In a crossing, stand-on may act when the give-way vessel is not taking appropriate action.

• A. Immediately on sighting the other vessel
• B. When it becomes apparent the give-way vessel is not taking appropriate action
• C. After signaling
• D. When the stand-on vessel takes action

Answer: (B)

In a crossing situation, the stand-on vessel is expected to keep its course and speed, giving the other vessel a chance to take appropriate action. The crucial moment is when it becomes clear that the give-way vessel is not taking the necessary action to avoid a collision. At that point, the stand-on must take evasive action to prevent a collision. You don’t react immediately just upon sighting the other vessel, and you don’t need to signal before taking action; you adjust only once it’s evident the other vessel isn’t responding properly. This is why the correct timing is “when it becomes apparent the give-way vessel is not taking appropriate action.”