The Superkavitierender Unterwasserlaufkörper (lit. Supercavitating Underwater Running Body) (formerly known as Barracuda) was a development project of the German armaments company Diehl BGT Defense in cooperation with the German Navy. The supercavitating torpedo for close-range defense of underwater targets was presented to the public in 2005 as a prototype, but it never went into development and procurement.
This form of torpedo solves the problem of high underwater drag by means of the supercavitation effect, where underwater at a velocity of around 180 km/h a cavitation filled with steam surrounds the moving object. Only the tip is in contact with the water, as such the frictional resistance is greatly reduced. The propulsion of such a torpedo can no longer be done by a propeller, but requires a rocket engine.
To steer, this torpedo has a pivoting head segment. If the torpedo rises or falls, the water pressure acting on it also changes, and the cavitation bubble changes. When sinking, the water pressure increases and the bubble is compressed; when the torpedo rises, the pressure drops and the bubble gets bigger. In order to keep the bubble intact with increasing water pressure, additional gas is pumped into the bladder.
According to the manufacturer, the torpedo reaches a speed of over 400 km/h underwater and is steerable. It is not dependent on the launch of submarines, but can dive into the water from air and continue its supercavitation trip there.
There is no known defence against such a torpedo and it would therefore be an effective short-range weapon against heavily protected and mobile military sea targets. The system would also be able to combat other unguided supercavitation torpedoes due to its high maneuverability.
The system is comparable to the 1977 Soviet VA-111 Shkval.
- Слюсар В.И. Электроника в борьбе с терроризмом: защита гаваней. Часть 2. //Электроника: наука, технология, бизнес. – 2009. - № 6. - C. 90 - 95. 
- Gerhard Hegmann: In unter einer Stunde den Atlantik durchqueren? (In less than an hour across the Atlantic?) In: Welt.de from 3 July 2016, retrieved on 16. March 2017.