🔍 Key Concepts

• Navigation Rules Rule 15 (Crossing Situations) and Rule 17 (Action of Stand-on Vessel) • Meaning of three white masthead lights in a line with a red sidelight visible • How seeing a vessel "on your port bow" and seeing its red sidelight tells you which side of that vessel you are looking at

💭 Think About

• From the red sidelight and three white masthead lights, what type of vessel are you looking at, and from which side are you seeing it? • If you see that vessel on your port bow, which vessel has the other on its starboard side, and therefore which one is the give-way vessel under Rule 15? • Once you know whether you are the stand-on or give-way vessel, which choice matches the proper action required by Rule 15 or Rule 17?

✅ Before You Answer

• Confirm that a red sidelight means you are looking at the other vessel’s port side • Confirm that the vessel you see is a power-driven vessel underway (towing or not) and not restricted in ability to maneuver, not under command, etc. • Decide clearly whether you or the other vessel is obligated to maneuver, then pick the answer that matches that obligation.