------------------------------------------------------------------
3/23/43  : 0443H :Lat. 38-37 1/4 N : 138d  : 8 knots:1-AK 2,427 tons
         :       :Long.121-01 1/4 E:       :        :KATYOSAN MARU
--------------------------------------------------------------------
3/24/43  : 1249H :Lat. 38-47     N : 265d  :10 knots:Freighter passed
         :       :Long.122-16 1/2 E:       :        :16,000 yards
         :       :                 :       :        :ahead 4-5,000 ton
--------------------------------------------------------------------
3/24/43  : 1949H :Lat. 39-01     N : 263d  :12 knots:1-AO 7,499 tons
         :       :Long.122-24 1/4 E:       :        :SYOYO MARU
--------------------------------------------------------------------
3/25/43  : 0436H :Lat. 38-12 1/2 N : 343d  :8.5knots:1-AK 2,550 tons
         :       :Long.123-24     E:       :        :SINSEI MARU
--------------------------------------------------------------------
3/25/43  : 0510H :Lat. 38-10     N :Various:13 knots:1-AK 1,000 tons
         :       :Long.123-26     E:       :        :similar to
         :       :                 :       :        :HADACHI MARU
--------------------------------------------------------------------
3/25/43  : 1222H :Lat. 38-01     N : 300/  :10 knots:Passenger
         :       :Long.123-36     E: 120d  :        :Freighter large
--------------------------------------------------------------------
3/25/43  : 1458H :Lat. 37-55 1/2 N : 300d  :12 knots:New type DD. It
         :       :Long.121-01 1/4 E:       :        :was echo-ranging
--------------------------------------------------------------------
3/29/43  : 0416H :Lat. 30-25 1/2 N : 080d  :8.5knots:1-AK 5,193 tons
         :       :Long.129-41 1/2 E:       :        :KIMISIMA MARU
--------------------------------------------------------------------

     NOTE:  Sampans, Junks, Trawlers and other fishing craft were
encountered daily.  As many as twenty being in sight at one time from
the bridge.  In general those off the KOREAN COAST and in the SHANTUNG
PROMONTORY and in the GULF OF POHAI were darkened and under sail.
Areas listed below held particularly heavy concentrations of fishing
craft.
           DESCRIPTIONS                        LOCATION

TOKARA KAIKYO                             : 30d - 10'N  : 130d E.
----------------------------------------------------------------------
SHIMONOSEK - FORMOSA (trade route)        : 31d - 50'N  : 127d - 25'E
----------------------------------------------------------------------
MAIKOTSU SUIDO                            : 34d - 20'N  : 125d - 40'E
----------------------------------------------------------------------
LACTIEHSHAN CHANNEL (Loathesome Channel)  : 38d - 35'N  : 121d - 10'E
----------------------------------------------------------------------
Southeast of SHANTUNG PROMONTORY          : 36d - 10'N  : 123d - 20'E
----------------------------------------------------------------------

     6.  DESCRIPTION OF PLANES SIGHTED.

TIME         :   TYPE    :   LATITUDE    :  LONGITUDE   :COURSE:  ALT
----------------------------------------------------------------------
3/24/43 0645H:   FLOAT   : 36d - 33'N    : 122d - 12'E  :  SW  : 2,500
----------------------------------------------------------------------
3/25/43 1345H:Large land : 36d - 27'N    : 121d - 02'E  :   W  : 3,500
             :Bomber     :               :              :      :
----------------------------------------------------------------------
3/31/43 0833I:Large land : 31d - 05"N    : 140 - 15E    :   S  : 1,000
             :Bomber     :               :              :      :
 

