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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.

About 1160 the Hanse seized the Swedish island of Gotland and developed Visby as a base and bastion for the Baltic trade. At its height in the fourteenth century the League bound fifty-two towns. It controlled the trade of northern Europe from Rouen to Novgorod. For a long time it monopolized the herring fisheries of the Baltic and the trade of the Continent with England. It established courts for the settlemen of disputes among is members, defended its members against law suits from without, and at times waged war as an independent power.

The Visby Project was the largest surface vessel project ever conducted by Kockums. The project, which had been in progress for more than a decade, evolved steadily, attracting considerable attention for its stealth technology. The vessels are built in plastic laminate, a material that makes the ship very strong and resilient in relation to their weight. The material is one of the factors that gives the vessels very low signature levels, in terms of radar, magnetic and hydro-acoustic. This makes them difficult to detect on radar and infrared camera. At the same time the vessels can withstand shock effects very well and they can also take a big load.

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.

At the very beginning it was thought that there would be 10 ships two versions with different specialties. Circumstances resulted in five ships with all functions - plans for an anti-air warfare capability fell victim to financial restrictions. The corvettes are some of the "stealthiest" ever developed but they are extremely costly [possibly $200 million each] and of the six ordered between 1995 and 1999 only five were completed. Kockums built the five Visby corvettes and delivered them to the customer, FMV (the Swedish Defence Matriel Administration), which conducted a program of trials and tests. There is some mystery as to when some of the units were commissioned. They had been operated by the procurement agency, Forsvarets Materielverk (FMV), which had conducted extensive testing and trials and continued to do so until the corvettes joined the fleet between 2012 and 2014.

Five years behind schedule, the first of the Visby class corvettes have been formally declared operational. The first to be commissioned was HSwMS Helsingborg, in April 2006, closely followed by three sister ships with HSwMS Karlstad scheduled to join them two years later. The fifth of series, HMS Karlstad, remained under construction in 2008. HMS Helsingborg and HMS Hrnsand were the first two corvettes in the Visby series delivered to the Swedish Armed Forces to be included in the organization and ready for missions. FMV handed over the two ships to the Armed Forces at a ceremony in Karlskrona on 16 December 2009. The two ships which were equipped with over-water and underwater sensors and were in this version (version four) able to be operational in a number of national and international tasks.

With these the ships reached their initial operational capability (the so-called Version Four) and they entered a "Special Period" which addressed signature, sensor as well as weapon integration and safety issues. This would bring the ships to full operational (Version Five) status. When the first Visby corvettes were delivered in version five in 2012, there were trained crews available. In 2012 FMV delivered two corvettes of Visby class to the Swedish Armed Forces. This meant that there were two Visby corvettes which can hunt submarines with torpedoes, depth charges and sonar. They can both deploy and clear mines, and fire anti-ship missiles. They also have an airport function for takeoff and landing helicopters. The ships have been supplemented by including mine clearance systems, helicopter landing capability, anti-surface ship missile and additional stealth adaption. Two were delivered in the second half of 2013, followed by the last in 2014.

There is considerable international interest in the Visby corvettes: open almost any international naval journal and the impact of the Visby-class ships is immediately apparent in many new naval designs. But so far, Sweden is the only country to have built a true stealth corvette. It is of course vital that Sweden exploit this lead. But one of the Swedish vessels must be fully operational with the Swedish Navy before export orders start arriving at Kockums, because a reference customer is crucial in securing an export order.

"In the Swedish Navy's operational environment, namely the littoral zone, the stealth-technology Visby-class corvettes are the right concept for the future. After final delivery and commissioning, these vessels will form the core of the Swedish Navy for years to come. And our stealth concept has already attracted considerable international attention," says Rear Admiral Anders Grenstad, Inspector General of the Royal Swedish Navy.

Despite Swedens continued abstention from the ocean option, its navy is likely to be called on to join others in military or security operations in waters farther from its traditional dominion. This has given impetus to the Visby of tomorrow, or the Visby Plus.

At Kockums development is going ahead on larger versions of Visby, designed in accordance with Det Norske Veritas Naval Rules, with a variety of equipment options aimed at the international market. The Visby Plus has been programmed to reduce production costs, even as it will have full stealth technology. Its design takes a modular approach to simplify customization, including weight and volume reserved for future modifications.

The initial Visby Plus carbon-fibre cored composite model is 88 meters LOA, with 1 500 tonnes displace-ment. Its prime functions will be anti-submarine warfare, surface attack, air defence, training, and patrol. According to preliminary calculations, when compared to a conventional propeller-driven steel vessel, with an aluminium superstructure, funnel exhausts, and non-stealth weapons and sensors, the new design will have the following considerable gains:

  • A lower profile for a reduced visual signature
  • A lighter, more shock-resistant structure
  • A lower displacement and draft, requiring less engine power
  • Reduced fuel consumption, hull maintenance, and operating costs
  • Lower hydroacoustic, magnetic, infrared, and radar signatures.

The new corvette will have berths for 71 crew, a helipad and hangar, two universal cranes and two ships boats. The propulsion will be four diesel engines of about 7 400 kW driving four waterjets. The engine room will be set aft, to leave appreciable volume amidships for operations. An integrated system will control, monitor, and provide support for navigation, propulsion, electrical power, peripheral systems, ship safety, fire protection, and damage control. Weapons and command-and-control systems will be NATO-compatible.

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Page last modified: 10-08-2013 17:27:22 ZULU