I have a foam sandwich racing rowing boat to build starting very shortly. there are some areas that are highly loaded & i was going to incorporate a fiber reinforced foam in the areas where fasteners & stiffening members are to go. This is to link the inner & outer skins better and provide places where fittings can be installed, i dont want to use wood inserts due to risk of expansion if it gets wet.
I will almost certainly  be using a PVC foam  for the main panels but fiber reinforced foam is harder to source.
Airex have just the stuff in their catalogue (Airex PXc / PXw & it would be ideal, trouble is though i can have small samples they do not supply it in the UK.
Anyone know of a source of equivalent core material here in the UK?

Thanks for the links, interesting stuff. Because of the curves of the hull a flexible insert is required, it seems the Airex ones are extensively used in the windfarm industry in blades. So far a complete blank in the UK, It looks like i am going to have to resort to laminated wooden inserts or lace the skins with roving, an old technique we used to use on bulkheads in the days before vinylester & epoxy! jeez showing me age now!