CONFIDENTIAL Subject: U.S.S. WAHOO - REPORT OF FIRST WAR PATROL. PERIOD FROM AUGUST 23 TO OCTOBER 17, 1942. AREA: North of latitude 7d - 15 and SW of a line bering 315dT from TAUARAR Pass. OPERATION ORDER: Number 73-42. 1. NARRATIVE. August 23- 0900 (VW) Departed Pearl. Made trim drive and received two indoctrinational depth charges from escort. Set speed 14 knots for area. August 26- 0630 (X) made trim drive August 26- 2230(Y) Crossed 180th Meridian. August 28- 0700(M) Lookout reported sighting airplane. Unconfirmed. Improbable. August 29- 0720(M) Submerged. Surfaced at 1730. August 29- 1830(M) Aircraft contact on Radar at ten miles. Sky heavily overcast and squally. Submerged. Surfaced at 1900. Position ninety miles East of TAONGI TOLL. August 31- 0625(L) Sighted airplane about six miles ahead. Submerged. Surfaced at 1730(L). September 1- 0600(L) Aircraft contact on Radar at three miles. Submerged. The time of day and geographical position (North of PONAPE) made this contact most unexpected. However there was a very bright moon and possibly this area is being given a thorough search. During the night O.O.D. had picked up three greenish lights at about half hour intervals in the distance. There maybe a connection between the lights and the early morning contact. September 1- Sound contact ahead. Nothing in sight by periscope. Sound followed contact 30d change in bearing and reported propeller beats and speed changes. Lost contact after about twenty minutes. (0720(L). September 3- 0500(K) Commenced periscope patrol. Submerged outside of assigned area between HALL and NAMONUITO Islands about 40 miles NE of boundary line, proceeding southwesterly. September 4- 2300(Y) Sighted TOL Island bering 090T distance about 30 miles. September 5- 0430(K) Picked up fast propellers which crossed the bow heading for TRUK. With a bright moon and glassy sea nothing was sighted, so it was presumed to be a small patrol boat. September 6- 0525(K) Sighted a loaded ship similar to WYOGO MARU class tanker, S77, except there was only one stack. Approached and fired three torpedoes at range of 1430 yards (using 50ft. masthead height). Position 15 miles off TRUK. Target headed for PIAANU PASS. Observed airplane on far side of target at about three miles just before firing. Observed target for about one and on half minutes after firing, and saw torpedoes leading her track. About 1 1/2 minutes after firing she started a turn toward us. Assured the torpedoes had all missed or run under so turned toward and went deeper to run under target. At approximately 2 minutes, 20 seconds after first shot one explosion was heard followed shortly thereafter by a second explosion. Lost sound of propellers shortly after explosions. From the timing it would appear that the actual firing range was about 3000 yards and that at least one and probably two torpedoes were detonated by the target or its wake. Because of sea conditions, proximity of the base, and the presence of an airplane screen no periscope observations were made after the explosions. There is no visual evidence to warrant claim of damage to the enemy. September 8- 0748(K) Sighted reconnaissance Bomber type 95 at about two miles distance. September 10- 0612(K) Heard distant underwater explosion, followed by others at 0620, 0634, 0644, and 0653. September 10- 1345(K) Heard five (5) distant underwater explosion at about ten (10) seconds apart. September 11- 0010(K) Picked up propellers bearing NORTH, and lost sound contact about ten minutes later on NW bearing. Nothing sighted. Presumed it was a small patrol boat passing fairly close aboard. September 13- 0452(K) Heard two (2) underwater explosions about ten (10) seconds apart followed by two (2) more at 0455. Estimated distance of 8 to 10 miles. September 14- 1025(K) Picked up propeller noises, and shortly thereafter sighted ship bearing 270dT, distance 12,000 yards, angle on the bow 65d port. Ship was screened by a single float plane similar to Navy Reconnaissance Bomber type 95, and by a small patrol boat. Came to normal approach course and approached by sound for thirty two minutes. At the end of thirty two minutes came to periscope depth for the shot and found range to be 4,000 yards and track about 110 port. Target was identified as a small freighter of about 2500 tons, and being in an unfavorable firing position broke off the attack. Ship proceeded into TRUK via PIAANU PASS. The surface escort was not observed through the periscope, but was plainly heard and tracked by our sound. It was the same high pitched, fast propeller beat as was heard on the 5th and 11th of Sept. The escort would run for about five minutes and get ahead of the freighter, then lie to and drop astern. It was presumed that the had listening gear but no echo ranging. There was no indication that we were detected, which is further born out by the fact that our target made a 25d zig in our direction during our approach. September 14- 2055(K) While engaged in routine servicing of torpedoes No.1 tube as [sic] inadvertently fired with a fully ready war