From summer 1943, a total of 91 submarines of the VII C / 41 type were put into service. By then, the operating conditions had changed completely. The pack tactics rarely led to the successful detection of ship convoys and special U-fighter planes now patrolled extensively. In order to be able to defend themselves better against air raids when exposed, the Type VII C / 41 submarines were given a tower structure that was expanded to form a large flak deck. Thanks to the better structural steel, the boats could now dive up to 250 m.