Question 2

The Correct Answer is C. ### Explanation for Option C (white stern light) **Option C ("white stern light") is correct because Vessel A is overtaking Vessel B.** 1. **Definition of Overtaking:** A vessel is defined as overtaking if it approaches another vessel from a direction more than $22.5^\circ$ abaft (behind) the beam of the vessel being overtaken. In this scenario, Vessel A is overtaking Vessel B, meaning Vessel A is situated almost directly behind Vessel B. 2. **Required Lights for Overtaking:** The vessel being overtaken (Vessel B) must display a **white stern light** (or masthead lights and sidelights, if observed from the front/side). The stern light is a white light placed as nearly as practicable at the stern, shining over an arc of the horizon of $135^\circ$ ($67.5^\circ$ on each side of the vessel). 3. **Observation by Overtaking Vessel:** Since Vessel A is approaching from the stern (behind) of Vessel B, the only navigation light Vessel A will see displayed by Vessel B is the $135^\circ$ arc of the **white stern light**. ### Explanation of Incorrect Options **A) green sidelight:** The green sidelight is displayed on the starboard (right) side and covers an arc of $112.5^\circ$ forward. Because Vessel A is overtaking Vessel B (approaching from the stern), the position of Vessel A is well outside the arc covered by Vessel B's green sidelight. **B) yellow towing light:** The yellow towing light is required only if Vessel B is engaged in towing operations, and it is displayed above the stern light. Unless specified that Vessel B is towing, its presence cannot be assumed. Even if it were present, the primary and required light visible from the stern is the white stern light. **D) None of the above:** This is incorrect because the white stern light is the specific light required by the COLREGs (International Regulations for Preventing Collisions at Sea) to be displayed toward an overtaking vessel.