Question 24 RVR03 - Mate of LT 500-1600 GRT

The Correct Answer is A. **Explanation for A:** Option A correctly represents the arc of visibility for a red sidelight (port light) as defined by both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules. A sidelight must show an unbroken light over an arc of the horizon of $112.5$ degrees (10 points of the compass), fixed so as to show the light from right ahead to $22.5$ degrees (2 points) abaft the beam on its respective side. The red light is mounted on the port (left) side. Therefore, the arc labeled 'A', starting from directly ahead and extending $112.5$ degrees aft on the port side, illustrates the required visibility for the red sidelight. **Explanation for B:** Option B represents the arc of visibility for the **green** sidelight (starboard light). The green light covers the same $112.5$ degrees arc, but on the starboard (right) side of the vessel. **Explanation for C:** Option C represents the arc of visibility for the **masthead light** (or steaming light). The masthead light covers an arc of $225$ degrees ($20$ points of the compass), fixed so as to show the light from right ahead to $22.5$ degrees abaft the beam on both sides. This arc is the combination of the arcs of the two sidelights (A and B). **Explanation for D:** Option D represents the arc of visibility for the **stern light**. The stern light covers an arc of $135$ degrees ($12$ points of the compass), fixed so as to show the light as equally as possible on both sides of the stern.