     7.  SUMMARY OF SUBMARINE ATTACKS.

Attack No.               :     1      :      2     :     3A
----------------------------------------------------------------
Date                     :  3/13/43   :   3/19/43  :   3/19/43
----------------------------------------------------------------
Location (Latitude)      : 32-57N     : 38-29N     : 38-27N
         (Longitude)     : 126-11E    : 122-19E    : 111-18E
----------------------------------------------------------------
No. of torpedoes fired   :     1      :      1     :     2
----------------------------------------------------------------
Hits                     :     0      : 1 Torpex   : 2 Torpex
                         :            :            : (1 dud)
----------------------------------------------------------------
Sunk (Tonnage)           :     0      :  4,065     :     0
----------------------------------------------------------------
Damaged or probably sunk :     0      :      0     :  5,973
----------------------------------------------------------------
Type of target           :1,000 ton AK:AK NANKA    :TOTTORI MARU
                         :            :  MARU      :
----------------------------------------------------------------
Range of firing          :    1,000   :    750     :  1,800
----------------------------------------------------------------
Periscope Depth          :     64'    :     60'    :     64'
----------------------------------------------------------------
Surface Night            :            :            :
----------------------------------------------------------------
Deep Submergence         :            :            :
----------------------------------------------------------------
Estimated draft of target:     12'    :   22 1/2'  :      8'
----------------------------------------------------------------
Torpedo depth setting    :      5'    :     10'    :     10'
----------------------------------------------------------------
Bow or stern shot        :    Stern   :     Bow    :    Bow
----------------------------------------------------------------
Track angle              :     90 P   :    120 P   :   126 S
----------------------------------------------------------------
Gyro angles              :  174 1/2 d :  358 1/2 d :352d 8 1/2 d
----------------------------------------------------------------
Estimated Target Speed   :     12     :      9     :      9
----------------------------------------------------------------
Firing interval          :            :            :1 min. 35 sec
----------------------------------------------------------------
Spread: amount and kind  :            :            : Divergent
                         :            :            : 2 knots
----------------------------------------------------------------
Time for target to sink  :            :2 min 26 sec:
----------------------------------------------------------------
 
 

Attack No.               :     3B     :     3C     :     4
----------------------------------------------------------------
Date                     :  3/19/43   :   3/19/43  :   3/21/43
----------------------------------------------------------------
Location (Latitude)      : 38-27N     : 38-27N     : 38-11N
         (Longitude)     : 122-18E    : 122-18E    : 124-33E
----------------------------------------------------------------
No. of torpedoes fired   :     1      :      1     :     3
----------------------------------------------------------------
Hits                     :     0      :      0     : 1 Torpex
----------------------------------------------------------------
Sunk (Tonnage)           :     0      :      0     : 7,210
----------------------------------------------------------------
Damaged or probably sunk :     0      :      0     :    0
----------------------------------------------------------------
Type of target           :TOTTORI MARU:TOTTORI MARU: SEIWA MARU
----------------------------------------------------------------
Range of firing          :    1,900   :  2,250     :  1,500
----------------------------------------------------------------
Periscope Depth          :     64'    :     64'    :     64'
----------------------------------------------------------------
Surface Night            :            :            :
----------------------------------------------------------------
Deep Submergence         :            :            :
----------------------------------------------------------------
Estimated draft of target:      8'    :     8'     :     27'
----------------------------------------------------------------
Torpedo depth setting    :     10'    :     10'    :     10'
----------------------------------------------------------------
Bow or stern shot        :     Bow    :     Bow    :    Bow
----------------------------------------------------------------
Track angle              :    140 S   :    180     :   117 P
----------------------------------------------------------------
Gyro angles              :  018 1/2 d :  358 3/4 d :359 3/4;356;
                         :            :            :   358
----------------------------------------------------------------
Estimated Target Speed   :      7     :      7     :     11
----------------------------------------------------------------
Firing interval          :            :            :14 sec 9 sec
----------------------------------------------------------------
Spread: amount and kind  :            :            : Longitudinal
----------------------------------------------------------------
Time for target to sink  :            :            : 4 minutes
----------------------------------------------------------------
 
 

