The Visby-class corvette concept has been developed as the result of collaboration between FMV, the Royal Swedish Navy, the Swedish defence industry, the Swedish Defence Research Establishment and Stockholm's Royal Institute of Technology (KTH), who are jointly responsible for technological development and planning. The Visby-class corvette has attracted considerable international attention, being the first "stealth" vessel in series production.
The primary roles of the first series of corvettes are for Mine Countermeasures (MCM) and Anti-Submarine Warfare (ASW). The second series is primarily for the attack and anti-surface warfare role. A helicopter can land, take off, and refuel on the upper deck.
The design of the Visby has been directed to minimising the optical and infra-red signature, above water acoustic and hydroacoustic signature, underwater electrical potential and magnetic signature, pressure signature, radar cross section and actively emitted signals. A conventional non-stealth-designed corvette could typically be detected at a range of 50 kilometres in normal environment and at 25 kilometres in a jammed environment. A stealth corvette of the YS 2000 design has a detection range of 13 kilometres in rough seas and 22 kilometres in calm sea without jamming. In a jammed environment the YS 2000 would be detected at a range of 8 kilometres in rough sea and 11 kilometres in calm sea.
The hull is designed on stealth principles with large flat angled surfaces. Every feature which does not necessarily have to be located outside the hull has been built in or concealed under hatches. The gas turbine exhausts have been concealed in hidden outlets close to the water surface at the stern of the vessel. The hull material is a sandwich construction comprising a PVC core with a carbon fibre and vinyl laminate. The material provides high strength and rigidity, low weight, good shock resistance, low radar signature and low magnetic signature.
The Visby is equipped with a combined diesel and gas (CODAG) turbine arrangement Four TF 50 A gas turbines from Allied Signal for medium and high speed manoeuvres and two MTU 16V 2000 N90 diesel motors for low speed long duration operations are connected to two gearboxes which run two Kamewa waterjet propulsors. The motors provide a maximum speed of 15 knots for long duration and 35 knots for short duration.
More information: Defence Systems Daily