The fleet of three River-class Offshore Patrol Vessels (OPVs) constitute the main force of the Royal Navy’s Fisheries Protection Squadron and regularly patrol the UK’s Economic Exclusion Zone (EEZ). A fourth vessel, HMS Clyde (P257) was modified for operations in the South Atlantic to operate around the Falklands Islands. Due to these modifications HMS Clyde is considered part of a sub group of the class. In 2013 an additional three vessels built to a slightly upgraded design to allow them to operate EH101 Merlins off the flight deck were ordered by the Royal Navy and will enter service from 2017.
Displacing 1,700 tons the River-class are the largest purpose-built patrol vessels ever operated by the Royal Navy; HMS Clyde is larger still being closer to 2,000 tons to increase endurance. The vessels were specifically designed with a large open deck aft allowing them to be fitted with mission specific equipment with relative ease. This means they can undertake a wide variety of roles if necessary and can include fire-fighting, disaster relief and anti-pollution work. To assist in any of these roles they are equipped with a 25 tonne capacity crane and two rigid inflatables for boarding other vessels. Two Ruston 12RK 270 diesel engines propel the vessel up to speeds of 21 knots and at a cruising speed of 12 knots it has a range of 7,500 nautical miles. Typical crew complement is 30 while there is room for an additional 20 persons should the need arise. Armament consists of one 20mm Oerlikon cannon and up to five General Purpose Machine Guns (GPMGs). HMS Clyde is more formidably armed however with a 30mm DS30B cannon and two fixed Minigun positions backed up by GPMGs.
The current fleet consists of;
HMS Mersey (P281)
HMS Severn (P282)
HMS Mersey (P283)
HMS Clyde (P257)
The three vessels of the Fisheries Protection Squadron enjoy a relatively quiet life as opposed to HMS Clyde which has to deal repeatedly with Argentine aggression over sovereignty of the Falkland Islands and Latin American solidarity with Argentina. This culminated in Brazil refusing to let Clyde dock in Rio De Janeiro in January 2011.