United States Coast Guard Captains License Practice Exam

If a vessel is underway in fog and you hear one prolonged and three short blasts, what does this indicate?

1. Vessel not under command

2. Sailing vessel

3. Vessel being towed (manned)

4. Vessel being towed (unmanned)

The correct answer is: Vessel being towed (manned)

Hearing one prolonged and three short blasts in fog signifies that there is a vessel being towed that is manned. This sound signal is an internationally recognized auditory signal under maritime navigation rules. It is used to communicate a specific condition of the vessel to other nearby vessels, enhancing safety in low-visibility situations such as fog. Understanding these sound signals is crucial for maintaining awareness of other vessels’ activities and intentions to avoid collisions. The prolonged blast indicates that the towing vessel is signaling its presence, while the three short blasts clarify that a manned vessel is being towed. This distinction is important for mariners, as it informs them about the possible navigation dynamics of the towed vessel and the need for caution when maneuvering nearby. Being familiar with these signals is critical for safe navigation and compliance with the Rules of the Road, which dictate how vessels should communicate in various conditions, reinforcing the necessity for preparedness while operating vessels in challenging environments.