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This article appeared on the Save the Royal Navy website in July 2018, but the topic is highly relevant given the support provided to the Bahamas after the recent hurricane that hit a number of their islands. The increased likelihood of such weather events in the future means that these ships might be appearing on our television screens more often in the years to come. Ed.

Like so many defence procurements, the delivery of the Bay Class landing ships was protracted and over-budget. Despite their difficult birth, the three vessels that remain in the fleet today have proved to be great assets to the Naval Service, offering flexibility and value for money in a variety of roles. Here we look at these ships and their history in detail.

The requirement to replace the 6 Round Table class LSLs, starting with RFA Sir Geraint and RFA Sir Percivale led to the establishment of the Alternative Landing Ship Logistic (ALSL) project in 1997. The 1998 Defence Review committed to a balanced amphibious capability for the RN and confirmed these ships would be constructed. The ALSL had evolved into the Landing Ship Dock Auxiliary, LSD(A) by Autumn of 2002 and the specification called for a ship that could carry at least 350 troops, had 500 lane metres for vehicles and embark 70 tonnes war maintenance reserves (stores, fuel and ammunition). The ship would be able to operate helicopters and mexeflotes, while being able to offload vehicles in conditions up to Sea State 3. The Albion class LPDs would provide the amphibious spearhead and command and control while the Bay class would back it up carrying a larger number of troops, vehicles and stores that will sustain the assault.

The MoD issued an invitation to tender for design and build of 2 ships with an option for a further 3 in 2000. A life major life extension refit of RFA Sir Bedivire had proved expensive and it was decided new ships would be more cost effective. On 26 October 2000 the MoD announced Swan Hunter on Tyneside had won the lead yard contract and would construct 2 ships, with a further 2 built by BAE Systems in Glasgow. The projected cost was around £300 million for the four vessels, all expected to be in service by the end of 2005. Swan Hunter planned to adapt the Dutch Royal Schelde Enforcer design used as the basis for HNMLS Rotterdam and the Spanish SPS Galicia, both commissioned in 1998. It should be noted that the design selected exceeded the original ALSL specifications by a considerable margin, in particular, the inclusion of the well dock which is still of great benefit today.

An ageing RFA Sir Percivale offloads Mexflote off Gosport after 13 months of operations in the Middle East in 2002. The Bay class are replacements for the 6 Round Table class LSLs (Landing Ship Logistic) originally completed between 1967-68
HNMLS Rotterdam based on the Enforcer design developed by Royal Schelde in the Netherlands and used as the basis for the Bay Class.
RFA Largs Bay being constructed at Swan Hunter, seen being assembled in the floating dock, March 2003.
RFA Mounts Bay
RFA Mounts Bay under construction in Govan, August 2003. (Photo: Stuart Cameron)

The old and the new – RFA Sir Percivale and her replacement, RFA Largs Bay on Tyneside, August 2003.
RFA Largs Bay, fitting out at Swan Hunter, Wallsend.
RFA Cardigan Bay, just after her launch at BAE Systems Govan yard in Glasgow, April 2005.

An unhappy genesis

By 2000 Swan Hunter was a shadow of its former self, having gone through upheavals and buy-outs with very different management since it completed it last warship, HMS Richmond in 1993. A famous brand with a fine warship construction pedigree, SH was one of the casualties of ever-declining warship orders and the inability of British yards to compete for commercial shipbuilding. It had limped on in reduced form, surviving on work from the offshore energy industry.

When bidding for the LSD(A) contract, SH significantly under-estimated both the work to adapt the Enforcer design to UK requirements, and the complexity of construction. The low cost and the attraction of creating 1,000 new jobs on Tyneside undoubtedly encouraged the MoD to enter into this conspiracy of optimism.Delays in receiving design details from Royal Schelde meant work the first ship RFA Largs Bay started almost a year late. The first of 32 blocks that would make up Largs Bay were placed in the floating dock used for assembly in May 2002.

