It could seem strange that the Royal Navy and USMC are planning early combined deployment of the short takeoff vertical landing F-35B as the only type of fighter to be carried on the 70,000 tonne HMS Queen Elizabeth-class aircraft carrier.
https://news.usni.org/2015/09/17/dse...abeth-carriers

The QE-class was specifically designed to operate up to 40 F-35B STOVL fighters together with non-catapult support aircraft. Hence it was optionally decided the ships scheduled for commissioning in 2018 and 2020 would be built with a bow ski-ramp similar to that developed for the Sea Harrier/AV-8 VSTOL fighter, and without launch and recovery facilities for operation of CATOBAR aircraft. That has caused the QE-class to be sometimes described as supersize Landing Platforms Helicopter. However, due to delays in the Joint Strike Fighter program the RAF/RN will not now receive their yet-to-be confirmed total of 138 or 148 F-35B fighters until well into the 2020s. So apparently the USMC as the principal operator of the F-35B may for several years be making up some or all of one particular shortfall that would affect the RN.

The USMC will anyway be interested in gaining first hand knowledge of how well the reduced weight undercarriage of the F-35B variant of the JSF withstands the stresses inherent in a short takeoff that includes transition to a ski-ramp. The USMC will also want to know if the gentle slope of the ski-ramp on the QE-class - which occupies about half the beam and 70 metres of port-side forward deckspace - enables short takeoff at a heavier weight than permissable from the flat deck of a typical USN amphibious warfare vessel.