U. S. S. WAHOO - REPORT OF FIFTH WAR PATROL

                     (Period from April 25 to May 21, 1943)

                                    PROLOGUE

     Arrived submarine base, MIDWAY ISLANDS April 6, 1943 after FOURTH War
     Patrol.  On April 7, 1943 commenced refit by Submarine base, relief crew,
     and ship's force.

     During April 21 to 22 conducted training exercises underway.

     Ship ready for sea April 25, 1943.

     1.   NARRATIVE

April 25: 1500Y; Departed MIDWAY under air escort for patrol area via Kuril
          Islands.

          Crossed the International Date Line.

April 27: Tested new flashless powder during complete darkness.  Still our
          powder is not flashless, but it gives off a diminished flash.  This
          powder cannot be compared with that employed by the Japs against us,
          on numerous occasions.  It is also understood that the British and
          German's flashless powder is as effective as the Japanese.
          Furthermore, this powder produces a great amount of smoke and is
          considered a handicap to the gun crew when firing with an unfavorable
          wind.

April 29: 1555N: Slowed to one engine speed (80-90) due to heavy head seas.

April 30: 1000N: Seas having diminished, speeded up to two main engines.

          1622L: Upon surfacing from daily submerged drills sheared the shear
          pins in bow plane rigging mechanism.  Stopped; lying to while
          replacing these shear pins.  At 1720L, all repairs completed continued
          course and speed.

May 2:    Encountered hail and snow on the morning watch.

          1423L: Sighted snow capped mountain peaks on ONEKOTAN ISLANDS of the
          KURIL ISLANDS.

          1639L: Slowed and commenced surface patrol along the KURIL ISLANDS.
          Will investigate NATSUWA tomorrow in close and submerged.

May 3:    0400N; Dived six miles east of NATSUWA and proceeded to reconnoiter
          the island.  Found a four to five thousand ton freighter broken on
          beach of NATSUWA opposite BANJO TO, apparently a victim of a storm.
          Fresh appearing paint on the protruding parts indicated that this was
          a recent wreck.  Observed will developed air field consisting of four
          large hangers with dispersal stowages in back, a large landing field
          apparently equipped with flood lights, administration buildings, radio
          station barracks etc.  This installation is considered comparable to
          the air station on Eastern Island, MIDWAY.  Took several photographs,
          and plotted positions of outstanding features on chart included as
          enclosure "A" then cleared island submerged.

          1105K; Due to absence of any plane activity surfaced and continued
          patrol of the KURIL CHAIN to the southward.

          The islands observed this far south are barren and completely covered
          with snow and ice, the installation on NATSUWA being the only
          indication of any activity.

May 4:    0420K; Dived and proceeded to reconnoiter NOYORO MAN on the northeast
          tip of ETOROFU ISLAND where there are sulphur works.  The harbor was
          jammed with float ice and no activity could be observed.  As the
          currents were apparently causing the ice floes to surround us, changed
          course to southeast to get clear.

                                      ATTACK No. 1

          0525K; The O.O.D. sighted, through the morning mist, what appeared to
          be a small ship or patrol, range about six thousand yards, angle on
          the bow 30d port.  This put him on course parallel to the Island
          Chain.  This observation was confirmed by the Commanding and Executive
          Officers.  Five minutes later the ship changed course presenting a
          zero angle on the bow.  The end on view through the mist prevented
          identification of the ship as other than a small freighter or patrol
          until the range was 3,200 yards.  At this time he was coming out of
          the mist and the angle on the bow was sufficient to identify him as a
          larger target and worthy of torpedo fire.  On the next observation
          identified target as an auxiliary seaplane tender and maneuvered for
          stern torpedo shots.

May 4:    0558L; Fired a divergent spread of three torpedoes using stack,
          forward goalpost and after goalpost as points of aim, range 1,350
          yards, 123d starboard track, speed 11 knots.  The first torpedo with
          torpex head hit between stack and bridge after sixty second run.  The
          torpedo fired at his forward goalpost evidently passed ahead and the
          one fired aft must have been erratic or a dud.  It is inconceivable
          that any normal dispersion could allow this last torpedo to miss a 510
          foot target at this range.  The target tooted her whistle, commenced
          firing to port, away from the WAHOO. and then turned away dropping
          four depth charges.  She was observed to have a slight port list, but
          was evidently quite under control.  As this ship, a KAMIKAWA MARU
          Class XAV-1 is capable of 21 knots and did not increase speed, it is
          considered probable that the one hit limited her speed to the 11 knots
          determined.

