Rover-class tanker

The Rover class is a British ship class of five small fleet tankers, active from 1970 to 2017 with the Royal Fleet Auxiliary (RFA), the naval auxiliary fleet of the United Kingdom. One remains in service, having been sold to Indonesia; the rest have been scrapped or are awaiting disposal, including the one sold to Portugal. They are tasked with the replenishment at sea (RAS) of naval warships with fuel oils and with limited supplies of other naval stores. For RAS tasking, they can refuel a vessel on either beam and a third trailing astern and have a large flight deck to allow vertical replenishment with helicopters.

History
Tenders for what became five ships were invited in 1967. Problems with the original propulsion led to the first three of the class being re-engined in 1974. The final two had minor changes including improved accommodation and different stern anchor arrangements. Blue Rover suffered a fire during construction in 1970 which killed two shipyard workers. Costs ranged from £3m for Green Rover to £7.7m for Gold Rover, last of the class.

Design
The Rover class are a 461 ft long, displacement 16,160 t, design of small fleet tanker, intended to operate with frigates or small fleet units.

For propulsion the first three vessels of the class, Green Rover, Grey Rover and Blue Rover, were powered by two 16-cylinder Ruston & Hornsby diesel engines capable of 16000 bhp. The choice of engine was a political one and they were found to be problematic with vibration issues.

These ships were all designed to replenish warships underway with diesel, aviation fuel, lubricating oil and fresh water. They can also supply a limited amount of dry and refrigerated stores. Situated in their middle, each ship was equipped with a single fuel replenishment gantry which supported a pair of abeam replenishment cranes. The ship could also supply fuels via stern hoses.

Additionally, to facilitate VERTREP (vertical replenishment) operations, the Rover-class tankers also had a helicopter flight deck which was located behind the accommodation structure and they were fitted with an aircraft refuelling facility, but the vessels had no aircraft hangar available.

The Rover-class tankers were launched in two batches; Green Rover, Grey Rover and Blue Rover were ordered in January 1968 with Gold Rover and Black Rover being ordered in November 1971 and differed slightly from the earlier batch. Following the issues with the Ruston & Hornsby diesel engines fitted to the earlier three, these were replaced with two 16-cylinder Crossley-Pielstick diesel engines capable of 15382 bhp. Swapping out was completed in March 1973 for Blue Rover, in June 1974 for Green Rover, and September 1975 for Grey Rover. Gold Rover and Black Rover were fitted with two 16-cylinder Crossley-Pielstick diesel engines capable of 15360 bhp, from the outset.