GL: Denser Water Wes: Roll Causes Yaw?

[joe]

Ralph, 
 I am not a naval architect but by experience know that this issue is more
complicated than that.  The use of "gentle and snap" is a little misleading
with regard to hard chined heavy displacement vessels with very low centers
of gravity and great residual buoyancy.  Obviously, roll is also a function
of wave size, period, steepness and direction of travel. The roll
sympathetic frequency of the hull has a huge impact as to the degree that it
rolls and to what extent in small versus larger waves at differing periods.
I agree that a deep keel sail boat with the leverage of a sail array has a
great stabilizing effect...under load.  The sail has little if any effect at
anchor or under way in no or a foul wind.  In those conditions you at the
mercy of the "roll monster" .  Hence the reason for all the various anti
roll devices from active to passive on round hull trawlers(sail less boats)
and at anchor mono-hull sail boats.  Non stabilized round bottom hulls can
pendulant in a beam sea in a very frightening and uncomfortable fashion.
Again not a naval architect but have experienced all of the above and
greatly prefer (find most comfortable) the hard chined (flat bottom) heavy
displacement trawler design.

Joe
"Carolyn Ann" N37





Snip"...Roll and yaw are more a function of hull design, shape than anything
else.
When exposed to a wave, a round hull will roll slower and gentle, whereas a 
hull with sharp corners will snap back more quickly, producing more of a 
jerking motion. The existence of a keel helps to counter it but will not 
eliminate it.
If you dont want a boat that rolls, then buy a sailboat round hull, deep 
ballasted keel and leveraged counter force (sail) to keep it stable.
R,..."