Final answer:
Excessive bow up trim and a higher risk of collision occur when a boat moves faster than the speed of a mechanical wave in water, leading to a raised bow and larger bow wave.
Step-by-step explanation:
The question pertains to the phenomenon of bow wake, which is relevant to both physics and maritime navigation. The speed range that produces excessive bow up trim and a higher risk of collision is when a boat goes over the top or moves faster than the speed at which a mechanical wave can travel through the water.
At these higher speeds, the bow of the boat lifts, reducing the visibility of the helmsman and increasing the bow wave size, which in turn increases the risk of collision. On the other hand, if the car were to go over the top at a slower speed than the mechanical wave in a medium, this excessive bow up trim would not occur, and there would be a lower risk of collision. It's important for navigators to understand the relationship between a vessel's speed, the wave it generates, and the resulting navigational risks, such as excessive bow up trim.