Our 38 RL with disc brakes sits just off the coast in Gulf shores, it stays in place for five months. I'm concerned about corrosion and rust damaging the rotors. Is there any way to protect them?

Try looking on the web under "disc rust"...

But here is an interesting article on discs and rust:

www.ebay.com/gds/How-to-Find-Brake-Rotors-That-Dont-Rust-/10000000177404702/g.html