shot in the tube, both outer and inner doors being closed, and with 400 lbs., per square inch, of impulse air. Details are given under "Major Defects Experienced." This tube is out of commission for the remainder of the patrol. September 20- Having spent seventeen days in Southeastern part of the area and seeing but two small ships heading toward PIAANU PASS, decided to spend a week patrolling south of NAMONUITO Island for East-West Traffic. September 20- 2255(K) With a bright moon, clear sky, no wind, and a flat sea, the O.O.D. sighted a column of smoke bearing 322dT. Ran toward it for half an hour on the surface and then submerged for a periscope attack. At 0001 target was identified as a freighter of about 6500 tons of the KEIYO MARU Class, similar to that of plate 69. Course estimated at 135dT. Speed 12 knots at this time, although at various times the ship would stop and lie to for appreciable periods. September 20- It was later discovered that we were at her rendezvous point with an escort. At 0005 it was seen that our tracks were very close together and we swung left for a stern tube shot on the starboard track. Target passed abeam about 200 yards distance and at 0008 we fired the first torpedo on 140 starboard track. This torpedo undoubtedly failed to arm. The second torpedo was fired with a 2d right spread on 155 starboard track. It apparently ran down the starboard side of the target and target saw it and turned left. Third torpedo was fired with a 2d left spread on 162 starboard track and also missed. By this time target presented a 90d port angle on the bow, and with a fourth new setup on TDC another torpedo was fired on 108 port track. This torpedo hit the target 1 minute and twenty seconds after being fired. Target took a port list of about 50d and settled bodily and by the stern, as witnessed by four or five observers, and her engines slowed radically. Four minutes later there started three series of underwater explosions, each series consisting of three or four explosions, and when upon observation through the periscope we first sighted the escort arriving on the scene. He dropped perhaps a dozen depth charges, none within a thousand yards of us. At about 0030 there was considerable confusion around the target. Accompanied by sounds believed to be internal explosions, a billow of heavy black smoke came off the target, and it was no longer seen or heard. By this time we were about 4000 yards away so we surfaced to clear the area. About the time we got to 21 knots the escort picked us up and with a tremendous stream of black smoke pouring out of his stack he gave us chase. He was closing the range by leaps and bounds when along came the most welcome rain squall that it has been our pleasure to encounter. We passed into the squall and made a radical course change. When we came out the other side we found that the escort had followed us through so we eased back into the rain and went the other way. When next we got into the clear the escort was barely visible on the horizon and he did not pick us up again. There is no doubt in the minds of any of this crew but that we sunk the freighter. September 24- 2200(K) Sighted patrol boat bearing 090dT., distance 5 miles, angle on the bow zero. Moon bright, sea calm, visibility good. Submerged. Patrol passed about 3000 yards astern, heading West. Surfaced at 2330 and remained in area so see if he would return escorting a target. Such was not the case. September 25- 0415(K) On routine daylight dive there was some trouble in getting the ship down. Upon surfacing at night found that the Bow Buoyancy vents were not operating properly. Removed bow buoyancy manhole cover for remainder of patrol. September 30- 0520(K) Sighted ship later identified as Aircraft Tender CHIYODA bearing 322dT., course 170dT, range 12,000 yards. Estimated target was headed for PIAANU PASS and that we were in ideal attack position. Two minutes later target zigged 40d left. Three minutes after this zig he went 35d further left. We turned to normal approach course and closed the range to 6,000 yards, at which point we were on 130d starboard track. Target then made another left zig presenting 175 starboard angle on the bow and went over the hill on course 075dT., heading apparently for NORTH PASS in to TRUK. Weather was ideal for submarine approach and we were able to watch target continuously except when making high speeds to close the range. There were no screens or escorts, and any planes might have been overhead never came within the periscope field. the Japs were just begging someone to knock off this Tender, but it was not our lucky day. In 24 minutes he zigged 95d away from us. September 30- 0745(K) Sighted airplane to Northward flying EAST. 0850(K) Sighted airplane to Northward flying EAST. October 1- 0700(K) Sighted airplane to Northward flying EAST. October 1- 1412(K) Sighted smoke bearing 220dT. Smoke in sight for two hours. By plot we estimate it to have been a ship on Easterly course, speed 10 to 15 knots, Minimum distance to our track 18 miles. October 1- From