'FK' was the British deployment of the battleship Malaya, escorted by the destroyers Impulsive, Saumarez and Scorpion from Scapa Flow in the Orkney islands group to Lock Cairnbawn (Port HHZ) on the north-western coast of Scotland within the programme to develop X-craft midget submarines and train their crews for attacks on major German warships (25 July/August 1943).