Under what condition can the stand-on vessel take action to avoid collision?

The stand-on vessel is typically required to maintain its course and speed when it is in a situation of collision risk with a give-way vessel. However, the stand-on vessel can take action to avoid a collision when the give-way vessel does not take early and substantial action to avoid the situation. This allows for proactive measures to ensure safety as the situation evolves, especially if it becomes apparent that the give-way vessel may not maneuver in a timely way to avoid a close-quarters situation.

In maritime navigation, the responsibility to avoid a collision primarily rests with the give-way vessel. However, the stand-on vessel must remain vigilant and be prepared to act if the circumstances change, ensuring that it does not become a contributor to a collision. Understanding this dynamic is crucial for ensuring safety at sea and avoiding potentially dangerous situations.

The other conditions listed, such as foggy weather, darkness, or both vessels approaching a port, do not intrinsically change the obligations regarding who is the stand-on vessel and who is the give-way vessel. While these conditions may affect visibility or navigation, they do not specifically alter the rules under which the stand-on vessel can take action.