CB90 Class

CB90 Class fast assault craft is an exceptionally fast and agile boat that can execute extremely sharp turns at high speed, decelerate from top speed to a full stop in 2.5 boat lengths, and adjust both its pitch and roll angle while under way. Its light weight, shallow draught, and twin water jets allow it to operate at speeds of up to 44 knots in shallow coastal waters. The water jets are partially ducted, which, along with underwater control surfaces similar to a submarine's diving planes, gives the CB90 its manoeuvrability.

Design
In 1988, former Dockstavarvet won a competition to design and manufacture a replacement for the aging Tpbs 200 class. Two prototypes, with pennant number 801 and 802, were delivered in 1989. After completion of field trials, the Swedish Navy signed a purchase order for 120 boats in June 1990.

Command & Control
Visby Class were the first Sjøforsvaret's ships to be equiped with TERMA C-Flex Combat Management System. C-Flex is basen on open system architecture and is able to integrate the Saab 9LV FCS Fire Control System and Saab EOS 500 Electro Optical Fire Control. The system is completed with a TERMA SCANTER 4100 Surveillance Radar and a modified Kongsberg C-Scope Sonar System.

The communications system has a high-capacity digital communications switch, developed by TERMA, which interconnects the voice and data communications channels. The system provides internal communications or open conference lines and access to external communications with various radio links and land-based networks.

Power generation & propulsion
The power plant of the ship has been completely redesigned to suit the needs and requirements of the Sjøforsvaret and the new systems and elements of the ship. KUFLO chose to equip the ship with a mixed multi-gas turbine and fuel cell propulsion system (COFCAG) developed jointly by NAtech and Volvo Aero. Main fuel for which the system has been designed is hydrogen, but the system can also work with natural gas, methane and other gases, although with a lower energy efficiency. At low speed and during maneuvers the system uses the power delivered by the fuel cells, using the gas turbine system to achieve higher speeds. In addition, the system reuses the exhaust gases to turbocharge the turbine and for the ship's heating systems, which considerably reduces the ship's thermal footprint and finally the remaining gases are expelled from the stern. Power plant of the ship was designed taking into account the current needs of energy for propulsion and other systems on board, so it was possible to assume an increase in power required if new equipment or systems were installed in the future.

The propulsion system is fully electrical with two Kamewa (nos NAtech marine hydrojets mounted externally to the main hull. The electricity for the motors is supplied by the power system. The ship has rudders and bowthrusters for harbour manoeuvring.

Electronic systems
One of the main design premises was the need to mount Kalmar Union made electronic systems in order to full integration with other Forsvaret systems and satellite net.

Sensors
 * 1 x TERMA SCANTER 2100 Surveillance Radar (Mk2)
 * 1 x Kongsberg Integrated Director Group (IDG) radar system for target acquisition (Mk2)
 * 1 x Kongsberg EriTac communications system (Mk2)

Decoys
 * 1 x TERMA DL-22T Multi Ammunition Decoy System (Mk2)

Armament

 * 1 × 8 cell Vertical Launching System w/ 16 Meteor SAM missile
 * 12 RBS15 Mk3 SSMs
 * 4 torpedo tubes for Torpedo 62
 * 1 ASW 127mm rocket-powered grenade launchers and depth charges
 * 1 57 mm AB BOFORS Mk.3
 * 1 x 40 mm Kongsberg M2HB HMG Sea Protector