At dusk that evening, and in atrocious weather conditions, Swordfish from Ark Royal launched an attack. The first wave mistakenly targeted Sheffield which had been detached from Force H under orders to close and shadow Bismarck. Although precious time was lost by this incident, it proved beneficial to the British in that the magnetic detonators on the torpedoes used against Sheffield were seen to be defective and for the following attack on Bismarck were replaced by those designed to explode on contact.