In the anti-submarine role, the Swordfish pioneered the naval use of air to surface vessel (ASV) radar; the aircraft holds the distinction of being the first such implementation upon carrier-borne aircraft, allowing the Swordfish to effectively locate surface ships at night and through clouds. As early as October 1941, the Swordfish was flying operational missions using the ASV radar. On 21 December 1941, a Swordfish based in Gibraltar located and sank a U-boat, the first such kill to be achieved by an aircraft during nighttime. On 23 May 1943, a rocket-equipped Swordfish destroyed German submarine U-752 off the coast of Ireland, the first kill achieved with this weapon.