DSK wrote:

MC wrote:

OK you seem determined to make me rub you nose in your error but here
it is. You said and reaffimed that the equation was:

"
CSR==(Beam / Disp ) ^ 0.333
"

but it is really

Beam/(displacment)^0.333


The second equation is right. Was the whole divisor included in the
parenthesis in my first post? If so, that was an error.

At last.


However, we now know for sure that this is indeed what you're talking
about, and it has nothing to do with initial stability (as you
repeatedly said) and it used to compare relative LPOS for similar
vessels when no more detailed measurements are available.

OK let me try to get you to see something else. If the beam of typical
vessels is the same inverted or the right way up would the capsise
screen be different?

Do you not agree that the underlying assumption of the screen is that
the inverted water plane width is directly proportional to the beam?

Now if you've got that, isn't the non-inverted water plane width also
likely to be directly proportional to the beam?

If that's so, could there be a connection between initial stability and
inverted stability as valid as the CSR formula itself?

Finally, the metacentric radius (BM) is the height of the metacenter
above the center of bouyancy. Clearly this is a very important figure
for initial stability as it determines the righting lever (If I remember
this is called Attwoods formula). Now BM can be shown to be the moment
of inertia of the water plane about an axis through the C of G divided
by the volume of displacement. The mathematical connection to the CSR
formula arises directly from the moment of an immersed wedge being
1/3y^3 theta where theta is the heel and y the waterline beam (of the
immersed wedge). The extension of this is exploited by Barnes method for
stability calculation -which you may know about.

OK?

Cheers