On 25 May, Topp took "U-552" on its third war patrol. The next day, "U-552" returned to Saint-Nazaire before heading for North Channel on 3 June. The BdU assumed that Topp sank three ships of and he was awarded the Knight's Cross of the Iron Cross () on 20 June 1941. This patrol ended on 2 July in Saint-Nazaire. Later analysis revealed that the true tonnage sunk accumulated to . One of the ships was the "Norfolk". The vessel carried mail an steel plates among 4,000 tons of general cargo. Captain Frederick Lougheed and 69 men were saved; one man was lost.