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Future Aircraft Carrier (CVF) Queen Elizabeth Class Part 14
By mid-2003 the MOD was seriously concerned about the escalating cost of the ever larger and more complex 'adaptable' CVF design. BAE Systems was warning the MOD that it wanted a lot more money (a billion pounds more) than the MOD had budgeted to build the ships, or the design would have be shrunk. There is no doubt that during the Assessment Phase design process, many "nice to have" features and systems were added with little regard to their cost. One source considered that CVF had become an aircraft carrier with the armament of a frigate and the radars and command and control systems of a destroyer. The time had clearly come to question how many of those sophisticated and expensive weapons, systems and sensors really had to fitted, and how much reliance should be placed on accompanying escorts to provide the necessary capabilities. Due to the projected cost over-runs with what was now termed the "Alpha" design, in June 2003 the DPA told BAE Systems to investigate what would be the minimum size of adaptable carrier in attempt to reduce costs. One particular concern was the use of deck edge lifts. These only work well on ships above a certain size - with a big ship its motions are less and a lift can thus be relatively lightly built, but in a smaller ship the lifts (and particularly deck edge lifts) have to be heavily engineered to cope with the movements of the vessel in rough waters. In the original Thales 'adaptable' CVF design concept the lifts were capable of carrying a 70-ton load, equivalent to two aircraft, and the lift itself weighs about 40 tons, but to make it sea-kindly for a smaller ship would need a huge increase in the weight of the lift and hence a huge increase in the mechanisms used to control the lift. Thus if the carrier weight fell dramatically during the cost trade-off process this might be one of the design features that would have to be reconsidered. BAE Systems believed that the Thales/BMT CVF design concept could not be shrunk below about 55,000 tonnes because of reasons such as its lifts, and any smaller CVF concept was effectively a new design. By July "quick look" design work resulted in the development of a smaller 'Bravo' design, some 265m in length and displacing approximately 55,000 tons. Compared with the bigger 'Alpha' carrier selected in January 2003, the new smaller 'optimised' design had had its displacement reduced by about 10,000 tonnes, one deck removed, 1 main engine (i.e. a gas turbine alternator set) deleted, and over 25 metres (82 feet) cut from the overall length. It had a capacity of about 35 aircraft. It was estimated that the smaller optimised 'Brave' CVF hull would cost about £200 million less to build than the old large adaptable design, and it was hoped that it could use much more existing base and dockyard infrastructure without significant and costly upgrades. Reductions in the size of the flight deck no longer permitted simultaneous conventional take-off and recovery operations. Other changes included the substitution of conventional shaftlines (driven by advanced induction motors) for the podded propulsors. While pods offered many attractions particularly with regard to shipbuilding schedule - it was judged that a number of outstanding risks remain with regard to damage survivability and signatures. Other trade-offs included the deletion of the intended fully automated weapon handling system in favour of a highly automated system (i.e. partially manual) and a reliance on soft-kill defences alone (while retaining 'fitted for but not with' provisions for close-in weapons).
The maximum airgroup capacity was reduced by the equivalent of one squadron of 12 F-35's strike fighters - being listed as to up to 30 JCA/JSF plus 4 MASC (if necessary, Merlin's can be operated by RFA's and other RN ships to free space on CVF for the maximum number of JSF's). Unfortunately the Bravo design suffered badly from reduced margins and volumetrically was extremely tight, with the designers facing problems in packaging the required machinery, air engineering, command spaces, fuel, magazines and accommodation within the smaller volumetric envelope (i.e. it was still a cramped design), also the smaller flight deck means that some of the desired aviation requirements could no longer be met, e.g. simultaneous launching and landing events were not possible. Also, the French had concerns about whether sufficient space was still allowed for catapults and auxiliary steam generation plant. Perhaps most importantly, attempting to squeeze everything in to the smaller hull meant that innovative technology and radical design approaches had to be used on a design that already had more than its fair share of these. The dark shadow of the desperate attempts to reduce the displacement and cost of CVA-01 in the mid-1960's began to haunt the project. In August 2003, Simon Knight of BMT Defence Services told The Engineer magazine that there was an "intensive cost trade-off process" underway, and stripping out some of the more sophisticated systems. "One of the trade-offs is to look at if we can have a smaller size of ship but principally we are trying to take out some of the excess functionality... pare back to just the aircraft carrier role. .... [We are] determined to hang on to the principle that size is all." In an aside he said that should the ship get any smaller it would not be an aircraft carrier at all, and where space onboard is concerned it is vital that there is room enough to cater for the principal payload ..." By September 2003 some £500 million of savings had been made compared with the May baseline - £200m due to the reduction in carrier hull size and the rest due to a deletion or down-grading of systems and equipment. It was always clear that the smaller Bravo design was associated