what we have seen and heard it is believed that a great portion of the shipping from the Empire to TRUK is running close to NAMONUITO, with medium and large ships entering NORTH PASS. We cannot patrol pass between NAMONUITO and EAST FAYU so, having but a few days left, decided to patrol for ships making a landfall on ULUL. This lane is not in any assigned submarine area. It is believed that the spirit of our orders will permit the stretching of our Western patrol limit to Longitude 149dE., especially if events turn out to favor us with a target or to discover a main shipping lane. October 3- 1350(K) Sighted ULUL Island, NAMONUITO, Bearing 035dT., distance 9 miles. October 3- 1535(K) Sighted fishing boat bearing 122dT., on course 320dT., distance 6,000 yards. Boat passed 1,000 yards abeam and continued on to North West. While watching it sighted masts of a similar boat to Northward. We were at this time about 8 miles West of ULUL Island. First boat was in sight about an hour, the second was only seen once. October 4- 1920(K) Sighted lights of a small craft bearing 220dT., and lost them 20 minutes later on bearing 244dT. Estimate it to have been a fishing boat similar to one seen on October 3, on course NW., and passing about 4 miles South of our track. There were two white lights in a horizontal line about 50 feet apart, and periodically a red flashing light showed between and below the white lights. We were on the ships starboard beam, so it was not a side light. Believe it to be a station ship for incoming traffic. Remained in position, lying to awaiting return of small craft in company with suitable target. October 5- 0400(K) Received Comsubpac despatch assigning us to Southern Sector of area in addition to sector already assigned. Started South and East to head for new sector. October 5- 0654(K) Sighted aircraft carrier RYUJO accompanied by two AMAGIRI class destroyers bearing 220dT. angle on the bow 60d starboard, range 11,000 yards, speed 14 knots. One DD was leading and second was trailing carrier. Made approach which, upon final analysis, lacked aggressiveness and skill, and closed range to about 7,000 yards. Watched the best target we could ever hope to find go over the hill untouched at 0800. A normal approach course at time of sighting and full speed for the whole twenty minutes would have brought us in to 3000 yards and a fair shot. At 0915 we surfaced and went ahead at 19 knots on course NORTH, which was the targets last course, in an endeavor to trail. About 1030 we ran into general rain squalls and reduced visibility and at 1200 broke off the chase. At 1315(K) sent message to Comsubpac giving contact. Called on 16460 KCs for 5 minutes, received no answer, so broadcast message twice. Considerable interference from Japanese station. October 6- 0230(K) Having opened to SW to change R. D. E. Bearing from TRUK, and not receiving any indication on Submarine Radio schedule that our contact report was received, sent report again on 4235 and 8470. Called for 20 minutes, then transmitted message twice. There was considerable interference from the Japanese and no report was obtained. October 7- 1200(K) Departed Patrol area. October 8- 0120(K) Having made three tries at getting off our message without success, using all the high- priced help and mechanical aids, we felt pretty discouraged and had ordered the usual radio silence. The radioman on watch, on his own initiative, tuned in on 4235 KCs and listened. He states that suddenly reception on this circuit became exceptionally strong, so he grabbed the message, called Pearl, sent the message and got a receipt. He then reported his violation of orders. Held mast and gave him a reprimand for his offense, and advanced him one grade in rating for his loyalty, initiative, and ability to get results. October 7- 2050(K) Broadcast contact report twice on 4265 KCs without interference, then called Pearl and Midway for about 30 minutes. No answer. October 9- 1240(K) Sighted airplane. Submerged. Surfaced at 1600. October 10- 1700(K) Aircraft contact on Radar at 2 miles. Sky almost completely overcast. Submerged. October 12- 1220(L) With the sky overcast and squally, sea rough with lots of whitecaps, sighted a MITSUBISHI 97 two engine, Army heavy bomber close aboard and headed directly for us. His range was less than 1 mile, position angle 30d. We made a pretty fast dive. There was a long silence. The only reason we can attribute to the lack of attacks is that he was either unarmed or was as surprised as we were. There was no indication on our Radar. Counting the O.O.D. there were seven (7) lookouts on the bridge when the plane was sighted. October 15- 0945(X) sighted U.S.N. PBY at about 10 miles. He passed within about 3 miles without registering on the Radar. Perhaps the SD Radar is not functioning. October 16- 1500(WX) Sighted U.S.N. PBY and exchanged recognition. Radar inoperative. October 16- 1750(VW) Sighted U.S.N. PBY flying E. altitude 1600 feet. October 17- 0630(VW) Met escort at rendezvous and proceeded to Pearl. 