Trial-S-Boats and Small-S-Boats developed by the
K-Unit od the KM
Developments of the KM
the end of the war great efforts were made, to build Small-S-Boats besides
of the Light-S-Boats "LS".
LS-Boat during Sea-Trials - Picture: Archives Förderverein
1932 to 1935 the German Dr. Tietjens worked on hydrofoils in America. 1932
he brought a hydrofoil of 6 m length and 240 kg weight on Delaware river
in America to 22 kts with the help of a 5 PS-motor. After his return to
Germany he reached a speed of 25 kts with a 5,5 m boat with 370 kg weight
with two persons and 28 kts with one person on board by a propulsion of a
10-PS gasoline-engine. In his constructions there was a
curved or a V-shaped main hydrofoil in the center under the boat
and in the middle of the rear end a hydrofoil took over the role of a
supporting plane and of an elevator.
1927 on Baron von Schertel worked on hydrofoils. His Hydrofoil-system
consisted of normally two V-shaped hydrofoils forward and aft. 1936
Schertel achieved with his eights boat built the awaited result. The boat
driven by a 50 PS gasoline-engine made during tests on river Rhine with
five Person on board a speed of 29 kts.
1937 on Baron von Schertel co-operated with the Gebrüder Sachsenberg AG
at Rosslau. Already 1938 from this co-operation originated the first
Schertel-Sachsenberg hydrofoil. The boat built at Wiesbaden at a length of
9,5 m an a weight of 2,8 t was propelled by a 150-PS gasoline-engine and
reached a speed of 40 kts. The boat was in operation until 1945.
summer 1939 the Sachsenberg-Shipyard got the order to build a
100-t-aluminium-hydrofoil in accordance with the System Schertel. At the
outbreak of the war however the order was cancelled.
1“ to „TS 6“
summer 1940 the Sachsenberg-Shipyard got the order for 36 small hydrofoils
with a displacement of 3,8 ts, which were to be used in the surveillance
of the Norwegian Fjords. The
order was later reduced to six boats. The boats „TS 1“ to „TS 5“
became because of the building of steel as V-shaped gliders somewhat
heavier than thought and displaced 4,9 ts empty respectively 6,3 ts full
load. The length was 11,96 m and the beam 2,7 m. The draft was 1,7 m,
airborne 0,85 m. The propulsion was performed by a 380-PS
Lorrain-Dietrich gasoline-engine, which brought the boat to a speed of 40
kts. The boat was armed with a 15-mm-Air Force-MG in a turn-ring-carriage
with an acrylic glass-dome and manned by four men. The boat „TS 6“ was
not completed before the end of the war, since it had to be reconstructed
by order of the OKM. Instead of the very long propeller-shaft, in which
reverberations occurred, a cone-wheel-Z-transmission should be used. The
boat captured by the Russians was completed under their control, tested
and transferred to the Wolga river.
Hydrofoil "TS 1" at full speed - Picture from Fock Schnellboote Vol. 2
following hydrofoils got the designation trial-S-boats
(Versuchs-Schnellboote = „VS“). „VS 1“ to „VS 4“ were plans
not realized. „VS 5“ was a floodable „Half-Submarine-S-Boat“. It
was expected to reach a speed of 50 kts by a propulsion of four
1500/2050-PS-MAN-11-cylinder-fourstroke-diesels L 11 working on one
propeller shaft. As armament two 20-mm-machineguns and two
53,3-cm-torpedo-tubes were planned. Already the first trials proved, that
the boat was a total bad design.
Half-submersible "VS 5"- Picture from Fock Schnellboote Vol. 2
of 1940 the Sachsenberg-Shipyard got the order to build a
trial-hydrofoil-S-Boat „VS 6“. It was to be a fast minelayer with a
loading capacity for four TMB-mines,
armed with a 20-mm-machinegun on a turn-ring-carriage with an acrylic
glass-dome. The complement was to consist of four men. The boat had a
length of 15,74 m, beam of the hull 4,25 m, beam across the foils 5,27 m,
draft 2,3 m, airborne 0,96 m. Propelled by two 700-PS-Avia-V 36
gasoline-engines working on two propeller-shafts the boat was expected to
develop a speed of 47 kts. The range at full speed was to be 300 nm.
