I've seen more aluminum bottom dinghies with the issue of the tubes coming unglued from the hull than I have with fiberglass. I believe there are some designs where the tubes are not glued/bonded to the hull so water won't get inside if they are separated. It seems that any small scratch through the paint on the aluminum hull eventually leads to oxidization causing the paint (and glue) to release. I've not seen this to be as big an issue on fiberglass. In the Caribbean most dinghies end up getting drug up on a sandy/rocky beach many times. I vote for a hull made out of unobtainum for it's light weight, strength and resistance to corrosion in the salt water environment.