Another key innovation was the addition of a special rudder arrangement beginning with S-2 (1932). Port and starboard of the main rudder were two smaller “rudders” that could be angled outboard to 30 degrees. By generating what became known as the “Lürssen Effekt," at high speed, the angled “rudders” drew a ventilation air pocket slightly behind the three screws, increasing their efficiency, reducing the stern wave and keeping the boat at a nearly horizontal attitude.

A wedge was added to the lower stern beginning with S-18 (1938). This deflected the water flow slightly downwards, counteracting any tendency for the hull to settle into the water as speed increased. Improvements were also made to the superstructure. On early boats, the commander stood outside on the deck behind a spray shield. Behind him in the wheelhouse stood the helmsman, navigator, radio operator and engine telegraphist. The commander communicated his orders through flexible voice tubes, or via a seaman equipped with a headset intercom.

The S-26 class (1940) instituted a 34.9m hull and several design changes. The torpedo tubes were enclosed in a decked-over forecastle, increasing interior space and reserve buoyancy. A cockpit was set into the wheelhouse roof, placing the commander in a central position with better visibility and shelter. Although they were wonderful sea-boats, they were notoriously “wet” and every scrap of shelter was welcome! From there, he could speak through portholes directly to the wheelhouse forward and navigator aft. His "instrument panel" consisted of glass windows through which he could observe a compass and the wheelhouse interior. (Note that there was no steering wheel in the cockpit.) Starting with S-30 (1939) several boats were built with a slightly smaller hull, 32.7m, and with the old style wheelhouse. The S-38 class, of which S-130 is an example, was a continuation of the S-26 class.

Experimentation with S-67 (1942) led to a design for a partially armour-plated cupola, the so-called Kalotte (skull cap), over the bridge. This added armour was a countermeasure to the growing firepower of British escort craft encountered in the English Channel. The S-Boote armament included a variety of combinations of cannon, from 20 – 37mm calibre, as well as the two 533mm torpedo tubes. Overall, there were many minor wartime changes to the armament, superstructure, and hull dimensions, but the hull design remained basically unchanged from S-18 onwards.

So there is no doubt that they were an outstanding design. In late July and early August 1945, future president John F. Kennedy visited defeated Germany with US Navy Secretary James Forrestal. As a former PT Boat commander, he was naturally interested in their German counterpart so he made a point of carefully inspecting an intact S-Boot at Bremen. Kennedy's diary records his conclusion: the Schnellboot was "far superior". Indeed, whilst a number of allied designs could just about keep up with or even (just) overhaul an S-Boot in calm water, nothing as fast was as heavily-armed and absolutely nothing could touch them in the typical conditions of the North Sea and Channel until the large (150 ft) British Fairmile “D” emerged, later in the War, as a reasonable adversary.

S-130 - The Last Survivor
The only known, surviving and seaworthy S-boot, S-130, was built at the Johann Schlichting boatyard as hull 1030 in Travemünde, on the Baltic Coast, and commissioned on October 21st 1943. Her Commanding Officer was Oberleutnant zur See Gunter Rabe and she was assigned to the 9th S-Boot Flotilla (commanded by Korvettenkapitän Götz Freiherr von Mirbach, one of the most famous S-Boot commanders of the war) to reinforce their presence in the Southern North Sea. They operated out of Rotterdam until mid-February 1944, when they re-deployed to Cherbourg in order to reinforce the 5th Flotilla (under Korvettenkapitän Bernd Klug) in their operations throughout the Central and Western Channel area. Throughout her service, her radio callsign was “Rabe” (Raven), her dashing Master was known by all in the 5th and 9th Flotillas as “The Raven” and she wore a ship’s crest incorporating a raven in addition to the usual 9th Flotilla sign. The two Flotillas in Cherbourg were directed from his HQ on the French mainland by Kapitän zur See Petersen (later to become Commander of the whole German Schnellbootwaffe).

Attack on Operation Tiger
Following a succession of dashing and violent night engagements during March and April 1944, S-130 took part in one of the most daring and successful S-Boot operations of the War. Both Flotillas had conducted a number of attacks against Allied shipping off the southern coast of England including, on April 22, a successful attack on British Motor Gun Boats in Lyme Bay and, on the 24th, a very successful attack on shipping in the same area. Then, on the afternoon of 27 April, a Luftwaffe reconnaissance aircraft reported a convoy of 7 merchant ships off Start Point, England.

S-130 at speed, 1944