with increased risks due to being very cramped, and during the autumn of 2003 the Royal Navy argued that many of the cost cuttings measure that had been hurriedly adopted had caused disproportionate reductions in platform capability and flexibility for often trivial savings obtained. The Royal Navy also considered that it was essential that in an emergency the new carriers were able to operate three JSF squadrons (normally 36 aircraft) adding vital MASC support aircraft set a minimum airgroup capacity of 40 - a total which the optimised design was simply unable to accommodate. According to Janes International Defence Review, a review of the 'Bravo' design by the DPA's Sea Technology Group (STG) also established that it did not comply with revised Damage Control Deck (DCD) code guidance validated by the STG. Completely dropping the originally selected Thales developed design was not politically acceptable at a time when the French were still considering adapting it for their new aircraft carrier , and also the Royal Navy simply did not believe that its requirements could be met by a smaller ship, as a result, further design iterations were developed:
By late 2003 it was widely agreed that the complexities of the smaller design made it too risky, and with backing for its case rumoured to becoming from as high as the Prime Minister, the Royal Navy succeeded in getting some of the cuts reversed, and the CVF design began to grow again. “If you wanted the ships to be just as capable, but smaller, it meant you had to be more innovative in some areas of design and construction, and it was felt that just brought more risk than was necessary,” an insider said. A MoD stakeholder conference in December 2003 thus decided to proceed with the 'Design Delta.
On 24 March 2004 the First Sea Lord, Sir Alan West, told the House of Commons Defence Select Committee that "Basically the capability required is they will carry about 40 aircraft, 36 Joint Strike Fighters. We are in stage three of the CVF assessment phase at the moment. A lot of successful work has been done in optimising the design. The sizing has veered up, down and wherever, but the most important thing is one should not get too fixated on size, we need the capability that is required. I think on the capability required at the moment it looks as though we have got something like 275 metres and about 60,000 tonnes, which is about the figure that has come out of that." With so much uncertainty surrounding even such basic features as the size and displacement of the new aircraft carriers, it is unsurprising that the CEO of BAE Systems, Sir Richard Evans, was saying in May 2004 that he believed that another year was required to refine cost and de-risk the design before Main Gate could be achieved, and indeed this was officially announced in July 2004. Also at this point in time, carrier design work was being increasingly hampered by the slow provision by Lockheed Martin of essential technical information concerning the JSF fighter - and the urgent need for the USA to approve the promised ITAR technology transfer waiver agreement began to be publicly mentioned by senior UK officials and even ministers. On 20 July 2004 the Minister of State for Defence Mr. Ingram stated that the Ministry of Defence had not yet fixed the dimensions of CVF, he wrote "The design of the ships will continue to evolve as we seek to balance the overall performance, time and cost parameters of this complex project as part of normal assessment phase activity. Decisions on the capability to be provided by CVF, including the number of aircraft capable of being deployed, and hence on the design and dimensions for the ships, will be taken at the Main Gate investment point [in 2005]". It seems that during 2004 the options for a much smaller CVF able to be accommodated with in the available budget (i.e. about £3 billion) were revisited, however these designs (they operated as few as 20 aircraft, including JSF's) represented such poor value for money (capability versus cost) that the project was not worth presuming. [Its worth noting that studies in relation to CVA-01 found that increasing the tonnage from 40,000 to 50,000 tons increased cost by 10%, but aviation capabilities by 50%, it would appear that the CVF platform design team found that achieving a 25% cost reduction (£4 billion to £3 billion) resulted in a 50% cut in capability). The judgment of Rear Admiral Nigel Guild, Senior Responsible Owner for Carrier Strike, and others in the MOD/DPA was that the CVF project was probably not worth proceeding with if it was based on the small designs and by the end of 2004 the conclusion had been reached that they represent such poor value for money that the CVF project would not be worth proceeding with on that basis. In a report published in early 2005, Rand Corporation proposed several options that might lead to lower CVF construction costs:
They also pointed out the trade off between initial acquisition and later operating costs - they suggested that a £1,000 per year operating saving for each of the two planned carriers would justify a £25,962 up-front investment across both ships. Similarly there is a trade-off between the use of technology and subsequent manpower costs, for example replacing the median crewmember with automated systems could potentially save up to £1.2 million over the life of the carriers. In February 2005 the MOD stated that the CVF design maturity was now around 60-65% - a figure it seemed to have been stuck at for some time! Design maturity represents the development of the design up to the point at which production drawings can be produced for the manufacturing phase. The MOD made clear that work was being taken forward on maturing the design of critical systems within the platform (for example waste management systems, heating ventilation and air conditioning (HVAC) systems and aircraft lifts).
