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fresh- vs salt-water displacement
By:Paul G. Jacobson
Date: 7/5/2000, 12:33 am
In Response To: Re: Plus the weight of the kayak (John B.)

: Here is another consideration that I never really thought about until
: recently, and mentioned to a marine engineer ... that is the salinity of
: the water. As expected, vessels will hold more (weight) in salt water than
: fresh. It might at first seem trivial, but in reality he said that it is
: material, as boats going up a river fed bay have to do some serious
: calculations about how much water they are drawing as the salinity
: changes. Anyone ever notice this in a kayak?

The difference in weight between a cubic foot of fresh water and salt water is about a pound. That's one pound out of 62 or so, or about 1.3%. With a bigger boat (ocean liner or supertanker) the difference in bouyancy of the water would be of greater significance that with a kayak.

With a boat designed to weigh in around 215 pounds, (that's under the weight of 4 cubic feet of water) your difference is only going to be 4 pounds. That is about the weight of a typical fast food lunch, or a 6 apck of cold beverage, or a freshly caught fish.

So, when heading from fresh to salt water, eat, drink, and fish. What more is there to a simple life?

PGJ

Messages In This Thread

Question on displacement
Ed Walshe - Dublin -- 7/3/2000, 9:11 am
Plus the weight of the kayak
Dale Frolander -- 7/3/2000, 11:29 am
Re: Plus the weight of the kayak
John B. -- 7/3/2000, 6:37 pm
fresh- vs salt-water displacement
Paul G. Jacobson -- 7/5/2000, 12:33 am
Re: fresh- vs salt-water displacement
John B. -- 7/5/2000, 6:38 pm
Re: fresh- vs salt-water displacement
Paul G. Jacobson -- 7/6/2000, 6:42 am
Re: fresh- vs salt-water displacement
Dale Frolander -- 7/7/2000, 12:55 am
specious origins
Paul G. Jacobson -- 7/7/2000, 12:16 pm
Re: fresh- vs salt-water displacement
John B. -- 7/7/2000, 6:10 am
Re: Thanks for the Physics lesson ...
John B. -- 7/6/2000, 5:42 pm
Re: Question on displacement
peter czerpak -- 7/3/2000, 10:54 am