There is a strip of closed cell foam strip that runs down each of the
sides. It meets the USCG requirements for small boats... It is thin,
so the boat can still fold almost flat. IIRC, about 4" when folded.
These boats are really nice. a little gangley, but very efficient once
on plane.
Some New Brunswick company used to show those at the Halifax Int
Boat Show, although I haven't seen their booth the last couple of years.
They were expensive when our $ was only worth 62 cents US. Wonder
what they cost now?
About half the cost of an inflatable the same length. Without those
fat tubes, it's a lot roomier, too.
Also needs far less power to plane, so there is a additional big
savings on the engine for it.
What's the hull material on those folding boats?
Never mind...found out.
The photos I saw looked as if there was no flotation on the boats.
Is that the case?