🔍 Key Concepts

• Relative bearings vs. the other vessel's heading • What a red sidelight indicates about which side of the vessel you are seeing • How the direction you see the light from (NW/315°) constrains the possible headings of the other vessel

💭 Think About

• Sketch yourself at the center with north at the top. Mark where NW (315°) is from your position and place the other vessel there. Which way must that vessel’s bow be pointing if you can see only its red sidelight? • Remember: red is the port (left) side of the other vessel. From your viewpoint, how must the vessel be oriented so that you are looking at its port side from the direction of 315°? • For each answer choice heading, draw an arrow showing that heading from the other vessel’s position and ask: would I be on its port side or starboard side?

✅ Before You Answer

• Confirm that a red sidelight means you are seeing the vessel’s port (left) side • Make sure you are treating 315° as a relative bearing from you to the other vessel, not the other vessel’s heading • For each possible heading, check whether you would logically be located within the arc of visibility of the port sidelight (red) rather than the starboard (green) or stern light