Why does a motor boat accelerate faster when starting up?

A motorboat accelerates faster when starting up due to the combination of the engine's power output and the relatively low inertia of the boat at rest. Initially, the boat's weight is not moving, so the engine can quickly convert fuel into thrust without needing to overcome significant momentum. As the boat gains speed, the water resistance (drag) increases, which requires more force to continue accelerating, resulting in slower acceleration over time. Thus, the initial surge of power from the engine allows for a rapid increase in speed during startup.