Soviet submarine K-21

On 5 July 1942, K-21 was in the vicinity of the Island of Ingay when she spotted the German battleship Tirpitz which was en route to intercept Convoy PQ 17 which was traveling from Iceland to Murmansk. However this mission was unsuccessful as the Tirpitz turned away. The convoy itself scattered upon hearing words of Tirpitz's imminent arrival, and most of the convoy's merchant ships were picked off by U-boats and the Luftwaffe.[1]

On 27 June 1942, the K-21 received an order to take up a combat position to cover Convoy PQ-17. Later, the submarine received a radiogram telling that a German squadron consisting of the battleship Tirpitz, the heavy cruiser Admiral Scheer, and several destroyers were moving to intercept the PQ-17 convoy. K-21 began to search for the enemy squadron. On 5 July, at 4:33 pm, noise of approaching propellers was heard. The squadron was maneuvering in a zigzag pattern. The first ships to be seen were destroyers of the 1936 class, and they covered Tirpitz and the cruiser Admiral Scheer from possible attacks from submarines. The commander of K-21 decided to attack. K-21 bypassed the destroyers' protective barrier and went inside the squadron. Having approached to a distance of almost 13,000 feet the submarine fired a four torpedo spread from stern torpedo tubes towards the Tirpitz. Acoustics and crew members in the compartments of the submarine heard two explosions however, after the war, historians in German documents did not find evidence of torpedoes making contact with the battleship; the Germans did not even take notice of the attack. Historian M.E. Morozov put forward a hypothesis about the impossibility of torpedoes hitting the battleship, and he explained the origin of the explosions saying that the torpedoes detonated early. There are no references to Lunin's attack in the Tirpitz documents of the event. K-21 sank four small Norwegian motor boats via gunfire on 12 February 1943 at Lopphavet. On 22 April 1943, the German merchant ship Duna was sunk by a mine laid by K-21 on 18 February 1943. In May 1945, the boat was repaired.[4]