The new Gong HIPE inflatable looks really good. A solid light weight carbon plate platform, with a inflatable attached to it, Portable compact, rigid where it counts, a little safer than the hard board, durable in some ways, and affordable. Down side you have to pump it up, and make sure you don't puncture it. (I don' know the weight compared to a hardboard)
So how would a foam board on a carbon platform compare? Performance body board type foam
A solid light weight carbon plate platform, attached to a mixed-density polyethylene foam board. You don't have to inflate, not as Portable or compact, still rigid where it counts, safer than hard board maybe even be safer than inflatable, still durable, and probably even more affordable. And if done right, you could have 1 carbon platform for multiple top boards, making it a even better value. You could have a quiver of tops and one base plate.
I've never had an inflatable and in not sure how long they last or how their weight is. But i do know some of these body boards seem to be very lightweight.
Any thoughts on the Foam board idea, Good, Bad, or Stupid?
You would probably need a top plate as well as bottom plate to bolt together and sandwich the board between the 2 plates. With this you could easily attach a foil to any closed cell board soft or hard by just drilling 4 holes. If the plates were as long as your foot placement area then the board flex or strength shouldn't be such a problem. Old polyurethane blank boards could be used too.
Yeah, a top plate would work for sure. I'd think a manufacturer could have internal structural support so it might not need a top plate. A lot of advanced body boards have internal rods and such. Maybe just something internal plate and the same type of hardware like foamy leash plugs in the four corners would work.
Unless you sail only off of sand beaches I'm betting the inflatable lasts longer.
The question is how well they can be repaired if something does happen.