Final answer:
A stand-on vessel is required to maintain its course and speed in a crossing situation but may take action to prevent a collision if necessary, following the navigational Rules of the road at sea.
Step-by-step explanation:
According to the Rules of the road at sea, a stand-on vessel is required to maintain course and speed in a crossing situation but may take action to avoid collision. In such situations, the stand-on vessel has the right of way, meaning that it should keep its course and speed, expecting the give-way vessel to maneuver around it to avoid collision. However, should it become clear that the give-way vessel is not taking appropriate action to avoid collision, the stand-on vessel must take action, often by altering its course, to prevent an accident. The stand-on vessel is not free to maneuver in any crossing or meeting situation as if it had absolute right-of-way; it must adhere to the navigation Rules to ensure safety at sea.