The Physics of Kayak Surfing
In order to understand how to best maneuver your vessel while kayak surfing, it's helpful to know a little about the basic physics of the sport. The same principles that underlie surfing also apply to kayak surfing. The following concepts of physics all come into play when kayak surfing:
Newton's laws of motion explain how matter moves, and they can help you understand how to maneuver your kayak and stay afloat. For example, Newton's third law states that for every action there is an equal and opposite reaction. So, when you lean your kayak into the water, the water will push back up against the kayak. This principle is one of the reasons for your ability to turn your kayak.
Both you and your kayak have a center of gravity that can be shifted to change the direction of the kayak. For example, if you move your weight to the back of the kayak, the front end will lift up in the water. While gravity pulls the kayak and helps you stay steady as you move, buoyancy keeps you and your kayak afloat. If you're sitting in the kayak, your weight acts as the center of gravity, pulling the kayak down until the push of the water below balances out to keep you afloat.
Hydrodynamic forces, such as lift and drag, can influence the size and shape of waves and also change the movement of your kayak. Wind speed, fetch (the distance of open water that the wind needs to blow over) and the length of time the wind blows over an area can affect the size of waves. As a result of these conditions, three different types of waves develop: ripples, seas and swells. Ripples are small waves; seas are larger, longer lasting waves with irregular movements; and swells are more stable waves formed by stable wind systems.
On the next page, we'll see how you can use these principles of physics in your kayak surfing techniques.