 U @-@ 36 was at sea when the war broke out , having set out from Wilhelmshaven on 31 August 1939 . She arrived in Kiel on 6 September and the following day departed for her first war patrol . She then patrolled the North Sea for three weeks , hoping to catch ships traveling between Britain and Scandinavia carrying war supplies . During this patrol , the boat sank two steamers , Truro and Silesia — one British and the other from neutral Sweden — carrying British produce . 
