Which factors must be taken into account when determining safe speed according to the Rules?

When determining safe speed according to the Rules, several crucial factors must be taken into account to ensure navigational safety. The state of wind, sea, and current are fundamental elements that influence how a vessel responds in different conditions. Additionally, the proximity of navigational hazards can dictate the necessity for reduced speed; this is particularly important when navigating through congested areas, around obstacles, or in conditions where visibility is limited.

Weather conditions encompass more than just wind; they include sea state, visibility, and any other environmental factors that can affect the vessel's performance and safety. By considering these factors, a mariner can adjust the vessel's speed in a way that allows for safe handling and the ability to take timely action in response to changing situations. Therefore, the combination of state of wind, sea, current, and the proximity of hazards provides a comprehensive view necessary for determining a safe speed.