There is a little voice in my head that told me I should find a temporary fix around this, until the rigger eventually shows up and replaces the tack ring. Thankfully, modern technology allows us to do things that were not possible just a few years ago.
Rather than disassemble the whole drum, I designed a larger tack ring that encircles the old one. It also has a bottom lip that secures it around the old one, so when you tighten it, it will never let go. The eye for the snap shackle is made to be even more reinforced compared to the original part.
Tested last weekend, its a go! The furler works again. You can see the version that I have left on the boat, with a quick coat of grey primer for UV protection.
It would be extremely difficult to call this a permanent fix, but it could help owners who get this failure while underway or during crossings. Having a couple of them as spares on board will probably cause no harm..