Re: [Paddlewise] wing theory

Work is defined as a change in energy. If you measure the work done by 
your hand and you have all the parameters of your paddle matched such 
that they multiply together right it is absolutely possible to make the 
work done by your hand match with substantially different paddles. But 
remember that the work done by your hand is not the same thing as the 
work done on your boat.

  Imagine paddling one boat in free water, while paddling another which 
is tied to shore. You should be able to make two paddle, one for the 
free boat and one for the tied boat which when you paddle feel the 
same. The one for the tied boat will probably be very small, so it 
doesn't feel that hard to pull when the boat isn't moving. You will be 
able to pull this paddle and your hand will be doing work, but no work 
will be done on the kayak because it is tied in place such that its 
energy can not change. With no change in energy there is no work done 
to it. All the work you are doing with your hand is going into the 
water.

In an ideal system all the work you do with your hand would transfer 
directly into work done to the boat. In a real system some of the work 
is inevitably dumped into the water. The goal is to find a paddle and a 
technique which reduces the the amount of work done to the water so 
most of it can go to your boat.

On Sunday, June 8, 2003, at 10:05  PM, Gerald Foodman wrote:

> Nick,
> If the paddle were to be drawn straight back with the blade normal to 
> the
> velocity, then the force applied by the hand depends on CD, paddle 
> area and
> velocity.  The work done by the hand then also depends on CD, area and
> velocity.  Now if you had two different paddles stroked identically, 
> working
> at the same velocity, with the same product of CD and area, would they
> necessarily be equally efficient?  Even though the flow pattern around 
> each
> would be different.
Nick Schade

Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
USA
Ph/Fx: (860) 659-8847
http://www.guillemot-kayaks.com/

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