Italian circling torpedoes and mechanical guidance

How did the Italian circling torpedo work?

It used a mechanical steering arrangement that could be set for a port or starboard circle, rather than a sophisticated directional seeker.

The Italian circling torpedo used internal navigation and mechanically programmed steering. An arm, eccentric projection and cogwheel could set a port or starboard turning direction. The weapon then continued its circular run according to that preset arrangement. The explanation concerns a mechanical search pattern, without a modern directional seeker.