What does “safe speed” mean as per the Navigation Rules?

"Safe speed" refers to the notion that a vessel should not travel at a speed that impairs its ability to take proper and effective action to avoid a collision. This concept is central to maritime navigation rules and emphasizes the importance of remaining vigilant and adaptable in navigating potential hazards or other vessels.

When determining a safe speed, factors such as visibility, traffic density, maneuverability, and weather conditions must all be considered. A vessel traveling at a speed that is too fast may not be able to stop or change course in time to avoid a collision, which could lead to dangerous situations. Thus, the key aspect of safe speed is having the ability to respond effectively to any changes in the operating environment.

The other options present ideas that do not fully capture the essence of “safe speed.” While reducing engine power or matching traffic flow might seem reasonable in some contexts, they do not emphasize the capability of effective response in potential collision scenarios, which is the crux of defining safe speed in maritime navigation.