The problem is that the computer designed ones are very difficult to manufacture. Maybe using 3D printing, but I'm not sure 3D printed metal is as strong as the usual stuff.
Galv is not salt proof, but salt resistant. I've seen aluminum sheeting rot right through. (Snowmobile trailers). Ask a sailor; even stainless steel gets eaten by salt spray.
Oh yeah, I believe iron alloys will get chewed up by corrosion. But I thought aluminum got harder and more durable when there was an oxide layer. Perhaps I'm wrong.
Re: Aluminum. Yes, aluminum is resistant to corrosion due to the oxide layer (harder no, that's a bulk property, not surface). The ions in salt spray penetrate the oxide layer and lift it off or crack through it, thus exposing more bare metal. The bare metal then oxidizes and the process repeats until the aluminum is gone.
Stainless does ok in salt spray, but nothing is impervious. What you really want for salt spray is some alloy with a VERY high nickel content.
Stainless does ok in salt spray, but nothing is impervious. What you really want for salt spray is some alloy with a VERY high nickel content.