Good 30' boats aren't that expensive. We got our 43' sailboat for $49k, needed a little work, but moved aboard for 4 years.

The hut on a spar idea doesn't appeal to me at all. Boats provided mobility, are well established tech, and have legal protections.

New, probably. But used sailboats aren't hard to find at good prices. Something about there being two great days for boat owners: the day they buy it and the day they sell it.

They go for US$20k-US$30k if you're okay with a 30 year old one. https://www.yachtworld.com/boats/Sail/Cruiser%252FRacer/Cata...