 "U-966" was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes or 26 TMA mines, one SK C/35 naval gun, 220 rounds, and one twin C/30 anti-aircraft gun.The boat had a complement of 44 to 52 men.On 10 November 1943, "U-966" was attacked by an RAF Wellington of 612 Squadron/B and then US Navy B-24 Liberators of squadrons VB-103 and VB-110.