Original British WWII Inert Clam Mk. III Magnetic Limpet Mine Original Items

Original Item. Only One Available. During World War II, the British developed several models of “limpet” mines, which used magnets to attach to its target. These were primarily underwater mines used on ships & submarines, but some smaller land-based mines were produced. This is an example of a Mk. III “Clam” mine, This is the first example we have ever offered! Like all deactivated ordnance, this mine is Not Available for Export.

The mine measures roughly 5¾” x 2¾” x 1½”, and was easily concealable, could be carried in a pocket, and were non-descript enough not to draw attention An estimated 68,000 clams were produced during the war, with most being used, making this a very scarce example!

Several variations of a small “magnet charge” evolved into ‘the Clam’, which was a smaller version of the magnetic Limpet mine. The Clam evolved through a number of marks with the MkI having a stamped sheet metal casing and the later MkIII using a bakelite, plastic casing.  Both were made up of a plastic explosive charge inside a rectangular, rounded case with a pair of magnets at either end. They were detonated by either a Time Pencil or an L Delay fuse attached to a No.27 detonator. The MkIII had 8oz (226g) of high explosive filler, such as TNT/Tetryl 55/45.

These originally would have a “pencil” style fuze which this example is missing. There are markings on the bottom of the mine, E7HI, and on one side of the mine, MПM 3-6 121 TГ-69.

This is a very nice example of a scarce mine, the first we have offered! Ready for further research and display.