Visby
The Visby Class corvette is the first vessel in the world to have fully developed stealth technology, combined with high operational versatility. The outstanding stealth properties fundamentally change the ship's survivability and improve its mission effectiveness.
Visby is a flexible surface combatant, designed for a wide range of roles: anti-surface warfare (ASuW), anti-submarine warfare (ASW), mine countermeasures (MCM), patrol and much more.
In 1986 the Swedish Defence Material Administration (FMV) initiated the development of a stealth test platform, HMS Smyge. It was launched in 1991 and used for testing stealth characteristics in all possible aspects. This formed the basis for the YS 2000 project - the Visby Class corvette.
The Visby is designed to minimize all signatures - optical and infrared signature, above water acoustic and hydroacoustic signature, underwater electrical potential and magnetic signature, pressure signature, radar cross section and actively emitted signals.
The difference in detection range between an ordinary vessel and Visby creates a considerable zone where the Visby can see but not be seen.
All missions are supported by CETRIS - the real-time command, control, communication, intelligence and interoperability system (C4I2). The system is modular and open, and allows for integration of future technologies, without expensive changes.
The Visby is designed for the installation of a surface-to-surface missile (SSM) system. On the Swedish version, eight SSM (RBS15 MkII) can be fully integrated into the hull and covered with smart rapid hatches.
The air defence system (ADS) is totally integrated, and it dynamically, automatically and simultaneously calculates and performs hard-kill as well as soft-kill engagements.
The active part of the ADS consists of the Bofors 57 mm multi-purpose gun, with a new, stealth cupola designed as an integrated part of the hull structure.
The Visby is designed for the installation of an air defence missile system (SAM), fully integrated into the aft part of the vessel.
The ADS also includes the ESM and various electronic countermeasures.
The MCM system consists of a combination of extremely low signatures, sensors and weapons, and very high shock resistance.
For detecting and classifying mines, the Visby uses ROVs (remotely operated vehicles).
A powerful sonar system is used to detect, locate, classify and supply real-time target data to the weapons.
In addition, the sonar-equipped ROV-S can be launched for surveillance and classification of targets.
The Visby is equipped with wire-guided, homing 40 cm torpedoes. A submarine can also be attacked with an ROV-E or the brand-new 5" ASW multiple rocket system.
The hull is designed on stealth principles with large flat angled surfaces. Every feature that need not necessarily be located outside the hull has been built in or concealed under specially designed hatches. The gas turbine exhausts have been concealed in hidden outlets close to the water surface at the stern of the vessel.
The vessel is built of sandwich-construction carbon fibre reinforced plastic (CFRP). The material provides high strength and rigidity, low weight, good shock resistance, low radar signature and low magnetic signature.
The material dramatically reduces the structural weight (typically 50% of a conventional steel hull). This results in a higher payload carrying capability, higher speed or longer range.
The Visby is equipped with a combined diesel or gas (CODOG) turbine arrangement for high speeds and two diesel engines for low-speed. The engines are connected to two gearboxes, driving two waterjet propulsors. The engines provide a maximum speed of 15 knots for long duration and 35 knots for short duration. The ship has bowthrusters for harbour manoeuvring.
