On Wed, 24 Jun 2009 21:47:34 -0400, Wayne.B
wrote:

On Wed, 24 Jun 2009 15:20:52 -0700 (PDT), Frogwatch
wrote:

Other than decreasing topheaviness and increasing beam, how do you go
about minimizing probability of capsize for a powerboat? Consider a
swamped boat, what factors cause it to want to float upside down?

Any boat can be capsized by a steep breaking sea with a height
slightly more than half the beam, *any* boat, swamped or unswamped.

Other factors play into it of course like center of gravity, center of
buoyancy, metacentric height, etc.

http://en.wikipedia.org/wiki/Metacentric_height

Quoting from above:

"If a ship floods (swamps), the loss of stability is due to the free
surface effect, as the water accumulating in the hull will be in the
bilges, lowering the centre of gravity and actually increasing the
metacentric height. This additional mass will however reduce freeboard
(distance from water to the deck) and the ship's angle of down
flooding (minimum angle of heel at which water will be able to flow
into the hull). The range of positive stability will be reduced to the
angle of down flooding resulting in a reduced righting lever. When the
vessel is inclined, the fluid in the bilge will move to the lower
side, shifting its center of gravity toward the list, further
extending the heeling force."

The only certain way to avoid capsize is to avoid steep breaking
waves, and to keep water out of the boat, i.e., maintain a low center
of gravity.

Way to kill a discussion with facts Wayne. :)

Nice job. :)