salt water
#2

That's about it. Just like a real boat....flush things out best you can. Even run a hose over as much as you can since your hardware will also corrode in not much time....ask me how I know...
#3

Flushing & washing.
Unless you have a anodized coating or some kind of clear coat on everything NOT stainless steel, expect the look Hemi has said. Unlike metals. Brass, Aluminium, SS. copper & steel make a battery in salt water. You will see corrision on the unprotected edges.
That is why SS, Teflon & plastic are so good in saltwater.
I use only 1/4" SS driveshafts, SS ball bearings & SS shaft tubing. Clunky, but NO problem to remove shaft & bearings. If you use SS shafts. Remember to smooth down any set screw burrs BEFORE tring to move a bearing over a burr.