Thanks

Depends on the loads.  For high compression areas 100Kg/m3, for low-compression 60Kg/m3 is adequate.  The rigidity comes down to the foam thickness you use rather than the density.

Hi, Ref; PET foam. What weight would you recommend for topsides & windscreen frame? cheers..... PS. I fired up the lift a few days ago. It had 5 adults, 1 male teenager & 2x10 year olds on board. No worries.

And it can be formed into shape then glassed. Once cured it holds its shape. The resin bond is much better than PU foam and it doesn't delaminate - no replacing floors every couple of years!

thankyou, for advice!
i am a fan of this PET foam, you can cut it to all sorts of accurate shapes on a table saw, its a wonderful thing.

For a floor or ant traffic areas, 1 layer CSM with cloth over will be fine (extend it up the side/bow planes 100-150mm to provide sideways rock protection) and use foam tiles inside for protection).  No CSM anywhere else (it just adds resin weight for little strength - 2.5 x weight in resin compared to cloth which is 1:1 AND stronger) except where you need to get cloth to go around a corner (40mm CSM strip under cloth in those areas usually does the job).

Jon, PM me your email address or What's App details

Walking surfaces, you should be OK with a layer of 450 csm and a layer of 200 cloth. Bulkhead I would have thought a layer of 300 csm & a layer of 200 gram cloth would suffice.  I think I have some Sevtec plans here, so will try and dig them out to see what they say

[should i just use 1 layer 300g csm and 200g woven?]

got some pet foam, got some 300g CSM and 200g woven, got a bucket of resin, and happily sat in the warm drawing a craft.
for the floor, i am going to use 25mm thick pet foam, looking for advice on layup, don't want to go overboard. was thinking on 2 layers of 300 both sides with 200g cloth on top, is that overkill? should i just use 1 layer 300g csm and 200g woven?
i also have 10mm PET for the seat and top of the craft and some 20mm to make bulkheads.
its not a sevtec but similar skirt, i.e. probably going to put a bag on it, as that will be easier.
what layup do sevtec builders use on the foam for the floor and bulkheads etc?
thanks in advance!