What action should a stand-on vessel take if a collision cannot be avoided by the give-way vessel alone?

The correct action for a stand-on vessel when it becomes evident that a collision cannot be avoided by the give-way vessel alone is to take action to avoid collision. According to the COLREGs, the stand-on vessel is generally required to maintain its course and speed when it is safe to do so. However, if it becomes clear that the give-way vessel is not taking adequate measures to avoid a collision, the stand-on vessel must take evasive action as necessary to prevent an incident. This requirement is rooted in the principle of safety at sea, which prioritizes the avoidance of collisions even when a vessel has the right of way.

In scenarios where a stand-on vessel fails to take action when it is clear that a collision is imminent, it might be held accountable for not fulfilling its obligation to avoid an accident, thus compromising both vessels' safety. The other options either suggest actions that could exacerbate the risk of collision or do not appropriately address the situation at hand. Taking proactive steps to avoid a collision, even when holding the stand-on position, is essential to ensure maritime safety.