          0636K; Continued on easterly course to clear ice-pack.

          1355K; Surfaced and continued patrol of KURIL CHAIN to southward.  Ice
          floes prevented investigating HITUKAPPU WAN on the south coast of
          ETOROFU.

          2047K; Sent contact report to ComSubPac concerning the XAV-1.

May 5-6:  Patrolling KURIL CHAIN.

May 78:   Entered area and closed coast at full speed.

          0420K; dived 12 miles from coast off BENTEN ZAKI.  Observed two
          freighters with a destroyer or patrol, and a third lonely freighter
          pass ahead of us well inshore out of range.

                                  ATTACK No. 2 A and B

          1039K; Sighted two ships on northerly course, hugging the shoreline.
          Commenced approach.  Leading ship identified as similar to YUKI MARU
          (5,704 tons) and the second like the YOMSEI MARU (2,861 tons).  The
          second ship however, was dark grey, fitted with gun mounts and was
          apparently escorting.

          1115K; Fired spread to two torpedoes at leading ship, range 900 yards,
          107d starboard track, speed 9 knots, followed immediately by a spread
          of four torpedoes at the escort.  The first torpedo hit the YUKI MARU
          under the stack and broke her back.  The second torpedo missed ahead.
          The patrol turned towards and successfully avoided the four torpedoes
          fired at her, though how she got between those four torpedo tracks
          will always remain a mystery.  As the YUKI MARU had sunk, went deep
          and avoided the patrol at full speed then silent running.  None of his
          depth charges were too close.  Observed him from periscope depth and
          cleared vicinity.  Heard considerable distant depth charging or
          bombing and observed planes searching remainder of the day.

May 8:    Proceeded down coast, skirted fishing fleet, and dived a mile and a
          half off KONE ZAKI.

          0512K; Sighted small ship and made approach.  He was running within
          fifteen hundred yards of the beach, turning into every cove.  Broke
          off attack when he was observed to be too small for torpedo fire.

                                     ATTACK NO. 3

          1413K; Sighted three ships coming down the coast, commenced approach.
          The convoy was zig-zagging, and when the range had closed was
          identified as two escort vessels, similar to the one encountered
          yesterday, escorting a naval auxiliary similar to the KIHRYU MARU
          (9,310 tons).

          1503K; Fired spread of three torpedoes, range 2,500, 90d port track,
          speed 10 knots, depth setting fifteen feet.  The first torpedo
          (torpex) aimed at MOT, prematured after 50 second run half way to the
          target.  The second torpedo aimed at mainmast, and down practically
          the same track as the first, was evidently deflected by the premature
          or failed to explode.  The third torpedo fired at the foremast hit the
          point of aim but failed to explode.  Both sound operators reported the
          thud of the dud at the same time that a column of water about ten feet
          was observed at the targets side abreast of her foremast as the air-
          flask exploded.

          1510K; Received first of the series of depth charges expected under
          these circumstances.

May 9:    Proceeded up coast with the intention of closing KONE SAKI prior to
          diving.

                                      ATTACK No. 4 A and B

          0245K; When 17,000 yards from KONE SAKI by SJ range, the radar
          operator observed two pips, 15,000 and 15,300 yards on the same
          bearing with the land.  Changed course and tracked target group and in
          the position they would occupy at dawn, dived to 40 feet.  Continued
          tracking by radar and periscope bearings until range was 7,000 yards,
          then went to sixty feet.  The targets were seen identified as a large
          tanker and freighter in column, evidently making the night run between
          ports without escort.

          0440K; Fired a spread of three torpedoes at tanker identified as
          similar to HUZISAN MARU (9,527 tons), range 1,200 yards, 100d port
          track, speed 10 knots, and immediately thereafter a spread of three
          more torpedoes at the freighter identified as similar to the HAWAII
          MARU (9,467 tons), range 1,130 yards 90d port track, speed 10 knots.
          All torpedoes were set to run at eighteen feet.  Just after the fifth
          torpedo was fired the first hit the tanker amidships breaking her
          back.  She sank by the bow and caught fire aft.  The fourth torpedo (a
          torpex) hit the freighter under the bridge breaking its back, and the
          fifth torpedo (TNT) hit her aft.  She sank by the stern.  Attempted
          taking some periscope pictures in the meager light; then when both
          ships had sunk cleared the area to the east.

