To reduce the threat posed by the Italian fleet, which was based in the port of Taranto, to convoys sailing to Malta, Admiral Cunningham organised an attack code-named Operation Judgement. Fairey Swordfish torpedo bombers from attacked the Italian fleet on 11 November 1940 while it was still at anchor. This was the first time that an attack such as this had been attempted and it was studied by Japanese naval officers in preparation for the later attack on Pearl Harbor. British Fleet Air Arm aircraft badly damaged two Italian battleships and a third was sunk putting half of the "Regia Marina"s major ships out of action for several months. This attack also forced the Italian fleet to move to Italian ports further north so as to be out of range of carrier-based aircraft. This reduced the threat of Italian sallies attacking Malta-bound convoys.