Submarines:A long-ranged submersible, the Type IX was the most successful U-boat of the war, with each vessel averaging over 100,000 tons of shipping sunk. One Type IX, U-107, made the most successful convoy mission of the war, with nearly 100,000 tons of shipping sunk out of Freetown in Africa. The latest variants of this design were capable of ranges of more than 23,000 miles, allowing them to rove far in search of convoys, while their heavy load of torpedoes allowed them to keep pace with a convoy, attacking night after night.
MTBs:The R1-class of R-Boat (from the German Räumboot, meaning minesweeper) was intended to be used as a shallow water minesweeper but, as the war went on, it became a multi-role craft. Its duties expanded to include patrol, antisubmarine, convoy escort, minelaying, and rescue operations. Some classes of R-Boat, such as the R310, were fitted with torpedo tubes, though performance was very modest compared to craft specifically designed for the role.
The ultimate S-Boat to be operational in significant numbers was the S-100-class, which was produced from 1943 and was said to be the best fast patrol boat of its time. The S-100-class was nicknamed the Calotte, as it featured a rounded armoured bridge. It was powered by three Daimler-Benz engines giving it an overall capacity of around 7,500 hp and developing an outstanding top speed of 48 knots.