I bought a pair of dinghy transom wheels which are on box section ally tube. I was thinking of either u bolts through the transom or maybe right angled brackets with butterfly bolts. Any other ideas.
Word of warning. I fitted some plastic dinghy wheels to my inflatable, which I keep locked up next to the launching ramp. They worked beautifully, but when I came back the following week, someone had unscrewed them and nicked them!