After a year of non errosion of the hull anode I checked the protection system on Artemis P27/136. The earthing wire connecting the stern tube had corroded under the jubilee clip holding it, hence no continuity and the 8mm ss nut and bolts holding the anode to the underside had no fan washer so they did not bite into the support bar of the anode hence no connection.(there was also much mud/sulphide corrosion on the anode support bar)
Main worry was that the cystic copper in the gelcoat around the two anode bolts had been acting as the anode and had 'rotted' away exposing fibre glass over a few sq cm. Seems this is worth checking!
Repair was simple using West and filler to make good the hull and replacing the bolts with M G Duff anode studs and connecting the stern tube with a s/s domestic earth continuity strap fitting. All connections now below 0.3 ohm so hope this fixes it.
Roll on Spring!
Chris N