The past century has brought a quiet revolution in the field of naval architecture. Today, largely through the use of the towing tank, where models are tested under controlled circumstances, we have access to an extensive body of knowledge about the motion of ships and the factors affecting that motion. Military and large scale commercial interests prompted most of this research, although in recent years the same methods have been used to design the expensive water toys for the obscenely rich. Eventually, what is learned in less savoury pursuits filters down for more prosaic use. The surprising thing (or perhaps, not so surprising) is that the application of this knowledge to canoes has been largely superficial, despite great strides in materials use. Certainly, to the layman, the connection may not be apparent between large naval ships, racing sailboats and the canoe, and it could be that the canoe industry has just been slow to recognize the connection as well.
To nature, of course, they are all but moving, floating objects; she treats them all equally and consistently, if not simply. If we know the principles that apply to one, we can, with some modification, apply them to the other. In doing so, a number of unfamiliar terms and symbols will be used. Naval architecture, like other sciences, has developed a language uniquely its own for precision and convenience. Don't be concerned. The terms quickly become familiar, and if you get stumped, the Glossary can be used for quick reference.
So, if you'll be patient with a bit of hydrodynamic arcanum (and recognize that, even though the basic principles are unchallanged, there will always be debate over the details), we will explore the theory behind the motion of canoes and how dimensions and shapes affect that motion.
Modern naval architecture began some 100 years ago when the physicist William Froude put forth the elegantly simple proposition that the resistance of a floating body in motion was the sum of two parts - frictional resistance (Rf) and residual resistance (Rr), and that the two could be analysed separately. We know now that this is not 100% true, that variations in speed cause incalcuable changes in wetted surface and turbulence. Fortunately, these errors are small, and from a practical standpoint, can be ignored. Frictional resistance is that which occurs between the hull and the water while the residual resistance is the sum of all other resistances of which wave-making, form, and yaw are the most important. Other forces come into play under special circumstances (air resistance due to headwinds and energy losses due to pitching are the most obvious), but as they can be avoided by the skilled or prudent canoist, they are rarely serious design considerations. We will deal first with friction.