During the sea trials it was detected that the steel of the hull was too
week. With an accordingly strengthened plating of the boat which was more
slim in the forward part of the hull the boat served until the end of the
war as a test-platform for trials with different foils. It became British
Hydrofoil "VS 6" at seatrials - Picture from Fock Schnellboote Vol. 2
be able to draw comparisons between the Schertel and the Tietjens
hydrofoils, Professor Tietjens got the order to build a boat with the same
dimensions as „VS 6“. The boat was built as a steel-boat with bent
ribs and had a construction-displacement of 17 ts but was also 4,5 ts
heavier than planned. The propulsion was planned to utilize 675-PS-Avia
gasoline-engines. Since the
hull was not able to made lighter, the Vertens-Shipyard at Schleswig got
the order in 1942 to build a new boat with identical propulsion and the
same designator „VS 7“. The boat had the dimensions length 14,00, beam
3,95 m and was built from special tapofilm-glued
poplar-playwood of a strength of 14 mm up front and 12 mm astern, It was
armed with a 20-mm-machinegun on a turn-ring-carriage
with an acrylic glass-dome and two 45-cm-stern-torpedotubes. Thereby it
displaced 15 ts fully loaded. Propelled was the craft by two
675-PS-Avia-Otto-motors and reached a speed of 54,5 kts. The complement
was four men. The boat was completed in fall 1942 and was merely operated
for trials in the Baltic.
7" at trials in the Baltic - Picture from Fock Schnellboote Vol. 2
„VS 8“ – „VS 9“
fall 1942 the Sachsenberg-Shipyard got the order to build two big
test-hydrofoil-S-boats. They got the designators „VS 8“ and „VS
9“. The boats were thought as transport-vehicles for one tank of 26 ts
for supply of the Africa-Corps with corresponding defence against
fighter-bombers and high speed. The boat was built at Harburg as an
aluminium bent-ribs glider with
a plane. At a length of 31,9
m, a beam of the hull of 8,0 m (across the foils 10,62 m) and a draft of
4,25 m (airborne 2,0 m) it had a displacement of 70 ts empty with a
loading capacity of 28 ts. The propulsion was performed by two
2500-PS-Daimler-Benz 20-cylinder diesels MB 511 working on two propeller
shafts. It was to reach a speed of 41 kts at constant speed and 45
kts at short-time maximal speed. The armament consisted of 15-mm-Air
Force-MGs in turn-ring-carriages with acrylic glass-domes. The complement
was 22 men.
Hydrofoil "VS 8" at Sachsenber-Shipyard- Picture from Fock Schnellboote Vol. 2
trails resulted in that the boat was 5 ts heavier than planned and that it
reached a speed of 41 kts, since the two planned motors had been
substituted by two 2000-PS MB 501 diesels, with that the boat could
maintain a speed of 37 kts against the sea at a height of the waves of 1,8
m and that in spite of the sea-water-resistant aluminium in the area of
the forward end of the boat strong effects of corrosion by the spray were
September 1944 „VS 8“ run aground in a tempest off Hela and had to be
9“ was to get a cone-wheel-Z-transmission instead of the long shafts. That,
however, remained an incomplete planning.
"VS 8" during high-speed trials in the Baltic - Picture from Fock Schnellboote Vol. 2
OKM in 1942 ordered Sachsenberg-Shipyard to build a hydrofoil-S-Boat with
the designation „VS 10“. At a length of 23,3 m, a beam of the hull 6,4
m (across hydrofoils 8,0 m) and a draft of 3,3 m (airborne 1,3 m) had a
displacement of 46 ts, the propulsion was to consist of four
1500-PS-Isotta-Fraschini-ASM-185 gasoline-engines and with two propellers
reached a speed of 58 kts and achieved a range of 300 nm at a speed of 58
kts. The armament was to consist of six 15-mm-Liftwaffen-machineguns on
turn-ring-carriages with acrylic glass-domes and two 45-cm respectively
53,3-cm-torpedotubes. The complement was to be 22 men. The boat was
destroyed at the shipyard by an Allied bomb raid a few days before the
planned the trials.
German Hydrofoil "VS 10" during shipyard-trials - Picture: Archives R. Nordland
of the hydrofoil-S-boats developed and built with great efforts came at
any time to a service at the front.
The conventional Small-S-Boats
May 1944 on in Germany the Italian Small-S-Boat Motoscafo Turismo
Silurante Modificato Allargato (M.T.S.M.A. or briefly SMA) was bought in
Italy respectively copied. The boat had a length of 8,8 m, a beam of 2,32
m and a draft of 0,7 m. At a displacement of 3,71 ts a propulsion-plant of
two 95-PS Alfa-Romeo-A.R.-6c-2500 gasoline-engines and an armament of one
45-cm-stern-torpedo-tube and two 70 kg pursuer-defence depth-charges were
installed. The speed reached was 29 kts at a range of 250 nm. Of this type
in total 78 boats were built in Germany from May 1944 until January 1945.
