A nautical chart is a specialized representation of maritime areas and adjacent coastal regions, specifically designed for maritime navigation purposes. These navigational tools are essential for mariners within the execution of their chosen routes, as they provide vital information like water depths, locations of dangers, the shoreline's shape, navigation aids, tide predictions, and information on the seabed characteristics. Some even include details of the land, including landmarks and port facilities. Thus, they are particularly useful in both navigating waters safely and efficiently, as well as aiding in the planning stages of a journey. Instead of merely being general geographic 'maps,' Nautical charts are meticulously detailed, and continuously updated to reflect the ever-changing marine environments.

1. Admiralty Chart: These are a series of nautical charts issued by the United Kingdom's Hydrographic Office. They cover a wide range of areas including individual ports, shipping routes, and large sections of the world's oceans, providing essential information for safe navigation at sea. 2. NOAA's Nautical Charts: The National Oceanic and Atmospheric Administration of the United States produces charts that cover both coastal waters and the Great Lakes. They show water depths, coastlines, dangers, aids to navigation, and other features useful to mariners. 3. Bluechart: Developed by Garmin, Bluechart is a type of electronic nautical chart specifically designed for use with Garmin GPS devices. The digital maps often include details such as depth contours, harbor approaches, and marine services. 4. Imray Charts: These are physical and digital nautical charts that cover many global cruising areas. Imray is noted for its comprehensive coverage of the Caribbean and Mediterranean regions. 5. French Nautical Charts: Produced by the French Hydrographic Office, these charts provide marine cartography for French territorial waters and other sea areas around the world. They typically include information on sea floor characteristics, navigational hazards, and tidal information.

A fun and detailed fact about nautical charts could be their unique representation of water depths. Nautical charts, which are essentially 'maps' designed specifically for sea navigation, depict not only the coastline, ports, and other geographical features but also display water depths. These water depths are typically measured from the average low water surface, also known as the chart datum. Accurate depth measurements are crucial as they provide essential information to mariners for safe navigation, anchoring, dredging, harbor construction and various marine operations. Interesting, isn't it? The concept of 'underwater topography' which is largely neglected in conventional maps becomes a central aspect in nautical charts.