Acoustic mine

The mine may freely drift, be moored at a certain location and depth, or lie at the bottom of the ocean floor.

[2] In naval warfare, an acoustic mine is defined as one being equipped with a hydrophone that functions as a listening device.

This initiates the closing of a switch causing an electrical circuit to flow and the mine to detonate.

Experiments were conducted with jackhammers, sirens, handgrenades, and bundles of loose metal pipes.

This was initially set up to hammer against a bulkhead of a minesweeper but this resulted in the mine exploding dangerously close to the vessel.