Question 33 UFV01 - Master - Uninspected Fishing Vessels

The Correct Answer is B **Explanation for Option B (67.5°):** Option B (67.5°) is correct because the Rule governing the positioning and arc of visibility for the stern light is defined under **Annex I, Section 2(a) of the COLREGs** (International Regulations for Preventing Collisions at Sea, which applies to both international and inland waters in many jurisdictions). The general rule (Rule 21(b)) states that the stern light must be an unbroken light having an arc of visibility of $135^{\circ}$ (one hundred and thirty-five degrees) and so fixed as to show the light $67.5^{\circ}$ (sixty-seven and a half degrees) from right aft on each side of the vessel. Therefore, the light shows $67.5^{\circ}$ to the starboard side of dead astern and $67.5^{\circ}$ to the port side of dead astern, totaling $135^{\circ}$. **Explanation for Incorrect Options:** * **A) 22.5°:** This angle is half the arc visibility of the sidelights ($112.5^{\circ}$ total arc, meaning $22.5^{\circ}$ forward of the beam on each side), but it is far too narrow for the stern light. * **C) 112.5°:** This angle represents the total arc of visibility for the sidelights (green or red lights), not the arc on each side of the stern light. It is too wide for the required coverage on only one side of dead astern. * **D) 135.0°:** This value represents the *total* required arc of visibility for the stern light (the full sector from port to starboard), not the angle measured on each side of the stern.