When two vessels are both stand-on, which statement about action to avoid collision is correct?

• A. Either vessel may take action to avoid collision; but the vessel with less maneuverability should give way.
• B. The stand-on vessel must always maintain course and speed.
• C. Both vessels must stop immediately.
• D. The vessel on the port side must give way.

Answer: (A)

When two vessels are both stand-on, there isn’t a fixed priority to avoid collision by one side; either vessel may initiate evasive action if needed. The important nuance is that the vessel with less maneuverability should give way, because it is harder for it to alter course or speed to avoid a collision. The other vessel, being more maneuverable, can adjust course or speed more safely to clear the risk.

In practice, stand-on means keep your present course and speed, but if the situation remains dangerous, any vessel can take action to avoid collision with sufficient early and decisive maneuvering. Stopping both or automatically yielding based on port side isn’t required or correct in this scenario.