Tenders were sought from various European boat builders in the United Kingdom, Norway and Germany including Lurssen who offered the new Jaguar-class design.

The Swedes ended up designing a bespoke vessel which became the template for subsequent Swedish fast attack craft.

The Bridge and Operations Room were located at the rolling and stamping centre of the ship which further improved stability for the crew especially in high seas.

The boats were fitted with an NBC support system where the hull could be closed down in the event of having to operate in a nuclear fall-out area.

The machinery consisted of three shafts powered by British built, Bristol Proteus gas turbines.