Attack No.               :     5      :     6      :     7
----------------------------------------------------------------
Date                     :  3/21/43   :   3/23/43  :   3/24/43
----------------------------------------------------------------
Location (Latitude)      : 38-05N     : 38-27N     : 38-01N
         (Longitude)     : 124-33E    : 121-01E    : 122-25E
----------------------------------------------------------------
No. of torpedoes fired   :     3      :      1     :     4*
----------------------------------------------------------------
Hits                     : 2 Torpex   :   1 TNT    :     0
----------------------------------------------------------------
Sunk (Tonnage)           :   6,543    :   2,427    :     0
----------------------------------------------------------------
Damaged or probably sunk :     0      :      0     :     0
----------------------------------------------------------------
Type of target           :     AK     :     AK     :     AO
                         :  NITU MARU :KATYOSAN MARU  SYOYO MARU
----------------------------------------------------------------
Range of firing          :    800     :   1,000    :  1,700
----------------------------------------------------------------
Periscope Depth          :     65'    :     57'    :
----------------------------------------------------------------
Surface Night            :            :            :   Radar
----------------------------------------------------------------
Deep Submergence         :            :            :
----------------------------------------------------------------
Estimated draft of target:   27 1/2'  :    20'     :     28'
----------------------------------------------------------------
Torpedo depth setting    :     10'    :     10'    :     10'
----------------------------------------------------------------
Bow or stern shot        :    Stern   :     Bow    :   Stern
----------------------------------------------------------------
Track angle              :    87d S   :    88d P   :   80d S
----------------------------------------------------------------
Gyro angles              :161;167;168d:   004d     :182;182.5d
                         :            :            :183.5; 196.5d
                         :            :            :   358
----------------------------------------------------------------
Estimated Target Speed   :     10     :      8     :     12
----------------------------------------------------------------
Firing interval          :  10s; 16s  :            :12s;21s;13s
----------------------------------------------------------------
Spread: amount and kind  :Longitudinal:            :Divergent 1d
----------------------------------------------------------------
Time for target to sink  : 3min 10sec : 13 minutes :
----------------------------------------------------------------
Remarks:  * First two torpedoes exploded prematurely at end of
            18 second runs.
 

Attack No.               :     8      :     9      :    10
----------------------------------------------------------------
Date                     :  3/24/43   :   3/25/43  :   3/29/43
----------------------------------------------------------------
Location (Latitude)      : 39-00N     : 38-13N     : 30-26N
         (Longitude)     : 122-16E    : 123-24E    : 129-41E
----------------------------------------------------------------
No. of torpedoes fired   :     3      :      2*    :     2
----------------------------------------------------------------
Hits                     :  1 TNT     :      0+    : 1 Torpex
----------------------------------------------------------------
Sunk (Tonnage)           :   7,499    :      0     :  5,193
----------------------------------------------------------------
Damaged or probably sunk :     0      :      0     :    0
----------------------------------------------------------------
Type of target           :     AO     :     AK     :    AK
                         : SYOYO MARU : SINSEI MARU:KIMISIMA MARU
----------------------------------------------------------------
Range of firing          :    1,200   :   1,300    :    900
----------------------------------------------------------------
Periscope Depth          :     60'    :     62'    :     64'
----------------------------------------------------------------
Surface Night            :            :            :
----------------------------------------------------------------
Deep Submergence         :            :            :
----------------------------------------------------------------
Estimated draft of target:     28'    :     24'    :     24'
----------------------------------------------------------------
Torpedo depth setting    :     10'    :      6'    :     15'
----------------------------------------------------------------
Bow or stern shot        :     Bow    :     Bow    :    Bow
----------------------------------------------------------------
Track angle              :    090 S   :    37 S    :    90 P
----------------------------------------------------------------
Gyro angles              :354 1/2d    : 012d; 018d :353d; 341d
                         :359 3/4d    :            :
                         :359 1/4d    :            :
----------------------------------------------------------------
Estimated Target Speed   :     10     :     8.5    :    8.5
----------------------------------------------------------------
Firing interval          : 44s; 30s   :     15s    :    18s
----------------------------------------------------------------
Spread: amount and kind  :Longitudinal:Longitudinal: Longitudinal
----------------------------------------------------------------
Time for target to sink  : 4min 25sec :            : 2min 32 sec
----------------------------------------------------------------