          Heard distant depth charges or bombs throughout the day, and one echo
          ranging A/S vessel which passed close on one occasion.  Our
          bathythermograph, which showed a two degree temperature inversion at
          170 feet gave us extra confidence in our 300 foot depth.

          2020K;  Distant explosions and echo-ranging still heard so on
          surfacing cleared area to northeast to patrol TOKYO-PARAMUSHIRU route.

May 10:   Commenced submerged patrol on above route.

          1010K; Surfaced due to poor visibility and conducted radar search.

May 10-   Patrolling TOKYO-PARAMUSHIRU  route.  Nothing sighted except one
    11     trawler or patrol which we avoided.

May 12:   Closed coast and dived two miles off KONE SAKI.  Numerous sampans and
          a glassy sea made periscope observation difficult.

          0646K;  Sighted light bomber searching vicinity.  Heard several fairly
          loud explosions.

          0730K;  Sighted another light bomber headed for periscope.  Cleared
          area to the east.  Heard numerous distant bombs or depth charges
          throughout the morning.

                                 ATTACKS No. 5 A, B, C, D.

          1725K;  Sighted distant smoke in the northeast which drew to the
          south.  Commenced approach at standard speed to close the range prior
          to sunset.  Identified target group as two freighters in column, the
          leading one similar to NYOKEN MARU (4,021 tons) and the second a huge
          freighter similar to the ANYO MARU (9,257 tons).  They were tracked at
          9 knots, zig-zagging on base course south, will beyond possible
          position for submerged attack.

          2005K;  Surfaced and went after convoy at full speed while charging
          batteries.

          2030K;  Sighted smoke of freighters in clear night.

          2051K; Picked up freighters on SJ, range 9,400 yards, and commenced
          working around their stern so that attack could be made with them
          silhouetted in the setting quarter moon.

          2245K;  Having determined enemy zig-zag plan, and speed as 8.5 knots,
          dived in position for a "two ship" shot where they would come by in
          column.  As both freighters were loaded set torpedo depth at 18 feet.

          2338K;  Fired spread of two torpedoes at ANYO MARU, range 1,200 yards,
          95d port track, speed 8.5 knots, and immediately thereafter a spread
          of two torpedoes at the leading ship, range 1,480 yards, 126d port
          track, speed 8.5 knots.  The first torpedo fired at the mainmast hit.
          The second torpedo, fired at his stack amidships, is believed to have
          been erratic or a dud.  The target course and speed had been most
          accurately determined and it is inconceivable that a normal dispersion
          could cause it to miss.  No hits were obtained on the leading ship.
          The ANYO MARU was now observed still going, so waited until the range
          had opened to 5,000 yards then surfaced and commenced another "end-
          around".  The moon had nearly set, so gained position for surface
          attack tracking target by radar with TBT bearings as he came in.

May 13:   0107K;  Fired last remaining bow torpedo at ANYO MARU, range 1,800
          yards, 90d port track, speed 7.5 knots, and then turned with full
          rudder and speed for an almost identical stern tube shot.  Nothing was
          seen of the bow torpedo or its wake and the enemy apparently did not
          know he had again been fired upon.

          0111K;  Fired last remaining torpedo into the ANYO MARU, range 1,800
          yards, 110d port track, speed 7.5 knots.  Some phosphorescence was
          observed as this torpedo headed to intercept the target.  It hit under
          the bridge with a dull thud, much louder then the duds we have heard
          only on sound, but lacking the "whacking" which accompanies a whole-
          hearted explosion.  It is considered that this torpedo had a low order
          detonation.  Some sparks were observed on the target above the
          impact, but he turned away apparently under control, belching smoke.
          At this time the NYOKEN MARU which was on our starboard bow opened
          fire and forced us to dive for six minutes.  When we surfaced and
          closed the ANYO MARU, she was lagging a mile behind the NYOKEN,
          smoking furiously, and making six knots.  We manned the deck gun, but
          withdrew, quite helpless to stop the cripple, when the NYOKEN turned
          and rejoined the ANYO.

          0225K;  Cleared area to east on three main engines.

          0336K;  Sent message to ComSubPac concerning expenditure of torpedoes.