2. WEATHER ENROUTE TO TRUK: Normal trade weather. Sea from NE or E, condition 1 to 3. Trade winds to ENIWETOK, then shifting Southerly. Sky generally overcast with occasional rain. ON STATION - TRUK: Glassy sea with no swells or white caps. Clear sky with some low clouds on horizon, especially during night. On the 8th the sea picked up a bit to condition 1, and visibility decreased. Very little breeze at night, humidity high. During the 9th the wind died down and the sea again became flat and glassy. Rainy and overcast on the night of 10-11 September, with sea condition 1, and NW breeze. During the day the wind shifted to Southerly and sea became good for periscope observations for the first time. By the 12th the Sea was condition 2, with white caps. Sky overcast and visibility spotty, but where clear of rain squalls horizon visible for 15-20 miles. Winds remained variable in strength and direction. During later part of September there was considerable rain, with shifting winds and seas, alternated with short periods of flat calm. Rain squalls covered large portions of the horizon, with visibility greatly reduced. This was no particular handicap until we tried to follow the RYUJO on the surface. We ran afoul of an area of reduced visibility that morning entered it at 1030, and remained in it until the chase was abandoned at 1200. During this period the visibility was variable between 100 and 3,000 yards. ENROUTE TO PEARL: The sky was almost completely overcast with much rain and reduced visibility the entire trip. From TRUK to TAONGI the sea was calm, with slight swells from S and SE. After passing TAONGI the sea shifted to E and became moderately rough, condition 3 to 5. Normal trade winds were encountered north of Latitude 15dN. 3. TIDAL INFORMATION. The normal set was in the direction of the prevailing wind, generally toward NW with drift from 0.4-0.7 knots. In the passage between NAMONUITO and HITCHFIELD-GRAY FEATHER Banks and inshore west of TRUK strong Easterly sets were encountered regardless of the wind and surface condition of the sea. 4. NAVIGATIONAL AIDS. TOL Island, TRUK was in sight a good portion of the time on station. Ordinarily the peak could be sighted from 35 to 40 miles, and was very valuable as an aid in checking position. ULUL Island, NAMONUITO, was sighted about 9 miles off and is an excellent landmark. No other Navigational Aids were noted. 5. ENEMY SHIPS SIGHTED: TIME & DATE : Position :Course:Speed: DESCRIPTION : REMARKS ---------------------------------------------------------------------- 0525(K) :15 Miles WNW : : :2400 ton tanker :Escorted by one 6 Sept. :of TRUK enr- : 145d : 10 :loaded, similar :airplane. Hit by :oute PIAANU : : :to that of plate:at least one and :PASS : : :577 except with :probably two : : : :only one stack. :torpedoes. : : : :One gun about 3": : : : :mounted at bow. : ---------------------------------------------------------------------- 1015(K) :12 Miles W : : :2500 ton freight:Escorted by one 14 Sept.:of PIAANU : 135d- : 10 :er similar to :airplane and a :PASS : 110d : :SENSEI MARU :surface patrol. : : : :listed on plate : : : : :163. : ---------------------------------------------------------------------- 2225(K) :Lat. 7-43N : : :6500 ton freight:Passed about 200 20 Sept.:Long. 150-36E: 135d : 12 :er similar to :yards abeam : : : :KEIYO MARU :during bright : : : :listed on plate :moonlight. Sunk. : : : :69. : ---------------------------------------------------------------------- 0010(K) :Lat. 7-43N : : :Single stack :Seen at about 21 Sept.:Long. 150-36E: - : 25 :ship of about :4,000 yards in : : : :700 tons oil :moonlight. This : : : :burning. :was the escort : : : :163. :of the above : : : : :listed ship. ---------------------------------------------------------------------- 2200(K) :Lat. 8-30N : : :Patrol boat : 24 Sept.:Long. 150-24E: 270d : 12 :similar to our : : : : :old 110 ft S/M : : : : :chasers. Very : : : : :long and low : : : : :with single : : : : :stack and bridge: : : : :structure slight: : : : :ly forward. : ---------------------------------------------------------------------- 0545(K) :Lat. 7-58N : : :Aircraft tender :Unscreened. 30 Sept.:Long. 151-02E: 170d- : 18 :CHIYODA. No :Headed for NORTH : : 075d : :planes on deck. :PASS, TRUK. Five : : : : :aircraft seen in : : : : :area during this : : : : :period. ---------------------------------------------------------------------- 1535(K) :8 miles west : : :Fishing boat of : 3 Oct. :of ULUL : 330d : 8 :about 150 tons. :No armament :Island : : :Rounded bow, :noted. :NAMONUITO : : :elevated fore- : : : : :castle, 2 masts : : : : :with fore about : : : : :50 ft. and main : : : : :about 30 ft.high: : : : :Two booms rigged: : : : :from amidships : : : : :at angle of : : : : :about 45d. : ---------------------------------------------------------------------- 0654(K) :Lat. 9-15N : : :Aircraft carrier:No aircraft on 5 OCT. :Long. 149-00E: 345d- : 14 :RYUJO and two :flight deck. All : : 000d : :AMAGIRI class :four masts up. : : : :destroyers. : ---------------------------------------------------------------------- 