The Spica I class comprised six patrol torpedo boats built for the Royal Swedish Navy around 1966. These boats were specially fast and provided
with gas turbine engines of very fast acceleration. Their bridge superstructure was placed backwards to grant
the widest firing arc possible to the 57-millimeter cannon. This particular weapon, built by the national company Bofors, is extraordinarily effective, with a rate of fire
of 200 rounds per minute and a wide elevation arc. The Swedish Navy considered this weapon to be more effective than a missile against
aerial targets and obviously it could be used as well against surface targets. It was controlled by a localization and tracking radar housed in
a fiberglass dome, whereas the torpedoes were controlled via cable link.
Between 1973 and 1976 were built twelve units of the Spica II class, featuring a modified hull and separated radar devices for localization and
tracking. Sweden did not adapt the Spica class to carry missiles, relying instead in a Norwegian project modified with Penguin surface-to-surface
missiles. The Royal Danish Navy produced ten units of the Spica class with modifications; they were armed with surface-to-surface missiles Harpoon
and a 76-millimeter cannon OTO Melara Compact, apart from the 533-millimeter torpedoes, and the bridge was reallocated into a more forward position.
Another four boats of the Spica class were built for Malaysia, fitted with Diesel MTV engines.
Spica I class: 6 units - Capella, Castor, Sirius, Spica, Vega, Virgo
Type: Patrol torpedo boat
Length: 43.8 meters
Beam: 7.1 meters
Draught: 1.6 meters
Displacement (standard): 203 tonnes
Propulsion: 3 x shaft, 3 x gas turbine Rolls-Royce Proteus, 12750 horsepower
Speed: 40 knots (74 kilometers/hour)
Armament: 6 x 533-millimeter torpedo tube, 1 x 57-millimeter dual-purpose cannon, 2 x 7.62-millimeter machine gun,
2 x 103-millimeter flare/chaff launcher, 1 x 57-millimeter rocket launcher, 2 x minerail for mines/depth charges