During his career, he gained notoriety among fellow U-boat commanders for exaggerating the tonnage of ships sunk.

After 5 patrols in U-100 she was heavily damaged on 17 March 1941 by depth charges from HMS Walker and Vanoc while attacking Convoy HX 112.

U-100 was forced to surface and was detected on radar and rammed by Vanoc.

Schepke claimed to have sunk 37 ships, for a total of 213,310 gross register tons (GRT) and damaged 4 more.

Nonetheless, at one point Schepke ranked first in the number of ships sunk, and was recommended by Admiral Dönitz for the Knight's Cross with Oak Leaves.