Mk 52 bottom mine

The Mk 52 was an older modified aircraft bomb that was deployed in an aircraft-laid bottom mine configuration by the U.S. Navy.

It was once rated as sensitive enough to detect a submarine moving at 3 knots. Arming delays ran from one hour to 90 days and the mine could count up to 30 ships before detonating.

It could also turn itself off between ship passages and self-sterilize at the end of its useful life. Several mods varied principally in their firing mechanism.

The Mk 52 was the...