The Type VII U-boats were German submarines whose construction was initiated in 1936. The length of the Type VII units, depending on the sub-type, ranged from 64.5 m to 77.6 m, width from 5.85 m to 7.3 m, and the underwater displacement - from 725 tons to 1181 tons. The maximum surface speed of the Type VII U-boats was approximately 17 knots, and the maximum underwater speed was approximately 8 knots. The main armament was 5 533 mm torpedo tubes with a total of 11-16 torpedoes carried on board the ship. The secondary armament consists of 1 88mm cannon, 1 20mm anti-aircraft cannon or 1 37mm cannon, and 2 duplicate 20mm cannons on the VII D and VII F.