The ring was only about $10-$12.00 form Frank.Mine is A single ring piston.I think A air boat would be a lot of fun until you had to go swimming for it
I have always wanted to drive A real air boat.Good luck with your engine let us know how it turns out and I will let you all know how mine does.I'm thinking of running mine on glow/gas.I think it will all depend on how good it idols down.
Thanks
clocknut