River class patrol vessel

HMS Clyde exercising off the Falklands in 2014
Class overview
Name:	River-class
Builders:	Batch 1: Vosper Thornycroft Batch 2: BAE Systems Maritime – Naval Ships
Operators:	Royal Navy
Preceded by:	Castle class
Subclasses:	HTMS Krabi Amazonas-class corvette
Built:	2001—2018
In commission:	2003—present
Building:	3
Planned:	9
Completed:	4
Active:	4
General characteristics
Type:	Offshore patrol vessel
Displacement:	Batch 1: 1,700 t (1,700 long tons; 1,900 short tons) Batch 2: 2,000 t (2,000 long tons; 2,200 short 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 2: 2 × MAN 16V28/33D diesel engines, 14,700kW/10,950HP, 2 shafts 2 × controllable-pitch propellers
Speed:	Batch 1: 20 kn (37 km/h) Batch 2: 25 kn (46 km/h)
Range:	Batch 1: 5,500 nmi (10,200 km) Batch 2: 5,500 nmi (10,200 km)
Endurance:	Batch 1: 21 days Batch 2: 35 days
Boats & landing craft carried:	Two Pacific 24 RIBs
Troops:	Batch 1: 18-20 Batch 2: 26-50
Complement:	Batch 1: 30 Batch 2: 34 HMS Forth will have a crew of 58
Sensors and 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 × 30 mm cannon 2 × Miniguns 2 × General purpose machine guns
Aviation facilities:	Batch 2: Merlin-capable flight deck
Notes:	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 are planned for the Royal Navy; four Batch 1 and five Batch 2. The Batch 1 ships of the class replaced the seven ships of the Island class and the two Castle-class patrol vessels. HTMS Krabi is a variation of the River design built in Thailand for the Royal Thai Navy. The three ships of the Amazonas-class corvette in service with the Brazilian Navy are also a variation of the River design.

In early 2001, the Ministry of Defence placed an order with Vosper Thornycroft (VT) for three River-class offshore patrol vessels to replace the Island-class. It was understood that the higher availability rates of the River-class (up to 300 days per year), would enable the three new ships to perform the duties of the five ships they replaced. The Royal Navy initially chartered (or leased) the ships under a five-year, £60 million contract from the builder VT. As part of the contract, VT would be responsible for all maintenance and support during the charter period. This contract was renewed in January 2007 for another five years at £52 million. However, in September 2012, instead of renewing the contract again, it was announced by the Defence Secretary Philip Hammond that the Ministry of Defence had purchased the vessels for £39 million. They are expected to leave service in 2023.

The River-class are significantly larger than the Island-class vessels and have a large open deck aft allowing them to be fitted with equipment for a specific role, which can include fire-fighting, disaster relief and anti-pollution work. For this purpose, a 25 tonne capacity crane is fitted. In addition, the deck is strong enough for the transport of various tracked and wheeled light vehicles, or an LCVP. The class are primarily used with the Fishery Protection Squadron and EEZ patrol.