 In 1939, the "Kriegsmarine" lacked the strength to challenge the combined British Royal Navy and French Navy ("Marine Nationale") for command of the sea.Instead, German naval strategy relied on commerce raiding using capital ships, armed merchant cruisers, submarines and aircraft.Many German warships were already at sea when war was declared, including most of the available U-boats and the "pocket battleships" ("Panzerschiffe") and which had sortied into the Atlantic in August.