River-class offshore patrol vessel

	Batch 1 River-class vessels HMS Severn, HMS Tyne and HMS Mersey exercising off the coast of Cornwall, 2012
Class overview
Name	River class
Builders	Batch 1: Vosper Thornycroft; Batch 2: BAE Systems Maritime – Naval Ships;
Operators	Royal Navy; Brazilian Navy; Royal Thai Navy; Royal Bahrain Naval Force;
Preceded by	Castle class
Subclasses	Krabi-class patrol vessel; Amazonas-class corvette;
Built	2001–present
In commission	2003–present
Planned	14
Completed	14
Active	8 (Royal Navy); 3 (Brazilian Navy); 2 (Royal Thai Navy); 1 (Royal Bahrain Naval Force);
General characteristics
Type	Offshore patrol vessel
Displacement	Batch 1: 1,700 t (1,700 long tons); Batch 2: 2,000 t (2,000 long tons);
Length	Batch 1: 79.5 m (260 ft 10 in); Batch 2: 90.5 m (296 ft 11 in);
Beam	Batch 1: 13.5 m (44 ft 3 in); Batch 2: 13.5 m (44 ft 3 in);
Draught	Batch 1: 3.8 m (12 ft 6 in)
Propulsion	Batch 1:; 2 × Ruston 12R270 diesel engines, 8,250 kW (11,060 hp), 2 shafts ; 2 × controllable-pitch propellers; Batch 2:; 2 × MAN 16V28/33D diesel engines, 14,700 kW (19,700 hp), 2 shafts; 2 × controllable-pitch propellers;
Speed	Batch 1: 20 knots (37 km/h; 23 mph); Batch 2: 25 knots (46 km/h; 29 mph);
Range	Batch 1 & 2: 5,500 nmi (10,200 km; 6,300 mi)
Endurance	Batch 1: 21 days; Batch 2: 35 days;
Boats & landing; craft carried	Two Pacific 24 RIBs; ; Batch 2: Small Unmanned underwater vehicles may be embarked for mine countermeasures;
Troops	Batch 1: c. 18; Batch 2: up to 50;
Complement	Batch 1: 28-30; Batch 2: 34-50;
Sensors &; processing systems	Batch 2:; Kelvin Hughes Ltd SharpEye navigation radar; Terma Scanter 4100 2D radar; BAE CMS-1; Shared Infrastructure operating system;
Armament	Batch 1:; 1 × Oerlikon 20 mm cannon; 2 × General purpose machine guns; Batch 2:; 1 × Bushmaster 30 mm cannon; 2 × Miniguns (replaced by Browning .50 caliber heavy machine guns as of 2023); 2 × general purpose machine guns;
Aviation facilities	Batch 2: Merlin-capable flight deck; small UAVs may be embarked
Notes	Batch 1: 25-tonne crane; Batch 2: 16-tonne crane;

The River class is a class of offshore patrol vessels built primarily for the Royal Navy of the United Kingdom. A total of nine were built for the Royal Navy (RN), four Batch 1 and five Batch 2. One Batch 1 (HMS Clyde), which was the Falklands guard ship, was decommissioned and transferred at the end of its lease to the Royal Bahrain Naval Force.

The three remaining Batch 1 ships perform fisheries security and border patrol tasks in UK waters. The five new Batch 2 ships provide overseas forward presence, performing maritime security duties and disaster relief operations, often supported by a Royal Fleet Auxiliary vessel.

The Batch 1 ships of the class replaced the seven ships of the Island class and the two Castle-class patrol vessels.

HTMS Krabi was the first of two ships adapting the River design for the Royal Thai Navy and built in Thailand. The three ships of the Amazonas-class offshore patrol vessel in service with the Brazilian Navy were developed from the Batch 1 River-class design, and the Royal Navy's Batch 2 ships were in turn based upon the Amazonas design.

Class overview
Batch 1 River-class vessels HMS Severn, HMS Tyne and HMS Mersey exercising off the coast of Cornwall, 2012
Name	River class
Builders	Batch 1: Vosper Thornycroft Batch 2: BAE Systems Maritime – Naval Ships
Operators	Royal Navy Brazilian Navy Royal Thai Navy Royal Bahrain Naval Force
Preceded by	Castle class
Subclasses	Krabi-class patrol vessel Amazonas-class corvette
Built	2001–present
In commission	2003–present
Planned	14
Completed	14
Active	8 (Royal Navy) 3 (Brazilian Navy) 2 (Royal Thai Navy) 1 (Royal Bahrain Naval Force)
General characteristics
Type	Offshore patrol vessel
Displacement	Batch 1: 1,700 t (1,700 long tons) Batch 2: 2,000 t (2,000 long tons)
Length	Batch 1: 79.5 m (260 ft 10 in) Batch 2: 90.5 m (296 ft 11 in)
Beam	Batch 1: 13.5 m (44 ft 3 in) Batch 2: 13.5 m (44 ft 3 in)
Draught	Batch 1: 3.8 m (12 ft 6 in)
Propulsion	Batch 1: 2 × Ruston 12R270 diesel engines, 8,250 kW (11,060 hp), 2 shafts 2 × controllable-pitch propellers Batch 2: 2 × MAN 16V28/33D diesel engines, 14,700 kW (19,700 hp), 2 shafts 2 × controllable-pitch propellers
Speed	Batch 1: 20 knots (37 km/h; 23 mph) Batch 2: 25 knots (46 km/h; 29 mph)
Range	Batch 1 & 2: 5,500 nmi (10,200 km; 6,300 mi)
Endurance	Batch 1: 21 days Batch 2: 35 days
Boats & landing craft carried	Two Pacific 24 RIBs; Batch 2: Small Unmanned underwater vehicles may be embarked for mine countermeasures
Troops	Batch 1: c. 18 Batch 2: up to 50
Complement	Batch 1: 28-30 Batch 2: 34-50
Sensors & processing systems	Batch 2: Kelvin Hughes Ltd SharpEye navigation radar Terma Scanter 4100 2D radar BAE CMS-1 Shared Infrastructure operating system
Armament	Batch 1: 1 × Oerlikon 20 mm cannon 2 × General purpose machine guns Batch 2: 1 × Bushmaster 30 mm cannon 2 × Miniguns (replaced by Browning .50 caliber heavy machine guns as of 2023) 2 × general purpose machine guns
Aviation facilities	Batch 2: Merlin-capable flight deck; small UAVs may be embarked
Notes	Batch 1: 25-tonne crane Batch 2: 16-tonne crane