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Paddle Blade Shape


An Article from the Lightning Library


Getting Into It --

Blade Shape

Okay, there's a lot to cover in this one.

There are three distinct aspects to blade shape:

Blade outline --
Looking at the blade flat on.
Lengthwise curve --
Looking at the blade from the side of the paddle.
Cross section --
As if you cut the tip half of the blade off and looked at the cut edge.

Blade Outline:
Most flat water (touring) kayak paddle blades are asymmetrical in shape, where most white water kayak paddle blades are symmetrical. White water paddlers are learning, though, and more asymmetrical white water kayak paddles are being developed and marketed all the time.

Draw a line down the center line of the paddle shaft, through the center of a blade. If the blade halves on either side of the line are the same (actually a mirror image of each other), that blade is symmetrical. If the two sides are different, the blade is asymmetrical.

Symmetrical Blade Asymmetrical Blade
Symmetrical Shape Asymmetrical Shape

The two blades indicated above are fairly typical shapes. There are lots of different symmetric shapes being made today, as well as many different asymmetric shapes.

For either white water or sea kayaking, asymmetrical blades offer more and better boat control than symmetrical blades, especially for the aggressive paddler. The distinctions between symms and asymms in the physical feel during use might require a bit of acquired expertise for most paddlers to notice much difference. Deep water paddlers will notice the difference more than shallow water paddlers like kayakers into white water "creeking." Properly designed asym blades seem to feather easier than symms for transitional strokes.

Symmetrical blades are usually more forgiving of mistakes than asymmetrical blades for the less aggressive "drifter" type white water paddlers. Very long, skinny blades do not offer as much grip on the water as shorter, wider blades when using a standard modern kayak or canoe stroke. Except for some experimental trials in very specialized racing applications, all canoe paddle blades are symmetrical.

Lengthwise Curve:
A paddle blade can have either a flat or curved shape when looked at edgewise, from the side of the paddle. Varying amounts of curve are possible, and different places on the blade might have different amounts of curve. The biggest advantage of the flat blade is forgiveness for beginners, and the biggest disadvantage is probably lack of grip on the water that more advanced paddlers prefer. Most kayak paddle blades (midpriced and more expensive paddles) are curved, but there are exceptions. Most canoe paddle blades (every price range) are flat, though many prominent whitewater slalom racers in both open and decked C-1 are now using curved blades.

Flat Blade Curved Blade
Blade Flat Lengthwise Blade Curved Lengthwise

The above two pictures show a flat blade and a curved blade from the side. A blade is either flat or it's curved, and varying amounts of curvature are possible. The above curve is exaggerated greatly.

Blade Cross Section:
Several different cross sections are available on paddle blades. Typical sections are flat, spooned, dihedral, and wing. The ribs indicated below are typical, some blades may have them on one or both sides, and other blades may not have any appreciable ribs. As a general rule (there are always exceptions) ribs on the side of the blade facing the back of the boat (powerface) have a detrimental effect, and ribs on the other side of the blade (non-powerface) don't matter very much.

Flat Cross Section Diheral Cross Section
Flat Blade Above Dihedral Blade Above
Spoon Cross Section Wing Cross Section
Spoon Blade Above Wing Blade Above

The above cross sections are typical, not specific. A flat blade is flat, but a given blade might be more spooned or more dihedral than another spoon or dihedral blade. The dihedral, spoon, and wing above are exaggerated a little for clarity. The amounts of spoon or dihedral will probably vary in different parts of the blade surface. There might even be combinations of two or more of each section on the same paddle blade. For instance part of a blade is flat and the rest is dihedral, or there could be a little bit of spoon in an otherwise flat blade. The side of the blade that faces the rear of the boat (power face) points to the top of the screen in the above drawings.

There are advantages and disadvantages to each sectional shape. Both spoons and wings offer a very powerful stroke, but are also very difficult to control during a stroke, especially for beginners. Dihedrals can be very forgiving, but many are so forgiving that they limit the capabilities of the paddler after the beginner learns the basics. Blades that are essentially flat across the face seem to offer the best balance between forgiveness, power, and control. I want to make a distinction between curved and spooned blades here. A true spoon blade is curved across the face, as well as lengthwise, like a soup spoon. Some blades are curved lengthwise, but are flat across the face. A curved blade is not necessarily a spooned blade. In fact, most blades that are called spooned, are not. A true spoon will hold water on the surface, where it will roll off of a flat blade that is curved lengthwise, only.


Article courtesy of Hank Hayes, Lightning Paddles

Copyright © 1996, 1997, 1998, and legal fine print
Revised: 25 June, 1998
http://www.paddles.com/library/basics7.html