I'm attempting to have a mastgate made by mastgate.com. I am also having difficulty providing all the necessary measurements. If I could provide the maker of my mast, I thought it may help. My boat was built in 1981, hull #333. I know he has made one for a J29, but I don't know if they are the same.
Anyone know what maker J/Boats were using. J/Boats have not responded to my request.

Thanks

BREAKAWAY
Hull #333
Sail #31884