If you have toured Battleship Texas and seen this odd looking thing on the side of a turret and wondered what it was?
It's a paravane, an underwater glider fitted with a warhead and it was used to cut the lines to sea mines. It attached to a tow cable, that strung through a skeg on the underside of the bow.
It would lowered down into the water when the ship was underway.
The wings, or "planes", will pull the paravane away from the ship.
"If the tow cable snags the cable anchoring a mine then the anchoring cable is cut by jaws on the paravane, allowing the mine to float to the surface, where it is destroyed by gunfire."
"If the anchor cable fails to part, the mine and the paravane are brought together and the mine explodes against the paravane. The cable can then be retrieved and a replacement paravane fitted."
In WWII, it was modified and used against submarines as well. Destroyers and minesweepers would deploy off the stern, while larger ships would still deploy the from the bow.
U.S. Naval History and Heritage Command: 80-G-K-1716, 80-G-K-1714, 80-G-K-1713, NH 124020, NH 60758