Jari has been developing the ball-raced gooseneck idea. For round booms (and maybe the Sails ETC booms too) there is now a typical 'tang' at the top. Using a rigid compression strut for the kicking strap seems to be questionable under the current rules, so here's a more conventional kicking strap based on a piece of stainless M4 thread, a threaded stainless cylindrical sleeve, and a piece of stainless wire with a 'blob' on the end which keeps it attached to the sleeve. There will be a thumb-wheel on the final version instead of the nut seen above, and probably also fixing-screws for attaching the fitting rigidly to the mast. Jari thinks these fittings could be sold for 60euros each (including all parts and the bearings).
Anders, have you sailed with this gooseneck? How did it work out?
I noticed in some later posts you had a different design that screwed to the mast. I was thinking of trying this design since it is easier to make, unless there were problems.
What is the offset between the center line of the mast and the center line of the bearing?
The fitting works OK. On my boat the bearing holders are fixed to the mast with M2.5 screws from the front side of the mast.
The bearings are 6mm o.d. and the center of the bearing is 11 mm from the center of the mast.