I use water and vinegar on the outside of the boat all the time. After I have rinsed off the salt with water I then use vinegar in a bucket about 10% vinegar to 90% water to keep the chamois working well. The boat looks great after, and it also helps remove the spot marks left behing from hard water.
I also use vinegar and water on the hull to remove the salt, we have a dark blue hull so it is tough to maintain. Again I make up the 10/90 solution and then wet the hull with the solution using a sponge. Then I chamois it off, call me a little anal if you like!!
Ian G. Fagg
Capt. SV Extarordinary