Alloy for mast step
Hi Gareth,
Looks like you'll be addressing the same problem as myself, but a year in advance......let me know how it goes - whether she falls or stays upright!
Actually, stainless steel is only subsectable to crevice corrosion if denied oxygen AND in a continual wet environment such as with threaded stainless components underwater (i.e. S.S.thruhulls and valves). However, there are some interesting alloys now like as those used for propeller shafts such as Aquamet 17, 18, 19, 20, 21, and 22. But, the whole idea is too keep water out no?
Thinking it through it, I maybe a good steel plate that is well coated with the new chemistry paints and sealers on the market now-a-days. There is some amazing stuff being used on steel in ship's ballast tanks and cargo tanks that last several years when exposed to nasty ballast water, petroleum products and corrosive chemicals.
Actually, now that I think about it, mabe a Copper-Nickel-Steel alloy (CuNiFe) would be a good choice - it has enough copper and nickel in it to prevent corrosion, is quite strong yet won't cost very much in such a small piece like a mast step. It's rated @15,000 lbs /sq. in.
So, there you have it, my thoughts on it. I guess I'd go with Copper Nickel unless I'm told otherwise. I'll ask around if I get the chance.
John M.
PS...drop me an e-mail, I have an account card for you to send out.
I'm not sure bronze would be up for it as it is fairly flexible and soft. Al.? same problem I suspect.