[Llarry]

The U.S. Navy had a major problem during the first two years of World War II with torpedoes. The Navy had developed three new torpedoes during the 1930s and had ramped up production quickly in the late 1930s and during the war. But the torpedoes had flaws. Since the nation was at war, the flaws were kept from the public, but the users -- the crews of torpedo bombers, PT boats, submarines and destroyers -- were aware of the flaws. The torpedoes often did not work properly. Inadequate pre-war testing was part of the problem, but even more scandalous was the reluctance and/or inability of the ordnance specialists to recognize and correct the deficiencies. Until well into 1943, there were numerous instances of torpedoes that ran straight towards an enemy ship, only to pass under without exploding or even bounce off the side of the enemy ship without exploding.

The torpedoes had two types of fuses. One was the straightforward contact fuse that would set off the warhead upon impact. The other was a magnetic fuse that would sense the magnetic field of the steel enemy ship and explode the warhead under the ship's keel, thereby breaking the back of the enemy ship. In addition, U.S. torpedoes had poor depth control and often would pass under the enemy without detonating. Needless to say, this was extremely frustrating to the U.S. crews who braved enemy fire only to have their primary weapon malfunction.

Well into the war, the Pacific Fleet took matters into their own hands and conducted a series of tests at the operator level. They fired torpedoes into a net and found that the "fish" ran far deeper than the set depth. They also found that the contact fuse was not robust enough and would deform upon striking the target and thereby malfunction. The magnetic sensing fuse worked, but not if the torpedo was too deep to sense the ship's magnetic field.

Compounding these problems was cost. Torpedoes cost about $10,000 each (well over $200,000 today) and both before and during the war, leadership would not approve expensive testing at $10K per test. Of course all the duds that were fired at enemy ships and did not explode cost $10,000 per shot as well, so one could say that the torpedoes were being constantly tested -- albeit not under instrumented conditions -- and were failing those tests.

The bureaucracy took some time to respond to the Pacific Fleet's findings, but by late 1943 the depth control problem had been fixed and the contact exploder beefed-up. Fired torpedoes started sinking Japanese ships, and the three types of torpedoes (Marks 13, 14 and 15) ended up as deadly weapons and remained in service for years. The sub-launched Mark 14 stayed aboard U.S. submarines until about 1980.