This was one of a series of Mother/Daughter combinations studies by BMT DSL ( http://www.bmtdsl.co.uk/ ) and the UCL DRC ( http://www.mecheng.ucl.ac.uk/research/marine/design-research/ ) in 2003, to meet the requirements of the FSC programme. A little background is about 80% of the way down this page:
UCL designed 7 motherships and 2 variants, whilst BMT, with their greater expertise in small craft, assessed the daughter craft and two highly radical mothership options. Most of the motherships were 30-50,000 tonnes and all could make 25knots - the variant version shown was a special study capable of 40 knots. Each of the mothership variants used a different method of daughter craft deployment - cranes, stern gantry, internal dock etc. The daughter craft themselves varied in size, with small assets being around 200 tonnes, and medium around 600 tonnes. One variant carried a 1600te SSK. As you can see from the BMT graphic at the supplied link, there was some variation in the daughter craft size, type and equipment.
The fast crane ship was 270m long at the waterline, displaced 46200te (deep) and carried 14000 tonnes of fuel for the 5 50MW gas turbine / waterjet propulsion lines, being a semi-planing monohull in operation. It could carry four small assets, or two medium ones.
Interestingly, this project subsequently lead to the BMT DSL "Venator" design for a reconfigurable corvette / light frigate.
So, theoretically, this design could offer global projection of two Visby class missile armed FPC's or equivalent... Impressive, projection wise, it would decrease the need for huge projects with blue water capabilities for " show of force" actions and brown water patrolling. Please not that I used the word decrease and not eliminate.
I do think that the high speed requirement would increase the development costs significantly. Oh well, another great idea down the drain. There is just no money to develop it all, let allone build it.