After three years ashore, we've bought a small dayboat / weekender with a retractable (swing) centreplate. The old plate (in mild steel) is rusted beyond use, so needs to be replaced. I wanted marine grade stainless steel (inox) sealed with epoxy paints and three coats of (EU compliant, of course!) antifouling. The yard says inox is expensive and difficult to cut and shape ;- galvanised is the way to go. The plate will be permanently immersed in seawater whether lowered of raised into it's trunking, and difficult to access when ashore without a crane.
With only a couple of seacocks (well protected behind epoxy) being the other metal parts permanently immersed in the sea, I'm comfortable with the notion of not having a sacrificial zinc anode wired-into all the boats metal parts. Also happy with the notion that this new plate will require replacement in less than twenty years (or even ten, at a push). The only 'galva' boats I've seen on my travels (typically Ovnis) have often had owners tearing their hair out about dissimilar metals and grounding their electrical circuits. I'm sticking to a simple 12v dc set-up to power some lights, the depthsounder and the stereo, and do not propose to install a earthing / ground plate - the boat is 20 years old and has survived thus far!
The yard also suggests that galvanised will not need priming or antifouling. True?
Any advice gratefully received. Regards. John