What does Rule 4 require in terms of vessel conduct?

Rule 4 of the USCG Rules of the Road establishes that all vessels must comply with the regulations under all circumstances. This rule emphasizes the importance of maintaining safe navigation practices, regardless of the conditions or situations a vessel may encounter. By requiring compliance at all times, it ensures that the safety of all vessels and their crew is prioritized effectively. This constant adherence to the rules helps to minimize the risk of collisions and enhances overall maritime safety.

The other options reflect scenarios that either limit or misunderstand the application of the rules. For instance, suggesting compliance under specific conditions or only in hazardous situations could lead to dangerous decision-making, as it might encourage laxity in adherence during seemingly safe conditions. Similarly, proposing a relaxation of rules in busy waterways contradicts the intent of the regulations, which are designed to provide structure and safety in all navigational contexts. Thus, it is crucial that vessel conduct aligns with Rule 4, emphasizing unwavering compliance to foster an orderly and safe navigational environment.