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What You Need to Know About Kayak Paddle Blade Shapes and Sizes
After spending a little time choosing the perfect kayak most people end up with the paddle that comes with the boat. This is fine. Spend a little time in the boat before you shell out dollars for a better paddle. In a previous article I showed how to determine paddle length. With over 50 years in boat and paddle design I can help with a little information about blade shape and size and how these attributes may affect paddling performance.
Dihedral is defined as having two plane faces. I mention this because it relates to paddles in that the power face may have an angle or curve that helps guide water across the face of the paddle. The theory is that it helps eliminate flutter as the paddle moves through water. In practice it's not needed if you have a firm wrist and stroke. You may not be able to find a paddle without dihedral so don't sweat it.
Symmetry refers to blade shape and size on either side of the center. A good example of an asymmetrical blade is the common European style blade that has an angle on the bottom and different shapes and sizes on either side of the blade center. The theory is to balance forces against the blade as it plunges into and through water. A symmetrical blade is naturally balanced.
Flat blades are generally flat with the exception that they may have dihedral. The back of the blade really doesn't matter much as long as it doesn't contribute to cavitation or turbulence. A flat blade can be used for all strokes. The power portion of a flat blade stroke is closer to the center of the stroke meaning closer to the body. This is important for smaller, weaker, recreational, or long distance paddlers. Moving stress closer to the body core helps eliminate injury and is less tiring.
Spooned blades are shaped like a spoon. You really don't find many of these. It's probably a good thing. During a stroke the spoon shape fills with water and becomes more like a flat blade. The exit portion of a spoon blade stroke must be early, at the hip, and can be sloppy. Many paddle strokes are difficult with a spoon blade unless you use the back side.
Curved blades are flat with a slight curve on the length of the blade. The curve provides early catch at the beginning of a stroke, but like the spoon blade must be withdrawn at the hip. The early catch with arms fully extended is hard on the body. This can lead to injury. A typical European style paddle is a good example. High performance paddlers (racers) generally use this type (or wings). This is what manufacturers generally sell. Most paddle strokes can be done with curved blades.
Wing blades are sort of spooned with the trailing edge relieved enough to allow water to flow along the backside to provide extra "lift". The shape is generally like the wing of an airplane and works on the same principal. My experience with wing paddles shows good early catch and power through the stroke. The stroke naturally moves out from the boat to help water move over the back of the blade. I'm liking my wing. I can get the same power with less effort by using a slightly smaller blade. This is a forward stroke paddle. Other strokes can be done with the back of the blade.
Blade size is very important…and most people get a blade that is too big. Size, meaning surface area, can come from width or length. Generally I'd say that cruising kayak blade length should be in the 20 to 18" length. Whitewater or power stroking blades can be shorter but usually wider. Width should be in the five to seven inch range with six inches as a medium width for cruising. Whitewater paddles may be up to eight inches wide. Unless you have a specific reason for a wide blade you are better off with a medium or small blade width. Forget being macho, go for what you need. This is a case where bigger is not necessarily better.
This is bittersweet because you really don't have much choice. Cheap paddles are fine for limited recreational paddling. Better paddles, meaning lighter and stronger (carbon fiber), are probably going to be limited to the asymmetrical Euro style curved blade paddle. That's generally all most manufacturers provide. Wing paddles are an option if you understand the limits and strengths. I use a wing paddle in marathon races. So be very thoughtful with blade size and paddle length. Remember that most people choose a paddle too long with a blade to big. Happy paddling.
Gerald is an outdoor sportsman who travels by land or water through mountain forest, rocky foothills, or shifting sand dunes. In his spare time he designs and builds kayaks, canoes and paddles. He has paddled many thousands of miles and still competes in select marathon races.
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