United States Coast Guard Captains License Practice Exam

In a narrow channel, an overtaking vessel intending to pass on the other vessel's port side will sound which signal?

1. One prolonged followed by two short blasts

2. One short blast

3. Two short blasts

4. Two prolonged followed by two short blasts

The correct answer is: Two prolonged followed by two short blasts

In the context of sound signals used by vessels in narrow channels, the correct signal for an overtaking vessel intending to pass another vessel on the port side is two prolonged blasts followed by two short blasts. This signaling is aligned with the International Regulations for Preventing Collisions at Sea (COLREGs), specifically Rule 34, which outlines the requirements for vessels when conducting overtaking maneuvers. The two prolonged blasts indicate that the overtaking vessel is signaling its intention to pass, and the addition of two short blasts specifies that the overtaking vessel is intending to do so on the port side of the vessel being overtaken. This sequence helps to ensure clear communication between vessels to enhance safety and avoid misunderstandings in challenging navigation situations. Understanding this signaling is crucial for maintaining safe navigation in confined waterways, where the actions of one vessel can significantly impact the safety and operations of others. Misinterpretation or failure to communicate intentions can lead to collisions, particularly in narrow channels where vessels are required to navigate with caution.