(Period from February 23 to April 6, 1943) 


               Arrived PEARL on February 7, 1943 from THIRD War

               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 SubBase 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 SubBase 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 the 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 caliber 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 overnight. 

               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. distance 
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 an 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 tonight - 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 tonight 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 they 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 overturned 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. 

               LAOTIEGHSHAN 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 warheads 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 end run 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 of 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 sank 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 hit 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 on the 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 too 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 (FISHY 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 too
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 not 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 water 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 were 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. 

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

                 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 


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 
           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 


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     :               :              :      : 


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 
          + 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 
           "      Wrecked with 4" gun hits. 
     Sampans: Wrecked. 


             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. 


             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 

             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 

             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. 


             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        . 


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


             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. 



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


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 

        (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 

            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 


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


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

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

        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: 

                            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. 

                            AK  TOTTORI MARU  - - - - - - - - 5,973 tons 

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



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 

        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: 

         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. 

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

DISTRIBUTION:                              J. H. BROWN, Jr., 
    (1m-43)                                Acting 
  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). 

Flag Secretary. 

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


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) 
                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: 

         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.