These midget submarines had as dimensions 24,900 (over all) x 1,880 metres and a diameter of 1,880 metres and a displacement of 49,783 tons while submerged. Their surfaced speed was 5,5-6,5 knots and while submerged 18,5 knots. They were fitted out with 2-45cm torpedo tubes and their crew numbered 3 men.
