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In article .com,
wrote:

Maybe I've killed too many brain cells over the years or just forgotten
some basic stuff but my understanding of Archimedes Principle is that
the buoyant force on an object is equal to the weight of the fluid it
displaces. This means that my boat that weighs 8000 lbs must displace
8000 lbs of water in order to float.

This is true and is a basic principle of floating objects.

If she takes on 8000 lbs of
water, she sinks cuz the buoyant force doesnt balance the weight.
Right?

I suspect that's false. Your boat may or may not have that much reserve
buoyancy. Our 3.5 ton boat is rated to carry at least 5 tons. Would take
somewhat more to sink her in calm water. Hull (without keel) is a bit
more than a foot submerged. We have 3'+ more freeboard and the hull gets
FAT up there.

So, why do people make a distinction 'tween displacement and weight?

Sounds better, and is more technically correct.

Reminds me of a hairy old story: New engineer is told to find out how
much more of something is on a barge. After hours of laborous
measurements and calculations, the foreman comes by to see what the
matter is and points out the numbers marked on the hull -- showing
displacement.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/