How is an intermittent light defined for vessels with action?

An intermittent light is characterized by a specific pattern of being on and off, providing important signaling to other vessels regarding actions or statuses. In maritime navigation, the definition that aligns with the standards is a light that is on for a certain duration and then off for the same duration, allowing for recognition and understanding from nearby vessels.

The option that states the light has 3 seconds on and 3 seconds off conforms to the established definition of an intermittent light. This pattern helps ensure that other mariners can identify the vessel's activities or intentions, contributing to safe navigation. The predictable timing of being on and off fosters better awareness for approaching vessels and reduces confusion regarding the buoy's or vessel's status.

The other choices depict different types of lighting systems. For instance, a light that remains continuously on would not provide the variation necessary for an intermittent signal. Similarly, the patterns of being on for 5 seconds and off for 5 seconds do not follow the typical definition, which often uses shorter cycles for maritime signaling. Lastly, a rapidly flashing light indicates a different kind of alert or action, distinguishing it from the more measured pattern of an intermittent light.