Remarks:  * Both torpedoes exploded prematurely.  Runs 26 and 49
            seconds.
          + This target was later sunk by 4" gunfire.
                         :     11     :     12     :    13
Attack No.               : First Gun  :Second Gun  : Third Gun
                         :   Attack   :   Attack   :   Attack
----------------------------------------------------------------
Date                     :  3/25/43   :   3/35/43  :   3/27/43
----------------------------------------------------------------
Location (Latitude)      : 38-13N     : 38-10N     : 33-39N
         (Longitude)     : 123-24E    : 123-26E    : 125-23E
----------------------------------------------------------------
Rounds of 4" Ammunition  :    90      :     80     :     11
----------------------------------------------------------------
Hits, approximate        :    60      :     50     :      8
----------------------------------------------------------------
Sunk (Tonnage)           :   2,556    :    1,000   :   ------
----------------------------------------------------------------
Damaged or probably sunk :   -----    :    -----   :     100
----------------------------------------------------------------
                         :     AK     :     AK     :DIESEL TRAWLER
Type of target           : SINSEI MARU:HADACHI MARU:    #825
----------------------------------------------------------------
Range                    : 3,800/300  : 3,000/200  : 3,000/200
----------------------------------------------------------------
Estimated Target Speed   :  Various   :     13     :  Various
----------------------------------------------------------------
 

                         :     14     :
Attack No.               : Fourth Gun :
                         :   Attack   :
---------------------------------------
Date                     :  3/28/43   :
---------------------------------------
Location (Latitude)      : 31-39N     :
         (Longitude)     : 127-41E    :
---------------------------------------
Rounds of 4" Ammunition  : 20mm 700   :
---------------------------------------
Hits, approximate        :    400     :
---------------------------------------
Sunk (Tonnage)           :    ***     :
---------------------------------------
Damaged or probably sunk : 2 sampans  :
---------------------------------------
                         :     AK     :
Type of target           : 2 sampans  :
---------------------------------------
Range                    : 1,000/50   :
---------------------------------------
Estimated Target Speed   :  Lying to  :
---------------------------------------

     FIRST AND SECOND SHIPS:  Sprayed with 1,000 rounds 20mm.
           "    "     "     "     Caught fire stem to stern.
           "    "     "     "     Sank.
     Trawler: Sprayed with 900 rounds 20mm. and 7 MOLOTOV
                 COCKTAILS.
           "      Wrecked with 4" gun hits.
     Sampans: Wrecked.

     8.  ENEMY A/S MEASURES

             The enemy used gun-fire whenever possible as a
nuisance factor to keep a submarine down.  The night firing of the
SYOYO MARU was good when our location was disclosed by our
prematures.  Their flashless powder gives off no more light than a
dimmed green flashlight.

     9.  MAJOR DEFECTS

             Periscopes:  The periscopes - particularly #2
periscope fogged badly at times.  During several approaches this
fogging was bad enough to necessitate ducking the periscope to
complete an observation.  The fogging became heavy enough during the
time required to take a bearing (less than 5 seconds) to make an
accurate stadimeter range impossible.

             This condition has existed in the past on this ship
and from conversation with other officers we find that it exists in
other ships.  It is greatly increased by a differential in
temperature particularly when the water is warmer than the air.
Unless definite action is taken to correct this defect, it will
continue to be a major handicap to the conduct of a successful
submerged attack.

             #1 periscope was constantly as a high lookout while
on the surface.  The training of this periscope was so stiff that it
greatly reduced the efficiency of the watch.  The overhaul by the
tender during the last refit made no appreciable improvement in this
condition.

             Torpedoes:  As noted in the narrative one torpedo
failed to explode although it definitely hit the target amidships,
and four other torpedoes exploded prematurely.  Although at first
glance this would appear to be just over a twenty percent failure, we
must consider also the additional expenditure of torpedoes involved,
for a target worth sinking remains worth sinking as long as she is
afloat.

             In the case of the TOTTORI MARU, the second torpedo,
a Torpex, would undoubtedly have sunk her had it exploded.  As it
turned out, a new 5,973 ton ship was only damaged and two additional
torpedoes had to be expended under unfavorable conditions in an
attempt to sink her and to preserve a new found "hunting ground".

             The SYOYO MARU, had been tracked by radar from
10,000 yards in.  Her course and speed were most accurately known.
There is every reason to believe that the initial spread of three
torpedoes would have sunk her.  Yet the first two torpedoes, exploded
prematurely, invited counter-attack and necessitated firing an
additional torpedo also requiring the expending of three more
torpedoes an hour and a half later to sink this 7,499 ton tanker.
Again the Japs new found traffic lane was spoiled for further attack.

