What should vessels do when encountering restricted visibility?

When vessels encounter restricted visibility, it is vital to reduce speed and increase lookout efforts as a means of ensuring safety. Reducing speed allows the vessel's crew to have more time to react to any potential hazards or other vessels in the area, thereby minimizing the risk of collision. Operating at a slower speed provides better control and quicker maneuverability, which is crucial in situations where visibility is limited.

Increasing lookout efforts is equally important. This involves having watch standers actively looking for navigational aids, other vessels, and any obstacles that may not be immediately visible. By enhancing watchkeeping, vessels improve the likelihood of detecting dangers that may arise unexpectedly in low visibility conditions.

This choice emphasizes the need for caution and heightened awareness when navigating in circumstances that reduce visibility, aligning with the maritime principle of ensuring safe navigation. The other options present less effective or inappropriate actions for maintaining safety in such situations. For instance, cruising at normal speed would compromise safety by increasing the risk of collision, while anchoring may not always be feasible based on the surrounding environment or traffic patterns. Turning off navigation lights could lead to greater confusion and danger for both the vessel in question and other nearby vessels.