6. Description of all aircraft sighted, including type, position, course, altitude and time of sighting. TIME & DATE : POSITION : TYPE :COURSE: ALTITUDE : REMARKS ---------------------------------------------------------------------- 1500(VW):Lat. 20-50N : USN :080d :2000 feet : 23 Aug. :Long. 159-30W: PBY : : : ---------------------------------------------------------------------- 1510(VW):Lat. 20-35N : USN :080d :2000 feet : 23 Aug. :Long. 159-35W: PBY : : : ---------------------------------------------------------------------- 1830(M) :Lat. 14-30N : - : - : - :Radar contact 100 29 Aug. :Long. 170-05E: : : :miles east of TAONGI ---------------------------------------------------------------------- 0625(L) :Lat. 12-45N : Large :000d :3000 feet :Sighted at long range 31 Aug. :Long. 161-05E: plane : : :Position 60 miles : : : : :North of ENIWETOK. ---------------------------------------------------------------------- 0600(L) :Lat. 11-30N : - : - : - :Radar contact. 1 Sept.:Long. 158-00E: : : : ---------------------------------------------------------------------- 0525(K) :15 miles WNW : - : East:2000 feet :Sighted while making 6 Sept.:of TRUK. : : : :approach. Did not : : : : :observe closely. ---------------------------------------------------------------------- 0750(K) :40 miles WNW :Reconn-: NE :2000 feet : 8 Sept.:of TRUK. :ais- : : : : :sance : : : : :bomber : : : : :type 95: : : : :single : : : : :float : : : : :biplane: : : ---------------------------------------------------------------------- 1025(K) :12 miles W :Reconn-: East:1000 feet :Air screen for 14 Sept.:of PIAANU :ais- : : :freighter. :PASS, TRUK :sance : : : : :bomber : : : : :type 95: : : : :single : : : : :float : : : : :biplane: : : ---------------------------------------------------------------------- 0520(K) :45 miles WNW :Small, : West:4000 feet :Formation flight 30 Sept.:of TRUK. :fast : : :observed at long : :planes : : :range. ---------------------------------------------------------------------- 0745(K) :40 miles WNW :Single : East:2000 feet : --- 30 Sept.:of TRUK. :float : : : : :sea- : : : : :planes : : : : :(95) : : : ---------------------------------------------------------------------- 0850(K) :35 miles WNW :Single : East:4000 feet : --- 30 Sept.:of TRUK. :float : : : : :sea- : : : : :planes : : : : :(95) : : : ---------------------------------------------------------------------- 0700(K) :35 miles WNW :Small : East:2000 feet : --- 1 Oct. :of TRUK. :sea- : : : : :plane : : : ---------------------------------------------------------------------- 1240(K) :Lat. 12-35E :Unident: East:3000 feet :Sighted at long range 9 Oct. :Long. 158-50E:ified : : : ---------------------------------------------------------------------- 0700(L) :Lat. 14-00N : - : - : - :Radar contact at two 10 Oct. :Long. 162-30E: : : :miles. ---------------------------------------------------------------------- 1220(K) :Lat. 15-50N :Two :South:3000-4000 : --- 11 Oct. :Long. 171-34E:motored:west :feet. : : :bomber : : : : :similar: : : : :to MIT-: : : : :SUBISHI: : : : :97 Army: : : : :Heavy : : : : :bomber : : : ---------------------------------------------------------------------- 0945(X) :Lat. 19-20N : USN : East:2000 feet : --- 15 Oct. :Long. 168-00E: PBY : : : ---------------------------------------------------------------------- 1500(WX):Lat. 2035 N : USN : East:1200 feet : --- 16 Oct. :Long. 161-24E: PBY : : : ---------------------------------------------------------------------- 1750(VW):Lat. 20-35N : USN : East:1600 feet : --- 16 Oct. :Long.161-16.5: PBY : : : :E : ---------------------------------------------------------------------- 7. SUMMARY OF S/M ATTACKS. Listed on printed form herewith attacked [sic] as enclosure (A). 8. ENEMY A/S MEASURES. Radar contacts indicated an A/S air patrol in the vicinity of TRUK during twilight hours. This apparently covered a distance of but a few miles beyond the reef. There is apparently a periodical sweep of the area by an offshore A/S air patrol during daylight which is infrequent. Ships are escorted during daylight by aircraft and by a surface patrol. One incoming ship made a rendezvous 60 miles West of TRUK at midnight with an A/S patrol boat of about 700 tons. Surface patrols of small craft pass through or patrol the area at infrequent intervals. It is possible that those heard and seen were either meeting, or had completed escorting, surface vessels. The presence of an airplane in the area usually meant that surface vessels were in transit. No echo ranging was heard during any part of the patrol. We encountered only one patrol that actually stopped to listen. It was acting as an escort. We heard ships at ranges varying from 3,000 to 12,000 yards, but there was no indication that we were heard by sound. Only one depth charge attack was encountered, and on that the A/S vessel dropped charges at random with none inside our 1000 yard range. The area north of MARSHALL'S is patrolled by air. Indications are that planes encountered were from ENIWETOK and possibly TAONGI. 9. MAJOR DEFECTS EXPERIENCED. 