RFA Fort Victoria modified to support the aircraft carriers
RFA Fort Victoria is currently mid-way through a major refit at Cammell Laird in Birkenhead. The usual maintenance and machinery overhauls are being conducted but she is also being modified to provide solid stores replenishment to the aircraft carriers.
Critical to the ability of Queen Elizabeth Class (QEC) aircraft carriers to deploy globally will be the support of auxiliary ships to supply oil and solid stores. The 4 Tide class tankers have been specifically designed to be compatible with the QEC and all 4 ships are expected to be in commission by the time HMS Queen Elizabeth conducts her first full operational deployment in 2021. While the supply of Dieso (F76) and aviation fuel (F44) to the carriers at sea is relatively straight forward, the arrangements for the transfer of bulk ammunition, dry stores and food is more complicated.
Replenishing the carriers with stores at sea
The 3 solid stores ships that remain in service with the RFA are fitted with NATO standard heavy jackstay replenishment rigs designed to transfer loads up to 2 tonnes. Rolls Royce has developed a completely new fast, high-capacity Heavy Replenishment at Sea (HRAS) system that can transfer 25 loads per hour of up to 6 tonnes. A complete land-based HRAS system for trials and training was installed at HMS Raliegh and has been in use since 2014. The ability to transfer large loads quickly reduces the window of vulnerability when the carrier is constrained by having to steam at restricted speed (typically 10-15 knots) parallel to the replenishment ship. HRAS combined with the advanced stores handling facilities of the QEC means large loads can be delivered into the spacious hangar and struck down into the storerooms deep in the ship, quickly and efficiently with minimal manpower.
US aircraft carriers benefit from Carrier Onboard Delivery (COD) aircraft that can deliver large and bulky items to the ship by air. There is no designated COD aircraft for the QEC. (Theoretically, non-marinised RAF Chinooks could be used in this role for short-medium range stores delivery. A UK purchase of V-22 Osprey is unlikely to be funded anytime soon). HRAS is therefore particularly important for the QEC and the original specification required the system be capable of transferring heavy and bulky items such as packaged Storm Shadow missile or a complete F135 jet engine for an F-35. It should be noted that there is currently no plan to integrate Storm Shadow on the F-35 but HRAS offers the option for resupply at sea for this and future large air-launched stand-off missiles.
The older RFA Fort Rosalie and Fort Austin are fitted with 3 pivoted arm Mk IA replenishment rigs (2 on the starboard and 1 on port side). This kind of rig is incompatible with the HRAS rigs fitted to the QEC and also lack the height required. It is clearly not worth upgrading the two much older Fort-class, due to go out of service by 2024, of which only one is active at a time. Lack of manpower and an effort to prolong their lives has seen these ships rotate between periods in lay-up in Birkenhead and on active service. Fort Rosalie and Fort Austin will only be able to transfer stores to the carrier by helicopter – vertical replenishment (VERTREP). Using helicopters to transfer underslung loads from the flight deck across to the receiving ship is more expensive in fuel and wear and tear on aircraft and can be constrained by weather conditions. The QEC is fitted with an additional small vertical lift towards the rear of the flight deck specifically designed to take stores that arrive by VERTREP down into the ship without the need to use the aircraft lifts.
RFA Fort Victoria is fitted with 4 Clarke-Chapman sliding padeye rigs, 2 port and 2 starboard, of a more modern design. Like the HRAS system, the padeye which carries the main weigh of the jackstay can be raised and lowered by chains running up and down the inside of the ‘goalpost’ gantry. The gantries are also much higher than in the older Fort class and are being adapted by CL to be compatible with the QEC. RFA Fort Victoria will emerge from this refit able to transfer stores to the carrier but will still be limited to 2-tonne transfers, primarily because she does not have the internal equipment to handle such large loads. Only when the new purpose-built Fleet Solid Support ships (FSS) fitted with HRAS rigs and mechanised stores handling systems arrive in the mid-2020s, will the full 6-tonnes be possible. When the QEC is conducting RAS, the gantry (moveable high point) is lowered, the jackstay cables attached and connect to the replenishment ship through the two open hangar doors on the starboard side of the ship. If both rigs were to be used simultaneously it will require the new FSS to have 2 HRAS rigs fitted on its port side and spaced the same distance.
Fort Victoria is a unique vessel in the naval service being an AOR (auxiliary Oiler/Replenisher), a combined stores ship and oil tanker. The International Maritime Organisation’s Marine Pollution (MARPOL) regulations that govern the design of merchant vessels were amended in 1992, stipulating that all oil tankers over 5,000 tons dwt would be required to have double-hulls. A history of environmentally damaging oil spills created pressure to attempt to mitigate the effects of tankers running aground. Fort Victoria was designed in the 1980s and was completing construction just as the regulations changed. Supposedly all single-hulled tankers should have been modified or scrapped by 2008 and several RFA vessels were sailing in breach of the rule for a few years. As Fort Vic is expected to remain in service, at least until the last FSS is delivered in the late 2020s, modification to meet MAROPOL standards had to be addressed. Constructing the double-hull involves adding plating inside the existing oil tanks, a potentially hazardous and unpleasant task for CL welders. Double-hull construction is more complex than it may first appear as the gap between the outer and inner hull can suffer corrosion or gas build up and must be accessible for inspection and maintenance.
Fort Vic can embark 3,377 m3 of ordnance and 2,941 m3 of dry stores. Her original oil capacity was a total of 11,000 tonnes but this will be reduced by the double-hull modifications. For context, to completely fill the QEC diesel fuel tanks requires around 4,800 tonnes with a further capacity of approximately 3,700 tonnes for aviation fuel. (Fort Vic can provide oil as well as stores but the QEC are likely to rely on the Tide class tankers as their main supplier of oil at sea).
The golden contract
If there is one thing a shipyard likes, it’s a guarantee of regular work. Cammel Laird has thrived recently, in part due to the Cluster contract with the MoD that made them the sole provider of maintenance for several RFA vessels. CL won the initial contract in 2008 for Lot 3, comprising RFA Wave Ruler, Wave Knight, Fort Rosalie, Fort Austin & Fort Victoria. In 2013 the contract was extended but it is due for renewal again this year. CL will be very keen to continue the arrangement, now called the Future In-Service Support (FISS) contract, and will probably be in competition with A&P Falmouth and Babcock (Devonport & Rosyth) who are likely to bid for one or more of the ‘lots’. (Lot 1 comprises RFA Argus, Lyme Bay, Cardigan Bay, Mounts Bay and HMS Scott, Lot 2 are RFA Tidespring, Tiderace, Tidesurge and Tideforce.) Efficient completion of this particularly important refit of RFA Fort Victoria would obviously be helpful to CL in this bidding process.
With years of experience maintaining the Fort and Wave class vessels, CL would appear to be in pole position retain Lot 3 but the MOD is under pressure from the Single Source Regulations Office (SSRO) to ensure this type of competition is “fair and transparent”. Ironically, at the time of writing, government is still blindly ploughing on with an international competition to build the FSS ships. This process cannot be described as ‘fair’ because British yards, which are likely to include CL, will be in competition with state-subsidised foreign yards. Should Cammell Laird be successful in one or more of its bids for FISS lots, the Type 31 frigate project or be involved in constructing the FSS ships, the continued revival of this large shipyard will be good news for the Navy and the economy of the North West.
Main image: Gerry Rudman, January 2018, via Flickr