Just a little touch can steer you straight. The first canoe stroke I learned was a ‘J’ stroke. You lean forward, put the paddle into the water far in front of you, and then you pull back strong and straight. Think about it, that alone would send the canoe veering off in the other direction, so at the end of the pull—in the same fluid movement—you give the paddle a little hook, making a ‘J’, which done well, keeps you moving straight.