Hi Peter:
I just saw your post on the SSB whip antenna. The plastic mounting ball at the base of my original Amel fitted SSB antenna failed and was un-repairable. I was in St. Thomas, USVI at the time and ordered a replacement Shakespeare 23 ft, Series 390, SSB antenna through Island Marine Outfitters,
http://shakespeare-marine.com/390
The antenna comes with a 1 inch threaded base that screws onto this base fitting
http://shakespeare-marine.com/410-r-swivel-mount . So as not to have to drill new holes in the deck, I used the existing aluminum 4 screw base mount and with an appropriate sized washer and nut, the 1 inch threaded antenna swivel base mount attached to the existing Amel deck fitting. Everything else remained the same and the reception/transmission, if anything is improved.
I remove the antenna and stow it belowdecks during hurricane season and the threaded base makes this a very quick and easy task compared to the fiddly pin mount of the original antenna.
All the best,
Gary Silver