1. Torpedo tube number 1. Tubes 1, 2, and 3 had been made ready for firing during the approach on September 14, but were not fired. After surfacing the torpedoes were examined in rotation. Two tubes in each end are habitually kept ready for firing except for opening the outer door and air master solenoid valve. Forward tubes 3 and 4 are the ready tubes. While 3 was being checked, number 1 was made ready as the standby tube. Number 3 was checked and preparations made to fire a 25-50 pound inboard slug. Instead of raising the firing interlock and firing number 3 by hand, this was inadvertently done on number 1 instead. There was quite a bang, and tube number 1 flooded. The torpedo officer was lowered over the side for external examination. He found the shutter intact, but the outer door sprung about 1 1/2 inches. This tube was pumped down and the inner door opened. The torpedo had traveled forward about 3 or 4 inches, and there was indications that the torpedo had started a hot run which was speedily terminated by the over speed trip. Several hours were spent in attempting to back the torpedo out of the tube, without results. When a 1 1/2 ton chain fall failed to budge the torpedo the attempts were abandoned. This piece of gross carelessness has cost the ships [sic] the use of this one tube, and probably the wreckage of one torpedo. The full extent of the damage cannot be determined until return to port. 2. Bow buoyancy operating linkage failed to function properly and the vents would not open. The manhole cover was removed. The cause of failure will be investigated and remedied on return to port. 3. HARDIE-TINE H.P. air compressor. Trouble continues with the discharge valve discs. A total of seven (7) first stage discs were broken during the patrol. 4. The ship's Hull Exhaust Ventilation system does not remove battery gases from forward battery when charging at the finishing rate and ventilating inboard. This condition can be corrected by installing dampers in the exhaust ducts in the pump room and galley. 5. SJ Radar caused considerable difficulty. The turning gear is of faulty design and becomes almost impossible to turn. The antenna tuning was thrown out of adjustment early in the patrol and without a willing target it is impossible to re-tune. Probably the major source of trouble came from improper operation by unskilled personnel, the whole unit will require checking and tuning. A small turning motor would be a distinct asset. 10. COMMUNICATION. Radio reception - Radio reception of the NPM Fox Schedules was very good and was complete. The 8 megacycles were used during almost exclusively on station. 12 megacycles were used during the day to and from station and occasionally during the early morning while on station. Low frequency reception depended on weather conditions. Low frequency was seriously interfered with by the SD Radar. High frequency suffered very little interference. Interference was encountered from enemy stations when transmitting on 4235 series. No interference was encountered on 4265. Last serial received OCHER 031911 of Oct. Last serial sent ANDROID 140930 of Oct. 11. SOUND CONDITIONS AND DENSITY LAYERS. In general, sound conditions varied from good to excellent. Propellers were picked up at ranges varying from 3000 to 12000 yards. At times there was a marked variation in sound intensity of a steady propeller beat, with sound fading in and out. It was being stopped and started. There were some sounds heard which were not caused by ships, these taking the form of grunts, groans, and clicking, but they were the exception and not the rule. They were heard in far less quantity than experienced in some other patrol areas. Temperature gradients were measured daily. The water temperature remained 85d F. to 150 ft., with a rare gradient, except that a layer of water of 86d F could be found of about 30 feet thickness at depth varying between 60 and 120 ft. Sometimes a change in density of the water could be felt through a change in the trim but not indicated by temperature change of the water. The fading of propeller noises is believed to have been caused by skip distances. Under conditions of zero temperature gradient, there results a bending up of the sound beam. This causes the beam to stay near the surface and bounce and re-bounce off the underside of the sea's surface. A sort of "skip distance" at a projecter [sic] depth of 68 feet could easily occur under such conditions. In general, it is felt that the sound conditions in the area to the Northwest of TRUK are favorable for submarine operations. Submarine listening conditions varied from good to excellent, while the positive velocity gradient (resulting from a zero temperature gradient) combined with the ever present density layer at a convenient depth would offer a fairly safe sanctuary against listening or echo- ranging by surface craft. 