What does a red sector on a chart indicate for a lighthouse?

A red sector on a chart, when associated with a lighthouse, typically indicates a danger area. This is important for mariners as it signifies that navigating within the area represented by the red sector may lead to hazards such as shallow water, submerged rocks, or other dangerous conditions. The purpose of the red sector is to alert vessels approaching the potential danger and to promote safe navigation by encouraging mariners to steer clear of that area.

In contrast, while some sectors on navigation charts may help identify navigable channels or provide information about the light characteristics, the specific role of the red sector is to highlight areas to avoid. Thus, understanding the function of color codes, including the red sector, is crucial for safe navigation and helps prevent accidents at sea.