Progress on outfitting was slower and more challenging than expected and by September 2003 the MoD effectively had to absorb liability for rising costs with an £84M bale-out of SH. As SH was lead yard, the problems had a knock-on effect, causing delays and cost increases to the construction of Mounts Bay and Cardigan Bay in Glasgow, with increasing tension between the two companies. RFA Mounts Bay was launched down a traditional slipway Govan on 9 April 2004 but received minor damage after becoming entangled in chains, hit the opposite bank of the river and a dock worker was injured while she was being secured alongside.

In November 2004 two of Largs Bay’s engines were accidentally filled with sea water and in June 2005 a crankshaft was written off during engine trials. Swan Hunter announced that after testing that both Largs Bay and Lyme Bay would need a further £20M spent on them to rectify construction errors. The MoD eventually transferred lead yard responsibility to BAE Systems and RFA Mounts Bay performed many of the lead ship functions, such as speed trials. The contract with SH was terminated entirely in 2006 and the unfinished RFA Lyme Bay was towed to Glasgow for completion. This marked the sorry end to a fine shipbuilder and foreseeable problems that cost the taxpayer at least £200 million beyond the original budget. The construction phase concluded in July 2007, when the last ship, RFA Lyme Bay was delivered to the MoD 18 months behind schedule.

General characteristics

At 16,190 tonnes, the Bay class are more than double the size of the Sir class LSLs they replaced. They have diesel-electric propulsion driving 2 azimuthing thruster pods. The pods are rotated to provide steering as well as thrust so the ships do not need rudders. Together with a bow thruster, a dynamic positioning system can hold the ship precisely in place, especially useful for mexefloat and small boat operations at sea. Electrical power for the thrusters is generated by 2 x Wärtsilä 8L26 (2.2 MW) and 2 x Wärtsilä 12V26 (3.3 MW) diesel generator sets. Maximum speed is a respectable 18 knots, with a range of 8,000 miles at 15 knots.

Standard RFA crew compliment is just 59 with accommodation for up to 75 to allow for additional RN personnel or trainees. There is good accommodation for an Embarked Military Force of 356 fully equipped combat troops, this can be increased to 500, using camp beds in spare compartments. Up to 700 could be carried for short periods in war “overload” conditions. The ship has been designed with wide passageways to allow fully equipped troops to reach disembarkation areas quickly and has an airtight NBCD citadel, usually found on warships. There are about 1,200 line-metres available on the vehicle deck with a theoretical load of up to 24 Challenger tanks and 150 trucks. Vehicles can be embarked through door in the starboard side and there is a lift to transport vehicles or stores between the vehicle deck and upper deck. There is also space on the upper deck for either 12 x 40-TEU or 24 x 24-TEU containers. Two 30-tonne upper deck cranes are used for cargo handling and to load LCVPs and boats on or off the upper deck. The floodable well dock has space for either 2 Landing Craft Vehicle and Personnel (LCVP) or 1 Landing Craft Utility (LCU). Two large Mexeflotes (powered rafts) can be carried, strapped to the port and starboard side of the ship.

An empty vehicle deck gives a good sense of the ship’s considerable capacity.


Despite the troubled build project, the lead ship RFA Mounts Bay was accepted off-contract in late 2005 and began extensive trials, culminating in mid-2006 with a successful amphibious capability demonstration involving landing Challenger Tanks, Royal Marines and helicopter operations. The original design has proved sound, although some minor modifications or additions have been made during the decade or so they have been in service. A weakness of the Bay class is the lack of permanent aircraft hangar but in 2008 Rubb UK was contracted to design and fit the first temporary aircraft shelter to RFA Cardigan Bay. All four ships have been subsequently been fitted with this 15m x 18m steel-framed and fabric-covered structure that offers some protection from the elements for aircraft, boats, stores and personnel (not always fitted).

The original design included two small funnels at the aft end of the ship with the exhaust in long horizontal ducts running almost half the length of the ship. This arrangement did not prove satisfactory as fumes could envelop the upper deck and interfere with flight operations in some circumstances. To rectify this, tall exhaust funnels have been fitted on the upper deck amidships, almost directly above the diesel engines below.

