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 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.
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.