What information is most important when passing near a lighthouse?

When passing near a lighthouse, the most critical information is water depth. This is because lighthouses are often situated in areas where the water depth can vary significantly due to tides, sandbars, or underwater features. Knowing the water depth helps to ensure that your vessel does not run aground, which could lead to damage or capsizing.

While the location of nearby boats, weather conditions, and distance to shore are also important considerations for safe navigation, they do not have the same immediate impact on the safety of your vessel as ensuring you are in sufficiently deep water. Adequate water depth allows for the safe passage of your boat without the risk of hitting submerged obstacles, which is paramount for navigating safely around any maritime structures, including lighthouses.