Andrew, I think the main question is whether the boat’s value from your point of view increases or decreases if you convert it - and the resounding answer is that it increases hundred-fold - but I would say that, wouldn’t I?
You might recall a magazine article written by JRA member Jeff, about how he came to lose his boat Sesi on the rocks. He came to see me this week, to talk over how he could get an unstayed mast to convert his current boat, a Westerly Konsort. The first thought was the Hydro tapered tubes, but the strength of the largest of these was not quite enough.
Now that I’m getting into 3D printing, it seems to us that the way to do is something like the old Needlespar way of sleeving a smaller parallel tube into the top of a tube that is sized for the righting moment of the boat - but using 3D printed tapered sleeves above the join as fairing pieces. We asked for Arne’s opinion on the size of this bottom tube, as three heads are always better than two, and decided that 7" diameter x ⅜” wall would be strong enough and that I could manage a deck ring at this size, but not bigger. My printer can make a maximum height of 220mm, so if we step down from 7” to 6”, two sleeves would result in a taper of 1.5˚, which looks reasonable. Then a 5” tube with two similar tapered pieces would get us up to a maximum length of 14m, using three tubes 5m long, 7”, 6” and 5” dia, with a bury of 0.5m at the two steps.
So I’m sure we can do something similar for your conversion, first choosing the tube size to be stepped into the boat, then the diameter of the next one, and that should be enough to get the required height. Then between us we can design and print all the components to make a mast and step it.
A modern version of the hybrid mast that has a wooden topmast going into a tube. Might this be something that other JRA members would be interested in?