Question 2 RVR04 - Master or Mate of LT 200 GRT

The Correct Answer is C **Why option C ("white stern light") is correct:** In this scenario, Vessel "A" is the overtaking vessel, and Vessel "B" is the vessel being overtaken. According to the International Regulations for Preventing Collisions at Sea (COLREGs), specifically Rule 21(d), the **Sternlight** is a white light placed as nearly as practicable at the stern, showing an unbroken light over an arc of the horizon of $135$ degrees ($67.5$ degrees from right aft on each side of the vessel). When one vessel is directly astern of another and performing an overtaking maneuver, the overtaking vessel will be within the $135$-degree arc of visibility covered by the sternlight of the vessel ahead. Therefore, Vessel "A" will observe the **white stern light** of Vessel "B". **Why each of the other options is incorrect:** * **A) green sidelight:** The green sidelight (Rule 21(b)) shows light over an arc of $112.5$ degrees from right ahead to $22.5$ degrees abaft the beam on the starboard (right) side. When Vessel "A" is directly astern of Vessel "B" (the overtaking position), Vessel "A" is outside the arc of visibility of Vessel "B's" sidelights. * **B) yellow towing light:** A yellow towing light (Rule 21(e)) replaces the sternlight when a vessel is engaged in towing. While Vessel "B" might technically be towing, the standard light shown directly astern of a vessel (which is what the overtaking vessel sees) is the sternlight (white) or the towing light (yellow). However, since the question provides the standard sternlight (white) as an option and refers to a general overtaking scenario, the primary and standard light observed directly from the stern is the sternlight. Unless specified as a towing vessel, the white sternlight is the definitive and expected light shown directly astern. * **D) None of the above:** This is incorrect because option C correctly identifies the light that must be shown directly astern to the overtaking vessel.