          2200K;  Set course for PEARL.

May 18:   2105Y;  Sighted four ships on starboard bow, two of them appearing to
          be destroyers.  Believe it to be the convoy for MIDWAY which STINGRAY
          had met earlier.  Tracked them on course 290, speed 7, and sent
          contact report.

May 19:   0130Y;  Received information concerning possible meeting with convoy.

May 21:   1000VK;  Arrived PEARL

     2.   WEATHER

          Excellent weather was encountered throughout the patrol.

     3.   NAVIGATIONAL AIDS

          All lights were burning, but dimmed.
 

     5.   ENEMY SHIPS SIGHTED

    Date     : Time  :  Position       :Course : Speed  :     Type
   ----------------------------------------------------------------------------
   5/4/43   : 0525K :Lat. 45-20 N     : 060d  :11 knots: XAV-1 KAMIKAWA
            :       :Long.149-00 E    :       :        : MARU CLASS
   ----------------------------------------------------------------------------
   5/4/43   : 0420K :Lat. 40-04  N    : 170d  : 8 KNOTS: 2 FREIGHTERS
            :       :Long.141-54 E    :       :        : 1 DESTROYER
   ----------------------------------------------------------------------------
   5/7/43   : 0832K :Lat. 39-59 N     : 350d  : 8 knots: 1 FREIGHTER
            :       :Long.142-04 E    :       :        :
   ----------------------------------------------------------------------------
   5/7/43   : 1039K :Lat. 40-05 N     : 350d  : 9 knots: YUKI MARU -(YONIE MARU
            :       :Long.141-53 E    :       :        : GUN MOUNTS) - ESCORT
   ----------------------------------------------------------------------------
   5/8/43   : 0512K :Lat  39-02 N     :VARIOUS: 8 knots: SMALL SHIP
            :       :Long.141-58 E    :       :        : (1,000 TON)
   ----------------------------------------------------------------------------
   5/8/43   : 1413K :Lat. 39-02 N     : 210d  :10 knots:2 ESCORT VES(CONVT'D AK)
            :       :Long.142-02 E    :       :        :1 AUX (KINRYU MARU)
   -----------------------------------------------------------------------------
   5/9/43   : 0245K :Lat. 38-57 N     : 210d  :10 knots:TANKER HUZISAN MARU
            :       :Long.141-49 E    :       :        :FREIGHTER HAWAII MARU
   -----------------------------------------------------------------------------
   5/11/43  : 1520K :Lat. 39-27 N     :VARIOUS: SLOW   :SMALL PATROL BOAT OR
            :       :Long.122-16 1/2 E:       :        :TRAWLER
   -----------------------------------------------------------------------------
   5/12/43  : 1725K :Lat. 39-40 N     :ZIGGING:8.5KNOTS: 2 FREIGHTERS: MYOKEN &
            :       :Long.122-24 1/4 E:  180d :7.5KNOTS: ANYO MARU
   -----------------------------------------------------------------------------

     6.   DESCRIPTION OF PLANES SIGHTED.

   DATE & TIME  :   TYPE    :   LATITUDE    :  LONGITUDE   : COURSE : ALTITUDE
   ---------------------------------------------------------------------------
   5/7/43  1400K:   SMALL   : 40d - 00'N    : 141d - 53'E  :CIRCLING: MEDIUM
   ---------------------------------------------------------------------------
   5/12/43 0636K: LIGHT     : 39d - 22'N    : 142d - 09'E  : 000d   : MEDIUM
                : BOMBER    :               :              :        :
   ---------------------------------------------------------------------------
   5/12/43 0730K: LIGHT     : 39d - 22'N    : 142d - 15'E  :VARIOUS : MEDIUM
                : BOMBER    :               :              :        :
   5/14/43 1218K: SD RADAR  : 38d - 43'N    : 151d - 20'E  : - - -  : - - -
                :4.5 MILES  :
   ---------------------------------------------------------------------------
     7.   SUMMARY OF SUBMARINE ATTACKS
 

   ---------------------------------------------------------------------------
                               :      (1)         :    (2)A       :    (2)B
   ---------------------------------------------------------------------------

