Any force on a boat afloat, whether exerted through paddle stroke, wind or water (or for that matter, through oar, sail, propeller, or jet thrust, or contact with another object) acts to change the vessel’s momentum and turn the boat around its pivot point. (Of course, if that force just happens to be exerted along a single line that, like an arrow, goes right through the pivot point, the force will alter the boat’s momentum, but it will not act to turn the boat. However, a force like that is pretty exceptional. Almost any force on your boat acts to turn the boat.)
Now here is the tricky and the important part: The location of the pivot point depends on the configuration of the hull and the mass of the boat, the relative motion of the hull and the water in contact with it, and the forces acting upon the boat. Only when a boat is drifting in outer space, with no unbalanced forces acting upon it, is the pivot point determined solely by, and located at, the center of gravity (mass, actually). That’s not true of a boat moving through water. When a non-planing displacement hull (like a canoe, a kayak, a fish tug, a cruise ship, or a supertanker) moves forward relative to the adjacent water, its pivot point moves forward relative to the boat. Figure that when you’re moving forward through the water, your canoe or sea kayak’s pivot point is about one-third of the length of the boat’s waterline, abaft the place where the forward end of the hull meets the waterline. And since the forces of nature don’t care about your intentions, or which way you’re facing, or which ends of your boat you call bow and stern, don’t forget that when you’re moving backwards (relative to the water close to your hull), the pivot point of your boat moves aft to a point about one-third of the waterline length forward of the place where the aft end of the keel meets the waterline. Remember, we’re talking about the relative motion of your boat and the water in immediate contact with it.
The basic seat-of-the-pants experience, and operating assumption you need to have is that the longitudinal pivot point of your canoe or kayak is “near” the bow when your vessel is moving forward through the water, and the pivot point is “near” the stern when you are moving backward through the water. (Notes: This pivot point discussion does not apply to a planing hull, like a speedboat when it is “on step”. “Force” has a precise definition, but it basically refers to anything that acts to change your boat’s speed, direction of motion, or rate of turn.)
The pivot point helps us to understand “weathercocking”. Wind pushes on all exposed parts of the canoe or kayak, but when you’re moving forward, most of the sail area is aft of the pivot point, so no matter what direction you wish to go, most displacement boats tend to head into a strong breeze, just like a weather vane. You will need to correct for this tendency. (Exceptions to this occur if the below-waterline shape and trim is radically uneven, and/or the above-waterline wind profile (“sail area”) is drastically unsymmetrical.) Conversely, if you’re backing through the water, your boat will tend to back into the wind. However, when a canoe or kayak is allowed to drift in windy conditions it quickly falls off to lay more or less broadside to the wind (again, depending on the geometry of the wetted area and the configuration of the area exposed to wind) as the pivot point returns to the fore-and-aft center of a reasonably symmetrical boat on an even keel that is making no way through the water.
The pivot point helps enable you to punch upstream out of an eddy into a strong current and to stem that current without getting swept away.
Awareness of the pivot point helps you anticipate that turning while you’re moving forward through the water, may cause your bow to move one foot to the right, while your stern simultaneously moves two feet to the left. Anything that moves one end of the boat to one side, moves the other end, generally in the opposite direction, and how much the other end moves depends on the totality of forces on the hull, which is greatly affected by the direction you are moving through the water. When a paddler moves the bow at the last second to avoid a hazard, the boat itself may not be out of jeopardy.
In a forward paddled tandem canoe or kayak the pivot point coincides approximately with the bow paddler’s position. So the bow paddler doesn’t have much leverage, and that’s why the stern paddler usually seems to “overpower” the bow. It has nothing to do with who is stronger. It’s about fluid dynamics.
In river descents or ascents with a competent paddling team, verbal tactical co-ordination can be initiated from either end of the boat, but typically the bow paddler reads the river and initiates the positioning or defensive moves. The stern paddler responds appropriately to the bow’s lead. In open water the bow paddler primarily provides forward propulsion and the stern paddler establishes and holds the desired course without slowing the forward motion unnecessarily, and efficiently paddling ahead. In open water it is better for the person with the more powerful stroke to paddle bow, provided that person doesn’t mind breasting the wind and waves and provided that the stern paddler enjoys paying attention to selecting trajectories, and to holding an efficient course.
However, the great majority of tandem mixed-sex couples paddle with the male in the stern and the female in the bow. On rivers, is this because these couples acknowledge the woman’s superior river reading skills and capability for decisive action? On open water is this due to their concurrence that the woman has the stronger stroke and because she has selflessly volunteered to take the brunt of the blast of wind and wave that is the special privilege of the bow station? Is it because of a tradition with no useful or rational basis that men always paddle stern? Is it because the guy would rather not be on the “short end of the stick” when it comes to the leveraged power of the pivot point? Tell me what you think.
The best way to learn and enjoy paddlesport is to begin in a solo boat. Develop an understanding of the subtle and complex interaction of the boat, the water, the environment, and yourself. You will almost certainly enjoy it more than you imagine. If, after you’ve achieved this understanding and joy, you wish to challenge the additional complexities of communication and coordination with another person in the same boat as you, do so with someone who has also achieved an enjoyment and comprehension of the basics through solo boating. Be proud to paddle with a partner who you acknowledge is as good as you are, or even a little better. And switch positions. Paddle on the other side of the pivot point. You just might like it, and you’ll definitely improve as a team.
Learn a tip or two on how to use the pivot point and turning maneuvers to achieve much better control, trajectories, and paddling performance, in “Energy and Momentum – Use It or Lose It“.
Go HERE to see the table of contents and other articles in this series. I appreciate any comments you care to make. This article and series is published and copyright by Clyde Winter, canoeist, kayaker, and U.S. licensed master and chief engineer of motor vessels to 1600 gross tons on any waters.
I first read about the peripatetic pivot point in “The Behavior and Handling of Ships”, an excellent text by Hooyer, about 20 years ago.
During the summer of 2009, an article and a video came to my attention that more closely examines and seeks to explain the complex, ever-changing forces that affect the lateral movement and the rotation of a displacement vessel. Although this article and video are directed towards large ship handling, they can significantly improve your thinking and increase your understanding of how and why your boat is affected by various forces, and provide important insights into canoe and kayak control.