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DSK wrote:
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.
Yep.
... This means that my boat that weighs 8000 lbs must displace
8000 lbs of water in order to float.
Yep.
... If she takes on 8000 lbs of
water, she sinks cuz the buoyant force doesnt balance the weight.
Right?
Not necessarily.
There is a relationship between weight, displacement, and immersed
volume. The "displacement" in reality is the immersed volume, and the
weight of that water *will* equal the actual weight (or mass would be
a
better term) of the boat & all it's contents.
So, if your boat weighs 8000#, and you add another 8000# (doesn't
matter
if it's inflooding water, bricks, or feathers) then your boat might
sink
*if* it does not have the hull capacity to create that new larger
immersed volume, and thus displace that much more water. Capische?
So, why do people make a distinction 'tween displacement and
weight?
Usually what people mean by "displacement" is shorthand for
'displacement when floating at the boat's designed waterline.' That
could be light, with no people or stores; it could be fully loaded ie
all tanks full and crew and stores, or it could be something like
'half
load displacement' which is defined as 1 average sized person for
each
bunk, no stores, and all tankage half full.
Most boat builders quote the lightest figure for displacement and
leave
the buyer to guess what the boat's capacity for stores etc etc really
is.
Fresh Breezes- Doug King
I believe Doug is correct.
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