   ATTACK                      :      XAV         :    AX         : ESCORT
   ---------------------------------------------------------------------------
   TIME                        : 1958             : 0115          : 0115
   DATE - G.C.T.               : 3 MAY 1943       : 7 MAY 1943    : 7 MAY 1943
   ---------------------------------------------------------------------------
   LATITUDE                    : 45 - 20 N        : 40 - 05 N     : 40 - 05 N
   LONGITUDE                   : 149 - 08 E       : 141 - 53 E    : 141 - 53 E
   ---------------------------------------------------------------------------
   NUMBER AND TYPE OF TORPEDOES: 3 - XIV3A        : 2 - X1V3A     : 4 XIV3A
   FIRED ON EACH ATTACK        : (1 TNT - 2 TPX)  : (2 TPX)       :3 TPX 1 TNT
   ---------------------------------------------------------------------------
   HITS                        : 1 TPX            : 1 TPX         : 0
   ---------------------------------------------------------------------------
   NUMBER SUNK (TONNAGE)       : 0                : 5,704         : 0
   ---------------------------------------------------------------------------
   NUMBER DAMAGED OR           : 1 DAMAGED        :               :
   PROBABLY SUNK (TONNAGE)     : 15,650           : 0             : 0
   ---------------------------------------------------------------------------
   TYPE OF TARGET              : XAV - 1          : AK            : PATROL
                               : KAMIKAWA         : YUKI MARU     :(2,500 CONV)
   ---------------------------------------------------------------------------
   RANGE                       : 1,350            : 900           : 900
   ---------------------------------------------------------------------------
   TYPE OF ATTACK: PERISCOPE(P):                  :               :
   SURFACE(S) NIGHT(N) RADAR(R): (P)              : (P)           : (P)
   ---------------------------------------------------------------------------
   ESTIMATED DRAFT OF TARGET   : 28'              : 26'           : 22'
   ---------------------------------------------------------------------------
   TORPEDO DEPTH SETTING       : 12'              : 15'           : 15'
   ---------------------------------------------------------------------------
   BOW OR STERN SHOT           : STERN            : BOW           : BOW
   ---------------------------------------------------------------------------
   TRACK ANGLE                 : 123d S           : 107d S        : 089d S
   ---------------------------------------------------------------------------
   GYRO ANGLE                  :                  :               : 353:353
                               :201:203:205       : 009:016       : 355:353
   ---------------------------------------------------------------------------
   ESTIMATED TARGET SPEED      : 11 KNOTS         : 9 KNOTS       : 9 KNOTS
   ---------------------------------------------------------------------------
   FIRING INTERVAL             : 11 SEC; 9 SEC    : 10 SEC        :13S:18S:22S
   ---------------------------------------------------------------------------
   SPREAD - AMOUNT AND KIND    : DIVERGENT        :               :
                               :(DIFF PTS OF AIM) : DIVERGENT     : DIVERGENT
   ---------------------------------------------------------------------------
   WAS TORPEDO PERFORMANCE
   SATISFACTORY?               : YES              : YES           : YES
   --------------------------------------------------------------------------
                               :      (3)         :    (4)A       :    (4)B
   ---------------------------------------------------------------------------