Small-S-Boat of the Italian Type SMA – Picture from Fock Schnellboote
Small-S-Boat type „Hydra“ was a design for the Luftwaffe in a common
effort of the OKM and the Kröger-Shipyard at Warnemünde. The design
based upon a type of boat, that had been planned for the Luftwaffe to
transport paragliders but than was put back. On 25.08.1944 the building
order for two prototypes was placed. The „H 1“ and „H 2“ had a
displacement of 7,45 ts with a length of 13,21 m, a beam of 3,1 m and a
draft of 1,05 m. They received an Avai-Hispano-Suiza gasoline-engine 12 y
31 reduced to 650 PS. With that a speed of 36 kts was reached. There was
no turn gear but only speed ahead and idling. The range was 290 nm at 25
kts, at 36 kts it was 152 nm. The armament consisted of two
45-cm-stern-torpedotubes for the aircraft-torpedo F 5 b. No information is
available about actions of these boats.
„Hydra“ during seatrials – Picture from Fock Schnellboote Vol. 2
boat „H 53“ trials were performed with a Jumo-Otto-motor. The speed
reached was only 34 kts. Therefore the trials were given up. On 04.12.1944
a series of 50 boats were ordered. Another order for a series of 115 boats
were placed on 08.02.1945. The shipbuilders were distributed over all
Northern Germany. The boats of these series were to get a anti-aircraft-MG
for self-protection. The fuel-storage was enlarged to 1400 litres in order
to widen the range. During the
building process three wagons with Rolls-Royce-Merlin-motors were
delivered, which did not make it to be installed, as well as only 39 boats
were completed until the end of the war. About actions of these boats no
information ist available.
in the planning was the idea of Ingenieur Driesen to join two
„Hydra-hulls“ by struts and to arm this catamaran with four
torpedo-tubes and to bring the boat with help of a jet of
Messerschmidt-turbin fighter to a speed of 60 kts.
type „Kobra“ was a design of Ober-Ingenieur H. Docter, which was made
on the basis of an invitation of tenders. The boat was to be used as an
autonomous Small-S-Boat or as a boat to be operated from a bigger ship as
a bearer. It had the dimensions length 8,72 m, beam 2,5 m and draft 0,56
m. It displaced 3,46 ts and was armed with a 45-cm-stern-torpedo-tube for
the torpedo F 5 b and was to be propelled by two 90 PS Ford-8-cyllinder
gasoline-engines with two shafts and two propellers to a speed of 29 kts.
Type „Kobra“ – Picture from Fock Schnellboote Vol. 2
the end of comparing tests with other Small-S-Boats the type „Kobra“
was no longer pursued.
design for a Small-S-.Boat of 10,6 m length, 3,2 m beam and a draft of
0,55 m was planned for two launching gears on either side for the
45-cm-aircraft-torpedo F 5b. The boat displöacing 7,65 ts was to get a
propulsion with two Hispano-Suiza
gasoline-engines 12 y 31 and reach about 37 kts. The design was not
pursued to an end.
S-Boats developed by Lürssen-Shipyard in co-operation with Ministerialrat
Dyckmann with dimensions of 15,95 m length, 3,5 m beam and a draft of 1,1
m were in the first place utilized as Coastal Minelayers (Küstenminenleger
= „KM“). The propulsion of these boats displacing 19 ts existed of two
not reversible 550/650 PS BMW
12-cyllinder-fourstroke-gaoline-aircraft-engines, which gave the boats
speeds of 30 to 32 kts empty and 24 kts fully loaded. The boats got two
Coastal Minenlayer Type „KM 1“ - Picture from Fock Schnellboote Vol. 2
first boats were finished 1942. Four boats were shipped to the Gulf of
Finland also were boats shipped to the Black Sea. Early 1944 eight boats
were originally subordinated to the Danube-Flotilla but than in the middle
of 1944 they were given to Croatia. There they were designated “KS 1“
to „KS 8“. „KS 8“ burned out, „KS 5“ deserted to the
other boats were taken back by the Kriegsmarine.
summer 1944 a part of the KM-Boats were fitted with two
45-cm-aluminium-torpedo-tubes and a 2-cm-machinegun and designated as
Coastal-S-Boats („Küstenschnellboote“ = „KS“-Boats). The
„KS-Boats“ had the numbers 1, 2, 9, 10, 11, 12, 16, 17, 18, 20, 21,
23, 24, 25, 26, 31, 32, 33, 34, 35, and 36. The fate und the whereabouts
oft he boats is not comprehensible.
S-Boat Type „KS 1“ – Picture from Fock Schnellboote Vol. 2
of the K-Units
the Small-Fighting-Craft Unit (Kleinkampfmittel-Verband = K-Verband)
noteworthy Small-S-Boats were developed. The leader of the Construction
and Test Department of the unit, Oblt.z.S. d.R. Fr. H. Wendel, conducted
on a provisional test-site at Boizenburg at the river Elbe
model-towing-tests to get answers for the fundamental question whether
conventional or totally new shapes should be used as hulls. Exact
measurements could not be gained on this provisional test-site but a
comparative evaluation was possible. As well gliders without step as
gliders with step, catamaran-gliders and a boat sailing on four
gliding-planes following an idea of Prof. Wankel were tested.
expectation oft he Allied invasion in northern France frameless
Small-S-Boats were built at Borgward-Fyctories at Bremen in
sheet-steel-shell construction. The craft was conceived as a one-man-boat
easy to build with help of bodywork-presses and in high numbers. It
had a length of 7,50 m, a beam of 1,60 m and a draft of 0,55 m.