             Against the SINSEI MARU, the two prematures
necessitated a battle surface with its inherent dangers, and the
expenditure of 90 rounds of 4" ammunition to sink the 2,556 ton
freighter.  That our position was again disclosed by this ship's
radio is indicated by the arrival of a plane within two hours.

             Thus in fact, torpedo failures caused the additional
expenditure of six torpedoes and 90 rounds of 4" ammunition.

             A conservative estimate is that the TOTTORI MARU and
two additional ships could have been sunk if all torpedoes exploded
properly, and that one SMOKY MARU could have been sunk with the 90
rounds of 4" ammunition.

     10.  COMMUNICATION

             Radio reception was good and complete.  No attempt
was made to use the under-water loop.  Difficulty was experienced in
clearing a message from in the vicinity of the BONINS.  It was
receipted for, probably somewhat garbled, by MIDWAY.

             Last serial received      ComSubPac 56 Yoke   .
             Last message sent         032130/April        .

     11.  SOUND CONDITIONS AND DENSITY LAYERS

             Sound conditions were poor, undoubtedly due to the
shallow water.  For the same reason no density layers were noted.

     12.  HEALTH AND HABITABILITY

             The general health of the crew during the patrol was
very good.  Climatic conditions were rigorous, cold weather
persisting practically all the time.  A most adequate supply of heavy
clothing was available and was distributed upon sailing.  The average
temperature while "on station" was approximately 40d F.

             There were about seven or eight complaints of colds
while underway, only one requiring bed-rest.  One case endured,
although mildly, from the time of contraction to the end of the
patrol, this by a man who was making his first run in submarines.
Skin diseases were at a minimum, only one or two cases of athletes
foot or "spic" itch in evidence.  One man complained of boils, and
was victimized constantly.  There was one case of cellutitus, and the
complaining patient was confined to his bunk for several days.

             There were no injuries other than a few minor cuts
and bruises.

             Habitability was excellent.

             The fresh meats, although kept frozen at 20d, again
acquired a most unpalatable taste early in the patrol.  This
condition persisted on each patrol in spite of every effort to locate
and remedy the cause.  After the second patrol of this ship shelves
and spaces were installed to permit air circulation, a thorough check
for possible fuel oil or freon leaks was made, and a fan installed to
insure air circulation.  Absorption of odors by charcoal was also
attempted, but with no apparent results.  During each upkeep period
the chill and cold room have been completely emptied, scrubbed, and
aired with blowers.  The situation has been called to the attention
of the tender Medical Department which could offer no solution.

==============================================================================

FB5-44/A16-3      COMMANDER SUBMARINE DIVISION FORTY-FOUR

Serial   04-B                       In Care of Fleet Post Office,
                                    San Francisco, California,
                                    April 9, 1943.

CONFIDENTIAL

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

Subject:    U.S.S. WAHOO, Report of fourth War Patrol - Comments.
 

    1.      The Fourth Patrol of the WAHOO covered a period of
forty-two (42) days between departure from Pearl Harbor, and
return to Midway.  Eighteen (18) days were spent in patrol area.
Patrol was terminated by expenditure of all torpedoes.

        2.                  During this patrol, as on the third patrol of this
ship, the outstanding aggressiveness and the magnificent fighting
spirit of the captain, officers, and crew were largely
responsible for the splendid results obtained.

        3.                  The Commanding Officer displayed great enterprise
and excellent judgement in covering his patrol area.  The area
was covered in a most thorough manner.  It is particularly
noteworthy that in order to increase the scope of the search a
surface patrol was conducted during daylight hours on seven of
the eighteen days in the patrol area.  This was done after
experience indicated that anti-submarine measures in the area
were not sufficiently effective to make surface patrol foolhardy.

        4.                  Comments on attacks.

        (a) Attack No. 1.

            Excellent firing position, but range was in error.  In
this        case a echo range to check the periscope range before
firing           would have been extremely valuable.

        (b) Second attack.

        Approach data on this attack was felt to be very
accurate.         Therefore, only one torpedo was fired and it
did the trick.

        (c) Third attack.

            On attack 3A firing interval was excessive.  However,
two          hits were obtained and target would probably have
sunk had            second torpedo exploded.  On attack 3B a
single torpedo fired         when spread might have been used to
advantage.

