Using Stainless below the waterline?

[bechelt]

I am asking all sailors whether, or not it is a valid idea to use stainless hardware below the waterline. Let me explain the projects:

1) Mounting seacocks. Seacocks are Marelon bedded onto the hull, have fiberglass backing plates epoxied to the hull, and the bolt heads are intended to be resessed into the hull, filled, and faired.

2) Mounting my fiberglass rudder gudgeons. Gudgeons are fiberglass, hull is fiberglass, bolts will be bedded into both, but have epoxy around heads and nuts. Possibly faired.

The boat will remain in fresh water for the next 20+ years, but will return to the open oceans someday. My alternative is to use bronze bolts, such as the ones that came with the boat.

Thanks for the feedback,

T.

 

[KD3PC]

not for use below the water line, crevice corrosion and water, salt and such are detrimental to the stainless....UNLESS it can be completely separated from the environment

 

[redhead78]

Use silicone bronze, I believe they r the best for this application...Red

 

[RichH]

Use silicon bronze, or even better NickleAluminumBronze if you can find it.

Even so, make sure that the bonding strap embedded (buried) in the fiberglass in the prop aperture and is electrically connected/bonded to the rudder pintels, the bottom rudder post 'shoe', and cutless housing is still electrically intact. ... it provides anodic protection of all the 'underwater rudder stuff' via a single zinc anode.

 

[kloudie1]

Since you are not using a lot of 'em, titanium might be an option .. corrosion free and not susceptible to crevice corrosion.
http://pitstopusa.com/c-135158-spri...-mettec-titanium-bolts-1-2-titanium-bolt.html
oh, and a good bit stronger than other stuff