Nautical Charts

Chris Riley by Chris Riley Updated on July 29, 2019. In

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In order to kick off the new Nautical Know How Coastal Navigation Course we thought it might be appropriate to give some information on the nautical chart. The following information has been compiled from U.S. Government web sites for the Office of Coast Survey, the National Ocean Service and the National Oceanic and Atmospheric Administration. Even as a recreational boater, you should always carry onboard charts of the area in which you are operating and you should know how to read them.


The Office of Coast Survey (OCS) is the oldest U.S. scientific organization and is the Nation’s only official chartmaker. Its history dates from 1807 when the United States Congress directed that a “survey of the coast” be carried out. In the ensuing years additional responsibilities were assigned to the young agency to meet scientific and engineering needs of a growing national population and economy. The Marine Chart Division collects marine navigational data to construct and maintain nautical charts, Coast Pilots, and related marine products for the United States.

By 1836, the (OCS) was called the U.S. Coast Survey. In 1871, a geodetic connection between the Atlantic and Pacific coasts was officially authorized and the name was changed to the U.S. Coast and Geodetic Survey (C&GS) in 1878. In 1926, the production of aeronautical charts was added to meet the requirements of the new air age. In 1970, U.S. Coast and Geodetic Survey became the National Ocean Survey under the newly established National Oceanic and Atmospheric Administration (NOAA) and in 1982, it was renamed the National Ocean Service (NOS). Later that year in December 1982, the Office of Charting and Geodetic Services was created within the new National Ocean Service was created to better focus on charting and geodetic activities, re-establishing the former C&GS acronym. In 1991, the office was renamed to its former 1878 name of Coast and Geodetic Survey.

What is a Nautical Chart ? A Nautical Chart is a graphic portrayal of the marine environment. In addition to its basic elements, a chart is a working document used by the mariner both as a “road map” and worksheet and is essential for safe navigation. In conjunction with supplemental navigational aids, it is used to lay out courses and navigate ships by the shortest and most economical safe route. A chart shows the nature and form of the coast, the depths of the water and general character and configuration of the sea bottom, locations of dangers to navigation, the rise and fall of the tides, locations of man-made aids to navigation, and the characteristics of the Earth’s magnetism.

The United States claims 12 nautical miles for its territorial sea and 200 nautical miles fisheries jurisdiction and Exclusive Economic Zone (EEZ) for the exploration and management of both living and nonliving marine resources. This vast area covers approximately 3.4 million nautical square miles. OCS provides accurate and timely nautical charts, maps, and related products for the coastal and adjacent ocean areas of the United States (including possessions and territories), the Great Lakes, other inland navigable waters, for the safety and efficiency of marine transportation, offshore engineering projects, naval operations, and recreational activities.

The update cycle for nautical charts is as often as every 6 months or as infrequently as 12 years for remote areas. The average revision interval per nautical chart is 2 years. The Cooperative Charting Program involving the U.S. Power Squadrons and the Coast Guard Auxiliary provides valuable feedback information on nautical charts. Additional contacts are made through professional organizations, technical conventions, boat shows, and similar activities. Marketing studies are conducted to determine user reactions to existing products and to formulate plans for new products, formats, and coverage.

Are Nautical Charts for Recreational Boaters?

Recreational boaters often navigate without information and the tools critical to their safety.

Increasing numbers of recreational vessels on the waters of the U.S. are competing for the use of those waters with commercial vessels. It is imperative that the recreational boater learn to read charts and navigate safely.

  • Between 1970 and 1996, the number of recreational boats owned by Americans nearly doubled – from 8.8 million to 17.5 million.
  • Although the number of fatalities from recreational boating has decreased over the last thirty years, accidents and injuries have steadily climbed, and the reported property damages have increased sevenfold to $35 million.
  • Because recreational boaters have limited storage space, they often navigate without essential information and basic tools critical to their safety.
  • The U.S. Coast Guard receives numerous calls each year from recreational boaters in distress who don’t know where they are. Often, even when in sight of land.
  • Although new technologies can help recreational boaters navigate safely by providing electronic charts and GPS positioning information in a simple and inexpensive manner, it is the obligation of a boater who is navigating to do so by all means available, which means checking that electronic fix the old fashion way, using a nautical chart.


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