On 1 September 1939, with six minesweepers, "Gryf" left the naval base at Gdynia for the Operation Rurka, a failed attempt to lay a minefield at the entrances to the Gdańsk Bay. After taking aboard naval mines from a floating depot, the flotilla headed for Hel Peninsula, assisted by ORP "Wicher" and two gunboats. En route she was attacked by a squadron of 33 German Ju 87B dive bombers and damaged with several close misses. Although the damages were minor, the ship lost 22 sailors, including its captain Lt Cmdr Stefan Kwiatkowski in what became known as the Battle of the Gdańsk Bay. His deputy, Capt. Wiktor Łomidze decided to throw all defused naval mines in the waters for fear of explosion and headed for Hel naval base. There it was decided to use the ship as a floating anti-air artillery battery guarding the harbour.