German submarine U-645

German submarine U-645 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 1 December 1941 by Blohm & Voss, Hamburg as yard number 621, launched on 3 September 1942 and commissioned on 22 October 1942 under Leutnant zur See Otto Ferro.

Service history
This boat's career began with training at 5th U-boat Flotilla on 22 October 1942, followed by active service on 1 May 1943 as part of the 3rd Flotilla for the remainder of her service.

In three patrols she sank two merchant ships, for a total of.

Wolfpacks
U-645 took part in eight wolfpacks, namely
 * Without name (5–10 May 1943)
 * Isar (10–15 May 1943)
 * Donau 1 (15–26 May 1943)
 * Leuthen (15–24 September 1943)
 * Rossbach (24 September – 9 October 1943)
 * Coronel 2 (13–14 December 1943)
 * Coronel 3 (14–17 December 1943)
 * Borkum (18–24 December 1943)

Fate
U-645 was sunk on 24 December 1943 in the North Atlantic in position 45.33333°N, -21.66667°W, by depth charges from USS Schenck (DD-159). All hands were lost.