Shepard commits large forces stripped from convoy escort and uses Catalina flying boats to search for the German battleship. His hunch proves correct, and "Bismarck" is located, apparently steaming towards the French coast. British forces have a narrow window to destroy or slow their prey before German support and their own diminishing fuel supplies preclude further attacks. Swordfish torpedo planes from HMS "Ark Royal" have two chances. The first fails. The pilots misidentify as "Bismarck", and their new magnetic torpedo detonators are faulty, with most exploding as soon as they hit the sea. Returning to the carrier and changing to conventional contact exploders, the second attack is successful. One torpedo hits "Bismarck" amidships causing minor damage; but a catastrophic second hit detonates near the stern, jamming the German battleship's rudder and drastically slowing her down.