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Prototype Seehund's

The Seehund was the final iteration of a number of miniature submarines inspired by the British X-Class submarine. Two of these X-Class boats, (HMS X6 and X7) were captured by the Germans during the allied attack on the Tirpitz at Kåfjord in Norway on the 22nd September 1943.

The first version was known as the XXV11A or Hecht (German: “Pike”) and was a two man, all electric, submarine. It was just over 10 metres long and its electric motor was one originally used on the AEG torpedo. The small electric motor gave it a poor range of only 69 nautical miles when travelling at 4 knots (about 4.6 miles per hour) with a top submerged speed of just 6 knots (6.9 miles per hour) Like the British X-Class vessel the Hecht was designed to place its lethal charges beneath enemy ships.


The Hecht was intended to pass through anti-submarine nets so that  it could reach its targets in protected harbours. To allow it to do this it was initially designed without hydroplanes or even ballast tanks and used instead adjustable weights within the pressure hull to control her trim. However, it was soon found that this method was completely unsuitable and hydroplanes and fins were soon added.

The submarine was designed to carry a deployable explosive charge in the nose section and either a single under slung torpedo or mine for attacks on vessels in coastal waters.

Key Features of the Hecht Miniature Submarine


12 tons submerged


10.4 metres (34 feet)


1 x 12 horse power AEG electric torpedo motor


6 knots (6.9 miles per hour) when submerged


69 nautical mile (79 miles) when travelling submerged at 4 knots (4.6 miles per hour)




1 x G7e torpedo or 1 x mine plus a deployable explosive charge held in the nose section

Whilst some 53 Hecht’s were built, as far as records show, none of them saw action, instead they were used to train the future crews of the Seehund boats.

The second iteration of the midget submarine was an advance on the original Hecht. The XXII1B had several improvements; the boat was now driven by both a 25 horse power electric motor (for use underwater) and a 22 horse power diesel motor (for surface use). In addition, the external casing was redesigned to have a more boat-like profile for better surface performance and the size of the hull was improved by moving the batteries into the keel. These changes gave this model much improved range and speed over the original Hecht, 5.5 knots on the surface (6.3 miles per hour) and 6.9 knots submerged (7.9 miles per hour). The armament was also changed; the nose no longer held an explosive charge and the single torpedo, slung beneath the keel, was now replaced by two side mounted G7e torpedoes.

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