Torpedo Depth and Roll Recorder
Canadian firms manufactured equipment for the Royal Canadian Navy, including this torpedo depth and roll recorder made by the Bata Shoe Company.
Fitted into a practice warhead that contained no explosives, the depth and roll recorder measured torpedo performance during testing and training. It recorded the depth at which a torpedo travelled after launching, and whether the torpedo rolled from side to side. If the torpedo ran too deep, or if it rolled from one side to another, it would be less likely to hit its target, or could miss it altogether.