First war patrol 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, and —one British and the other from neutral Sweden—carrying British produce. , a British submarine, later fired on
U-36 and subsequently claimed to have sunk her, although in fact the torpedo missed. On 27 September Fröhlich and his crew captured another Swedish vessel, , which he proceeded to escort back to Germany as the patrol came to an end.
Second war patrol On 17 November 1939,
Naval High Command (SKL) issued orders for
U-36 and to scout the location for
Basis Nord, a secret German naval base for raids on Allied shipping located off the
Kola Peninsula and provided by the
Soviet Union. The mission required coded messages to be flashed to Soviet naval vessels patrolling the area preceding a Soviet escort to the prospective base location. However,
U-36 never left the
Norwegian Sea. During the same patrol, the
Salmon also torpedoed the light cruisers and . Following the loss of
U-36,
U-38 continued towards the Kola Peninsula, successfully reaching the location and accomplished the scouting mission for
Basis Nord. ==Summary of raiding history==