Not at the boat so unable to check directly, but would the R&D flexible coupling supplied with my Beta 38 (WOC K35616) have come with an earthing conductor? Of course, I still need to verify installation even if the earthing conductor is supplied as standard, but I am still trying to figure out why my engine anode at the heat exchanger wears so quickly.

The old engine that the Beta replaced was a Volvo-Penta MD17D and pretty much all of the surrounding equipment excepting the prop itself was carried over. The batteries and electronics are all the same, our sailing and mooring of the boat are the same (we are almost never in marinas or on docks for any length of time), and there were no other relevant modifications that I can recall.

One difference that I am now considering is that the old engine was steel flange-to-steel flange mounted to the prop shaft and thus electrically connected whereas the R&D flexible coupling is in line with the Beta and may be electrically isolating. Could it have been that the shaft zinc was previously offering protection to the MD17D, which had no engine zinc and yet never showed any sign of electrolysis? The shaft zinc was much larger than is the Beta engine zinc, but the shaft zinc never wore unusually quickly. Of course cooling seawater remains a potential path of some electrical conductivity to the Beta, so could lack of electrical connection to the shaft zinc somehow cause the Beta engine zinc to wear quickly?