Astraea has a Westerbeke 44 Engine. In the heat exchanger there is a pencil zinc exposed to the saltwater cooling loop. The pencil zinc corrodes away sacrificially instead of the engine. Monthly I check the zinc to see how much has corroded. In December I changed the zinc out with a new one. I searched online for the zincs and found them at first for $6 each. After further searching on Amazon I found them for $2.50 each plus $10 shipping. Since they’re a common wear item I bought 10 to bring the total price each to $3.65.
The part information is here for anyone else who may be looking for the best deal on these zincs. Westerbeke / Universal Part number 011885. They’re shipped and sold by RotoMetals, a 5 star seller from San Francisco. Here’s the link to the best priced zincs.
All I need to change the zinc in the heat exchanger is a 9/16 socket wrench. There’s an old and new zinc to show when to change out. It’s best to leave some pencil on the zinc and not go down to the nub, because then you’ve gone too far and may have begun to damage your engine.