Built by Kvaerner Mandal in 1996 - 7 the Alta class are surface effect catamaran vessels with fibre reinforced plastic hulls with a low magnetic signature. Two large fans located on each side create an air cushion between the two hulls and a front and aft rubber skirt, lifting the vessel, giving low drag and a high cruise speed, as well as low susceptibility to the shock of exploding mines since only a small portion of the hull is actually exposed in the water.