Last updated The front cover of Distances Between Ports
Distances Between Ports (PUB 151) is a publication that lists the distances between major ports. Reciprocal distances between two ports may differ due to the different routes of currents and climatic conditions chosen. To reduce the number of listings needed, junction points along major routes are used to consolidate routes converging from different directions.
The positions listed for ports are central positions that most represent each port. The distances are between positions shown for each port and are generally over routes that afford the safest passage. Most of the distances represent the shortest navigable routes, but in some cases, longer routes, that take advantage of favorable currents, have been used. In other cases, increased distances result from routes selected to avoid ice or other dangers to navigation, or to follow required separation schemes.
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation.
A nautical chart is a graphic representation of a sea area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land, natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and human-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial printing company as recently as the night before printing. With each daily download, critical data such as Local Notices to Mariners are added to the on-demand chart files so that these charts are up to date at the time of printing.
Piloting or pilotage is navigating, using fixed points of reference on the sea or on land, usually with reference to a nautical chart or aeronautical chart to obtain a fix of the position of the vessel or aircraft with respect to a desired course or location. Horizontal fixes of position from known reference points may be obtained by sight or by radar. Vertical position may be obtained by depth sounder to determine depth of the water body below a vessel or by altimeter to determine an aircraft's altitude, from which its distance above the ground can be deduced. Piloting a vessel is usually practiced close to shore or on inland waterways. Pilotage of an aircraft is practiced under visual meteorological conditions for flight.
A navigator is the person on board a ship or aircraft responsible for its navigation. The navigator's primary responsibility is to be aware of ship or aircraft position at all times. Responsibilities include planning the journey, advising the ship's captain or aircraft commander of estimated timing to destinations while en route, and ensuring hazards are avoided. The navigator is in charge of maintaining the aircraft or ship's nautical charts, nautical publications, and navigational equipment, and they generally have responsibility for meteorological equipment and communications. With the advent of GPS, the effort required to accurately determine one's position has decreased by orders of magnitude, so the entire field has experienced a revolutionary transition since the 1990s with traditional navigation tasks being used less frequently.
A second mate or second officer (2/O) is a licensed member of the deck department of a merchant ship holding a Second Mates Certificate of Competency, which is issued by the administration. The second mate is the third in command and a watchkeeping officer, customarily the ship's navigator. Other duties vary, but the second mate is often the medical officer and in charge of maintaining distress signaling equipment. On oil tankers, the second mate usually assists the chief mate with the Cargo operations.
In celestial navigation, lunar distance is the angular distance between the Moon and another celestial body. The lunar distances method uses this angle, also called a lunar, and a nautical almanac to calculate Greenwich time if so desired, or by extension any other time. That calculated time can be used in solving a spherical triangle. The theory was first published by Johannes Werner in 1524, before the necessary almanacs had been published. A fuller method was published in 1763 and used until about 1850 when it was superseded by the marine chronometer. A similar method uses the positions of the Galilean moons of Jupiter.
The American Practical Navigator, originally written by Nathaniel Bowditch, is an encyclopedia of navigation. It serves as a valuable handbook on oceanography and meteorology, and contains useful tables and a maritime glossary. In 1867 the copyright and plates were bought by the Hydrographic Office of the United States Navy. As of 2019 it is still published by the U.S. Government and is available free online from the National Geospatial-Intelligence Agency (NGA), the modern successor agency to the 19th Century Hydrographic Office. The publication is considered one of America's nautical institutions.
Passage planning or voyage planning is a procedure to develop a complete description of a vessel's voyage from start to finish. The plan includes leaving the dock and harbor area, the en route portion of a voyage, approaching the destination, and mooring, the industry term for this is 'berth to berth'. According to international law, a vessel's captain is legally responsible for passage planning, The duty of passage planning is usually delegated to the ship's navigation officer, typically the second officer on merchant ships.
Sailing Directions are written directions that describe the routes to be taken by boats and ships during coastal navigation and port approaches. There are also products known as Sailing Directions, which are books written by various Hydrographic Offices throughout the world. They are known as Pilot Books, because they provide local knowledge of routes and landmarks, which would typically be provided by a local marine pilot. As such, they are used frequently by naval and government vessels, who are exempted from 'Compulsory Pilotage' in many ports.
A notice to mariners advises mariners of important matters affecting navigational safety, including new hydrographic information, changes in channels and aids to navigation, and other important data.
A Local Notice to Mariners is an authoritative instruction issued by a designated official, typically the harbormaster.
United States Coast Pilot is a nine-volume American navigation publication distributed yearly by the Office of Coast Survey, a part of the National Oceanic and Atmospheric Administration's National Ocean Service. The purpose of the publication is to supplement nautical charts of the waters of the United States.
Nautical publications is a technical term used in maritime circles describing a set of publications, either published by national governments or by commercial and professional organisations, for use in safe navigation of ships, boats, and similar vessels. Other publications might cover topics such as seamanship and cargo operations. In the UK, the United Kingdom Hydrographic Office, the Witherby Publishing Group and the Nautical Institute provide numerous navigational publications, including charts, publications on how to navigate and passage planning publications. In the US, publications are issued by the US government and US Coast Guard.
The World Port Index contains a tabular listing of thousands of ports throughout the world, describing their location, characteristics, known facilities, and available services. Of particular interest are the applicable volume of Sailing Directions and the number of the harbor chart. The table is arranged geographically, with an alphabetical index.
The Radio Navigational Aids publication contains a detailed list of selected worldwide radio stations that provide services to the mariner. The publication is divided into chapters according to the nature of the service provided by the radio stations. The services include Radio direction finder and Radar Stations; stations broadcasting navigational warnings, time signals or medical advice; communication traffic for distress, emergency and safety including the Global Maritime Distress Safety System (GMDSS) and long range navigational aids. It also contains chapters describing procedures of the AMVER System, and the interim emergency procedures and communication instructions to be followed by U.S merchant vessels in times of crisis. A new edition of Publication 117 is published annually. This publication is available in its entirety on the website and there are also database queries available for much of the data contained within.
Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time is a best-selling book by Dava Sobel about John Harrison, an 18th-century clockmaker who created the first clock (chronometer) sufficiently accurate to be used to determine longitude at sea—an important development in navigation. The book was made into a television series entitled Longitude. In 1998, The Illustrated Longitude was published, supplementing the earlier text with 180 images of characters, events, instruments, maps and publications.
A rutter is a mariner's handbook of written sailing directions. Before the advent of nautical charts, rutters were the primary store of geographic information for maritime navigation.
The rule of marteloio is a medieval technique of navigational computation that uses compass direction, distance and a simple trigonometric table known as the toleta de marteloio. The rule told mariners how to plot the traverse between two different navigation courses by means of resolving triangles with the help of the Toleta and basic arithmetic.
A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship.
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