Let me define what I mean by this; where is the water that will give you the best purchase/catch/hook? This is nowhere near as obvious as it first appears.
We all know that aerated water is not particularly grabby. If it is frothy or foamy, it does not allow a good pull. And we know that if we cavitate or tear water, we don't get a good pull. If the paddle moves relative to the water, the canoe is not moving an equivalent amount. Imagine spinning a car's tires on snow or ice. So we want to be connected to the water when we pull on it. Leaving aside the dreaded escape from the pull (moving your top hand forward creating the illusion of movement, or sitting up through the stroke creating the same illusion, or changing the angle of your blade to allow the water to shed, another escape) there are ways to improve your pull.
Consider this...the water nearest a moving canoe is moving along with the canoe. As a canoe moves through the water, it drags water with it. The closer the water to the canoe, the more it is moving with the canoe. If you are pulling in that moving water, you are actually pulling on water going in the same direction as the canoe is going and that means for any stroke length you generate, your canoe will move more than just that length. You have to get your blade right in close to the hull to get that really sticky water. Try it.
The opposite often happens in seats 3 and 5, moreso in the latter seat. The paddlers ahead have created a pool of water moving backwards. If you put your blade in the water, you have to pull longer and faster to move the canoe the equivalent of the stroke length. You know you are in that pool of water because your blade will feel fluttery. That is why I like to try to put paddlers with very quick hands in seat 5 if you have equivalent paddlers down the canoe. You need a quick catch and pull to counteract the effect of the moving water.
Now let's introduce waves into the equation. As a canoe moves through waves, whether into or away from them, the hull movement relative to the water will create light and heavy water for different paddlers down the canoe. If into the waves, the seats towards the rear will experience an easier pull as the stern drops into the wave. This is a time for those paddlers to pull faster and longer to propel the canoe over the wave. As a canoe tips over while paddling into a wave, the front seats have to pull deep to get the canoe to go over the wave. If paddling with the waves, the front seats will feel very heavy water as the canoe drops stern first into the trough and then the stern begins to rise. Meanwhile as the stern comes up the front of the wave, the rear seats will feel lighter faster water and they need to pull longer and faster.
Again we come back to stroke flexibiity. You are not machines doing exactly the same work at exactly the same interval all the time. Your stroke has to change, sometimes incrementally, and very frequently to take advantage of the water and create the best pull for the conditions of your seat at that time.
Bring your brain with you in the canoe. Look at the water for visual clues as to what will happen next. Associate the weight of the pull with the visuals. There are lots of clues out there.
Have fun.
BVB