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Your questions answered: HMS Queen Elizabeth aircraft carrier

After five years of construction at six different shipyards, one of the UK’s most-challenging engineering projects is almost at an end. In just a couple of months’ time, HMS Queen Elizabeth — Britain’s first new aircraft carrier in more than 30 years — will float out of its dry dock in Rosyth, Scotland.

For the latest of our reader Q&As, we put your questions on the design and production of the new ship to BAE System’s David Downs, engineering director of the Aircraft Carrier Alliance (ACA).

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Source: BAE Systems

The ship was originally expected to weigh 65,000 tonnes, but is now thought to have a displacement of 70,600 tons. What caused this discrepancy?

The displacement of the Queen Elizabeth-class aircraft carriers upon delivery to the customer will be approximately 65,000 tonnes, which is the same as the predicted displacement when we started the manufacturing phase, although the design allows for weight growth in excess of 70,000 tonnes through the service life of the ship due to upgrades.

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Source: BAE Systems

What was done to make the ship as manoeuvrable as possible? How does it compare to modern cruise liners and does it make similar use of things such as side thrusters and electric drives?

The QE-class aircraft carriers have an integrated electric propulsion system, which provides a high degree of control and manoeuvrability, but among the key design drivers for the aircraft carriers are issues such as survivability, endurance, speed and even stealth. Manoeuvrability is not as fundamental as it would be to a modern cruise liner, which would regularly need to enter congested harbours without assistance. Bow and stern thrusters are not a requirement for the QE class as the home port, HM Naval Base Portsmouth, will have the infrastructure and assistance needed for the ships to come alongside and would normally remain at sea if away from home.

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Source: BAE Systems

What defences does the aircraft carrier have against long-range missiles? What consideration has been given to future potential threats such as weaponised lasers? How easy would it be to adapt the carriers for changing requirements in the future, for example, by fitting arrestor gear for STOBAR operations?

The QE-class aircraft carriers have very sophisticated and capable radar systems, and other sensors for the detection of threats, but they would be deployed as part of a carrier task force and the escort vessel would take the lead for the engagement of an incoming threat, although the QE-class carriers also have their own close-in weapon system (CIWS) and small calibre guns. Like other ships in the carrier task force such as the Type 45 destroyer, the QE-class carriers are intentionally designed with the ability to be retrofitted at a later stage in their life as technology, requirements and threats evolve.

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Source: BAE Systems

Has anything been done to enable the carrier to act as an amphibious assault unit carrying Royal Marines and their kit, perhaps including some light vehicles?

The primary role of the QE-class carriers will be carrier-enabled power projection; their size, versatility and complexity allows for a wide range of roles, which could include amphibious assault, although this is not a key design driver. New innovations and highly mechanised systems mean that the ships will require a crew of just 679, but there is the capacity, the facilities (and the bunks) for 1,600. This space would be needed when all air elements are on board, but could also accommodate personnel such as the Royal Marines or prove vital when providing humanitarian aid or disaster relief.

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Source: BAE Systems

How did you manage the project across the supply chain? For example, did you use a digital mock-up i.e. a single version controlled CAD model, across all suppliers?

Yes, across the supply chain we have been using a virtual prototype of the entire ship using modern 3D CAD systems, which has proved very successful. A single version-controlled model wasn’t required, but the technology for virtual modelling has been developing fast in recent years and this has brought us significant benefits.

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Source: BAE Systems

Artist’s impression of the finished carrier.

What innovations developed for the carrier programme could have a commercial use elsewhere and what are the partners doing to exploit these developments?

Virtual modelling is one example of technology that was exploited for the benefit of the QE-class carriers and is likely to become ever more important for the design of complex warships in the future. The way in which different companies across the UK collaborated on this from the design stage through to the build, transport, integration and eventually the delivery has also proved very successful so the Aircraft Carrier Alliance is itself an innovation when it comes to delivering large complex projects. The alliance is comprised of the Ministry of Defence, BAE Systems, Thales and Babcock, and with more than 200 direct suppliers and many more across the wider supply chain there are more than 10,000 people involved in this project.

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Source: BAE Systems

Artist’s impression.

One of The Engineer’s readers mentioned a rumour that HMS Queen Elizabeth will require some additional buoyancy to allow it to float over the caisson bases and leave the Rosyth dockyard. Is this rumour true and, if so, how will you achieve this float-out?

Although this rumour is not true, the float-out of HMS Queen Elizabeth in July following the naming ceremony is certainly going to be a quite a challenge for all involved, but this is a milestone we are really looking forward to. Buoyancy tanks were used successfully during the transportation and docking of Lower Block 04. In contrast, we’re actually going to use 4,000 tonnes of ballast water when floating the ship out of the dock.

