Small Boat Big Load

This morning I looked out my window and saw this small boat pulling this rather large dock. Let's analyze how this was done. The boat and its load were traveling to the right, in the positive direction so naturally the boat applied a force in the positive direction on the dock. There was only horizontal acceleration (not vertical) so the weight of the boat was equal to the normal force of the water. The acceleration of the boat is determined by Newton's Second Law that states that net force equals mass times acceleration. In this case the net force on the dock was the tension applied by the boat on the rope connecting it and the dock. This force was strong enough to overcome the (minimal) force of the resistance of the dock in the water.Also the current was flowing in the same direction as the boat was traveling so the current added to the velocity of the boat and dock together.

Here brings up another interesting point. I know realize that while I was watching the boat I was standing in a certain reference frame and that my perception of the velocity of the dock and boat was different than that of say someone either in the boat or in another boat floating in the current of the water.