What does Rule 6 require all vessels to be able to do?

Rule 6 of the International Regulations for Preventing Collisions at Sea (COLREGs) focuses on the responsibility of vessels to take action to avoid collisions. It specifically emphasizes that vessels must maintain a proper lookout by sight and hearing, as well as assess the situation based on the prevailing circumstances and conditions.

Being able to stop within a distance appropriate to the conditions is vital for ensuring safety at sea. If a vessel can effectively stop within an appropriate distance, it demonstrates that the crew is aware of their surroundings and can react timely to prevent potential collisions. This ability depends on factors such as the vessel's speed, maneuverability, and the environmental conditions, including visibility and sea state. Therefore, adherence to this requirement is essential for safe navigation, ensuring that the vessel can respond promptly to any changes in the situation that may necessitate stopping to avoid a collision.

The other options do not align as closely with the central focus of Rule 6. Making quick turns, traveling at maximum speed, or signaling intentions may be tactics employed during navigation but do not encapsulate the overarching safety guideline of taking precautionary measures to ensure proper stopping capability in response to the current conditions at sea.