"Frogwatch" wrote:

About three years ago, I moved my sailboat to a slip in a real
marina
for the first time ever. I was surprised to see my shaft zinc go
away
really fast.

You are in a bad neighborhood.

My money says either your neighbors have "hot" (improperly grounded)
boats or the marina wiring has problems.

Either way, it's either for your neighbors and/or marina to make
repairs or find another dock.

You probably have to build a case.

Yoou need a meter that can detect ground currents.

I'd find another dock, if I could.

Good luck.

Lew