Castle Class Offshore Patrol Vessels

During the 1960s a number of Ton Class minesweepers underwent conversions into patrol craft and served with the Fishery Protection and Northern Ireland Squadrons. The Castle Class were designed as purpose built Offshore Patrol Vessels (OPVs) to either relegate the aging Ton Class vessels to coastal waters or replace them altogether. However, only two vessels of a possible class of six were ever ordered. Like the Island Class, both Castle Class vessels- Leeds Castle and Dumbarton Castle- were build in Aberdeen by Hall Russell. Costing £12 million each they entered service in 1982.

Officially designated 'Offshore Patrol Vessels Mark II' the design of the Castle Class incorporated significant improvements over the Island Class. Displacing 1,450 tonnes and measuring 81 metres in length, 11 metres in beam, and 3 metres in draught, they are much larger than the Island Class and can spend longer periods at sea. Powered by two Ruston Diesel engines they are also much faster with a maximum speed of 20 knots and a cruising speed of 15 knots (the Island class travel at 17 knots maximum). Most importantly they were built with a large flight deck capable of supporting a Sea King helicopter. Although no hanger is provided, refeuling facilities are available and allow the helicopter to operate at sea for longer periods of time without needing to return to base. For short periods of time the Castle Class vessels can accommodate up to 120 troops or for longer durations 30 troops.

As Offshore Patrol Vessels (OPVs) the two of the primary duties of these ship have been to patrol North Sea Gas and Oil Fields (with up to 50 Royal Marines embarked for anti-terrorist operations) and to act as Fishery Protection Vessels. However they are capable of a fulfilling a number of additional roles including that of environmental protection vessels (they have detergent spraying facilities for dispersal of oil slicks) and as minelayers (they have undergone tests for this role). During the Falklands Campaign (1982) they served as dispatch vessels and in recent years they have alternated the role of Falkland Islands Guardship, spending long periods of time (up to three years) in the South Atlantic, with their crews rotating every four months.

Class Details

Above: HMS Dumbarton Castle pictured just having executed a swift turn. © Crown Copyright.

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© Written and researched by Jeremy Olver. Last updated 29th October 2000. Disclaimer.