Bronze or Stainless Steel Thru-Hulls ?

[Kefaa]

Through Hull seacocks below the waterline. may help you. The short version is to test them. If you are really willing to pull all of them for replacement, then pull all of them for inspection. My boat is 1988 and I believe the thru-hulls are original. But one (or all) could have been replaced at any time, gotten dirty, etc.
Replacing Thru-Hulls and Seacocks Photo Gallery by Compass Marine at pbase.com is another site I have used as a reference. It has good pictures and I am following the advice to replace the existing backing plates with fiberglass. Either cut from some boatyard scrap or as one person recommended, taping wax paper over the hole and making one myself with a custom fit.

At the same time I am putting a protection ring around the seacock. I am still working on what exactly to use. The intent is three fold: 1- protect the sea cock from someone accidentally tossing something onto it and damaging it. 2- Keeping it clear of anything in case I need to get to it. 3 - ensuring I have a plug that will fit in case the worst happens.

Other seacock bookmarks I have:
Seacock Removal and Replacement
Surveying Fiberglass Sailboats: A ... - Google Books

[Hampus]

Originally Posted by S&S

if the body isn't turning pinkish you're fine from an electrolysis standpoint- they're supposed to be greenish. If they aren't leaking, at haulout remove and grease the cones and reinstall- they're fine. They're seacocks right? Not gate valves or some other such horror?

Nope, ball valves. Seacocks, as you know them and as I have seen on sale from US chandleries are virtually unheard of over here and almost impossible to find. The good news is that the ball valves are approved by Lloyds.

I agree on the gate valves thouogh. We have one on this boat and it's stuck. I've had severa on other boats and they were all stuck. The only gate valves that aren't stuck, for obvious reasons, are the ones for the diesel lines.

/Hampus

[boatpoker]

Whether you decide on stainless or bronze, make sure they were not made in China, Groco already had a major recall due to dubious Chinese metalurgy.