One design, however, I want to upload here, my AU Schnellboot
which itself was an "evolution" of the S-100 class the world knew.
These boats differed from the S-100 mainly in the shape of the hull (a more V-shaped stepped hull than S-100), its length (more 6,2 meter than S-100), the partial armoured protection made out of light materials based on "Dural" (hardened aluminium) and a mesh of wood. Two types were made, the "A-class" MTB Tarantula
, primarily a torpedo launching fast vessel, with one forward placed torpedo tube at each side of the bow having a recharging device at the rear able to load further two units. This tpe of fast vessel had two 20mm single guns, one front, another one aft. The "B-class" Skorpion
was a so-called "UZ" (U-Boot Zerstörer) or "submarine chaser". This version was equipped with an automatic trigger equipped depth charger launching device at the stern, able to launch 18 120kg depth charges. The B-class boats had one heavy 12.9mm machine gun mounted in front and two 20mm AA guns mounted amidships, one covering the port side of the boat, the other one the starboard side.
The propulsion was made by three new developped Daimler-Benz 12 V-mounted cylinder supercharged Diesel engines of the type MB OM-512, delivering 1.875 shp each to three controllable pitch screws which propelled the 107 ton vessels up to 38 knots. From 1941 onwards, a bigger engine version, the MB OM-516 with 16 cylinders and intake air cooling ("intercooling") delivering 2.500 shp were installed, increasing the speed at full load to 42,6 knots. The range allowed the boats to sail from Kiel and reach Helsinki at a speed of 32,6 knots average and still have a fuel reserve for another hour.
The boats were equipped with FuMO radar devices with a range of 18km in clear weather and about 5km in rainy weather. The boats operated normally in Rudel
("packs") of four to six boats or even more, depending on the target vessel. In case of surface targets, they followed normally a zigzagging attack course, to confound the defensive artillery, until delivering the torpedos. In the case of the attack on the naval base at Kronstadt in the rainy and windy night of December 19th, 1939, they closed in at slow speed to lessen the noise level and taking use of the radar, they entered the base's main bassin until being able to deliver the torpedos at very close range and engines at idle. Then they turned around and left equally at slow speed first, until reaching the harbour's entrance and then at full speed until arriving at the mouth of the Viborg gulf. (scene somewhat similar to Günther Prien's
attack with U-47 at Scapa Flow in the early II War days, sinking HMS Royal Oak