United States Coast Guard Captains License Practice Exam

If you see a vessel's green sidelight bearing due east from you, where might the vessel be heading?

1. East

2. Northeast

3. Northwest

4. Southeast

The correct answer is: Southeast

To determine where a vessel is heading when you see its green sidelight bearing due east, it is essential to understand the visibility of navigation lights in terms of their orientation. The green sidelight is positioned on the starboard (right) side of a vessel when it is facing forward. If the green sidelight is due east from your position, this indicates that the vessel is heading toward the east or away from the east but is likely approaching you from the east or reducing its distance from you. Since the green sidelight is visible when looking toward the starboard side of the vessel, and you are seeing it directly east, the most logical heading for the vessel is southeast. This means the vessel is moving toward the southeast direction and thus can be heading in a path that includes east as well as south in its trajectory. Understanding the visibility of navigation lights and their relation to a vessel's direction is crucial in marine navigation, especially when assessing the movement and intentions of other vessels on the water.