   ATTACK                      :      AK          :    AO         :   AK
   ---------------------------------------------------------------------------
   TIME                        : 0503             : 1840          : 1840
   DATE - G.C.T.               : 8 MAY 1943       : 8 MAY 1943    : 8 MAY 1943
   ---------------------------------------------------------------------------
   LATITUDE                    : 39 - 02 N        : 38 - 57 N     : 38 - 57 N
   LONGITUDE                   : 142 - 02 E       : 141 - 49 E    : 141 - 49 E
   ---------------------------------------------------------------------------
   NUMBER AND TYPE OF TORPEDOES: 3 - XIV3A        : 3 - X1V3A     : 3 XIV3A
   FIRED ON EACH ATTACK        : (1 TNT - 2 TPX)  : (2 TPX 1 TNT) :2 TPX 1 TNT
   ---------------------------------------------------------------------------
   HITS                        : 0                : 1             : 2
   ---------------------------------------------------------------------------
   NUMBER SUNK (TONNAGE)       : 0                : 9,527         : 9,467
   ---------------------------------------------------------------------------
   NUMBER DAMAGED OR          :                  :               :
   PROBABLY SUNK (TONNAGE)     : 0                : 0             : 0
   ---------------------------------------------------------------------------
   TYPE OF TARGET              : AK               : AO            : AK
                               : KINRYU MARU      : HUZISAN MARU  :HAWAII MARU
   ---------------------------------------------------------------------------
   RANGE                       : 2,900            : 1,200         : 1,200
   ---------------------------------------------------------------------------
   TYPE OF ATTACK: PERISCOPE(P):                  :               :
   SURFACE(S) NIGHT(N) RADAR(R): (P)              : (R) (P)       : (R) (P)
   ---------------------------------------------------------------------------
   ESTIMATED DRAFT OF TARGET   : 28'              : 28'           : 28'
   ---------------------------------------------------------------------------
   TORPEDO DEPTH SETTING       : 15'              : 18'           : 18'
   ---------------------------------------------------------------------------
   BOW OR STERN SHOT           : BOW              : BOW           : BOW
   ---------------------------------------------------------------------------
   TRACK ANGLE                 : 090d P           : 100d P        : 090d P
   ---------------------------------------------------------------------------
   GYRO ANGLE                  :001:002:359       : 340:335:334   : 357:355:352
   ---------------------------------------------------------------------------
   ESTIMATED TARGET SPEED      : 10 KNOTS         : 10 KNOTS      : 10 KNOTS
   ---------------------------------------------------------------------------
   FIRING INTERVAL             : 12 SEC; 23 SEC   : 17 SEC 13 SEC :13SEC 14 SEC
   ---------------------------------------------------------------------------
   SPREAD - AMOUNT AND KIND    : DIVERGENT        : DIVERGENT     : DIVERGENT
   ---------------------------------------------------------------------------
   WAS TORPEDO PERFORMANCE
   SATISFACTORY?               : NO*              : YES           : YES
   ---------------------------------------------------------------------------
   REMARKS:       * I DUD, 1 PREMATURE, 1 ERRATIC RUN.
   ---------------------------------------------------------------------------
                               :      (5)A        :    (5)B       :    (5)C
   ---------------------------------------------------------------------------

   ATTACK                      :                  :               :
   ---------------------------------------------------------------------------
   TIME                        : 1338             : 1338          : 1507
   DATE - G.C.T.               : 12 MAY 1943      : 12 MAY 1943   : 12 MAY 1943
   ---------------------------------------------------------------------------
   LATITUDE                    : 38 - 40 N        : 38 - 40 N     : 38 - 52 N
   LONGITUDE                   : 142 - 53 E       : 142 - 53 E    : 143 - 00 E
   ---------------------------------------------------------------------------
   NUMBER AND TYPE OF TORPEDOES: 2 - XIV3A        : 2 - X1V3A     : 1 XIV3A
   FIRED ON EACH ATTACK        : (1 TNT - 1 TPX)  : (1 TPX 1 TNT) :  TPX
   ---------------------------------------------------------------------------
   HITS                        : 1                : 0             : 0
   ---------------------------------------------------------------------------
   NUMBER SUNK (TONNAGE)       : 0                : 0             : 0
   ---------------------------------------------------------------------------
   NUMBER DAMAGED OR           :                  :               :
   PROBABLY SUNK (TONNAGE)     : 9,257            : 0             : 0
   ---------------------------------------------------------------------------
   TYPE OF TARGET              : AK               : AK            : AK
                               : ANYO MARU        : MYOKEN MARU   : ANYO MARU
   ---------------------------------------------------------------------------
   RANGE                       : 1,200            : 1,200         : 1,800
   ---------------------------------------------------------------------------
   TYPE OF ATTACK: PERISCOPE(P):                  :               :
   SURFACE(S) NIGHT(N) RADAR(R): (R) (P) (N)      : (R) (P) (N)   : (R) (P) (N)
   ---------------------------------------------------------------------------
   ESTIMATED DRAFT OF TARGET   : 30'              : 24'           : 30'
   ---------------------------------------------------------------------------
   TORPEDO DEPTH SETTING       : 18'              : 18'           : 18'
   ---------------------------------------------------------------------------
   BOW OR STERN SHOT           : STERN            : STERN         : BOW
   ---------------------------------------------------------------------------
   TRACK ANGLE                 : 095d P           : 126d P        : 090d S
   ---------------------------------------------------------------------------
   GYRO ANGLE                  : 190:183          : 149:150       : 008:1/2
   ---------------------------------------------------------------------------
   ESTIMATED TARGET SPEED      : 8.5 KNOTS        : 8.5 KNOTS     : 7.5 KNOTS
   ---------------------------------------------------------------------------
   FIRING INTERVAL             : 14 SECS          : 15 SECS       : -------
   ---------------------------------------------------------------------------
   SPREAD - AMOUNT AND KIND    : DIVERGENT        : DIVERGENT     : -------
   ---------------------------------------------------------------------------
   WAS TORPEDO PERFORMANCE
   SATISFACTORY?               : YES              : YES           : NO*
   ---------------------------------------------------------------------------
   REMARKS:       * APPARENTLY A DUD.
   -----------------------------------------------
                               :      (5)D
   -----------------------------------------------

