BOTH INTERNATIONAL & INLAND Vessel "A" is overtaking vessel "B" as shown in illustration D017RR below, and will pass without changing course. Vessel "B" is an air-cushion vessel operating in the non-displacement mode. Which light will vessel "A" observe from vessel "B"?

Correct Answer: Option C — flashing yellow light

Rule 23(b) requires an air-cushion vessel operating in the non-displacement mode to exhibit an all-round flashing yellow light. Regardless of the aspect from which you view the vessel, this light is all-round and will be visible to an overtaking vessel, identifying the craft's specific operational mode.