Re: [Paddlewise] Pictures of my Northbay (Changing to : Lifting vs. Plunging Bow)

From: John Fereira <jaf30_at_cornell.edu>
Date: Thu, 20 Jul 2000 08:44:22 -0400
At 09:45 PM 7/19/00 -0700, Matt Broze wrote:
>Joan wrote:
>
>>>Which reminds me of a question I asked this weekend, and nobody really
>had an answer: if the bow goes through the wave instead of up and over,
>wouldn't you maintain speed better?  (Mine goes up & over, & it seems to
>me that it slows me down, but I'm not really sure...)<<
>
>When we get done arguing blade feather, wide vs. narrow (blades and kayaks),
>paddlefloat vs. reenter and roll, Swede form vs. fishform and rudder or no
>rudder we sometimes get down to this. So here is my take on it.
>
>The rocking and slamming caused by heave/dip motions can add considerable
>extra resistance to a hull.  Sea Kayaker Magazine tested five sea kayaks in
>both calm water and directly into 8" high waves that were 16.6 feet long.
>(Note: 16.6' long waves travel at about 5.5 knots -- the wave speed (in
>knots) is equal to 1.34 times the square root of the wavelength (in feet)).
>The kayaks traveled into the waves at 3 knots.  There was no wind.  The
>waves increased the average resistance (the actual resistance varies as the
>waveform passes) by about 1.5 times for the kayak that did the best and up
>to 2.3 times for the kayak that did the worst. While these may seem like
>small waves my videos show that most of the kayaks plunged enough to put
>their bows under at times.

Ok.  So, what would you do to change the design to reduce the amount of bow
plunging?


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Received on Thu Jul 20 2000 - 05:44:43 PDT

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