   ATTACK                      :
   -----------------------------------------------
   TIME                        : 1911
   DATE - G.C.T.               : 12 MAY 1943
   -----------------------------------------------
   LATITUDE                    : 38 - 52 N
   LONGITUDE                   : 143 - 00 E
   -----------------------------------------------
   NUMBER AND TYPE OF TORPEDOES: 1 - XIV3A
   FIRED ON EACH ATTACK        : 1 TNT
   -----------------------------------------------
   HITS                        : 0
   -----------------------------------------------
   NUMBER SUNK (TONNAGE)       : 0
   -----------------------------------------------
   NUMBER DAMAGED OR          :
   PROBABLY SUNK (TONNAGE)     : 9,257
   -----------------------------------------------
   TYPE OF TARGET              : AK
                               : ANYO MARU
   -----------------------------------------------
   RANGE                       : 1,800
   -----------------------------------------------
   TYPE OF ATTACK: PERISCOPE(P):
   SURFACE(S) NIGHT(N) RADAR(R): (R) (S) (N)
   -----------------------------------------------
   ESTIMATED DRAFT OF TARGET   : 30'
   -----------------------------------------------
   TORPEDO DEPTH SETTING       : 18'
   -----------------------------------------------
   BOW OR STERN SHOT           : STERN
   -----------------------------------------------
   TRACK ANGLE                 : 110d S
   -----------------------------------------------
   GYRO ANGLE                  : 162
   -----------------------------------------------
   ESTIMATED TARGET SPEED      : 7.5 KNOTS
   -----------------------------------------------
   FIRING INTERVAL             : -------
   -----------------------------------------------
   SPREAD - AMOUNT AND KIND    : -------
   -----------------------------------------------
   WAS TORPEDO PERFORMANCE
   SATISFACTORY?               : YES
 

     8.   ENEMY A/S MEASURES

          The A/S vessels encountered definitely belonged to the second team.
          They invariably dropped single charges after attempting to locate us
          by stopping to listen.  Aircraft were used to search in conjunction
          with these vessels, but arrived too late to be effective on all but
          one occasion.  Only one echo ranging vessel was encountered.  Their
          doctrine seems to require dropping lots of charges and bombs whether
          they know the submarine's location or not.  The A/S vessels observed
          were all converted freighters with gun mounts fore and aft and
          characterized by black and white checkered painting forward and after
          of the bridge structure.

     9.   MINE SWEEPING OPERATIONS

          No mine sweeping operations were observed.

     10.  MAJOR DEFECTS

          No major defects were experienced.

     11.  COMMUNICATIONS

          Radio reception was good and was complete.  No difficulty, other than
          ineffective enemy jamming and spurious transmissions, was encountered
          in clearing messages to NPM on 8,470 Kcs.

          The loop coupling adapter was tested regularly.  In the KURILS, NPM
          could usually be copied at 60 feet, occasionally as deep as 65 feet.
          In the area results were not as good, reception being difficult at 60
          feet.

          Last Serial received - Comsubpac Serial 74

          Last Serial sent - WAHOO  192230 May.

     12.  SOUND CONDITIONS AND DENSITY LAYERS

          Sound conditions in the KURILS were fair to poor.  The one ship
          sighted was not heard until at a very short range.  In the area sound
          conditions were good to excellent.  Ships were picked up at 5,000 to
          8,000 yards.

          In the KURILS water temperature varied from 28 to 34 degrees depending
          upon proximity to land, ice floes, etc.; however, no pronounced
          gradients were encountered.  In the area water temperature was usually
          36 to 40 degrees.

          All types of gradients were encountered.  In the extreme case of May
          9, ten miles east of KONE SAKI, the temperature dropped from 37
          degrees to 32 degrees in going from periscope depth to 100 feet.  It
          is felt that this alone prevented the echo ranging AS vessel from
          gaining sound contact.  The bathythermograph was used constantly
          during dives and was very valuable for predicting the sound conditions
          existing.