On 24th January 2006, the UK and France agreed to co-operate to create a Common Baseline Design, based on the CVF Delta design to meet France’s requirements for an additional carrier.
The CVF Delta design, probably dating to early 2006, the common baseline design has evolved from this. In April 2006 the MOD website stated that the key characteristics of CVF were:
It appears certain that some of these figure have been rounded. It was announced by the MOD in April 2006 that contracts had been placed with KBR, Thales UK, VT Group, Babcock, BAE Systems Naval Ships and BAE Systems Integrated System Technologies with a total value of about £143 million, covering development of all aspects of the ship and ship equipment including hull, structure, propulsion and mission systems and the involvement of shipyard and industry design teams. The design work was centred at the ACA Carrier Team's offices in Bristol and, since December 2005, in two new design offices in Glasgow (BAE) and Portsmouth (VT). Since joining the CVF project, France has requested a range of design changes, many agreed to by the UK - for example increasing aviation fuel storage and an increase in beam to allow more volume for catapult and arresting gear related equipment; French studies showed that the existing allowance was inadequate. These requests have increased displacement and reduced speed, but a French request to reconfigure the engineering to increase speed is however unlikely to be agreed due to cost. The French version of CVF will apparently displace more than the UK variant, DCN quoting a 74,000 tonnes displacement in October 2006. However this should be considered in the light of the fact that the ACA Ship Design team had previously conducted studies on ship stability and forecast CVF would have to be re-ballasted twice during its service life (with a total of 15,000 tonne) to counter topside weight growth (including the possible fitting of catapults and arresting gear) to become a 75,000 tonnes vessel. Considerable margin has therefore been allowed for - some of which the French appear to be using. Based on a review of all sources it appears that in late 2006 it is expected that CVF FR will have a full load displacement of about 70,000 tonnes upon completion, and CVF UK about 65,000 tonnes - the difference due to more equipment, ballast and fuel on the French vessel.
Achieving and maintaining commonality between the French and UK variants has not been easy. In July 2006 the French MOPA2 proposed making major changes to the CVF design for PA2 - which the UK team was decidedly far from happy about. With the two variants starting to drift apart, it was decided by the DGA on 21 September 2006 to require the MOPA2 to achieve 90% commonality with the UK during a new design contract . Since then some of the design changes proposed in July have been dropped (e.g. relocation of the air wing operations room and alterations to accommodation arrangements) , while five others have now been better provided for in the common baseline design with UK agreement - slightly widened lifts able to handle the Rafale fighter; improved allowance for the steam catapults and associated boilers, arresting gear, increased fuel storage, and the SATRAP stabilisation system. The agreement by the Anglo-French team on common arrangements for accommodation, operations/command, wet and engineering spaces represents significant progress - although the last is dependent on the French Navy not insisting on a significantly higher speed.
An official press release regarding the CVF project was sent to this website on 19 February 2007, stating:
It is perhaps worth quoting CVF IPT Leader John Cole from a talk in March 2007: "The principal features [of CVF]. It is about 270m long on the waterline, which is just under 900 ft. It is 40m on the beam (130ft), and at the start of life it displaces about 65,000 tonnes, with a 10 per cent growth to grow over the life. There are nine decks below the flight deck, with a minimum deck height of three metres – about 10ft – to ease manufacturer and the running of systems. These are, therefore, very large ships, in terms of volume, width and length. Indeed, they are volume-driven, rather like cruise ships." In April 2007, the CVF IPT Team Leader gave the following "Design Principal Particulars" for the UK's CVF variant:
Hull Form For simplicity of build, and to reduce the risk and costs associated with using a modular construction technique, the CVF hull shape will share many features with merchant ships rather than "traditional" large warships. For example, the CVFs will have a full-bodied hull similar to that of a large, modern merchant ship. It's expected that CVF will be fitted with a bulbous bow which is relatively novel for naval vessels but a common feature in merchant vessels of similar shape. The bulbous bow, along with other features common to merchant ship practice such as fore and aft shoulders and parallel middle body, combine to give a harmonious design with minimum powering requirements at the cruise and maximum speed. The vessel also includes an advance appendage design which gives good quality flow into the propellers. This contributes to efficient propeller operation and hence good powering levels. In October 2005, BMT SeaTech Ltd, a subsidiary of British Maritime Technology Ltd (BMT), announced that it had undertaken a series of model tests to examine the hydrodynamic characteristics of the CVF hull design. BMT SeaTech’s hydrodynamic consultancy team worked with Thales Naval UK in support of the Aircraft Carrier Alliance on the hydrodynamic hull design. One objective was to utilise BMT’s expertise with merchant ship hull forms to help minimise propulsion requirements for the given length, speed and displacement of the vessel. Extensive tests on several models were undertaken to investigate and validate concepts as the design evolved. Further tests were then performed on the final design to investigate the resistance, propulsion, manoeuvring, seakeeping and capitation characteristics of this vessel. A brochure issued by the Swedish company SSPA gave further details of the work. It stated that "since 2003, BMT SeaTech has conducted all the CVF model tests at SSPA". The work involved the manufacture of four models in two major hull form variants, and the model tests conducted in the towing tank and seakeeping facility included:
The French officially joined the project in January 2006, they were soon making a number of suggestions for changes to the hull form, including a revised bow shape in order to increase maximum speed. These changes would make the hull form more complex to manufacture and there was some doubt as to whether the UK would agree given the increased costs and risks. It became apparent during early 2007 that the UK had agreed to changes to the bow form, maintaining standardisation of the Superblock 1 between the two countries.
