🔍 Key Concepts

• Relative bearing vs. the other vessel's heading • The arc covered by a vessel's green sidelight under the Navigation Rules • How the sidelight sectors relate to the vessel's bow (dead ahead)

💭 Think About

• If you see only the green sidelight exactly due east of you, are you looking at the vessel’s port side, starboard side, bow, or stern? • What range of headings (in degrees relative to you) would still keep that green light visible to you on your position due west of it? • Which of the answer choices fall within the sector where a green sidelight is visible?

✅ Before You Answer

• Remember that a green sidelight shows from dead ahead to 22.5° abaft the beam on the starboard side (Rule 21) • Sketch your own ship at the center, place the other vessel due east, and draw the sidelight sector around its bow to starboard • Convert the multiple-choice headings into directions (e.g., northeast ≈ 045°) and check which one(s) could place their green light toward you on the west side