Techniques and tips for the big blow Heavy-weather paddling BY JOHN WINTERS
THE CRUNCH
Waves affect paddlers according to their length (distance from crest to crest) and their height (distance from trough to crest) relative to the length and speed of our boats. When your speed is moderate and waves are long, the boat can follow the wave surface without additional resistance. But, when wavelength and boat length begin to coincide, things get serious. That’s when the boat refuses to follow the wave surface or cut cleanly through them. Instead, the boat rises over the crest of one wave and crashes into the next. The resulting spray, noise, and waves radiating away from the boat are energy lost. In the worst case, you can come to a complete halt. The natural reaction is to use a bigger hammer and paddle harder, but it’s usually a mistake. There are three easier and more efficient methods to combat head seas. Two of them alter the period of encounter either by slowing down enough so the bow can rise and fall in
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time with the waves, or by changing course to hit the waves at an angle. Both increase the apparent wavelength and permit slow, but uniform, progress. Paddling harder will simply wear you out. Meeting waves at an angle does have a drawback. Any angle to the headwind increases air drag and leeway. The net effect is to reduce your progress directly to windward – the worst possible angle is at 30 degrees to the wind. A third method is to change the boat’s natural pitching period. When weight is spread out over the boat’s length (high moment of inertia) the natural period is long, which is advantageous in short, small waves. Conversely, when weight is concentrated near the middle (low moment of inertia) the boat will have a short natural period, which is better when waves are longer and pitching is more severe. Since small waves (relative to your canoe) pose few problems, it makes sense to load gear for the worst
case and keep weight out of the ends. There is nothing you can do about long overhanging ends that contribute to a high moment of inertia. Such are the costs of our aesthetic values.
PHOTO BY HENRY GEORGI
I AM PARTIAL to heavy weather, possibly from watching too many reruns of Victory at Sea. Sometimes I plow ahead at full speed, just to watch the bow rise and come crashing down into the largest waves. Childish perhaps? Sure, but it’s fun when time and destination aren’t pressing. But when they are, and you have to hunker down for a hard and sometimes scary paddle, the fun part fades. Knowing what to do can help when the going gets tough. Truly terrifying paddling calls for survival conditions, but that’s another topic. Now, onward into the waves.
ACROSS THE WAVES
An interesting thing happens when we paddle across really large waves. Because the local gravity is directed towards the wave centre, the boat follows the wave face, yet we get no impression of heeling unless the horizon is available as a reference. That hasn’t stopped so-called experts from conjuring up misleading illustrations of wide, flat boats tipping wildly while their roundbottomed cousins remain more upright. The best shape for large beam seas is one that will follow the face of the wave – wide and flat! Nevertheless, most of the time we coastal and lake paddlers encounter much shorter waves. When the wavelength approaches the size of the
OTTAWAOUTDOORS SPRING/SUMMER 2006
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