I just started to refurbish a Sol Cat 18 for a friend. First thing we need to find is a new base for the mast (heel). We don't know why, but the base of the mast was missing. It is the part that fits into the end of the mast. I've only seen pictures of one. It is basically an oval shaped block which fits into the heel end of the mast and has a hole so when the mast is raised the hole goes over a pin on the companion piece which is mounted to the crossbeam.
I found a pic on the "Get started" forum and can email it or direct anyone who can help to the pic.