Question 33 FCP01 - First Class Pilot

The Correct Answer is B. ### Why Option B ("67.5°") is Correct The requirement for the positioning and arc of visibility of the stern light (or 'sternlight') is defined in the **International Regulations for Preventing Collisions at Sea, 1972 (COLREGs)**, Annex I, Section 9 (Horizontal Sectors). These rules are adopted identically for both international and inland navigation in many jurisdictions. Rule 21 defines a sternlight as a white light placed as nearly as practicable at the stern showing an unbroken light over an arc of the horizon of **135 degrees** and so fixed as to show the light **67.5 degrees** from dead astern on each side of the vessel. Therefore, the stern light shows from dead astern to $67.5^\circ$ on the port side and $67.5^\circ$ on the starboard side, totaling $135^\circ$. ### Why the Other Options are Incorrect **A) 22.5°:** This figure represents the overlap between the sidelights and the masthead light (where the sidelight continues to show forward of the beam), or half the forward arc covered by the masthead light (which covers $112.5^\circ$ on each side of dead ahead). It does not relate to the stern light's individual arc on one side. **C) 112.5°:** This figure represents the total arc of visibility for the **sidelights** (from dead ahead to $22.5^\circ$ abaft the beam) or half the arc of visibility for the **masthead light** (from dead ahead to $112.5^\circ$ on either side). It is not the arc for the stern light on one side. **D) 135.0°:** This figure represents the **total** arc of visibility for the stern light (the sum of both sides: $67.5^\circ + 67.5^\circ$). The question asks for the arc "on **each side** of the stern," making $135.0^\circ$ incorrect for a single side.