Ships deploying to higher threat regions have been fitted with two 20mm Phalanx CIWS and two DS30B 30mm cannons. Initially, the Phalanx units were bolted to the upper deck amidships, port and starboard. For her service in the Gulf in 2016 Lyme Bay was fitted with Phalanx in a fore and aft arrangement as the original design intended, one placed on the foredeck mount and one on the aft superstructure. This offers better arcs of fire and less clutter on upper deck area.

RFA Mounts Bay deployed in her intended primary amphibious role. Exercise Armatura Borealis in Norway, March 2008.
Mothership to minehunters – RFA Cardigan Bay with HMS Ramsey, Quorn and Shoreham escorted by HMS Diamond, Arabian Gulf, August 2012
RFA Largs Bay crosses the Atlantic with stores for the Haiti earthquake relief operation, Feb 2010.
Vehicle deck full of Land Rovers donated by the UK for Haiti earthquake relief operations.
Royal Marine vehicles offloaded onto Mexeflote from RFA Mounts Bay, Exercise Corsican Lion, 2011.
Royal Marines embark in RFA Cardigan Bay at Marchwood, prior to the Cougar 2011 deployment.
RFA Mounts Bay docked down during post-hurricane Irma relief operations in the Caribbean, 2017
RFA Mounts Bay alongside in Portland, used as accommodation ship and base for small boats during security operations around the Olympics sailing events in 2012.

Largs Bay sold

The ill-conceived and brutal round of cuts to the Navy in the 2010 SDSR resulted in the sale of RFA Largs Bay. Brazil, Chile and India were all potential buyers but she was sold to Australia in March 2011. After a refit and training period for the new crew in Falmouth, the ship recommissioned as HMAS Choules in Sydney in December 2011. Unexpected defects with voltage converters kept the ship out of service until April 2013 but she has since served the Australian navy well as part of a programme to substantially enhance their amphibious capability. Considering the sale raised just £65M for the UK Treasury and the approximate operating cost of a Bay class is under £10M per annum, the loss of such a useful ship is a continuing source of regret, a triumph of fiscal short-termism over common sense.

Our flexible friends

In service the Bay class have proven to have the capacity and capability to take on a wide range of tasks. They are the hardest working ships of the RFA flotilla and there is no doubt we could use more vessels of this type. A detailed history of each vessel can be found here but a few important highlights of their diverse work in the last decade include;

In 2006 RFA Mounts Bay participated in Operation Vela – the largest deployment of amphibious vehicles by the UK since 2001 and aimed at demonstrating the ability of the UK to conduct coastal and amphibious operations in the unique environments of West Africa. The Bay class vessels have participated in most of the annual Cougar/JEFM deployments (2011-2016) and occasionally in the Joint warrior exercise series, proving their amphibious capabilities.

While conducting her first Caribbean deployment (APT(N)), in December 2007 RFA Largs Bay intercepted a boat carrying 1.125 tons of cocaine worth £45 million. In February 2008 RFA Lyme Bay was sent to Tristan da Cunha in the South Atlantic for Operation Zest – emergency repairs to Calshot Harbour, critical to the Island’s ability to land supplies. Lyme Bay landed construction materials, equipment and personnel who were able to re-open the harbour.

In March 2016 RFA Mounts Bay was assigned to Standing NATO Maritime Group 2 (SNMG2) in response to the migrant crisis in the Aegean Sea where she patrolled off the island of Lesbos, escorting over 350 migrants to safety. In June 2016 she was reassigned to Operation Sophia, tracking human and arms smugglers operating off Libya. The ship had effectively demonstrated a Bay class could also be used for patrol and maritime security tasks.

