Question 24 RVR04 - Master or Mate of LT 200 GRT

The Correct Answer is A. **Explanation for A being correct:** Option A (labeled "A" in the illustration) correctly represents the arc of visibility for a red sidelight according to both International (COLREGs) and Inland rules. A sidelight (either red on the port side or green on the starboard side) must show an unbroken light over an arc of the horizon of **112.5 degrees** (or 10 points of the compass). This arc extends from right ahead to $22.5^\circ$ abaft the beam on its respective side. The diagram segment labeled "A" clearly depicts the $112.5^\circ$ arc of visibility for the red (port) sidelight, extending from dead ahead to just aft of the port beam. **Explanation for why other options are incorrect:** * **Option B (B):** This area typically represents the arc of visibility for a **sternlight**. A sternlight shows an unbroken light over an arc of the horizon of **$135^\circ$** (or 12 points of the compass), centered dead astern ($67.5^\circ$ to port and $67.5^\circ$ to starboard). * **Option C (C):** This arc represents the visibility for the **green sidelight** (starboard side), not the red sidelight. Like the red sidelight, it covers $112.5^\circ$ on the horizon, but on the starboard side, extending from right ahead to $22.5^\circ$ abaft the starboard beam. * **Option D (D):** This area typically represents the arc of visibility for a **masthead light** (or steaming light). A masthead light shows an unbroken light over an arc of the horizon of **$225^\circ$** (or 20 points of the compass), centered on the fore-and-aft line, extending from right ahead to $22.5^\circ$ abaft the beam on either side.