What does a blue tint on a chart indicate?

A blue tint on a chart indicates shoal waters or areas considered dangerous. This color coding is used to alert navigators and boaters to areas where the water depth is shallow enough to pose a risk to vessels, especially those with deeper drafts. The blue areas signify that caution is required when navigating in these regions, as they may not be safe for all types of vessels or may require careful maneuvering to avoid running aground. This information is crucial for safe navigation and helps to prevent groundings and other accidents in shallow water.

In contrast, deep water is typically represented in dark blue, while shallow areas may use other color gradients to depict varying depths, highlighting the nuance in chart design to convey essential safety information to mariners. Clear sailing zones are usually marked in lighter colors to denote safe navigation without significant hazards.