On 5 September, he sank the British SS Bosnia of 2,407 gross register tons (GRT), the second ship of the war to be sunk by a U-boat. His boat sank two British vessels, Rio Claro of 4,086 GRT on the 6th, and Gartavon of 1,777 GRT on the 7th. U-47 returned to Kiel on 15 September having sunk a total tonnage of 8,270 GRT.