Graphic of CVF published in July 2007, the new bow design is shown. (Source: DE&S) At the time of Main Gate approval in July 2007, the DE&S said "The carrier will be similar size and weight as the ocean liner QE2. The carriers will displace 65,000 tonnes at full load; be 284m (931ft) long by 73m (239ft) wide at flightdeck level; 11m max draft (keel to waterline); and have ten decks. The maximum Air Group is 36 Joint Strike Fighters and four airborne early warning aircraft, weighing more than 1,000 tonnes. The carriers will carry more than 8,600 tonnes of fuel to support the ship and her aircraft. The ships can carry more than 1,000 tonnes of food – enough to feed the crew for six weeks. The flight deck area is nearly 13,000 square metres – the equivalent of 49 tennis courts or three football pitches."
Use of commercial systems CVF has been designed to a tailored set of standards, using civil or commercial standards in preference to military standards wherever there is no adverse impact on operations or safety. These principles have been extended to equipment selection, where commercial off-the-shelf (COTS) equipment has been incorporated into the design in preference to military standard equipment. Examples from this approach include:
Although commercial systems will be used where practical on CVF to reduce cost, the RN is very keen to avoid the reliability issues that have plagued the LPH HMS Ocean. Excessive economies had to be made during her design and build in order to meet budget (about £200 million), as one former member of her crew noted "On Ocean, the [cost] problem was always solved by going to the commercial market and things that were not known and well tested in the Navy.” The result has been excessive unreliability of equipment and systems - not helped by 'lean manning' and a lack of engineers to keep on top of maintenance and repairs. The initial savings been balanced by higher than expected maintenance and refit costs, and the hard-worked ship has a distinctly aged feel less than 10 years after entering service (1998). Hopes that she might be able serve beyond 2018 seem optimistic as of 2007 The CVF's are expected to be in service for 40 or even 50 years, and a similar experience would be a disaster for the service.
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© 2004-8 Richard Beedall unless otherwise indicated. |
... and Redesign
By late 2005 it appeared that the latest version of the 'Delta' design had a waterline beam of 39m,
69m at flightdeck level, was
283m in length (263.5m between perpendiculars). It had a deep
displacement of approximately 64,500 tonnes, with allowance made for this to grow to about 70,000 tonnes by the end of a 50
year service life. These numbers were unlikely to change bar for
another down-sizing exercise which would delay the programme. The vessel
was sized to embark up
to 40 aircraft and helicopters, of these up to 24 JSF's could be accommodated in its hangar deck
with remaining air group elements spotted on the flight deck. The
distinctive twin-island arrangement remained, the Aircraft Carrier
Team believing that it enables simplified uptake/ downtake arrangements and
improves electromagnetic interference/ electromagnetic compatibility
(EMI/EMC) characteristics by permitting greater antenna separation.
However EMI/EMC remains a major technical challenge that drives close
examination of advanced antenna working using common multifunction
aperture technology. Additional low visibility design features
have also been included, while the carrier design is in no sense
"stealthy", the reduced signatures allow soft-kill off board decoys
to work much more effectively.
In March 2007 it was further revealed that Commodore (promoted
to Rear Admiral on 16 March)
Bob Love, the new IPT Team Leader had signed the 'blueprints' for
the carrier with the Carrier Alliance chief executive Peter McIntosh", and
that the project was now at "Stage 2' baseline, marking the start of
detailed design by the shipyards and the delivery of production drawings
for manufacture. It was also stated that the new carriers will
have four times the internal hull volume of the Invincible Class.
