had to edit my response, after looking at the bluewater specs it looks like pretty tough stuff, not the typical foam based core- per their site
high density, polyurethane foam reinforced with layers of woven roving and continuous strand fiberglass.
27 lbs per cf for the 1/2" stuff (4' x 8' sheet)
might be worth it to send them an email with your question.
contact@coosacomposites.com