        (d) Sixth Attack.

            This ship was not observed to sink but the Commanding
Officer feels certain she went to the bottom.  He bases this on
the belief that the ship was so small it could not have survived
the explosion, plus the fact that ship was not sighted when WAHOO
surfaced thirteen minutes after firing.

        (e) Seventh and Eight Attacks.

            While frustrated by faulty performance of torpedoes on
seventh attack the /Commanding Officer would not be denied this
valuable target.  After an unsuccessful attack, WAHOO surfaced,
gained a favorable position, and executed a second attack which
resulted in the destruction of the ship.

            Attention is invited to the remarks in the patrol report
to the effect that tracking the target with submarine making high
speed gave different target speed than when tracking at low
submerged speed.

        (f) Ninth Attack.

            Here again faulty performance of torpedoes ruined an
attack.  It will be noted that torpedoes were set on six feet
depth on this attack.  The sea was calm.

        (g) Third Gun Attack.

            The need for some effective means of setting fire to
wooden trawlers and sampans was demonstrated during this attack.
During current refit period WAHOO plans to have personnel
practice throwing buckets of oil with a view to using this method
of setting wooden boats on fire during future patrols.

        5.                  Comments on Material.

        (a) Main Control Cubicle.  As result of the flooding of the
main induction small fires were started which resulted in the
damaging  beyond repair of certain parts of the main control
cubicle.  Replacement parts must be obtained from Pearl or other
outside source before repairs can be completed.

            After the water started coming through the auxiliary
induction valve it was impossible to close the valve against the
flow of water.  This valve is located overhead in the starboard
side of the maneuvering room aft, very close to after starboard
corner of the control cubicle.  It is impossible to keep the
water from entering the control cubicle if the leakage is at all
serious.  In order to prevent a recurrence of this casualty the
WAHOO plans to operate with this valve closed.  This will
increase the temperature in the maneuvering room but appears to
be the only safe procedure until such time as the design of the
auxiliary induction valve is changed to correct the present
undesirable features.

        (b) Periscopes.  The difficulty with training number one
periscope will be investigated during the refit period and effort
will be made to improve the condition.

        (c) Torpedoes.  Four premature explosions were experienced.
It is possible that the second torpedo fired on attack number
seven exploded prematurely as a result of passing into the
disturbance caused by the first torpedo.  It will be noted that
both of these torpedoes exploded about the same distance away
from the submarine.  While the time of the second explosion on
attack number nine corresponds quite closely with the expected
torpedo run to the target, the Commanding Officer is positive
that the torpedo exploded before it reached the target.  The
target was obscured by extensive spray from the explosion and
later observations of the ship before it was sunk by gunfire
proved conclusively that it was not damaged by torpedo.

            It was the practice on the WAHOO to keep all torpedoes
set on depth of ten feet.  Deep depths were not set on torpedoes.
The seas were calm during firing where prematures were
experienced.

            The Commanding Officer is convinced that Torpex heads
are far superior to TNT.  The outward effects of the explosions
are much more pronounced and ships sink faster, indicating
greater destructive power.

        6.                  The tainting of foods kept in chill and cold rooms
may eventually have an adverse effect on the health of the
personnel on patrol.  Investigations should be conducted to
determine how this condition can be improved.  It is understood
that the HERRING experienced this trouble and found it necessary
to renew the cork lining of the refrigerator because the cement
used on the cork affected the taste of the foods.

        7.                  WAHOO returned from patrol in very good material
condition.  While tired and visibly worn by the strain of the
patrol, officers and crew were in good health and excellent
spirits.
 

FC5-10/A16-3(FB5-102)  SUBMARINE SQUADRON TEN

Serial   053                        In Care Of Fleet Post Office,
                                    San Francisco, California,
                                    April 12, 1943.

CONFIDENTIAL

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

Subject:    U.S.S. WAHOO (SS238), Fourth War Patrol - Comments
on.
 

        1.                  The fourth war patrol was again outstanding and
marked by maximum aggressiveness and cool daring.  The
intelligent planning and sound judgement of the Commanding
Officer in making his decisions enabled the WAHOO to outsmart the
enemy, retain the initiative, and inflict a considerable amount
of damage.

