-- Last Updated: Jul-08-13 9:58 AM EST --
I'm talking about in the physics of displacement. Kayaks are usually wider and flatter. This means they have a shallower draft than a canoe of equal weight. They still displace the same amount of water (A boat won't float unless the volume of water it displaces is equal or greater than it's mass.). But, the displacement occurs distributed across a greater surface area. Think of a board floating on the water. When it's flat, it floats because it distributes the weight across the surface to displace the water. But, turn it on it's narrow edge and it sinks because there is less water displaced compared to the weight.
When talking boats, Light verses Heavy is not always about the physical weight of the boat. You would never consider a huge, steel, cargo ship "Light." But, when she's running empty, they call her "Light in the water" as she's almost floating on top of the water than riding down in the water. This also means she can be blown off course by a steady wind easily.
Same physics apply. Most "Traditional" Canoes have a very sharp hull, down to a keel. This allows them to ride lower in the water, and track straighter. It also means they were faster. In the last few decades, we've seen canoes "Morph" into more of a kayak style hull where the center of the boat is flat and the boat has a much shallower draft. This allows them to be able to carry much more weight as it's distributed across a greater surface area.
Here's an illustration: http://www.paddling.net/guidelines/Images/bottoms_body.gif
However, not to get into a full on physics lesson (Physics and Chemistry are my favorite topics!), the greater the surface area of a boat, the greater the friction between the hull and the water, the slower she goes and the more effort it takes to move her.
Hope I haven't totally confused ya!
Kayak Motor Kit
|Table of Contents|