Torpedo Data Computer
More info
- Creator
- Arma Corporation, for the US Navy
- Released
- 1938
- Type
- Electromechanical analog fire-control computer
An electromechanical calculator in the submarine's conning tower that solved the firing problem continuously — and proved far more reliable than the torpedoes it aimed.
The Mark 1 was delivered in 1938 and the Mark 3 became standard across the US submarine fleet in the Second World War. The machine had two halves working together. A position keeper continuously updated the target's assumed position from its estimated course and speed, so the solution stayed current as time passed. An angle solver converted that constantly moving picture into the gyro angle the torpedo needed. Six hundred kilograms of cams, gears, differentials and servo motors.
The point was that the angle was fed electrically into the torpedo while it still sat in the tube. The boat therefore did not have to turn towards the target in order to shoot, a decisive advantage: no other navy fielded a fully integrated solution of that kind during the war.
The irony is that the weak link was at the far end. The Mark 14 torpedo ran about three metres too deep and carried a magnetic exploder that fired early or not at all. For two years the Bureau of Ordnance blamed the crews' marksmanship — on firing solutions the machine had been getting right all along.