'Probestück' was a German naval minelaying operation in the North Sea off Harwich and Orfordness, on the east coast of England (24/25 September 1943).

The operation was undertaken by 29 S-boote of Korvettenkapitän Klaus Feldt’s 2^nd Schnellboots-Flottille, Korvettenkapitän Werner Lützow’s 4^th Schnellboots-Flottille, Korvettenkapitän Albrecht Obermaier’s 6^th Schnellboots-Flottille and Kapitänleutnant Felix Zymalkowski’s 8^th Schnellboots-Flottille, which laid 120 LMB mines off Harwich and Orfordness, and in a surface action S-96 sank the trawler Franctireur but was herself rammed by ML-145 and had to be abandoned. Three British motor launches suffered damage of various degrees.