Hi Kibo & Symphony thanks for the input regarding this,
Symphony, i was under the same thought as yourself with the fact that the keel is cast iron just seems strange that the anode for the sail drive has very little damage to it and i have seen two bav 30`s up in the marina with extra anodes, one has them bolted on both sides and the other has one just aft of the keel, i thought this was because they were copper coated !
Anyway the course of action for this time has been to clean out and treat the pits and then fill them with liquid steel, this is only as i am due back in the water next week and to strip the keel back would be to long at this time, however i have planed for the next haul out that if the problem is still persistent then i will strip it back to bare metal then drill and thread some bar for the anodes then give it 4 coats of interprotect then 4 coats primocon then the antifoul.
Kibo, Was there a particular reason that you welded the bolts instead of getting the holes drilled and then taped out to receive the studs?