Source Information on Nautical Charts
|The nautical chart conveys a wealth of information to the mariner. The graphic below illustrates a sample of the type of information that appears on nautical charts.
1. Floating aids to navigation established and maintained by the U.S. Coast Guard mark channels and other features such as wrecks and obstructions.
2. The U.S. Army Corps of Engineers dredges channels so that deep draft vessels can transit into and out of ports. Mariners must know the position and depth of these channels.
3. Nautical charts delineate the location of anchorages for military, commercial, and recreational vessels.
4. NOAA shows official geographic names in conformance with the U.S. Board of Geographic Names.
5. Fixed aids to navigation , such as lighthouses maintained by the U.S. Coast Guard, help mariners navigate safely.
6. Mariners need to know bottom characteristics in order to determine where adequate holding grounds for anchoring are located.
7. Depths determined by NOAA surveys are critical to safety of navigation.
8. Mariners must know where underwater hazards and obstructions are located. The chart shows the precise position and depth of water over the obstruction.
9. Most commercial ships entering a harbor need to know where pilotage areas are located. These areas are used for taking on and leaving off marine pilots.
10. Mariners need to know the position and depths of dangerous wrecks , so they can lay out a track to avoid these features.
11. Wire drag cleared depths show the safe navigation depth. This charting symbol indicates that there was at least 20 feet of depth available over the top of the obstruction located here.