Which light is a requirement on all power-driven vessels?

The requirement for power-driven vessels to have a masthead light is based on maritime navigation rules, specifically the International Regulations for Preventing Collisions at Sea (COLREGS). The masthead light is positioned on the centerline of the vessel at a height that ensures visibility from a distance. This light indicates the presence of a power-driven vessel to other mariners and is critical for safe navigation, particularly at night or in low visibility conditions.

The masthead light emits white light and is visible from a specific distance, typically 225 degrees around the vessel's forepart, allowing other vessels to identify the type of vessel and its heading. This is fundamentally important for avoiding collisions and maintaining safety on the water.

While other lights, such as a stern light and an all-round white light, may be required in specific situations or for certain types of vessels, the masthead light is the key requirement for all power-driven vessels, ensuring that they are identifiable during nighttime operations or in reduced visibility.