HMS Opportune (S20)

HMS Opportune (S20) was an Oberon-class submarine of 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 241 ft in length between perpendiculars and 295.2 ft in length overall, with a beam of 26.5 ft, and a draught of 18 ft. 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 3,000 shp electric motors, each driving a 7 ft 3-bladed propeller at up to 400 rpm. Top speed was 17 kn when submerged, and 12 kn on the surface. Eight 21 in 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.

Opportune was laid down by Scotts Shipbuilding and Engineering Company on 26 October 1962, and launched on 14 February 1964. The boat was commissioned into the Royal Navy on 29 December 1964.

Operational history
On 15 February 1967, Opportune was in collision with sister submarine HMS Orpheus (S11) when Opportune was leaving Portsmouth harbour as Orpheus was entering at night and in heavy weather, with only minor damage caused. Orpheus's commanding officer was found guilty of hazarding his vessel and was reprimanded. In 1971, Opportune collided with a merchant ship, causing damage to the upper front part of the fin as well as both periscopes.

Opportune attended the 1977 Silver Jubilee Fleet Review off Spithead when she was part of the Submarine Flotilla.

Decommissioning and fate
Opportune was paid off on 2 June 1993. For several years the vessel resided at Pounds scrapyard in Portsmouth.

Every year since the vessel was scrapped, senior rates from the boat have annually met together to celebrate their service and life on the boat.