Hi All,
Over the years I have sailed models in fresh and salt water. We all know that water and electronics don't mix, but electronics and salt water is just the worst as its not just the water but the corrosion that does the most damage. I would say that apart from good cleaning down and shaft lubrication as mentioned, if you have to sail in salt water then take extra precautions like waterproof radio boxes and the like if you have the space, or even just sealed compartments that protect most of the electronics.
An 'End of Season' strip down, like taking out rudder and prop shafts, cleaning and oiling them, a new bag of silica gel in the radio box is a good idea as well. Don't just leave a model used in salt water to sit and dry over time, you are asking for trouble, Apart from those not too arduous tasks there is no more danger in salt than fresh, just don't drink it!.
Cheers….Ron.