Thanks for the follow up – I should have mentioned my saildrive is a 120.
Machining the anodes, whether ring or split type is relatively easy; the hardest part is getting the locating pin hole in the right place. I placed two anodes, one old and one new, un-machined, back to back and marked the hole position on the anode to be machined. Then set up on a pedestal drill and drilled the hole. The cut out on the edge of the anode was filed by hand to fit the rope cutter.
As an aside, when I purchased two anodes recently, I was advised by Zincsmart that Aluminium anodes would work ok, ( a lot lighter too) I will try to remember to report on performance at the end of the season.
My anode ‘consumption’ is pretty high. I have in the past had to replace the ring anode and the Brunton’s nose anode every year.