Are there any Stainless Steel "Through-hull" valves and fittings?

Question

I know many through-hulls are made of bronze, but I cant recall any made of SS. Im sure there around. There is an abundance of Stainless above the waterline, why not below as well?

wouldnt they be preferred to bronze or are there other corrosion issues with them?

Answer 1

You can certainly get stainless through-hull fittings, but generally bronze is preferred to stainless steel because of the corrosion issues with stainless.   When I first went sailing I thought that stainless would be better.  My husband explained that below the waterline bronze is much preferred.

Answer 2

Stainless would be great to use on a boat, above and below the waterline and in fact it is used in many applications in high end yachts and on military vessels. As you said stainless is used for prop shafts and props. The reason you don't see many in use on the average pleasure boat is cost, plain and simple. Go down to the marine supply store and ask them to get you a 2" ball valve in stainless and see. There is no need to use stainless when bronze will do nicely, and even plastic is used where it can be.

Answer 3

Electrolysis becomes more of an issue when Stainless Steel is used.  To make it worse the cathodic erosion, occurring in a damp or wet environment, can occur anywhere within the path of conductivity.  Even in Air, if the humidity is above 60%.

Try these sites for a better understanding,

http://boatingsailing.suite101.com/artic...

http://www.finishing.com/319/84.shtml