S-Boats in the Imperial Navy (Kaiserliche Marine) 1916 - 1919

The base of the German S-Boat-Forces goes back to World War I. Workingboats requisitioned from civilian sources - "Boncourt", "Anette IV", "Max", "Brase", and "Ursus" - which were employed in the clearing of nets off the coast of Flandres since 1916 were proving as too small and to weak. The Imperial Navy therefore required biggere and fastere boats with a speed of 30 kts so that they were able to avoid destroyers garding the nets.

In 1917 four net-working boats (LM 1 and LM 2) especially built for that purpose and armed with a 3,7 cm machine-cannon and two additional safety boats armed with a 45-cm bow-torpedo-tube to launch the 6 m long aircraft-torpedo F52 and a machine-gun (LM 5 and LM 6) were commissioned. All boats were equipped with three propulsion shafts each driven by a 210 horse power Maybach CX  6-cylinder four-stroke gasoline airship-engine without reverse gear unit (the capability to reverse was neglected).

The boats had a complement of seven to eight men. They attained a speed of about 30 knots, the radius of action was 150 to 200 nautical miles and the endurance was five to seven hours.

LM 5 and LM 6 (picture from H. Fock: Schnellboote Band 1)

The originally planned stern-torpedo-tubes were substituted by one bow-torpedo-tube during the building phase. The firing speed was up to 20 knots. The boats were employed against enemy  barrier guards with some success.

LM-Boat under shipyard trials (picture: Archives Lürssen)

Yet in 1918 15 boats of a second series were commissioned (LM 7 - LM 21).  With these the Imperial Navy had more than 21 LM-boats under its command, seven of which were stationed in the Baltic Sea and 14 were employed off Flandres. The boats of Navycorps Flandres were subordinated the Motorboatdivision (Kptlt. Ellendt.)

Plan LM 7 with friendly permission of Peter Dewitz

The builders of these LM-boats were Lürssen, Oertz, Naglo and Roland. LM 1 was lost on 05.03.1918 due to gasoline-explosion, LM 2 was lost on 17.04.1918 due to engine-explosion.  As replacement LM 22 and LM 23 were ordered. Boats LM 1 through LM 4 were equipped with a pair of netscissors and 3,7 cm gun, starting with LM 5 the boats got a bow-torpedotube and a machinegun.

Firing of an Exercise-Torpedo by a LM-Boat - Picture: Archives Förderverein

During the night 22./23.08.1917 an attack by boats of the LM-Boat-Division Flandres was performed on a number of ships anchored off Dunkirk. In a fierce fighting the first attack-group (boats LM 9, LM 15, LM 17 and LM 18) achieved two hits on a destroyer, which immediately listed and caught fire. The small cruiser of Arabis-class also attacked was not hit. The boats taken under fire could enter harbour undamaged, only on LM 17 the forward radiomast was shot down. 

The second attack-group (boats LM 7, LM 8 and LM 16) attacked a destroyer-group of three ships. The intense fighting did not result in losses on either side. Also this group could return to harbour undamaged.  

The Imperial Navy had furthermore ordered three gliders designed of Ingenieur Brase at Müggel-Shipyard at Friedrichshagen. While Boat 1 was being built as a one-stage-boat, Boats 2 and 3 were constructed as two-stage-boats. Required was a speed of 40 knots. Therefore Boats 2 and 3 got three Maybach-6-cyl.-gasoline-motors each with 720 PS driving three air-propellers, Boat 1 got only two engines and two air-propellers and the speed was no more than 34 knots. The armament was composed of a dropping-installation for a 45cm-torpedo in the stern and one machinegun.

"Gleitboot 1" under commanding officer,  ObLt.z.S. Georg Peytsch, who had a great deal of trouble to get the boat ready for engagement, was transferred to the eastern front and sailed an advance from her deployment-harbour Ventspils/Estonia, during which the only success of a motortorpedoboat in the Baltic was obtained sinking the British 1202 BRT freighter "Penelope" one mile east-south-east of lighthouse Sõrve on 24.08.1917.  (In some documents she is stated as a Russian minelayer, e.g.  Fock: Die deutschen Schnellboote 1914 - 1945 and Fock: Schnellboote Vol. 1). 

In the Estonian newspaper Meie Maa dated 07.05.1938 it is reported about the breaking up of the ship, however, it is stated that the ship was sunk by German sea-aircraft with a torpedo.

The text was translated for this site by Veikko Horm, a former minediver of the Estonian Navy, from an ancient Estonian language into English, the result of which is as follows:

"The steamer shot down during World War  is being demolished.

Sõrve on May 7th. Diver entrepreneur Aleksander Põld started demolishing the steamer from Sõrve lighthouse in the direction of east-south-east, about one mile from the beach. The wreck of the English steamer "Penelope" sank with a load of cement during World War .

When demolishing the wreck, one diver works with three helpers. The hull is to be crushed to the seabed with explosive charges and the hull plates to be brought out later.

The steamship "Penelope" was sunk by German planes.

Seeing that the planes were threatening to bomb, the ship tried to ground. Prior to that intent, "Penelope" was hit by a torpedo from a German seaplane. The ship sank, the depth is 7 fathoms."

"Gleitboot 1" sank on 10.10.1917 in the Irbenstraits (Irbes jūras šaurums) due to a mine- or a motor-explosion. ObLt.z.S. Georg Reytsch and his three-man-crew did not survive the explosion.

"Gleitboot 2" had two avarages during two seatrials by getting leaks from the seastate rsp. the wake of another ship, she was salvaged two times and reconstructed two times but when "Gleitboot 3" got a leak during a seatrial in July 1918 all further trials with these boats were omitted.