Aluminium foam.

His next yacht?
I meant that as a serious question.
That's just BS.
Do you mean a sofa in the yacht, or an anchor chain or the hull or what?

The open cell foam is an invite to corrosion as was said before, and the closed cell is really high density for a core.

This material is just about as practical as discussion on "3d printing the hull".

 

Superstructure or decks, like this high speed train cab assembled from aluminium foam components.

http://www.railwaygazette.com/news/...ord_list[]=metal&sword_list[]=foam&no_cache=1

I was intrigued by another foam, created from glass cullet & carbon powder, but the surface is friable & epoxy resin & glass cloth delaminated from the Foamglas.

http://www.boatdesign.net/forums/materials/foam-composite-construction-19932.html

Perhaps the core foam would work, if it were smooth rendered before being encapsulated with epoxy resin & glass cloth?

https://www.youtube.com/watch?v=IGdsIO6_4bc

https://www.youtube.com/watch?v=lummv_v5zi0

https://www.youtube.com/watch?v=lnOWPMZnhsQ

Leave no stone unturned.

http://www.boatdesign.net/articles/foam-core/