In the wake of a major earthquake in 2010, RFA Largs Bay was hurriedly loaded and despatched with relief supplies. Working under the auspices of the World Food Programme, using Mexefloats she delivered food and vehicles across beaches to the populations of Haiti’s Southern Peninsula that were cut off from supply by road. In August 2015 RFA Lyme Bay was sent to Dominica to provide assistance in the wake of Tropical Storm Erika which caused widespread damage. The ship provided 7,170 hot meals, 78,000 litres of water, 20 tonnes of dry provisions and treated 35 medical cases. She provided similar help in October 2015 when a hurricane hit the Bahamas. The immense work of RFA Mounts Bay in the wake of Hurricane Irma in 2017 is covered here.

HMAS Choules conducts humanitarian aid exercise Croix du Sud with French forces in New Caledonia, May 2018. Note she retains the original aft funnel configuration. (Photo: RAN)
Offshore Raiding Craft and LCACs from 539 Assault Squadron, Royal Marines loaded onto RFA Lyme Bay in Devonport prior to Exercise Joint Warrior April 2018. Note the deck shelter not fitted.

Current operations

RFA Mounts Bay has been in the Caribbean since June 2017 and played a major role in relief operations after hurricane Irma. She conducted a maintenance period at Detyen Shipyards, Charleston, South Carolina with help from A&P Group engineers in May 2018. She is now back in the Caribbean and prepared to provide assistance, should she be required during this year’s hurricane season. She will stay in the region well into 2019, the longest ever sustained deployment of either a warship or RFA on this task. (RFA crews rotate with personnel typically serving for approximately 4 months at sea, followed by 3 months off).

Based in Bahrain, a Bay class vessel is permanently deployed in the Gulf for extended periods, serving as the mothership to the RN and US mine countermeasures vessels. RFA Cardigan Bay replaced RFA Lyme Bay in this role in mid-2017. Lyme Bay’s medical facilities were tested with simulated casualties and surgeries during a 7-day US-UK exercise Azraq Serpent in January 2018. In June 2018 she participated in one of the frequent US-UK Mine Countermeasures Exercises (MCMEX) which enhance cooperation, mutual mine countermeasure capabilities and interoperability.

RFA Lyme Bay completed a major refit at A&P Falmouth in March 2018 and exercised her amphibious role during Joint Warrior in April. Lyme Bay is completing another maintenance period in Falmouth and being fitted out for operations in the Gulf. In the Autumn, she is expected to participate in the tri-service exercise Saif Sareea 3 off Oman, the largest UK training activity in the Gulf region for 17 years which will involve Army Challenger 2 main battle tanks and Warrior infantry fighting vehicles.

A bright future

When permanently deployed in the Gulf the ships have not only excelled as motherships for the MCMVs, but also hosted small boats and unmanned vehicles. UUVs involved in mine warfare operate from the well dock and surveillance UAVs have been launched from the flight deck. There is a growing school of thought that suggests relatively cheap motherships hosting sophisticated unmanned systems could be force multipliers and play a significant role in future naval combat. The Bay class are in pole position to develop and expand this concept for the RN.

The Bay class design also has the potential to be the basis for a dedicated aid ship, a hospital ship or a Joint Casualty Treatment Ship (JCT). In 2001 the MoD actually began the Assessment phase for two JCT ships, slated to enter service by 2012. In desperate straits and looking for further work in 2005, Swan Hunter proposed that they convert the completed RFA Lyme Bay into a JCT but the MoD had already abandoned the project, accepting RFA Argus will have to soldier on until 2024.

With two of the three vessels almost permanently “forward-deployed” to the Gulf and the Caribbean, it effectively leaves just one vessel available for amphibious work. To some extent, they have been a victim of their own success because of their ability to excel in a variety of roles. The RN’s amphibious lift which looked so healthy in the 1998 plans has now been reduced to a single LPD and a single Bay class (with a QEC carrier able to offer a part-time LPH capability from around 2023). Although a very faint hope, the aspiration to procure another 2 or 3 similar ships would be a very cheap way to help re-invigorate amphibious capability.

All three ships have recently joined Twitter and you can follow them at @RFACardiganBay / @RFAMountsBay / @RFALymeBay

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