The second patrol on "U-552" began on 7 April 1941 from Saint-Nazaire and targeted the shipping routes in the North Atlantic, south of Iceland. On this patrol, the BdU credited Topp with the sinking of three ships and one escort totaling . The patrol ended on 6 May, again in Saint-Nazaire. In reality, Topp sank three ships totaling , and damaged one ship of which was then sunk by (Adalbert Schnee). The third ship sunk during Topp's second patrol in command of U-552, was the troopship S.S. Nerissa (5,583 GRT, 207 casualties and 84 survivors) on 30 April 1941 about 140 nautical miles west of the North Channel. This sinking resulted in the third largest loss of life for a ship sunk by U-boats in the approaches to the British Isles during the Second World War.