USCG Rules of the Road Practice Test

The presence of a single white light as depicted in illustration D080RR indicates that the vessel is likely a vessel under oars. According to the International Regulations for Preventing Collisions at Sea (COLREGs), a vessel that is not using its engine and is therefore rowing must exhibit a white light visible in all directions. This specific light configuration is distinct and helps in identifying the type of vessel operating under specific circumstances on the water.

Fishing vessels, sailing vessels, and power-driven vessels typically have additional light configurations that indicate their various operational states or underlying characteristics. In contrast, a vessel under oars is specifically identified by the simplicity of its single white light, reflecting its unique mode of operation without auxiliary propulsion. This understanding is crucial for safely navigating and responding appropriately to other vessels on the water.