Interestingly concrete yachts are a thing. Ferro-cement is the term, but it is just reinforced concrete. You can buy very large yachts for small amounts of money with yachts made this way in the 70s.
Was this created by AI and not proofread or created by a human and not proofread? The paragraph relating to the Musgraves taking over a factory is repeated and it reads rather oddly.
Anyway, regardless of that nitpick, it was an interesting read.
Or melt the sand and form it into long strips, fibers, then glue the fibers together in some sort of glass-fiber-epoxy type material. Get the patent done quick because that sounds viable imho.