I know that this has been covered by others, but I thought I'd put my experiences with Jack on too.
I bought the Sam Robinson/Gemini tubed rib some 4 to 5 years ago.
Sam told me it was a Ring 21 hull & he had bought the moulds from Mike Ring.
Gemini Industries supplies the tubes to Sam who fitted them.
I left it in my garden uncovered that winter.
during the cold spell, the tubes simply fell off the rib!
I then got a company in essex to fit the tubes properly, they warned me about the issues with these tubes.
For reasons I now can't explain, I did nothing with the rib till last week, when I decided to assemble it.
Me & my 12 yr old son took it out last saturday at Rye, first time the rib had seen water, all very exiting!, no leaks, floats well, looking good: engine runs well (150 Mercury XR6)
go out to sea, had a long run in her, very impressed with performance (I think the boat is pretty light for it's size 7+m)
We were out at the Fairway buoy, when the coxwain says "Dad is the tube meant to flap like that", sure enough the starboard rear tube had deflated.
This was a new experience for both of us, quite character building in fact.
Making sure we kept planing, we zoomed back into Rye (sorry Mr HM). (Boat stayed afloat even when statonary...)
Stitching had failed on both cones, on starboard side, the innertube had burst, the port one close to failing, with innertube showing.
Spoke to Jack at Gemini Industries, "stitching had rotted due to me leaving boat outside & I had over pressurised the tubes". He offered to send me patches & stitching to repair it my self. "the factory is in Belgium & we dont have facilities to repair here, & I only returned to England to retire"
The tubes were underinflated if anything, as I couldn't find an adaptor to pump them up, nothing came with the boat.
Their website says stitching is good for ten years....
Moral: buy cheap buy twice
Been quoted £4k for hypalon, anyone got any ideas??