cvj wrote:
Hi Chuck,

Thanks for setting my mind at ease.

First question: are the bronze seacocks connected electrically (i.e., by
wire) to your engine ground? If not, you have nothing at all to worry
about.
No, they are not.

It is good & common practice to bond all bronze through-hulls together
on a nonconductive hull to spread/equalize galvanic currents (and
reduce localized problems).

If they are grounded by wire, is there a reason? There are many
different bronzes, of course, but in the old days, they would last the
life of the boat. Were they replaced 4 years ago because of corrosion or
failure?

No, that's when the boat was built.

I believe a reasonably knowledgeable diver would be able to detect
energetic corrosion of the seacocks, as well as any other underwater
metals, like the ruddershaft. I gather you used a diver to inspect your
prop shaft zincs after you installed the isolator but you didn't check the
seacocks at the time?

No, I replaced the prop shaft zincs when the boat was hauled out in May.

Why didn't you do normal through-hull & seacock inspection &
maintenance at the same time? FWIW real seacocks (meaning the tapered
bronze plug variety & not ball valves) often show pitting on their
explosed closed-position side of the plug, which may be rotated 180 for
more life before regrinding. You're supposed to
pull/inspect/clean/lube/repack & otherwise care for seacocks at every
reasonable opportunity, esp when doing the rest of antigalvanic things.
You should also be viewing any signs of excessive through-hull fitting
wastage for yourself.

Good luck, and hopefully, suspend the paranoia.

It is guilt, not paranoia. ;-)

Frank
Hates ball valve seacocks & other expensive, dumass, hard-to-maintain
things people put on boats.