        2.                  The patrol extended over a period of 42 days, of
which nineteen days were spent in the area.  The patrol was
terminated on expenditure of all torpedoes.

        3.                  One of the outstanding features of the patrol was
the successful penetration into the area by surface cruising
alone.  The WAHOO was almost as successful on return from the
area, being forced down on only a few occasions.

        4.                  A total of 24 torpedoes were fired during ten
separate attacks.  Eight hits were scored, and a ninth hit was a
dud.  In the attack on the KIMISIMA MARU on March 29, the second
torpedo would have been a hit had the first torpedo not done the
job too completely.  Counting this as a hit, a score of 37.5% was
made.  Had it not been for the dud and four prematures, this
percentage would have been still higher and the tonnage sunk,
although considerable, would have been still greater.

        5.                  The gun attacks on the AK's, the trawler, and the
sampans were well executed.  The percentage of hits obtained and
the sinking of over 3500 tons of cargo-carrying ships bye the 4-
inch gun crew is most gratifying.  The recommendation made by the
Commanding Officer for larger tubes for the 20 MM guns is
concurred in.

        6.                  The Commander Submarine Squadron Ten takes pleasure
in extending a "Well Done" to the Commanding Officer and
personnel of the WAHOO for a highly successful patrol, during
which the following damage was inflicted on the enemy:
 

                                 SUNK
                            AK (NANKA MARU) - - - - - - - - - 4,065 tons
                            AK (SEIWA MARU) - - - - - - - - - 7,210 tons
                            AK (NITU MARU)  - - - - - - - - - 6,543 tons
                            AK (KATYOSAN MARU)  - - - - - - - 2,427 tons
                            AO (SYOYO MARU) - - - - - - - - - 7,499 tons
                            AK (KIMISIMA MARU)  - - - - - - - 5,193 tons
                            AK (SINSEI MARU)  - - - - - - - - 2,556 tons **
                            AK (HADACHI MARU) - - - - - - - - 1,000 tons **
                            Trawler - - - - - - - - - - - - -   100 tons **
                            2 Sampans (approx. 50 tons each)-   100 tons **
                                              __________
                                TOTAL SUNK:   36,693 tons
                            ** Sunk by gunfire.

                                               DAMAGED
                            AK  TOTTORI MARU  - - - - - - - - 5,973 tons
FF12-10/A16-3(5)/(16)  SUBMARINE FORCE, PACIFIC FLEET

Serial   0484                       In Care of Fleet Post Office,
                                    San Francisco, California,
                                    April 13, 1943.

CONFIDENTIAL

COMSUBPAC PATROL REPORT NO. 164
U.S.S. WAHOO - FOURTH WAR PATROL

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

Subject:    U.S.S. WAHOO (SS238) - Report of Fourth War Patrol.

Enclosure:  (A) Copy of Subject War Patrol Report.
            (B) Copy of Comsubdiv 44 conf. ltr. FB5-44/A16-3
                Serial 04-B of April 9, 1943.
            (C) Copy of Comsubron 10 conf. ltr. FC5-10/A16-3
                (FB5-102) Serial 053 of April 12, 1943.

        1.                  Outstanding in aggressiveness and submarine warfare
efficiency, this was the fourth war patrol of the WAHOO and the
second under its present /commanding Officer.  Sinking eight
ships, one trawler and two sampans and damaging one other ship,
the WAHOO continued the outstanding record established on its
third war patrol.

        2.                  Faulty torpedo performance in the form of prematures
subjected the WAHOO to dangerous shell fire on a night attack.
Another torpedo, a dud, allowed a damaged ship to get away.

        3.                  It is gratifying to note that all of the WAHOO's gun
battles were executed only after a careful estimate of the
situation was made; each was carried out with military
aggressiveness, professional competence and yet free of foolhardy
recklessness.  These attacks were carried out when they could be
made with the submarine having the definite advantage.  It is
well to remember that our submarines are very valuable and, at
the same time, vulnerable targets when gunfire is used as the
attacking weapon.

        4.                  Throughput the patrol, the Commanding Officer
exhibited excellent judgement in his strategic study of the
shipping lanes, thus covering the area efficiently and most
productively.

