It was a beautiful day for flying over the South Pacific in the month of July 1943. I was on my way to Guadalcanal under orders “as a volunteer” to inspect a beached Japanese two-man midget submarine. My job was to determine if it was safe to transport the sub back to the United States.
My boat, the USS S-31, had just returned from her 7th War Patrol–a reconnaisance mission of Aneityum Island in the New Hebrides group. We were refitting in Noumea, New Caledonia, prior to resuming our primary mission of training United States, Australian and British warships in anti-submarine warfare tactics.
Admiral Halsey, Commander Southwest Pacific, learned that a small Japanese submarine had been abandoned on a beach at Guadalcanal. He believed that it might be in a good enough state of preservation for salvage, and possible return to the u.s. He requested ComSubPac to furnish a submariner to make this determination. I was the only available submarine skipper in the area so Vice Admiral Lockwood “volunteered” me for the job. Hand-written TAD orders sent me on to Guadalcanal.
I had no idea what I was getting into. I was not an ordnance expert. In fact, I was rather naive regarding most aspects of ordnance except for routine operations involving torpedoes. The staff gave me sketchy information indicating that the submarine had been ashore for some time, that no one was on board, and that all hatches were still closed. I was also told that abandoned Japanese installations were frequently booby-trapped. This gave me something to think about. However, my enthusiasm for a new angle on submarining offset any undue alarm I might have felt for this mission.
We took off early in the morning from Noumea in a J2F and flew 800 miles to Guadalcanal arriving just before noon.
We made no aircraft contacts during the flight, but on reaching the big island, several Navy planes escorted us to the site of the beached submarine. Our “old flying Duck” landed in calm blue water and taxied to the beach where a large number of Army personnel and natives were gathered near the submarine. I jumped ashore and told the pilot that while I was inspecting the submarine he could refuel and return in an hour to pick me up.
The senior Army non-com in charge was a Master Sergeant who briefed me on the situation. He said that the sub had either been washed up on the beach or been driven ashore by its crew some time before he’d arrived in the area. And, that no one wanted to approach the sub since its two yellow torpedo warheads were exposed and were probably armed.
The submarine had grounded just above the water line. It was canted ten degrees to port, and there were no signs of damage. I was given a wooden ladder–a small tree trunk with hand-hewn crossbars–which I leaned against the hull alongside the conning tower. Then I advised all the observers to move about 200 yards off–just in case the sub blew up.
The small, two man mini-sub was about 80 feet long. It had a diameter of 8 feet, a small conning tower amidships, and displaced about 50 tons. Two vertical in-line muzzle loaded torpedoes with large warheads protruded from the bow. Control planes and rudder were located at the stern just forward of a five foot three-bladed propeller. The unpainted hull was in good condition except for a few rust spots here and there.
Having made these observations, I climbed the ladder to the top of the conning tower. By gently shifting my weight athwartships I was able to test the stability of the. sub. But she was well anchored in the sand. Then I turned my attention to the small hatch, which was, surprisingly, cracked open about half an inch. The air coming out of the sub didn’t smell too bad. I felt around the hatch-combing for wires which would indicate a trigger for an explosive device. But there were no wires. Then, I opened the hatch being very careful not to jar it when it reached the lock-open position. All went well. The air in the conning tower was musty, but breathable. The hatch into the sub was much smaller than our 30″ S-boat hatches–probably less than 20″ in diameter. After feeling around the internal edge of the hatch and down the first three rungs of the ladder for obstructions which would restrict my going below, I started down, wiggling back and forth in order to squeeze through the hatch. All the way down I looked for any gadgetry which might activate an anti-personnel device. At the bottom of the ladder, my flashlight disclosed no triggering devices, so I began to feel much better.
Looking forward from my badly cramped position, I realized that I couldn’t stand erect in any part of this small sub. My flashlight illuminated a narrow corridor leading forward to the two torpedo tubes. Crawling forward, I noted that on either side of the passageway there were food storage spaces of shelves and small mesh baskets–some of which still held canned goods. Several cable runs leading forward were connected to brown metal boxes at the tubes. The boxes evidently held the launching circuits for the tubes. At this time I wondered how the Japanese C.O. controlled his depth and attitude after he got rid of either of these monstrous torpedoes. I hadn’t seen any compressed air tanks for blowing water ballast to compensate for the discharged torpedoes. I felt certain that the battery powered electrical system had been dead for a long time. So the torpedoes even if armed weren’t about to be accidentally launched. I finally turned myself around in the cramped quarters and started back to the midships section. The deck over which I crawled was damp and slimy from the tropical humidity and rotting of food. I also noticed that a duct in the overhead contained vent holes for recirculation of air through the sub. That didn’t however reduce the foul odor stirred up by my passage through the compartment. When I returned to the conning tower hatch area where the controls and the periscope were located, I tried the driver’s seat where the CO handled the boat. It was comfortable for a five foot human, but I had to squeeze to get into the conning position. Facing forward my legs straddled the scope which looked like a German Kollmorgen periscope but on a smaller scale. Although I wanted to take a look, the periscope eye-pieces were too low to peer into, since the periscope was housed with no hoisting power. Several control devices and indicators were located around the base of the scope. These controls were so arranged that the CO could operate the scope, steer the boat, control the depth, change speed and determine the trim of the sub–all within arm’s reach of the CO’s seated position. I didn’t dare touch any of the controls for fear of activating fluids or power which could disturb the neutral position of moveable parts.
Through the hatch leading to the after compartment, I observed about 100 small storage batteries lined up on eiher side of the narrow passageway which led to a centerline motor. It seemed similar to a 600 SHP induction type direct drive DC motor which uses a resistance type speed control. This compartment contained vented air ducts for air circulation plus lots of the cabling–necessary for propulsion, lighting and equipment operation. To satisfy my curiosity, I used the old submarine electrician’s trick for testing DC grounds. Wetting my index and middle finger with saliva, I passed them lightly over the plus and minus battery connections, then over the main motor leads, an~ finally over the cable connectors leading forward. There was no shock or tingling in my fingers, indicating that the electrical power in this mini-sub was totally exhausted. After this test, I felt much safer. Retracing my way forward, I made a note to include in my report to ComSoWesPac that this Japanese mini-sub could be safely cleaned up but with some effort, and could be used as a display after the warheads were disarmed and the torpedoes removed.
My one last look at the Commanding Officer’s battle station, where all controls fitted together so neatly, was an envious one–for the efficiency with which he could operate his boat while his subordinate did all the checking, testing and upkeep of the sub’s equipment. However, I wouldn’t have enjoyed being cooped up in such a small space during a short patrol. When I finally climbed the conning tower ladder, closed the hatch and left the boat, it was only a little over an hour after I had gone aboard.
My “flying Duck” pilot was ready. I told the Army Sergeant that since the warheads were still probably armed, no one was to board the sub until I had arranged for an Explosive Ordnance Detachment to disarm the torpedoes. I also told him to put “restricted” signs around the area–which he passed on to the natives hanging around the sub. Dangerous mission completed!
On an uneventful flight back to Noumea, I observed a gorgeous sunset over the South Pacific, and resolved that never again would I be conned into such a risky situation over which I had so little control. A War Patrol was much preferred!
(Ed. Note: This mini-sub may be the one which is on display in front of the Submarine School at Groton, CT. It is expected that this Japanese two-man submarine will be moved to the Museum-Library area just inboard of the Nautilus when the Submarine Museum is inaugurated.)