Under COLREGS, what does overtaking require the overtaking vessel to do?

• A. The overtaking vessel must pass on the starboard side
• B. The overtaking vessel must pass on the port side
• C. The overtaking vessel must keep clear of the vessel being overtaken; there is no mandatory passing side
• D. The overtaken vessel must alter course to avoid

Answer: (C)

The essential point is that when a vessel is overtaking another, the responsibility lies with the overtaking vessel to stay clear of the vessel being overtaken until it has completely passed. There is no fixed requirement about which side to pass on; the overtaking vessel may pass on either the starboard or the port side as long as the maneuver can be done safely. The goal is to avoid creating a collision risk during the approach and the passing phase, so the overtaking vessel should take early, clear action to pass safely and not impede the other vessel. The vessel being overtaken should not be expected to alter course to accommodate a specific passing side; its role is to maintain a stable course and speed to allow the overtaking maneuver, if possible, to proceed safely.