Date: Mon, 20 Mar 1995 04:07:56 -0500
Message-Id: <199503200907.EAA29506@postbox.acs.ohio-state.edu>
To: baidarka@imagelan.com
From: hazel.2@postbox.acs.ohio-state.edu (Paul W Hazel)
Subject: Re: Paddling...
MRPK81A@prodigy.com writes:
>I'm confused... how can slippage in the water of the paddle
>not be a problem...
>If I paddle against the air, I would not move forward very
>quickly...If I paddled against the bottom (ignore the 'drag
>in shallow water' issue) virtually all of my energy would be
>used in moving the kayak forward... any slippage of the
>paddle is non-productive...
Airplanes and helicopters paddle through the air quite successfully. My
point is that slippage is not the problem - moving enough mass (or reacting
against it in the case of mud) fast enough is the problem. Trying to move a
mass of air equivalent to the mass of water you are moving with a paddle, in
a given amount of time, would require either a huge paddle or a VERY rapid
stroke. :)
>Using the biking analogy, it would be as if the cranks were
>made of rubber...a portion of the pedaling energy is being
>used to bend the cranks, vs. propel the bike...
>If the paddle slips, energy is being used to create turbu-
>lence, rather than forward motion...
>Reduce turbulence, increase forward motion...
>What I get out of all of this is that I use bigger bladed
>paddles to reduce the slippage... the problem is that I'm
>not strong enough to push the boat...so I use a smaller
>bladed paddle, with more slippage (less pushing the boat)...
>kind of like using a 100 inch gear, up hill, vs a 50 inch
>gear...
The presence of turbulence, in and of it self, means absolutely nothing.
Turbulence is nothing more than a fluid (water) rushing to fill the "hole"
left by the paddle. "HOW"
the water was moved, resulting in turbulence, is the point. The width,
length, area, shape, edge, and speed of a paddle all contribute to the
amount of turbulence because they first are responsible for the initial
movement of the water. Turbulence is a byproduct, like smoke from a fire.
A small fire burning green wood will make a lot of smoke. A fire of the same
size burning dry wood efficiently may produce considerably less. However, a
big efficient fire may produce as much smoke as a small inefficient one.
Just seeing the smoke won't tell you much, and neither does seeing turbulence.
>New thought... is the stroke of the Greenland style paddle
>in any way like the yalu used on sampans... certainly the
>yalu uses'lift' to propel the boat, vs. pure drag...
>
>One more thought, an extraordinarily strong lashing is
>obtained by using Turk's head... these were used to lash
>split spars together as a temporary fix... they can be
>brought up so tight that they will bury themselves in the
>wood...they'd certainly hold the blade on a shaft.. and look
>kind of nice too... and act as a drip ring...
>
>Another thought or two on paddles... why not put an edge...
>let's say 1 cm high, perpendicular to the flat of the blade,
>in order to prevent slippage...
>Also, why not cant the blade to the shaft by 10 or 15
>degrees, as is done in racing single paddles, so that the
>strongest part of the stroke, next to our hip, is vectored
>aft, as opposed to vectored 10 to 15 degrees upwards...
>Both of these ideas may create some 'minor' problems with
>braces...:-)
>I was thinking of building a double paddle using these two
>concepts, blade (and 'ridges' from aluminum), shaft of wood,
>attached to the 'center' of the back of the blade such that
>the paddle could spin about it's long axis...
>Just thinking outloud...TLC
>
>
>
Paul Hazel
hazel.2@osu.edu