I“ being launched from a bigger ship – Picture from Fock Schnellboote
standard-torpedoes G 7 a respectively G 7 e could be carried in two spaces
in the hull. A 90 PS
gasoline-engine was utilized for propulsion. With it the prototype reached
12 kts in trials with torpedoes loaded but only using the own propulsion.
For the attack, the torpedoes could be started and used for the propulsion
of the boat. With
that a speed of 25 kts could be achieved. The boat without torpedoes could proceed at 18 kts. The
range was 300 nm at marching-speed.
I“, G 7 a in the side-openings, in the middle propeller and rudder –
Picture from Fock Schnellboote Vol. 2
positive experiences made with this type during the trails considering the
small dimensions and the weakness of the propulsion lead to the planning
of a bigger and more seaworthy boat with a stronger propulsion-system with
the same construction features as in „Schlitten I“.
Typ „Schlitten I“ at full speed – Picture from Fock Schnellboote
Type „Schlitten II“
further from „Schlitten I“ the boat „Schlitten II“ had a length of
8,5 m, a beam of 1,70 m and a draft of 0,55 m. The boat obtained a 600 PS
gasoline-aircraft-engine and reached thereby with torpedoes 20 kts
sustained speed. The maximum speed with torpedoes was 30 kts and after
launching of the torpedoes the boat could retreat at 48 kts. A MG 34
respectively MG 44 was used for self-protection. The range was 300 nm.
II“ on the especially developed trailer – Picture from Fock
Schnellboote Vol. 2
crew was a helmsman and an engineer from the Luftwaffe, since the Navy did
not train men for this high-performance engine.
the trials it showed, that the boat listed considerably by effect of the
propeller and only at higher speed the effect of the water-stream on the
bottom of the boat compensated for that.
August 1944 the K-Unit developed a 9-m-plane-boat. This boat got the name
“Wal I” (Whale). The hull consisted of fully-welded steel and had a
length of 9,0 m, a beam of 2,3 m and a draft of 0,40 m without propeller.
The boat displacing 4,2 ts got a 700 PS gasoline-aircraft-engine, which
gave the boat a speed of 39 kts with torpedoes and 42 kts without. The
range was 300 nm. Since the conventional torpedo-tubes were to heavy for
the boat, a special construction was made to fire the torpedoes with a
Type „Wal I“ – Picture from Fock Schnellboote Vol. 2
armament served two 45-cm stern-torpedo-tubes for the aircraft-torpedo F 5
b, one 13-mm-MG and two 86-mm-rocket launchers. The crew were a helmsman
and an engineer from the Luftwaffe.
the OKM objected to the type „Wal I“ as plane-glider because of
limited seaworthyness and possible strength and tightness problems the
plane-less „Wal II“ was developed. It had a length of 10,00 m. The
boat was built at Boizenburg. The 700-PS gasoline-aircraft-engine brought
the boat to 38 kts with two tropedoes and to 42 kts without. The armament
consisted as in “Wal I” of two 45-cm stern-torpedo-tubes, one 13-mm MG
34 resp. MG 44, and two 86-mm rocket-launchers. The rocket-launcher could
launch explosive, fragment, parachute, and fog ammunition.
boat could be launched directly from its trailer driven into the water.
Type „Wal II“ – Picture
from Fock Schnellboote Vol. 2
of the limited availability of steel the type „Wal“ was redesigned
again. „Wal III“ emerged, which was built as a conventional
wood-construction. All experiences made with the predecessor-types were
taken into account. The crew was increased to three to four men in order to
allow for relief during the march back and forth. As propulsion-plant
alternatively 600-PS or 800-PS gasoline-aircraft-engines were planned.
Thereby the boat reached a speed of 35 resp. 39
kts with torpedoes and 38 resp. 42 kts without.
type „Wal III“ rockets to assist take-off obtained from the Luftwaffe
were tested to provide the boats with a higher escape speed after having
launched their torpedoes. The speed could be increased to 58 kts and the
exhaust fumes had an effect like a red-brown fog-wall. The trials resulted
in the experience that the boat could not be kept on course well and that
it could even capsize. Therefore,
this trails were called off. The series-building of „Wal III“ did not happen because the OKM hade
made up their mind fort he type „Hydra“ as a result oft he comparative
of the K-Unit
large number of plans and of the K-Unit among others also the most
different hydrofoils were not pursued because of the development of the
war and were only pursued after the war.