Features: The ship is designed to tow an array of underwater listening devices to collect acoustical data. The ship also carries electronic equipment to process and transmit that data via satellite to shore stations for evaluation. The ship, the listening devices and electronic equipment are all part of a system called the Surveillance Towed Array System, or SURTASS. Victorious class ocean surveillance ships are built on a Small Waterplane Twin Hull, or SWATH, design for greater stability at slow speeds in high latitudes under adverse weather conditions. Impeccable class ships have a hull form based on that of Victorious. Acoustic systems should include an active low frequency towed array, which has a series of modules each of which houses two high-powered active transducers. These can be used with either mono or bistatic receivers.