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Source: BAE Systems

Artist’s impression

Another good example is Platform Navigation. The QE-class carriers are incredibly complex workplaces as there are more than 3,000 compartments and virtually no windows so even routine journeys can take up to 20 minutes. We needed a navigation system for new or infrequent visitors that could work indoors where satellite navigation cannot penetrate so we created Platform Navigation by combining the deck plans with route-finding logic and installing it onto commercially available handheld devices. Platform Navigation now has the potential to be used inside other large ships and structures, both during construction and in service, and its ability to record inspections and patrols makes it suited for environments such as hospitals or underground transport networks. 


Readers' comments (14)

  • Once again, I congratulate those involved in integrating all elements of this 'cutting-edge/white-heat/pivotal technology and manufacture. You have 'jointly and severally' harnessed the great forces of Nature to the benefit of .....?
    As Engineers, surely pride in achievement is appropriate: but I ask, yet again, if this skill, technical development, ability management now shown to be effective ....isn't/shouldn't now be made available to manufacture revenue-earning vessels of similar size and complexity.

    Mike B

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  • A stupendous waste of money.it will end up being flogged to India-or possibly Argentina. Why do we have to import foreign technology for our railways,etc etc. Yet the ludicrous "Defence Industry" is subsidised to produce costly overpriced,obsolescent junk?

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  • I don’t always agree with the things that Mike says, but in this case I wholeheartedly agree. This is a great piece of engineering and, in my opinion, something that is needed by the Navy to defend British interests.
    The technologies and techniques developed in the construction of these vessels must be applicable to commercial shipping construction, and BAe Systems should be encouraged to commercialise what has been learned. A first base would be for the contract for the RFA ships currently being built in Korea (MOD madness!) to be curtailed and the remainder to be built in the UK.

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  • Agree with Mike B and Edward, we really need to exploit this fantastic acheivement and huge investment for commercial shipbuilding.

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  • Thank you!
    In a long and fascinating career, worldwide-our Editor knows much about it- I have had the privilege of working with Engineers and technicians almost all over the world. I believe you may be aware that my primary activities have been in the functional textile areas and the machinery and processes that apply.
    I have had many projects with a military/ extreme forces 'link' from assisting in the design of the machines that were developed to produce Kevlar (before it had a name) and the NBC suits for protection from those 'nasties' which Mr Blair assured us we were threatened by!
    Amazingly, no trace whatsoever was found?
    Almost my final project was to assist in trying to contain the effects of road-side bombs (as used by the Taliban, et al) IEDs

    My father died in WWII (as did those of most of my school contemporaries as I was educated at an orphanage for freemason's sons) so if my views on 'defense' may appear somewhat different from the norm, perhaps there is a good reason.

    I still hope that this outstanding technology (and the management /administration which is certainly there to support it) is now directed towards civilian use.

    [I never went to Albania, but neither has anyone else, so it probably does not count!]

    Time and again, I have been humbled to hear of the outstanding reputation in which our profession [and those (like me) with the privilege of a UK based education] is held by our peers and technically trained colleagues in other lands. Why in heavens name do we still allow the conflict groups in our own nation absolute power.

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  • Yes its a great piece of engineering one which we should be proud. But from the commercial side, where does the big crane go after the contracts complete ? is it staying at Rosyth?

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  • I for one applaud the UK for investing in the Royal Navy. The RN has always led the world in Naval innovation and engineering. Personally I'd like to see six more Type 45's. With the current number of blue water ships the RN could not sustain the loss of one ship without being crippled. In addition the US Navy cannot forever be protectors of the worlds shipping lanes. It would be nice to see the Royal Navy and other EU Navies step up their role.

    Can't wait to see the HMS Queen Elizabeth at sea with an F35B squadron.

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  • As with other ships, I find the idea of having no "wastes" to take a breather from below decks a bit claustrophobic - Although there is the Flight Deck on occasion, I suppose ? (no deck hockey?)unless I've misread the article above. But then my experience was with the carriers, HMS Implacable and HMS Victorious when I had extensive duty steering them, in all kids of weather and flight operations.
    This one is "something else"!

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  • This ship is nothing more than a costly, poorly thought out, planned and executed folly. Politics have once again got in the way of military requirements. Not having cats n traps is a BIG mistake as is not being nuclear powered. Why is the ski ramp not offset leaving a full deck runway? I also suspect that the defence element for the ship is FFBNW. Had we had a government that could see past its nose we may still have had Shars to fly at least.

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  • Until these ships have any aircraft (there is a hint in their name, AIRCRAFT carriers...) they are effectively virtually useless.....

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