What is a masthead light required for on power-driven vessels?

A masthead light is a crucial navigation light that must be exhibited on power-driven vessels when they are under engine power. This light helps to indicate the presence and the operational status of the vessel to others in the vicinity, especially at night or during low visibility conditions. Typically, the masthead light is white and is positioned at the highest point on the vessel to provide a clear signal to other boaters about the vessel's orientation and movement.

When a power-driven vessel is underway, having the masthead light on is essential for safety and for compliance with maritime navigation regulations. It helps prevent collisions by making the vessel more visible and indicating that it is not adrift or at anchor.

The other scenarios described do not require the masthead light. When the vessel is at anchor, other lights or signals come into play, while fishing at night may utilize different lighting requirements. Lastly, favorable weather conditions do not alter the requirement for navigation lights, as the safety of the vessel and its crew is paramount regardless of weather. Thus, a masthead light is specifically required when a power-driven vessel is actively using its engine and is underway.