12. HEALTH AND HABITABILITY During the early part of the patrol colds were numerous. As soon as we became acclimated and took proper precautions these cleared. There were no serious illnesses. One man had a small Furuncle on his right buttocks which required lancing, and one Electricians's Mate suffered a second degree burn on his hand and was temporarily blinded by flash when he drew an arc in pulling a fuse from the auxiliary power board on a hot circuit. Habitability was good. The average submerged temperature was about 90dF., with humidity decreasing shortly after diving. The air conditioning units were operated at capacity and were just adequate. On several occasions one air conditioning unit had to be secured for repairs, and it was not very comfortable at this time. 13. Miles steamed enroute to and from station. Miles steamed enroute to station 3,109. Miles steamed enroute from station 3,075. 14. FUEL OIL EXPENDED. Fuel oil expended enroute station - 28,633. Average speed - - - - - - - - - - - 12.9 knots. Fuel rate - - - - - - - - - - - - - 9.22 gallons/mile. NOTE: Conditions were ideal. Clean bottom, smooth sea, wind and sea from astern, and set in direction of travel. Fuel oil expended returning from station 37,052 gals. Average speed - - - - - - - - - - - - - - 12 knots. Fuel rate - - - - - - - - - - - - - - - - 12.05 gals. per mile. Three fourths of the return trip was made against head winds and seas, with adverse set. Some three and four engine speeds were used. 15. FACTORS OF ENDURANCE REMAINING Torpedoes - - - - - - - - - - 17 (one probably wrecked) Fuel - - - - - - - - - - - - 16,295 Provisions - - - - - - - - - 30 days. Fresh water - - - - - - - - - 1000 gallons. This is no longer a factor of endurance unless the stills break down or become dirty. We could have ended the patrol with 10,000 gallons of water if we had desired. Personnel - - - - - - - - - - 10 days. 16. The patrol was ended by the time written in the operation order. 17. REMARKS. From departure for patrol on August 23rd until about September 30th this was a routine patrol, marred only by the unfortunate accident to No. 1 torpedo tube on September 14th. During this period we sunk one medium freighter and got one or two hits on a small tanker. The remainder of the patrol was a fiasco. On the 30th we sighted the CHIYODA. Actually it was not possible to get within torpedo range, but that was the bad luck of initial position and subsequent target movements, which is an excuse but not a suitable result. Then I decided to patrol West of NAMONUITO and to try to find out where ships were coming from. After sighting various small craft, suddenly on the 5th there came onto view the RYUJO heading for the Empire. Had I but required a more rigorous and alert watch we might have picked her up sooner. Had I correctly estimated the situation and made a more aggressive approach we could have gotten in a shot. Had I taken up the surface chase without allowing over an hour to elapse we might not have lost the target. Had I continued the search through the rain squalls until dark we might have picked her up again. None of these happened and the second target proceeded unharmed. The rest of the time allotted to the patrol was spent in changing position and attempting to transmit the information on the contacts to the Task Force Commander. In studying over both approaches I find that they each conform to my normal method of attack, and confronted with the same situations again the results would probably be identical. 18. The Loop antenna was not used on this patrol. On previous tests it has given excellent reception at depths to 58 feet, where fading begins. All our submerged patrolling was done at 62 feet or deeper, so there was no occasion to use this loop. FC5-10/A16-3(FB5-102) SUBMARINE SQUADRON TEN Serial 043 Care of Fleet Post Office, San Francisco, California, October 20, 1942. CONFIDENTIAL From: The Commander Submarine Squadron Ten. To : The Commander Submarine Force, Pacific Fleet. Subject: U.S.S. WAHOO (SS238) - First War Patrol - Comments on 1. The WAHOO's patrol covered a total of fifty-five days, of which thirty-four were spent on station. The last four days were spent patrolling to the westward of the assigned area. More time should have been spent in closer proximity to Piannu [sic] Pass. 2. In the attack on September 6, there is insufficient evidence to support a belief that a hit was obtained upon the tanker. the masthead height was probably underestimated. 3. On September 14, sea and weather conditions are not stated. Under certain conditions, when an aircraft screen is known to be present, the practice of going deep between periscope observations is sound. However, to resort to an approach wherein no periscope observation is made for thirty-two minutes invites failure. 4. The attack on the freighter which was sunk was conducted in such a way as to indicate that again ranges were in error. If ranges had been more accurate, a more favorable firing position would have been obtained. It appears that the firing mechanism of the first torpedo failed to arm due to the short run. The subsequent tactics used in evading the escort were well conducted. 