While going on the boat journey, you can walk from one end to the other and reverse jump back to the first end to add momentum to the boat forward. Due to drift, a mechanic in water where some objects have a tendency to move in one direction over the other, the addition of momentum going forward will make the boat go faster, but momentum in the opposite direction won't affect the overall momentum too much. During the ride, you can achieve about 8 jumps before reaching the shore.