Frank-
Very similar I just called mine a split bushing is all. I think the rivet or set screw would work best-I don't know about welding the extrusions together. I don't think it would have worked on my set up.
For those of you wondering a "Boat Unit" is a $100. When referring to boat expenditures it is easier to talk in terms of boat units rather than dollars. Saying something like "Gee, my new bottom job only cost me eight boat units" feels a lot better than saying "I just spent another $800 on the boat"-don't you think? I am also attaching a photo to show you what my break looked like. I don't know if it helps since it does not show a close up of the split fitting.