        5.                  The Commander Submarine Force, Pacific Fleet, again
takes great pleasure in commending the Commanding Officer,
officers and crew of the Wahoo on this, their second successive
outstanding war patrol.  The Wahoo is credited with inflicting
the following damage to the enemy:

                             SUNK
         1 Freighter (NANKA MARU class)      - -  4,065 tons
         1 Freighter (SEIWA MARU class)      - -  7,210 tons
         1 Freighter (NITU MARU class)       - -  6,543 tons
         1 Freighter (KATYOSAN MARU class)   - -  2,427 tons
         1 Tanker (SYOYO MARU class)         - -  7,499 tons
         1 Freighter (KIMISIMA MARU class)   - -  5,193 tons
        *1 Freighter (SINSEI MARU class)     - -  2,556 tons
        *1 Freighter (HADACHI MARU class)    - -  1,000 tons
        *1 Trawler (#825)                    - -    100 tons
        *2 Sampans                           - -    100 tons
                                             __________
                                   TOTAL:   36,693 tons
*Sunk by gunfire.

                                DAMAGED
         1 Freighter  (TOTTORI class)        - -  5,973 tons
 

DISTRIBUTION:                              J. H. BROWN, Jr.,
    (1m-43)                                Acting
LIST III, SS
Special:
  P1(5), EN3(5), Z1(5),
  Comsublant (2), X3(1),
  Comsobsowespac (2),
  Subschool, NL (2),
  Comtaskfor 72 (2),
  Comsubron 50 (2),
  Comsopac (2),
  Cinclant (2),
  Comtaskfor 16 (1).
 

<signature>
E. R. SWINBURNE,
Flag Secretary.
FF12-10/A16-3(18)   SUBMARINE FORCE, PACIFIC FLEET

Serial 067                          Care of Fleet Post Office,
                                    San Francisco, California,
                                    1 Feb. 1946

CONFIDENTIAL

From:       The Commander Submarine Force, Pacific Fleet.
To  :       The Chief of Naval Operations
Via :       The Commander in Chief, U. S. Pacific Fleet.

Subject:    U.S.S. WAHOO (SS238) - Report of Fourth War Patrol.

Reference   (a) ComSubPac second cnf. FF12-10/A16-5(5)/(16)
serial
                0484 of 13 April 1943.

        1.                  In reference (a) U.S.S. Wahoo was credited with
sinking a total of 36,693 tons of enemy shipping and damaging one
freighter of 5,973 tons.  The damaged freighter was estimated to
be of the TOT TORI class and was attacked in position 38-27N. and
122-18E. on 19 March 1943.  Reliable intelligence, subsequently
received, indicates that the KOMA MARU (very similar to TOT TORI
class of 4,520 tons sank on 20 March as a result of submarine
attack.  The only other ship attacked in that location on either
19 or 20 March was the NANKA MARU which was sunk by WAHOO at 0513
19 March 1943 and whose loss has been verified by intelligence
reports.  Accordingly, WAHOO is hereby credited with the sinking
of KOMI MARU - 4,520 tons.

        2.                  Accordingly reference (a) is modified as follows:

        (a) Strike out all after the word "enemy" in paragraph 3 and
substitute therefor:
 

                             SUNK
         1 Freighter (KOMI MARU)             - -  4,520 tons
         1 Freighter (NANKA MARU class)      - -  4,065 tons
         1 Freighter (SEIWA MARU class)      - -  7,210 tons
         1 Freighter (NITU MARU class)       - -  6,543 tons
         1 Freighter (KATYOSAN MARU class)   - -  2,427 tons
         1 Tanker (SYOYO MARU class)         - -  7,499 tons
         1 Freighter (KIMISIMA MARU class)   - -  5,193 tons
        *1 Freighter (SINSEI MARU class)     - -  2,556 tons
        *1 Freighter (HADACHI MARU class)    - -  1,000 tons
        *1 Trawler (#825)                    - -    100 tons
        *2 Sampans                           - -    100 tons
                                             __________
                                   TOTAL:   41,213 tons
*Sunk by gunfire.
 

                                     Frank T. Watkins,
                                     Chief of Staff.



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