Final answer:
If the paddle broke, moving the canoe would become more difficult because the paddle is essential for propulsion and navigation. Upstream, one should stay near the shore where the current is slower, while downstream, being closer to the middle to use the faster current can aid in movement.
Step-by-step explanation:
If the paddle broke, it would be more difficult to move the canoe. This is due to the critical role that a paddle plays in propelling and steering a canoe through the water. Paddles function by pushing against the water to generate forward movement and to make navigational adjustments. Without a functional paddle, the canoeist would lose the ability to efficiently control their speed and direction.
While paddling upstream, it's advised to stay close to the shore where the current is slower and the resistance to paddling is reduced. Conversely, when traveling downstream, staying near the middle can be more beneficial as the flow is typically faster there, enabling the canoeist to take advantage of the current to increase their speed with less effort.
In essence, a broken paddle deprives the canoeist of the ability to exploit the dynamics of the water's speed and resistance, and as a consequence, would make maneuvering and propelling the canoe more challenging regardless of the direction of travel relative to the current.