Question 2

The Correct Answer is C ### Why Option C ("white stern light") is correct: The scenario describes Vessel "A" (the overtaking vessel) approaching Vessel "B" (the vessel being overtaken) from astern, intending to pass without changing course. According to the International Regulations for Preventing Collisions at Sea (COLREGs), a vessel is deemed to be "overtaking" if it is approaching the other vessel from a direction more than $22.5^\circ$ abaft her beam. In this arc, the only light the overtaking vessel will see on the vessel ahead (Vessel B) at night is the **stern light**. The stern light is a white light placed as nearly as practicable at the stern, showing an unbroken light over an arc of the horizon of $135^\circ$ (which covers $67.5^\circ$ from dead astern to port and $67.5^\circ$ from dead astern to starboard). Therefore, Vessel A will observe Vessel B's white stern light. ### Why the other options are incorrect: * **A) green sidelight:** The green sidelight (starboard light) shows an unbroken light over an arc of $112.5^\circ}$ from dead ahead to $22.5^\circ$ abaft the beam on the starboard side. Since Vessel A is approaching from astern (overtaking), it is outside the arc of visibility for the green sidelight. * **B) yellow towing light:** The yellow towing light is only carried by a power-driven vessel when towing. While Vessel B *might* be towing, the standard and guaranteed light visible from astern, irrespective of the vessel's activity (towing or not), is the **white stern light**. The towing light, if present, is displayed above the stern light but is not the primary identifying light from this specific angle of approach (moreover, the white stern light is always present, whereas the towing light is conditional). * **D) None of the above:** This is incorrect because the white stern light is definitively visible from the overtaking position.