Maryland Boating Certification Practice Exam

Vessels measuring 39.4 feet or longer are required to carry a whistle or horn when operating in restricted visibility. This requirement is based on the International Regulations for Preventing Collisions at Sea (COLREGs) and is designed to ensure safe navigation and communication between vessels when visibility is poor, such as in fog, heavy rain, or during the night.

The whistle or horn serves as an audible signal that can be heard over a distance, helping to alert nearby vessels of the boat's presence and movement. It is crucial for preventing collisions in situations where visual cues are limited. The specific sound signals prescribed by maritime regulations outline how and when these devices should be used, such as two prolonged blasts indicating that a vessel is making way through the water.

While other signaling devices, such as flashlights, bells, and foghorns, may have their uses in different contexts, they do not meet the requirements established for vessels of this size operating in restricted visibility. A flashlight, for example, primarily serves as a visual aid and does not provide a necessary auditory signal. Bells are typically used on vessels at anchor, while a foghorn may refer to larger installations that are not standard for all vessels. Therefore, the whistle or horn is the