Tonan Maru had become a "sitting duck", "... Hit. No apparent effect. This torpedo hit well aft on the port side, made splash at the side of the ship and was then observed to have taken a right turn and to jump clear of the water about from the stern of the tanker. I find it hard to convince myself that I saw this." He took his sub to the other side of the target and fired the eighth and ninth torpedoes even as he saw a destroyer approaching from the east. As Tinosa went deep they heard the last torpedo hit and stop running. Daspit recorded in his log, "No explosion. Had already decided to retain one torpedo for examination by base." After shooting nine torpedoes at a sitting duck over almost an hour and a half 1009 to 1131, and taking time out to examine the fish in the torpedo room between shots, Lieutenant Commander Daspit took Tinosa back to Pearl Harbor with the single remaining weapon. Daspit stormed into SUBPAC's office. He had shot 15 torpedoes at Tonan Maru over two days and only 2 of them had worked. The others shot under ideal conditions failed to explode. Rear Admiral Lockwood, COMSUBPAC wrote: "I expected a torrent of cusswords, damning me, the Bureau of Ordnance, the Newport Torpedo Station and the Base Torpedo Shop, and I couldn’t have blamed him – 19,000 ton tankers don’t grow on trees. I think Dan was so furious as to be practically speechless. His tale was almost unbelievable, but the evidence was undeniable." When, upon inspection, nothing obvious was found wrong with that last torpedo, Commander Swede Momsen suggested conducting tests on actual warshots by firing them against the cliffs of Kahoolawe, a small island south of Maui from the submarine USS Muskallunge. The first two exploded. The third one did not. Within a few days the cause was traced to a firing pin that was mounted athwart-ships such that when the torpedo hit a target dead-on (ninety degree track angle) the deceleration forces slowed the pin's motion in its bearings and its spring could not move it fast enough to set off the explosive train. A glancing blow, however, would result in the proper behavior (which is why Daspit's first two torpedoes, fired at less optimum track angle, did explode). Two solutions were worked on. One involved recycling a very