In what scenario is a stand-on vessel allowed to take action without waiting?

The stand-on vessel is permitted to take action without waiting in situations where it becomes obvious that the give-way vessel is not responding appropriately to avoid a collision. According to the rules that govern navigation at sea, the stand-on vessel has a responsibility to maintain its course and speed, but this duty is dependent on the assumption that the give-way vessel will act in accordance with the rules of the road.

When it is clear that the give-way vessel is not taking necessary action to avoid a collision, the stand-on vessel must then alter its course or speed in order to prevent a dangerous situation. This principle emphasizes the importance of maritime safety and ensures that vessels can take necessary precautions to avoid accidents, even if they are initially classified as stand-on vessels.

In other scenarios presented, feelings of necessity, distress signals, or impaired visibility do not provide a clear legal basis for the stand-on vessel to act independently. Each of these situations may involve complex interpretations of responsibility, but they do not inherently grant the same level of urgency or clarity that is present when the lack of action from the give-way vessel is evident. Thus, choice C is the only scenario that aligns with the established rules and promotes safe navigation practices.