It's been several months, and the circuit is working perfectly.

I relaxed at anchor in Roscoe Bay (Desolation Sound, BC Canada) knowing my underwater metals were protected.

Thanks again to all who participated.

Steve

 

Excellent! I'm still astounded that it works. I never did quite get my arms around it.

 

SIX months later, it's still within a couple hundredths of a volt, and working great !
Thanks to Ron's circuit and all of you who posted help.

Steve

 

After a year, I am happy to report the circuit is working fine and my zincs have been protecting the underwater metals.

The zincs are intended to slowly dissolve while protecting the above metals, but with this circuit, their lifespan has greatly increased.
So much so that instead of having to replace the propeller zinc twice a year, it will now be a biannual event !
The main zinc which protects all the rest of the thruhulls and the refrigeration keel cooler assembly used to go away in one year. It looks like it will be good for 2-3 years!

Thanks again for all that participated.

One happy camper,

Steve