HMS Onslaught was a British submarine operated by the Royal Navy. Design and construction The Oberon class was a direct follow on of the Porpoise-class, with the same dimensions and external design, but updates to equipment and internal fittings, and a higher grade of steel used for fabrication of the pressure hull. As designed for British service, the Oberon-class submarines were in length between perpendiculars and in length overall, with a beam of , and a draught of . Displacement was 1,610 tons standard, 2,030 tons full load when surfaced, and 2,410 tons full load when submerged. Propulsion machinery consisted of 2 Admiralty Standard Range 16 VMS diesel generators, and two electric motors, each driving a , 3-bladed propeller at up to 400 rpm. Top speed was when submerged, and on the surface. Eight diameter torpedo tubes were fitted (six facing forward, two aft), with a total payload of 24 torpedoes. The boats were fitted with Type 186 and Type 187 sonars, and an I-band surface search radar. The standard complement was 68: 6 officers, 62 sailors. Onslaught was laid down by Chatham Dockyard on 8 April 1959, and launched on 24 September 1960. The boat was commissioned into the Royal Navy on 14 August 1962. Operational history Her patrols in the Mediterranean and Baltic from 1986 to 1988 are classified. Decommissioning and fate Onslaught was paid off in 1990. References Publications . Oberon-class submarines of the Royal Navy Ships built in Chatham 1961 ships Cold War submarines of the United Kingdom