Thetis (decoy)

Thetis was the name of a floating radar decoy used by German U-boats during the Second World War.

The device was stored dismantled in the bow compartment as a pole about two metres long.

Later versions could be launched from a standard torpedo tube (FuMT 4 - Thetis US).

The upper half had a series of reflectors that were tuned to Allied anti-submarine radar wavelengths to give the same return signal as a U-boat.

"Thetis" was introduced in January, when large numbers were released into the Bay of Biscay in July to simulate U-boat patrols during the Battle of Normandy.