In February 1940, U-33, then captained by Hans-Wilhelm von Dresky, had been ordered to lay mines in the Firth of Clyde, in Scotland. However, the minesweeper HMS Gleaner, captained by Lieutenant-Commander Hugh Price, detected the U-boat on the 12th and dropped depth charges over a period of several hours. Eventually, the damaged U-33 was forced to surface and the crew abandoned the boat, which sank soon afterward. 25 men died while 17 survived. Before the boat was abandoned, the U-boat’s secret Enigma rotors were distributed amongst a few of the crew, who were instructed to release them into the sea to avoid capture. This was not done, however, and as a result the British captured three rotors, including two (VI and VII), that were only used by Kriegsmarine and for which the wiring was previously unknown.