What action should you take when encountering a vessel showing a red light on its starboard side?

When encountering a vessel displaying a red light on its starboard side, the appropriate action to take is to give way. This situation indicates that you are approaching another vessel that is likely on your port side, and you must yield to it. According to the Navigation Rules, a red light signifies the port side of a vessel, and if you see this light, it means that the other vessel has the right of way.

In maritime navigation, the general rule is that when two power-driven vessels are on a collision course, the vessel that sees the red light must give way to the vessel displaying the green light on its starboard side, thereby ensuring a safe passage between the two. Giving way is crucial to avoid collisions and maintain safe navigation practices.

Continuing on your course or altering course to port might lead to unsafe situations or potential collisions, while sounding the horn would not be the appropriate response in this situation. Understanding the implications of light signals helps in making safe and informed decisions while at sea, reflecting the key principles of the Rules of the Road.