"DSK" wrote in message

Maxprop wrote:

Not sure I comprehend that concept, but I'll assume you know what you're
talking about here.


Not sure if I can explain, but here's a try:
When you look at stability, two things help. Weight down low and beam. As
the boat heels from 0 to 90 degrees, beam loses it's effectiveness &
weight down low gains. The lever arm between the center of bouyancy &
center of gravity is determined by these, so if you increase weight you
increase the leverage of the boat's beam but sink the hull deeper in the
water which decreases the lateral shift in bouyancy. Unless that weight is
down real low, you're reducing both modes of static stability.

Okay. Makes sense.



Sounds a bit extreme, or tongue-in-cheek.

Not at all. Consider a hull shaped like a cylinder, with a weight at the
bottom. This will have zero stability due to beam; called initial
stability or form stability. It will have very very little righting moment
at low angles of heel, then as it approaches 45 the righting moment starts
increasing steeply, then nears max somewhat short of 90 and increases
slowly to the max at 90... a sine wave. A diagram could explain this much
much better.

Not really--that's quite clear.


Most monohulls have elements of a sine curve in the stability.

Hmmm. The Beneteau graphs didn't appear sinusoidal at all, rather
asymmetrical.

No, never heard of them, but it might be a good idea for recreational
boats to keep such figures handy as well. Then again, perhaps it's
difficult to exceed those critical figures in terms of load.

Depends on what you're carrying. In the old days, sailors used to love to
carry lumber because it's bouyant and when stacked up & strapped down on
deck, the boat was very safe (although a PITA to work around the deck
load).

About Plimsoll marks-

http://amchouston.home.att.net/plimsoll.htm

The story I heard was that the basic idea behind Plimsoll marks came from
a lowly insurance clerk who tabulated ship losses & their loading, but
could not get anybody to pay attention... ship captains being rather set
in their ways...

I did a search after posting my reply. Didn't see that website, but several
others. Interesting stuff, actually.

Still working on it. No solution in sight.


I don't want it all. I just want a time travel machine.

Hey, I gotta good used flux capacitor I could let ya have real cheap . . .


Max