Under COLREGs, when a PDV is following a vessel in a Traffic Separation Scheme (TSS) and the lead vessel has not taken action, what is your primary obligation?

• A. Keep out of the way
• B. Stop immediately
• C. Pass ahead on starboard
• D. Maintain current course

Answer: (A)

In a Traffic Separation Scheme, the vessel behind has the responsibility to take early action to keep well clear if the vessel ahead isn’t taking action. When the lead vessel in the TSS does not maneuver, you must actively do what’s needed to avoid a collision, which means keeping out of the way by adjusting your course or speed so you pass safely clear of the other vessel.

This emphasizes not relying on the lead vessel to move and not assuming they will; safety comes from taking action yourself to prevent a collision. Stopping immediately isn’t required just because the other vessel isn’t moving, and passing ahead on starboard or simply maintaining your current course could put you at risk if the lead vessel is not adjusting. Keep out of the way as the appropriate response to ensure safe passage.