What is the significance of the red and green lights on a vessel?

The significance of the red and green lights on a vessel primarily lies in their representation of the port and starboard sides. The red light is placed on the port side (left when facing forward) and the green light is on the starboard side (right when facing forward). This color-coding is crucial for safe navigation, especially at night or in poor visibility conditions, as it helps other vessels determine the orientation and direction of approaching boats.

These lights allow mariners to visualize the relative position of vessels to one another. For instance, if a boat sees a red light, it knows that the other vessel is approaching from its left side, whereas seeing a green light indicates an approach from the right side. This identification plays a significant role in avoiding collisions and ensuring safe passing maneuvers.

While there are other uses for navigation lights, such as aiding in general navigation at night or indicating a vessel's direction of travel, the primary purpose of the red and green lights is to denote the respective sides of a vessel, which is essential for safe maritime operations.