salt water vs fresh water bouyancy in boat plans

I was just peeking in to ask about the water line and balance change from fresh water to salt. Will it have a major effect on a boat usually sailed in fresh water?

Salt water is denser, weighs more, and displaces less, so a boat built for fresh water sailing will act differently on salt water?

Thank you for your time.

 

If you're talking about a 300m supertanker...yes
If you're talking about a small dinghy...no.

 

It's a small boat, but I was wondering what a difference it would make. Even small ones with ballast or keels would be effected by a relevant change. I was wondering if that would be needed in choosing a design.

 

The difference, if a small boat, is so minor it is not worth even worrying about. In reality you wont notice any difference at all, even though there is technically a "difference".

 

The difference is 1.6 lbs/cu ft of displacement. say 16-32 lbs in a smallish boat. total difference in draft is in the order of an inch or less. You'll float a bit higher in salt than in fresh...so bring another case of soda or whatever.

Steve

 

I can tell you that I remember a 'well previsioned' 46' 1950 Chris Craft floating maybe an inch lower on her lines in fresh water than in salt water, so as said, not a big differance.

 

Is it better to be higher than lower in a design? I would think I would want to build for fresh water and be higher in the water than for it to be lower.

 

Many BC fishboats with greedy skippers have been loaded to deck level in salt water. They do OK until they hit the freshwater of the Frazer River , then they sink like a stone. Not a problem ,unless your decks are awash in salt water.
Brent

 

I'll remember that. You never know when that may come in handy. Don't be a greedy sailor in fresh water.