A paddle I bought last summer veers off course when I do an in water recovery. I’ve marked one face of the blade so I can keep track and it always pulls in the same direction. The faster I slice through the water, the harder it pulls. What gives? Is there anything I can do about this or should I just give up on it and save if for a spare?

When a paddle veers off course as you described it is generally because the camber on each face of the blade is not matched. The camber is the curvature of the blade from one edge to the other. If the camber is different on each face, the blade will pull toward the face that has the most camber or curvature.

If I remember my high school physics, there is something called the Bernouli Principle. (I’ve undoubtedly spelled Bernouli wrong.) It essentially states that a fluid flowing across a surface will exert less pressure on that surface the faster the fluid flows over it.

The greater the curvature from one edge of the blade to the other, the greater the distance the fluid must flow as you knife the blade through the water and as such the blade will pull in that direction. This is the same principal that allows aircraft wings to provide lift. The upper surface of the wing has greater curvature than the lower surface.

Take your paddle, sight across the blade and see if you can see the difference. You may need to lay a straight edge on the blade as a reference.

Many paddle blades are shaped by hand using either planes, spokeshaves, or large sanding drums. A skilled craftsman can get reasonably matched camber most of the time. Someone who is not so skilled probably won’t get it right very often. Some paddle makers use jigs or automated machines that insure matched camber. Here at the shop (Dogpaddle Canoe Works) I use a jig that I designed that insures matched camber.

It is possible that your paddle can be retuned. Depending upon the thickness of the blade and how far off the camber is, it may be possible to reduce the camber on one side. If the blade is too thin, it may be possible to build up the other. How much work it is worth depends upon the quality and value of the of the paddle.

MarcO

If the blade is symmetric, it’s operator
error. Your body wants to feel some “lift” on that blade, and so you’re managing it in such a way that it seems to veer. It’s veering outward, no???

Even my curved c-1 blades will do an underwater recovery without misbehaving. In fact, curved blades would never have been adopted in slalom racing if they were not acceptably neutral when slid through the water.

Also, some symmetrical blades, like my old Norse paddles, have a lot of “lift” unless the paddler keeps them on course. When slid through the water, they just want to lift outward, but if you try, you can get them to “fly” in toward the side of the boat.

Curved blades where one face is concave and the other is convex but both parallel to each other will not veer unless of course the blade is not held neutral or parallel to the keel line while being sliced forward on the recovery. Camber refers to both faces of the blade being convex. In cambered blades the radius of all cross sections of the blade must be equal on both sides. If they are not, the blade will achieve “lift” toward the side with less radius (the rounder side).

BOB

Well, MarcO, I think you’d find that the
front and back sides of Mitchell and Clinch River curved slalom blades are not that similar, and that if one slices the blade with a soft grip, some lift is detectable.

I have about 15 canoe paddles, and my Norse paddles are the only ones that have a noticeable tendency to veer, even though they are absolutely identical on both faces. But it’s still very controllable. It is hard for me to imagine any quality commercial paddle that could be so “out” that veering could be a practical issue.

In theory, the blade faces could be dissimilar and still be balanced by modifying other factors. Perhaps that is the case with the paddles that you have mentioned.

As I stated earlier, most quality,commercial paddles have reasonably matched camber but I have seen exceptions.

Veering may not be much of an issue in whitewater and in slalom racing. Unless the problem were severe, the other forces at play would likely mask it. In more delicate disciplines such as freestyle, small idiosyncrasies become more sygnificant.

MarcO

angle of attack
Marco’s descritpion of curved surfaces and lift is spot on,and this effect is the same for wings, sails and paddles. But with any cambered surface you can change the angle between the blade (or wing) and the fluid and change the flow. You can make a pefectly balanced padlle veer by changeing your recovery angle. And you can probably find a neutral or stall position with an assymetrical blade.

Can you find a neutral recovery angle with this paddle? Is it possible that the shaft or grip is differnt on this paddle causing you to recover at a differtn angle than you “normal” paddles?

Like Bob said

I think you would find slalom paddlers
just as fussy about neutral blade behavior as freestyle paddlers. They just have to accept a little less neutrality in order to get a hard catch. Experienced WW paddlers and slalom paddlers have sensitive hands and feel the blade as an extension of their arm, as if it were an outlying hand.