customer question - tabbing bulkhead into 30' sailboat

This question comes from a website order. Will answer it here....

Thanks for the help Joel. one question - what sort of polyurethane foam should I use for the trapezoidal bulkhead spacer on my 30' sailboat project? the home insulating stuff at home depot??

I think you might have two uses for foam mixed together.

A structural fillet must not be PU foam. PU does not have the peel/sheer strength for this (until you get up to a very high density). The trapezoid fillet pieces you see used in boat construction are PVC foam (divinycell)

You can use little shims of any foam (blue PU foam from home store will do) in order to hold the bulkhead off from the hull, but the fillet will then be made with a putty (woodflour/silica), then the glass goes over the putty. This is done in order to avoid hard spots, so the bulkhead pushes into the hull evenly across the fiberglass tabbing, spreading the loads evenly.

Joel