Testboats of the Reichsmarine

(Pictures Archiv 7. S-Squadron unless otherwize statet)

The massive testprogramme of the Reichsmarine was to determine the basis for future building of S-Boats. These trials were conducted with allmost no exemption as covered activities of TRAYAG (Travemünder Yachthafen A.G.), Hochseesportverband „HANSA“, and Motor-Yachtclub von Deutschland in co-operation with Neustädter Slip GmbH, all institutions founded with support of Kapitän zur See Lohmann, Chief of the Seastransportdepartment. Lohmann had been supplied with the necessary means and with the general authority for their use. The trials-personnel belonged regularly to the so called Black Reichswehr („Schwarze Reichswehr“).

In fall 1926 the trials-boat "K" built by Abeking & Rasmussen at Vegesack was delivered. She had the meassurements 17,4 m length, 3,48 m beam, and a draft of 1,16 m. The boat displacing about 16 ts was driven by two 450/530 PS gasoline-engines and was to reach a speed of about 40 knots. The shape of the boat was related to the example of the English 55‘-Thornycroft-CMB by the designer Professor Ehrenburg (Technische Hochschule Berlin). The wavebinder-plane-glider-hull suffered heavy damages during the first tests already at 25 knots and light seastate. A new substantially strengthened hull showed permanent leakages in the area of the plane. The planned 45-cm torpedotubes for stern-launching and the MG were replaced by ballast weights for reasons of camouflage.

Testboat „K“ at maximum speed off Travemünde about 1926

Testboat „K“ at maximum speed - Picture from Fock Schnellboote Vol. 1

Testboat „K“ - Picture from Fock Schnellboote Vol. 1

AS a follow-on of the fast so called Express-Motor-Cruisers built by Lürssen-Shipyard at Vegesack on account of American water sportsmen, the shipyard built the trailboat "Lür" on own risk.

She was a round-rib displacement-boat with the measurements 21,0 m length, 3,6 m beam, and 1,28 m draft. The boat displacing about 23 ts was driven by three 450-PS-Maybach gasoline-engines and reached a speed of 33 knots.  The hull was performed as a mahogany-kraweel-build and was to substanciate the good results achieved with the smaller boat "Lüs 1" - also known as "Liesel" - and prove that displacement-boats were behaving better in the short rough seastate of the Northsea an also of the Baltic than gliders.

Trialboat „Lüsi 1“/“Liesel - Picture from Fock Schnellboote Vol. 1

Trailboat "Lür" - Picture from Fock Schnellboote Vol. 1

The testboat "Narwal" built in co-operation of TRAYAG and Caspar-Shipyard at Travemünde as a contrast to the round-rib-boat although the experiences made had shown that the round-rib-shape was better suitable for the sea-areas of the Northsea and the Baltic.  „Narwal“  had the measurements: length 21,3 m, beam 4,06 m and draft 0,9 m. The boat displacing about 26,4 ts (at full load 31 ts) was driven by three 375-PS Atlantik 12- cylinder-V-engines and reached a speed of 34,8 knots. Also for this boat the Thornycroft 55‘-design was the model. In spite of her strengthened building-method the better suitability of the round-rib-boats “Lüsi 1“ and „Lür“ was proved in seastate 2 to 3. 

Trialboat „Narwal“ off Travemünde about 1928

Trialboat „Narwal“ off Travemünde about 1928

Trialboat „Narwal“ before Launching - Picture from Fock Schnellboote Vol. 1

Trial-S.Boat „Narwal“ at maximum speed off Travemünde End of the 20ies

Trial-S-Boat „Narwal“

Trial-S-Boat „Narwal“ off Travemünde about 1928

Wake of „Narwal“

„Narwal“ at maximum speed

 The hazards of the gasoline-engines on board of S-Boats was proven again when a S-Boat burned out in the harbour of Priwall at Travemünde; also at sea this experience was confirmed and some crews had to leave their boats until the burning boats could be extinguished by cutting of the oxygen-supply or by blowing in tetrachlorine.

Fire on a S-Boat on Priwall at Travemünde about 1926

Breaking up of a burned-out Trial-S-Boat

During the years 1923 to 1926 the Reichwehr bought the Worldwar-LM-boats „LM 20“, „LM 21“, „LM 22“, „LM 23“, „LM 27“, and „LM 28“  from private owners. The LM-boats sailed at first with "civilian" crews and unarmed. From 1926 on they got Mercedes-Benz gasoline-engines of new construction and shifting gear. Three boats got three 260 PS-engines, two boats one 260 PS-Motor on the middle-shaft and two 210 PS-engines on the outer shafts. One of the boats later got two 500-PS-engines on two shafts .

Worldwar-LM-Boat on a Reichsbahnwaggon - Picture from Fock Schnellboote Vol. 1

Trialboat „Gerda“ off Travemünde about 1926

Trial-S-Boat „Siegfried“ with stern-torpedotubes at 30 knots

Launching a Torpedo dead ahead from a LM-Boat

On 16.04.1929 the Reichsmarine formed the „Ostseesperrverband“ (Baltic Blocking Unit). The unit consisted of 24 blocking-training-craft and a number of so called „Bewachungsfahrzeuge“ (Guarding Craft). To these guarding-craft belonged  UZ-Boats (Uboot-Zerstörer = Submarine-Chaser) with the supplement „(S)“ for Schnellboot. These were formed by the former LM-boats with the designators UZ (S) 13, 14, 15, 16, 17, 20, and 21, by the boats ex „Lür“ as UZ (S) 11, ex „K“ as UZ (S) 12,  ex-„Narwal“ als UZ (S) 18, and  ex-„Lüsi 1“ rsp. „Liesel“ as „UZ (S) 19".

But all trials indicated, that with boats of this size the requirements of the Reichsmarine for seaworthy fast boats armed with two 53,3-cm torpedotubes and antiairguns with a as long as possible range and with speeds of more than 30 knots could not be fulfilled.

Barrier-Unit Baltic - Picture from Fock Schnellboote Vol. 1

Besides of that the Lürssen-Shipyard built two Turbine-S-Boats „Bremse“ and „Brummer“. They were 55 ts boats with the measurements 29,00 m length, 4,40 m beam, and 1,50 m draft, which reached a speed of 29 knots with a propulsion by two boilers and a high-presssure-steam-turbineplant with 1600 PS each turbine working on two propellers via a wheel-gearbox. They proved their worth in sea-duty, however, they were only two single units due to the beginning diesel-developments for S-Boats.

The development of the new big S-Boat at Lürssen-Shipyard on the basis of the Express-Cruiser "Oheka II" built by Lürssen for American customers and the test-boat "Lür" emerging thereof led to the known type-boat "S 1" of  26,85 m length, 4,20 m beam, and 1,10 m draft, which, however, as also boats „S 2“ to „S 5“ were still equipped with gasoline-engines. „S 1“ was commisioned as "UZ (S) 16" on 07.08.1930. She was redesignated as Wachboot (Guard-Boat) "W 1" on 31.03.1931, and on 16.03.1932 as Schnellboot „S 1“. The camouflage-designation „S“ for Schnellboot thus became the official type-designation.  

Seatrials of „S 1“ on river Weser – Picture from Italieri Schnellboot Typ S 100