Which of the following is a purpose of nautical charts?

Nautical charts serve a critical role in navigation by providing essential information about waterways, and one of their primary purposes is to convey details about water depth. This information is vital for mariners to ensure safe passage and to avoid underwater hazards such as rocks, shoals, or obstructions that could impede a vessel's navigation. By indicating varying depths, nautical charts help boaters determine whether the water is deep enough for their vessel, thus preventing groundings and accidents.

Other factors, such as weather forecasts and vessel speed, are important for safe boating but are not the direct purposes of nautical charts. Charts focus on the geographical and physical characteristics of waterways, making them indispensable tools for anyone navigating in these environments.