Castle-class patrol vessel

BNS Dhaleshwari (ex-HMS Leeds Castle) in 2018
Class overview
Builders	Hall, Russell & Company
Operators	Royal Navy (retired)  Bangladesh Navy (active)
Preceded by	Island class
Succeeded by	River class
Built	1979–1981
In commission	1982–Present
Planned	6
Completed	2
General characteristics
Type	Offshore patrol vessel
Displacement	1,570 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 (2,100 kW)
Speed	20 knots (37 km/h)
Range	10,000 nautical miles (19,000 km) at 10 knots (19 km/h)
Complement	40
Sensors and processing systems	Type 1006 radar Simrad RU sidescan sonar (Bangladesh Navy installed Type 360 Radar as the main radar)
Armament	Royal Navy: 1 × Bofors 40 mm gun Mark III, replaced by 1 × 30 mm gun Bangladesh Navy: 1 x 76 mm (3.0 in) main gun 4 × C-704 AShM Small caliber guns or autocannons
Aviation facilities	Flight deck capable of supporting a Sea King helicopter

The Castle class was a class of British offshore patrol vessels of the Royal Navy. Two ships were constructed and after nearly 30 years service were sold to the Bangladesh Navy in 2010. The Bangladesh Navy upgraded these with more armaments including C-704 anti-ship missiles and sensors. These ships are now reclassified as corvettes by the Bangladesh Navy.