Converting an HBI to solid fiberglass tubes

After workin with hbi´s for many years at a well used coaching facility, i have witnessed how fragile and expensive they can be. A tube for a twenty footer is 10k and I have seen them last less than ten years. I rarley loan one out from the facility because in the past they have returned with expensive holes. Yes all of these issues are debatable but with many users, lots of days on the water coaching and small budjets this is spot we are in. Because of this i would like to design and construct a permenant hard fiberglass tube with a replaceable foam outer layer. Construction would possibly be on a 7 foot male mold with foam core reinforcement. Pieces would be cut to the correct angles to momic the shape of the old tube and married inside and out with lots of reinforcement. Finish could be somewhat rough as the tube surface would be covered with thick eva foam to soften the collisions between coach and sailor that could be replaced in pieces as needed. The tube would then be attached with enough glass on both sides to keep things tight. Here are a few questions for the group. How will the new rigity of the solid tubes near the stern affect the ride, could the section of the tube near the stern be veed to provide some give in chop, would this make it catch an edge, do whalers use a simar shape of a tri hull. i believe a twenty footer could be done for 2.5k materials and 500lbs with basic materials and methods. Thanks for your thoughts.

 

I assume a HBI is an inflatable boat ? When I googled HBI, Heartless Bitches International featured, can't be that !

 

If it is some sort of acronym for an inflatable, or maybe a RIB, then others have made rigid tubes that work OK. Around 35 years or so ago a friend made a series of workboats for the salmon farm industry that were an alloy rigid hull (very like that on a GRP RIB) with welded on alloy tubes to provide additional buoyancy, ultimate stability and a rounded gunwale for ease of hauling ropes etc over.

It was a pretty good idea, and the boats worked well, every bit as as well as a RiB. They would take knocks better, but did end up looking a bit beaten up after a few seasons (but as workboats this didn't matter)

I think he could have grown this into a successful business, but he was the sort of guy who really likes new ideas and constantly wants t change things, so once he'd made and sold a few he moved on to something else.

 

Hard bottom inflatable?

Replacing a flexible tube with a solid fiberglass one doesn't make sense to me. It would then be a regular, solid hull boat with a lot less room inside.