In a casual perusal of FOI requests this one stood out
Dear Ministry of Defence,
Were other inovations and designs of catapult considered before EMALS was selected for use on the Queen Elizabeth class?
If so, what were they and to what level were costings completed?
QUEEN ELIZABETH (QE) CLASS AIRCRAFT CARRIERS
Thank you for your email dated 24 May 2012 in which you ask whether consideration was given to alternative designs of catapult and arrestor gear for the QE Class carriers, other than the Electro-Magnetic Aircraft Launch System (EMALS). Your letter has been passed to me to respond as it falls within the responsibility of Defence Equipment and Support.
You may be aware that the Secretary of State for Defence announced to the House of Commons on 10 May 2012, that we will be reverting to a Short Take-off and Vertical Landing (STOVL) based carrier strike capability using the F-35B variant of the Joint Strike Fighter (JSF) aircraft, rather than the Carrier Variant (CV) of the JSF.
In the 2010 Strategic Defence and Security Review (SDSR), the Government committed to a future carrier strike capability based around the new QE Class carriers as part of Future Force 2020, announcing that one would be fitted with catapults and arrestor gear (cats and traps) to enable operation of the Carrier Variant (CV) of the JSF. At that time however, we said that more detailed investigatory work was needed before a decision could be taken on conversion. That work, known as the Conversion Development Phase (CDP), had matured sufficiently by the spring of this year to provide both the MOD and Industry with a much better understanding of the technical risks associated with conversion to a CV-capable carrier. This greater understanding underpinned the 10 May announcement, as it was clear that an operational Carrier Strike capability, based on the CV JSF and a ship fitted with cats and traps, could not be delivered until 2023 at the earliest.
Prior to the detailed investigatory work undertaken during the CDP, a number of Aircraft Launch and Recovery Equipment (ALRE) solutions were considered and discounted. These included two electro-magnetic catapults – the Electro-Magnetic Catapult (EMCAT) produced by the UK company, Converteam, and an alternate version of the EMCAT system produced by US company, The Steelman Group, Inc. Following initial consideration and discussions with the respective companies, both EMCAT systems were discounted as not being sufficiently technologically mature to offer a viable solution. Consequently, neither option was costed.
Steam-based catapults were also considered for the QE Class, and initial indicative costs were obtained for these during the early stages of our CDP work. However, due to the fact that the use of steam would have necessitated the installation of unique generation plants (thereby increasing the amount of time needed for conversion), and compared with the greater operational capability of EMALS (currently in development by General Atomics and planned to be fitted to the US FORD Class carriers), these early estimates were not developed any further.
I hope that this has clarified the situation with regards to the ALRE options that were considered for the QE Class both before and during the CDP.
There you go