Re: [Paddlewise] speed and resistance

At 11:35 PM 7/5/98 -0700, you wrote:
>I was just reading Matt Broze's article in August's Sea Kayaker magazine
>about the amount of resistance generated at different speeds.  Its clear
>that the drag resistance builds up pretty quickly going from
>3.0->3.5->4.0 knots:
> 
>3.0 knots -> 2 pounds of resistance
>3.5 knots -> 3 pounds of resistance
>4.0 knots -> 4 pounds of resistance.
> 
>So, going from 3.0->3.5 knots there is a 50% increase in resistance for
>only a 17% increase in speed, and from 3.5->4.0 knots a 33% increase in
>speed for only a 14% increase in speed.
> 
>Given the significantly increased resistance going from 3.0 to 3.5
>knots, and that this is in the common cruising speed range, I wonder why
>Sea Kayaker doesn't give resistance figures for 3.5 knots in their kayak
>reviews.  Are kayak's resistance just too similar at this speed to make
>this info worthwhile?
> 
>I've also noticed that when short sprint speeds are given (determined
>with a knotometer),they often peak out at about 6.25 knots, even though
>the resistance fiqures at the 5 & 6 knot range may be quite different.
>Any thoughts?
> 
>Norman Strutin
>(SF Bay Area)

	The esteemed Prof. Winters understands this hull resistance  best. I just
know that MUSCULAR exertion at the top end of the curve gets really steep
while gains in speed flatten out for all sorts of reasons. I.e. It requires
much more effort to increase speed  from 6 kt. to 6.25 than it does to
increase from 3 kt. to 3.25. Hull resistance is part of the equation, but
the cardiovasular and aerobic/anaerobic indices come into play too. 

	If we could get the hulls to plane, that would toss a whole new set of
parameters into the mix. So what *do* the stat and math people call all
this??? "Poly-factorial?" "Multi-variable?" "Can of worms?" 


		Quasi-numerically, Geo./Svenn 

______________________________
George Bergeron, Secretary '99
Oswego Heritage Council
www.europa.com/~heritage/
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