Date: Sat, 18 Mar 1995 08:38:02 -0800 (PST)
From: George Dyson <gdyson@henson.cc.wwu.edu>
To: baidarka@imagelan.com
Subject: Re: Paddling...
In-Reply-To: <013.04584222.MRPK81A@prodigy.com>
Message-Id: <Pine.ULT.3.91.950318081523.9604A-100000@henson.cc.wwu.edu>
Well, this raises a conceptual issue best illustrated by a thought
experiment:
Ignore the kayak dynamics, and other realities, just imagine a perfectly
ideal kayak, paddler, paddle, and planet.
Paddler can pull with a 1-lb force (weak paddler). Forgets paddle and
uses a pencil, pulls it through the water which churns around with
turbulence, causing 1lb drag on the pencil and paddler pulls kayak
forward with 1lb of force. Planet stays still.
Paddler finds the perfect paddle, so perfect that the water doesn't move
at all. So with this perfect paddle she actually pushes the rest of the
planet the other way (however slightly) with that 1lb of force, and thus
moves the kayak ahead, as previously.
Result is the same. Whether you move the water or the earth you are
doing the same amount of work, with the same effect on the boat.
Paddling efficiency derives from all the other little details we have
ignored, like putting the paddle into and out of the surface, and how
much energy you waste performing the non-driving portions of your stroke.
Paddles (and accompanying technique) that can develop lift going into and
out of the stroke (or a continuously lifting stroke) will be more
efficient. I believe this is what some of the old paddle designs and
techniques were about, as modern "wing" paddle users are rediscovering in
different form....
George B. Dyson Fairhaven College / MS 9118
gdyson@henson.cc.wwu.edu Western Washington University
(360) 734-9226 Bellingham, WA 98225-9118