They're quite light for their length and perform well. With proper materials and some vacuum bag work, that whole deck and house could be about 150#! The owner could have a real screamer there.
Helped a friend build a 39' custom about 12 years ago. People accused him of building a stripped out race machine, and he'd invite them below to see his granite counter top. And there is was next to the propane stove (with oven) for hot pots. The granite was about 3/16" on an aluminum honeycomb - he found a source through the Lear jet people.