5. To get in an attack on such a valuable target as an aircraft carrier calls for the greatest degree of aggressiveness. The fact that the RYUJO was not sighted until at a range of 11,000 yards bears out the Commanding Officer's statement that a more alert watch could have been kept. 6. It is regretted that so much difficulty was encountered in the operation of the SJ Radar. This has greatly handicapped the WAHOO since valuable training in the use of this equipment has been missed. During the current refit period, Radar personnel should receive special instruction in its use. A training motor will be installed if available. 7. The excellent material condition of the WAHOO upon return from patrol is commendable. The following damage is considered as done the enemy: SUNK 1 Freighter ............ 6,500 tons. CONFIDENTIAL From: The Commander Submarine Division ONE HUNDRED TWO. To : The Commander Submarine Force, Pacific Fleet. Subject: U.S.S. WAHOO (SS238); First War Patrol, Comments on 1. The WAHOO spent 34 days in or in vicinity of the assigned area. During this period five worthwhile torpedo targets were contacted. Two of the targets were extremely valuable vessels, the RYUJO and CHIYODA. Of the five, one 6500 ton freighter was sunk. More targets probably would have been sighted had Piaanu Pass been kept under closer observation then shown in the track chart. 2. Japanese tankers and other fast auxiliaries have been observed to be carrying depth charges which they apparently drop either to embarrass the attacking submarine or to countermine approaching torpedoes. This might have been the tactics employed by the small tanker attacked on the morning of September 6th and is offered as an explanation of the two delayed explosions which were heard one minute after torpedoes were estimated to have crossed the track. 3. It is very unfortunate that attack positions were not attained on either the CHIYODA nor RYUJO. In the case of the former, luck alone was the factor that saved her from certain destruction or severe damage. In the case of the latter, the situation upon sighting indicated that attack position, if attainable, could be gained only by the most aggressive kind of approach. It is regrettable that the need for such immediate action was not recognized. 4. S.J. Radar. It is regretted that so much difficulty was experienced with the S.J. Radar. Had the radar been kept in operation condition it might well have made the desired contact with RYUJO at noon on October 5th. No effect should be spared to keep this valuable instrument in perfect operating condition throughout a patrol. In regard to the tuning of the system it is suggested that the proximity of any high land in the patrol area at night will provide the "willing" target required for this purpose. The urgent need for trained radar maintenance men in submarines is again noted. 5. While the patrol was not outstanding in either results or aggressiveness it is certain that the resultant seasoning of the officers and crew has prepared them to most any situation on future patrols with resolution and effectiveness. 6. MATERIAL. WAHOO will be refitted by SPERRY assisted as necessary by the Navy Yard. It is assumed that steps have been taken to prevent a repetition of the gross carelessness which placed tube number 1 out of commission. Serial 01249 Care of Fleet Post Office, San Francisco, California, 1 November 1942 COMSUBPAC PATROL REPORT NO. 83 U.S.S. WAHOO - FIRST WAR PATROL CONFIDENTIAL From: The Commander Submarine Force, Pacific Fleet. To : Submarine Force, Pacific Fleet. Subject: U.S.S. WAHOO (SS238) - Report of First War Patrol. Enclosure: (A) CSS-10 Ltr.File FC-10/.16-3(043) of 26 Oct. 1942 (B) CSD-102 Ltr. FB5-102/A16-3(1) Serial 016 of October 20, 1942. (C) Subject Patrol Report. 1. The Commander Submarine Force, Pacific Fleet, agrees with the comments of Commander Submarine Division 102 and Commander Submarine Squadron TEN that more time on this patrol should have been spent in close proximity to PIAANU PASS. 2. A successful attack on the RYUJO would have had far reaching results and it is unfortunate that the WAHOO failed to press home an attack in this instance. Opportunities to attack an enemy carrier are few and must be exploited to the limit with due acceptance of the hazards involved. The Commanding Officer realized his mistake in the instance, as noted in paragraph 17 of the report. The lesson learned by this experience should impress on all Submarine Commanding Officers the necessity for continuous alertness, and quick, positive action immediately when a contact is made. 3. Firing of four single torpedoes in the attack on September 20th undoubtedly resulted in the needless expenditure of torpedoes over what would have been required to obtain the same results had a torpedo spread been used in the initial attack. 4. The WAHOO is credited with having inflicted the following damage on the enemy: SUNK 1 Freighter 6,441 tons R.H. ENGLISH. DISTRIBUTION (35CM-42) List III: SS Special P1(5), EN3(5), Z1(5), Comsublant (2) Comsubsowespac (2) ** signature ** E. R. SWINBURNE, Flag Secretary