It looks like people are getting displacement, density and bouyancy mixed up.  
Any object that has a total density less than water will be bouyant and will 
float.  The weight of the water displaced by the object will equal the weight 
of the object.  Objects that are more dense than water will not float and will 
not displace as much water as their weight.

Looking at it from another direction, if you take a cubic foot of water and a 
cubic foot of another object (lets say a piece of wood) and weigh each, any 
object with the same volume that weighs less than the water will float.  The 
hull of our boats create a very large volume (mostly filled with very light air 
and other things that are less dense than water) compared to the total weight 
of the boat, so the density is much less than water, and our boats float 
instead of sink.

Fair winds
-------------- Original message -------------- 
From: "Joe McCary" <[EMAIL PROTECTED]> 

I don’t think that is how the displacement measurement works.  My understanding 
is all floating or non floating bodies have displacement.  When those bodies 
are placed in or on the water a certain amount of water is displaced. Example, 
fill a bucket to the absolute brim and float a piece of wood in the bucket; 
some of the water spills over the rim of the bucket. The water that over flows 
is equal to the displacement of the wood now floating.  The same is true if the 
object is a toothpick or an aircraft carrier; the water pushed away by the 
placement of the object in or on the water is the displacement.  The steel 
aircraft carrier floats because it’s hull is deeper that it’s displacement.
 
 
Joe McCary
Aeolus II, West River, MD
[EMAIL PROTECTED]
 
 
Behalf Of Jim Bernstorf


 
I understand the definition of displacement.  The logic of that though is that 
if the 6000lb boat displaces 6000 lbs of water then it theoretically would be 
sitting with the water at the gunnels of the boat and adding another pound 
would push the boat under water and sink it

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