Insufficient testing caused early-war torpedo failures

Why did so many torpedo designs malfunction early in the Second World War?

Navies did too little realistic testing across too few environmental conditions, allowing defects to survive into combat.

Inadequate testing caused many early-war torpedo malfunctions. Navies provided too little money, fired too few weapons, and tested across too narrow a range of realistic conditions. British torpedoes still had faults, but an imperial navy could conduct trials in several oceans and magnetic regions. That geographic variation made it more likely that influence-fuze and other environmental defects would appear before combat than they would at one familiar local range.