I´m thinking about differents ways to remove weight in my future project, and…
someone has made big drilling in the deck or in the bottom, even in the lines, and later, before glassing, has covered the edges with foam, shape it and then proceed with the glass??? It could be an option in order to remove up to 40% by weight or more, I think.
I’ll try drilling in a structure like a fish skeleton, without reinforcement drill core.
Also, you must be talking about reducing the weight of the shaped blank by 40% not the finished product by 40%, because the significant weight is in the skin, not the core. So removing foam won’t make much of a difference.