I had a cast aluminum chock that was integrated with the toe-rail that broke. It was a closed D shaped loop. I have looked for another but not found a matching one. I am thinking about using a square stainless u-bolt for the chock. I would like the line to be protected whether it is running forward of the cleat or aft of the cleat and the skene or angled chocks seem to work only in one direction. If I use a large diameter u-bolt (say 3/8") is that a large enough diameter to protect the line?