I googled this topic. I like the idea of supplementing the cooking water supply with sea water when in clean waters. Whenever we do clam bakes at the beach, we use seawater but I'd never thought of it on the boat. Duh on me, I guess.
It's all a matter of trial and error but I can't wait to try it this summer and I love of idea of conserving water.
Salt content is different everywhere but the ratio of 1 part seawater to 3 parts drinking water for cooking seems like a good starting point. With a long cruise of a month or more, I'd rather take more dried foods than canned, so I like the idea of rehydrating with some portion of seawater.
What do you think ?