The foam boards provided an easy way for me to get some fairly complicated shapes made.  The problem with the foam is that it is incompatible with the resin (polystyrene versus Polyester).  The 2 ‘Poly’s’ do not get along. 

I could have used Polyurethane foam, but it is more $$$ and not as easy to work with.  Instead, I coated the foam with polyurethane.  The polyurethane  did not work as well as I hoped, but it was good enough to get the parts made.  An epoxy coating on the foam would have been better.

The hatch needed some modification to secure the latch.  So, I added a stiffener as well.  Once the big pieces were fiberglassed, it was on to a few odds and ends and other prep work.