Tinosa reveals more torpedo problems



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The U. S. submarine Tinosa had successful war patrols when in July of 1943 she added to the detective work on the frustrating failures of our torpedoes.

She patrolled under the command of Dan Daspit between Palau and Truk to intercept the tankers essential to fueling the Japanese ships. The code breakers vectored him to a large tanker, the Nippon Maru, that Daspit found and fired four torpedoes that should have hit, but all missed. A destroyer appeared that prevented a follow up attack. Because of the torpedo failures, he ordered each torpedo to be checked thoroughly.

The code breakers vectored Daspit to another large tanker, the Tonan Maru. He ran ahead to gain optimum attack position and fired four torpedoes. He saw two splashes of water that may have been explosions, but the target was not slowed. As it turned away, Daspit fired two more torpedoes that hit near the stern and stopped the ship that slowly settled by the stern.

Daspit studied the ship, moved to line Tinosa up for the “perfect” shot at ninety degrees. Their crew were firing guns at his periscope. Daspit fired a torpedo at 1009 that he saw hit the target with a splash, and the sound man heard the hit, but no explosion. Daspit methodically and slowly fired eight more torpedoes, moving around to the other side for some. All were ninety degree shots. For each he saw the small splash and the sound man heard it thud against the target. One torpedo even glanced off the target, flying through the air. Daspit kept his last torpedo to be analyzed by the Pearl Harbor torpedo shop.

Normally a calm man, Daspit was in a rage when he saw Admiral Lockwood. He later wrote, “I think Dan was so furious as to be practically speechless. His tale was almost unbelievable, but the evidence was undeniable.” It was the more critical because after Trigger’s experience off Tokyo Bay the magnetic exploder was gone, and now the contact exploder obviously failed.

Swede Momsen, who was on Lockwood’s staff, suggested a submarine fire torpedoes into the vertical cliffs of the small island of Kahoolawe until one failed to explode, retrieve it, and examine it to see what happened.

The unexploded torpedo, with 685 pounds of TNT was hauled onto deck and delicately examined. The tracks designed to carry the firing pin into the exploder were so bent that the firing pin never reached the exploder. An ordinance expert named E. A. Johnson with Lockwood and Momsen had a cherry picker drop torpedoes onto a steel plate so they hit with the same force as running through sea water. A ninety degree hit failed most times, while in 45 degree angled shots the firing pin worked half the times.

Admiral Lockwood radioed all submarines at sea to avoid ninety degree shots and seek angled shots. Meanwhile the men in the torpedo shop designed and fabricated a new system of rails and firing pin that worked every time they were dropped onto the steel plate. Submarines leaving on patrol finally had a torpedo that worked.

It took our Navy twenty months to correct three problems, each of which hid the others, while the Germans and British quickly eliminated their torpedo problems, and Japanese ones had worked very effectively from the beginning.