Castle-class patrol vessel
|Builders:||Hall, Russell & Company|
|Preceded by:||Island-class patrol vessel|
|Succeeded by:||River-class patrol vessel|
|Displacement:||1,427 tons full load|
|Length:||246 ft (75 m) (overall)|
|Beam:||37 ft 9 in (11.51 m)|
|Draught:||11 ft 3 in (3.43 m)|
|Propulsion:||2 shafts, 2 Paxman diesels, 2,820 hp|
|Speed:||20 knots (37 km/h)|
|Range:||10,000 nautical miles (19,000 km) at 10 knots (19 km/h)|
|Type 1006 Radar
Simrad RU sidescan sonar
|Armament:||1 × Bofors 40 mm gun Mark III, replaced by 1 × 30 mm gun|
|Aviation facilities:||Flight deck capable of supporting a Sea King helicopter|
Ships in Class 
HMS Leeds Castle (P258) (Commissioned August 1981)
HMS Dumbarton Castle (P265) (Commissioned March 1982)
The Castle class was intended as a series of six offshore patrol vessels for the Royal Navy, designed in response to criticism of the previous Island class for insufficient speed, non optimal sea keeping and lack of a flight deck for rescue helicopters.
In the event, only two ships were built, HMS Leeds Castle and HMS Dumbarton Castle. Both vessels were built by Hall Russell in Aberdeen. These had significant improvements over the Island class - they are 300 tonnes larger, more stable in heavy seas, 3 knots (5.6 km/h) faster and are fitted with a large flight deck that is capable of supporting a Sea King. For brief periods, the ships can accommodate up to 120 troops.
Their primary mission is to serve with the Fishery Protection Squadron, protecting both the fishing fleets and the oil and gas fields of the North Sea. In addition, they can also serve as minelayers, and have detergent spraying facilities on board for dispersing oil slicks.
Since the Falklands War, one ship had been kept long term in the Falkland Islands as a guardship. Leeds Castle and Dumbarton Castle rotated the role on a three-yearly basis, although the ship's crew usually did a six month rotation.
The Castle class has now been replaced by a unique vessel based on the River class, HMS Clyde, and both vessels of the class are now decommissioned. Originally due to transfer to the Pakistani Maritime Security Agency in 2007, the deal fell through and both ships have now been sold to Bangladesh.
- "Bangladesh Secures 2 Used British OPVs". Defense Industry Daily. 2010. Retrieved 2010-05-06.
- "Shipyard deal safeguards 100 jobs". BBC News. 2010-04-26.
- Conway's All The World's Fighting Ships 1947-1995
- D.K. Brown, The Design of the Castle Class, a personal view in Warship 2006, Conway's Maritime Press
- Janes Fighting Ships 2007