Message-Id: <199704211240.IAA18052@onlink4.onlink.net>
From: "John Winters" <jwinters@onlink.net>
To: <baidarka@lists.intelenet.net>
Subject: Re: bow piece
Date: Mon, 21 Apr 1997 06:47:39 -0400
Paul MacIntyre wrote;
(SNIP)
> I went paddeling yesterday with two friends in moderate waves. I was
> in a "Dyson 5.28" with the upswept bifid bow, one of the other boats was
> a flared bow Greenland style boat the third boat was a "Shields" boat
> with the straight bifid bow. The "Shields" boat pentrated the oncoming
> waves with reletively little pitching compared to the other two boats.
This may be true but one would be hasty in attributing the behavior
strictly to the bow. There are a number of other factors such as moment of
inertia, waterplane area, vertical prismatic coefficient, waterline length,
displacement, and hull and hull surface flexibility. Unless one runs
controlled tests in which the only variable is the bow shape then one
cannot know for certain what is causing what.
I think it would be valuable to establish that a specific type of bow
profile did effectively reduce pitching. For what it is worth, some bulbs
do reduce pitching on ships by increasing the entrained water. They also
increase slamming loads so it is unclear if there is a net overall
improvement. certainly this is an area worth objective experimentation.
Cheers
John Winters
Redwing Designs
Specialists in Human Powered Watercraft
http://www.onlink.net/~jwinters