Re: [Paddlewise] "Regular" paddle stroke

From: "John Fereira" <jaf30_at_cornell.edu>
> 
> Did the instructor also cover the sweep stroke?  When doing a sweep stroke 
> the most effective part of the stroke is the last half. If you're doing a 
> forward sweep, the greatest turning motion is achieved when the paddle 
> blade is the water from about the cockpit back towards the stern. 

I know one BCU instructor that states quite emphatically that this is completely
wrong.  He says that the water is too turbulent near the rear of the hull for the
stroke to be effective and insists you stop just past the hip.  I think he's wrong,
IMNSHO, because the turbulent water is very close to the kayak and you'd have 
to whack the kayak with the blade to get into that region.

Personally, I have a real problem with all these explanations.  If you do a sweep
stroke from the torso, with hands low (paddle shaft close to horizontal) and in a 
more or less static position relative to the body, you are applying a constant 
moment (torque)* that will turn the kayak regardless of the point where the paddle 
is inserted!  Or to get to the point, the stroke is just as effective in turning at the 
front as at the back.

I wonder if the illusion that the power is at the back comes from the fact that the 
beginning of the stroke uses power to accelerate the kayak, while the later part
of the sweep just maintains the rotation speed?

I always do a sweep with a full rotation (as close to 180 degrees as I need) and 
often do a return stroke as a low brace.  The latter keeps me confident if on a 
hard edge.

Mike

*Technically, this is a wrench rather than a moment.  You are generating a moment
and a linear force simultaneously.  In this case, the linear force changes direction
continously, so you slide away from the stroke side of the kayak at the start of the 
stroke, forward in the middle of the stroke and toward the stroke side at the end, 
assuming you go roughly 180 degrees.


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