Schnellboot Weapons and Tactics

PrinzEugen.com Schnellboot Archive


Weapons and Tactics

Thomas Whitehead's 1866 invention, the torpedo, was a revolution in naval warfare. The first examples were short ranged and ponderously slow but the implications were great: it could enable a small craft to destroy a much larger one, or a small navy to threaten a great navy. It could also be fired underwater. In the naval arms race that preceded the First World War the potential of such a device was fully understood and appreciated by German naval engineers seeking ways to undermine the British Navy's global power. The German U-Boat fleet, while not securing a victory for Germany, proved beyond any doubt the effectiveness of Whitehead's invention.

In the 1920's German Naval Command once again found themselves in the position of a weak force anticipating battle with a much stronger one. And once again the torpedo presented a viable solution. Using considerable experience gained in Germany during the First World War, Naval Command began working on improving torpedos and creating vessels to deliver them.

The Schnellboot carried 53.3 cm torpedos. Typically one in each tube, although provisions were available for two reload torpedos. In practice, reload torpedos were infrequently carried, as their weight adversely affected boat performance, and the hit-and-run tactics used by the boats rarely allowed time for reloading.

The Schnellboot's other weapons were chiefly for self defense. As the war progressed, defense was increased and adapted to meet the demands of an ever more hostile environment. The chief threat came from the air and anti aircraft weaponry increased dramatically. While the early S-Boats carried a single 2 cm Flak gun and a compliment of several light machine guns, the later armored bridge boats carried multitude of weapons including the 4cm Bofors, the 3.7cm Flak 42 and in a few cases the the four barelled 2cm Flakvierling.

Later boats beginning with the S-38 class mounted a specialized 2cm gun turret on the bows, between the torpedo tubes. The position gave the gunner a good field of fire, and some protection. The first type of bow gun was a simple Scarff ring, with ammunition passed from belowdecks through a hatch inside the tub. Later an experimental Luftwaffe turret design was adapted for S-Boot use as the "Drehkranzlafette 41". It could deliver fire in a hemispherical arc, from 0 to 90 degrees of elevation, and 360 degrees of traverse. It had a pantograph gunsight that enabled the gunner to fire upwards at aircraft without crouching. The gun was stowed by swinging the mount downwards into the tub on a hinged pivot and removing the barrel, which was stowed separately. A cover was manually fixed over the turret, protecting it from salt water spray. Several different ammunition stowage arrangements were used, with clips stowed for ready use on the deck. The earlier detachable metal retainers were later replaced with simplified fixed wooden retainers.

The Schnellboot was essentialy a torpedo delivery system. Its basic function was to bring a torpedo within firing range of an enemy vessel, aim, and shoot. The rest was up to the torpedo alone. Peacetime wargames showed that the most effective way to accomplish this task was to operate in small groups under the cover of darkness. Boats might lie in wait at a particular spot where a convoy was expected. If it was sighted the S-Boats would approach, fire and flee under a smokescreen.

To aim the torpedo, the target was sighted through a binocular bearing finder mounted in center of the bridge or cockpit. Bearing and range was mechanically passed into an analog torpedo computer directly beneath it. The torpedo computer could make fine helm adjustments. When heading, range and course was coordinated with the computer's firing solution, the torpedos were fired. Simple in theory, it demanded great skill and steady nerves in practice.

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2cm Ammunition is stowed around the bow gun position.

2cm bow gunner in action. He wears an inflatable life vest.

Same gunner, close up.


S-100 class bow gun arrangment.



2cm bow gun in Drehkranzlafette 41.


Postwar view of S-Boats used by the Danish Navy.


The bow 2cm was manned by a crew of two who stood in the gun tub.


A close up inside the forward gun tub. The gun has been removed from this salvaged boat. Note the interior door. (USNA Courtesy of Chip Marshall)

3.7cm Flak as used in type 100 boats.









Superb computer graphics courtesy Stefan Draminski from Poland.



A color image of a 4cm Bofors salvaged from an S-boot. These guns were used on the S-38 class.


A depth charge is loaded. These were lashed to rails on the deck.


Stern view of mid war boats taking on standard 45cm depth charge from tender.


The meaning of the yellow color is unclear. Practice or live?


2cm "Zwilling" Flak



Smoke generator, and ready ammunition locker.


Close up of smoke generator.


Rear view. This gun was fully automatic, fed 5 round clips and fired by foot pedal. This example is on U-505.


MK151 Drilling (triple) mount as used on S-30 and S-151 classes in the Med. (Signal Corps Photo)



2cm MG C/30, a training manual photo.


Early boats had the standard Kriegsmarine 2cm Flak pedistal at the stern. Notice the opened ammo box and the uncovered master compass.


Notice the simple AA sight. The optional basket collected spent shell casings.


The wooden slats of the stern 2cm were a feature of the early boats.


A color shot of the 2cm in action onboard a "Vorpostenboot", a converted fishing cutter.



Cleanliness and constant maintenance was routine on every boat.


The tube covers were cranked open by the torpedoman.


The torpedo tube covers.


On a mid war boat, the torpedoman waits for the order to fire.


Torpedo tube trigger mechanism



Reloading using the torpedo winch.


Reloading at night.


The torpedo is coaxed into its cradle


The torpedo cradle was used when loading torpedos and occasionally for stowing spares. This is a mid-war boat.


The torpedo cradle on an early war boat. The torpedo was winched into the tube by block and tackle.


Notice the covered torpedo aiming sight/computer, and the highly polished brass cooling sleeve of the antiquated 08/15 machine gun.



The binocular sight is uncovered in this view. Notice the antler talisman. Lucky horseshoes were also popular.


A close up of the torpedo tube of a salvaged boat. (USNA Courtesy of Chip Marshall)


Tube door of the same boat. Part of the gear cover is missing. (USNA Courtesy of Chip Marshall)


Alongside a tender, torpedos are loaded.



Torpedo stowed in reload cradle on a camouflaged type 26. (From Marines Magazine No 7 Les vedettes au combat)


Stern 2cm on a type 26. (From Marines Magazine No 7 Les vedettes au combat)


Stern 2cm on early boat, in action. The spent shell basket was not always used. (From Marines Magazine No 7 Les vedettes au combat)


Stern 2cm on mid war boat. The deck is covered with a slip resistant matting.