During WWII, the Kriegsmarine had about 200 S-boats in service. They saw action in coastal waters of the North Sea, the English Channel, the Gulf of Biscay, the Mediterranean, even the Black Sea. They sank over 40 enemy warships, including 12 destroyers, and more than 100 merchant vessels. They also damaged 2 British cruisers which say a lot about their daring aggressiveness. Their own losses, unlike those of the U-boats, were comparatively light. Their chief area of operations was the East coast of England where they wrought havoc among British coastal convoys. Their 2,500 horsepower Diesel engines gave them a maximum speed of over 40 knots per hour. Being the perfect craft for sudden hit-and-run attacks, no enemy vessel could catch up with them. They were armed with 2 torpedo tubes of 533 mm, one 37mm and 4 20mm AA guns. They had a length of 35 meters, a beam of 3.5 meters a draught of 1.7 meters, and weighed about 100 tons. The majority of them were built at the Friedrich Lürssen-Werft in Bremen-Vegesack which was the target of several US 8th Air Force bombing raids in 1944 (they damaged it, but never knocked it out). S-boats were also actively engaged in the legendary evacuation by the Kriegsmarine of German refugees from East Prussia in early 1945. After the German surrender, most of the surviving boats (like the 100-odd U-boats) became the property of the British Navy which eventually sold them for scrap. But what about the men in charge who ran them : 21 S-Boot commanders earned the Ritterkreuz, 8 of them the Oak Leaves as well – a remarkable record of awards equalling that of their more famous brothers-in-arms, the U-boat commanders.
In my opinion the German “Schnellboote” – let me use the German term for them – were among the best, if not THE best warship design of the German navy.
Their main advantage over all foreign designs was their hull form, which allows them to displace the water and not sliding over it.
Together with the diesel propulsion, which is much safer than the petrol powered engines of their counterparts, their also larger size, which increased their seaworthiness massively, allowed them, to operate not only under the coast, but also in the open water of the North Sea, for example.
In fact, a lot of motor torpedo boats of other countries were much faster than the German’s, but only a calm sea. The German boats could run their speed even at a motion of sea, which didn’t permit their counterparts to leave their harbor!
Achtung Schnellboot Commanders!!
My favorite Schnellboot story taken from a magazine account from “Sea Classic’s”. It told of a British Spitfire pilot who one day, chanced upon a German S-Boat, idly lazing about the sunny, surface of the Mediterranean. Aroused by a seemingly “easy kill”, he horsed his fighter plane into an attack run on the S-boat and just as he was about to “pull the trigger”, his plane was buffeted by a series of blows that left his ship a lurching, crippled wreck that required ditching. He had no sooner ditched and escaped his sinking, aircraft when the S-Boat slowly, cruised alongside, its crew, happily, clapping its Executive Officer on the back for having made a trade that allowed them to install an Army, 20 mm. Flakvierling (four barrelled, 20mm. cannon) amidships. The Spitfire pilot apparently, survived captivity and was responsible for the story. The S-Boats were a very stable firing platform, due to their hull design and towards the end of the war, some boats boasted of carrying 105 mm. guns and a much heavier array of automatic cannon than they were designed for.
The earliest S-Boat that I know of that received a 2 cm Flakvierling was S65, which received its weapon in July 1944.
There were S booten that received the installation as it is documented in the final battles and retreat from the Baltic in 1945
One Example: page 71 of Siegfried Beyers Die Deutsche Kriegsmarine 35-45, the action shot is in April of 1945 upon the retreat from Pillau, the boot covered with refugees. Clearly showing the flakvierling.