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Re: [PSUBS-MAILIST]
Metacentric height can be explained in a pretty simple manner. If you
imagine a line drawn through the center of your vessel which passes
through CG, as your ship rolls, CB shifts outboard. If you subsequently
draw a vertical line through CB, it will intersect the first line (hull
centerline). This intersection is known as the metacenter, and the
distance between the metacenter and the vessel's CG is the metacentric
height. This is not a constant value, but rather a function of both the
angle of roll of the vessel and the shape of its hull. Metacentric
height is a useful measure for describing the amount of stability a
surface vessel has for any given angle of roll. For a submarine in the
submerged condition, it has less meaning, since CB is higher than CG and
the position of CB does not change, and hence the metacentric height is
constant, and equal to the distance between CB and CG.
-Sean
Jay K. Jeffries wrote:
In naval architecture terms, you are attempting to establish a low
center of gravity and and a high metacentric height (don't ask me for
a definition, its been years since I had the class ;-) ). You need
to be careful with George's explanation when the sub comes out of the
water as it might still roll over with the center of gravity just
below the the waterline as the metacentric height and center of
gravity switch positions. Buoyancy is no longer in the equation. You
should strive for a large separation between center of gravity and the
meta centric height.
Respectfully,
Jay K. Jeffries
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