     13.  HEALTH AND HABITABILITY

          Health and habitability were excellent, except for one threatening
          case of appendicitis during return voyage.

     14.  MILES STEAMED

          Enroute to Area............................. 2,964
          In Area.....................................   803
          From Area................................... 3,061

     15.  FUEL OIL EXPENDED

          Enroute to Area............................. 8.68 gal. per mile.
          In Area..................................... 8.53 gal. per mile.
          From Area...................................15.80 gal. per mile.

     16.  ENDURANCE FACTORS

          Torpedoes.................................. NONE
          Others..................................... Indefinite.

     17.  PATROL ENDED

          Patrol ended by orders of ComSubPac after expenditure of all
          torpedoes.
 
 
 
 
 

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

Serial   086                        In Care Of Fleet Post Office,
                                    San Francisco, California,
                                    May 22, 1943.

CONFIDENTIAL

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

Subject:    U.S.S. WAHOO, Fifth War Patrol - Comments on.
 

     1.   The fifth war patrol of the U.S.S. WAHOO was again outstanding in
aggressiveness and efficiency.  In ten action packed days the WAHOO delivered
ten torpedo attacks on eight different targets.

     2.   Although the results were gratifying, faulty torpedo performance cut
positive results probably as much as 50%.  Such must have been a source of keen
disappointment to the Commanding Officer and personnel of the WAHOO.  Seven hits
were observed of twenty-four torpedoes fired, for a score of 29.2%.  One of
these seven was believed to have been of low order detonation.

     3.   During this patrol, aggressiveness, determination and fighting spirit
of the Commanding Officer, officers and crew again manifested in the excellent
results obtained.  The Commander Submarine Squadron Ten takes pleasure in
congratulating the Commanding Officer and personnel on inflicting the following
damage on the enemy:

                                  SUNK

     AK (YUKI MARU Class).................................5704 tons
     AO (HUZISAN MARU Class)..............................9527 tons
     AK (HAWAII MARU Class)...............................9467 tons

                                    TOTAL                 24698 tons

                                 DAMAGED

     XAV-1 (KAMIKAWA MARU Class)..........................15650 tons
     AK    (ANYO MARU Class).............................. 9257 tons

                                    TOTAL                  24907 tons
 
 
 
 
 

FF12-10/A16-3(5)/(16)  SUBMARINE FORCE, PACIFIC FLEET

Serial   0484                       In Care of Fleet Post Office,
                                    San Francisco, California,
                                    May 29, 1943.

CONFIDENTIAL

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

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

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

Enclosure:  (A) Copy of Subject War Patrol Report.
            (B) None.
            (C) Copy of Comsubron 10 conf. ltr. FC5-10/A16-3
                (FB5-102) Serial 086 of May 22, 1943.

    1.  The U.S.S. WAHOO's fifth war patrol was the third for the present
commanding officer.  Typical of the previous two patrols, this on was carried
out in the same aggressive and successful manner.  These three patrols establish
a record not only in damage inflicted on the enemy for three successive patrols,
but also for accomplishing this feat in the shortest time on patrol.  The WAHOO
has sunk a total of 93,281 tons and damaged 30,880 more in only twenty-five
patrol days.

    2.  Once again the WAHOO utilized all the weapons available in
conjunction with wound strategic and tactical judgement.  This combined with
team work of personnel made this fifth war patrol another outstanding example of
how to conduct submarine warfare.

    3.  The Commander Submarine Force, Pacific Fleet, congratulates the
Commanding Officer, Officers, and Crew of the U.S.S. WAHOO for this their third
successive aggressive and successful war patrol during which the following
damage was inflicted on the enemy:

                SUNK

        1 Freighter (YUKI MARU Class)              5,704 tons
        1 Tanker (HUZISAN MARU Class)              9,527 tons
        1 Freighter (HAWAII MARU Class)            9,467 tons

                 TOTAL           24,698 tons

                                 DAMAGED

        1 Ex-Seaplane Tender (KAMIKAWA Class) 15,650 tons
        1 Freighter (ANYO MARU Class)              9,257 tons

                TOTAL           24,907 tons
 

                C. A. LOCKWOOD, Jr.



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