What is the minimum audible range of a whistle on a vessel greater than 75m in length but less than 200m in length?

The minimum audible range of a whistle on a vessel that is greater than 75 meters but less than 200 meters in length is indeed 1500 meters. This requirement is outlined in the International Regulations for Preventing Collisions at Sea (COLREGs) under the section pertaining to sound signaling appliances.

The standard specifies that vessels falling within this size range must have a whistle that can be heard at a distance of at least 1500 meters in favorable conditions. This is crucial for safety and to facilitate communication between vessels, especially in situations where visual contact may be limited due to fog, night-time, or other factors.

This specification helps ensure that vessels can adequately signal their presence to others in close proximity, thereby reducing the risk of collisions. The choice of 1500 meters reflects a compromise between operational needs and the practical limits of sound propagation in various environmental conditions.