Muraena is another innovative idea for littoral and counter terror warfare is proposed by HDW for submarines. The system is a hoistable, mast-mounted automatic gun designed specifically for submarines. HDW expects to complete the system development by 2007. The unique design enables the submarine to use lethal force without having to surface, therefore maintaining the element of surprise. The hoistable mast, designed by Gabler Maschinebau, is fitted wit a Mauser 30mm automatic gun (RMK 30×230) from Rheinmetall Waffe Munition (Mauser Werke) without having to surface. The gun can be operated from periscope depth, enabling the submarine to remain underwater and not expose itself to hostile small arms, RPG or missile fire. The gun is accommodated in the submarine’s super structure, in a pressure-tight container and can be hoisted hydraulically like a snorkel. For a gun of this calibre to be installed on top of a hoistable mast, it is essential for it to be recoilless. The gun has already been tested on a light armored vehicle.