OVERVIEW: The Limpet Mine is a manually attached underwater explosive device designed for sabotage operations against ship hulls and underwater infrastructure. It is typically emplaced by combat divers or swimmers and uses timed or remote detonation.

DETAILS: Limpet mines are compact, magnetically-adhering charges placed directly onto the metallic hulls of vessels or structures. Developed and widely used since World War II, these mines are configured for clandestine delivery by naval special forces, including combat swimmers and diver delivery vehicles. Most models include a timing mechanism, acoustic trigger, or command detonation feature, and are shaped to optimize explosive force against steel plating below the waterline. The casing is hydrodynamically designed for ease of diver transport, and the explosive filler varies by mission requirement. Their effectiveness lies in stealth deployment and precise placement for hull breach or mobility kill.

FUNCTION: Carried by combat swimmers or SDVs, the mine is magnetically attached to a ship’s underwater hull or pier foundation. After placement, a time-delay or remote trigger detonates the charge, damaging or sinking the vessel or disabling port infrastructure.

NOTE:
IOC: 1940 (initial British SOE/UDT operational use), multiple modern variants still in service
Operators: United States, United Kingdom, Russia, China, Israel, North Korea, others
Platforms: Combat swimmers, SDVs (Swimmer Delivery Vehicles), midget submarines, unmanned underwater vehicles (UUVs)
Conflict used in: World War II (1942–1945), Vietnam War, Iran–Iraq War (1980s), Persian Gulf (1987), covert operations (various)

SOURCE: U.S. Navy Naval Special Warfare Ordnance Handbook ; Jane’s Underwater Warfare Systems ; British SOE Archives ; U.S. Naval Institute Proceedings ; https://www.navy.mil ; https://www.janes.com