There are several publications in book and in chart form which are either necessary or convenient for use in connection with nautical charts. These comprise the coast pilots, notices to mariners, tide tables, light and buoy lists, and various special charts.

Coast pilots, or sailing directions, are books giving descriptions of the main features, as far as of interest to seamen, of the coast and adjacent waters, with directions for navigation. They contain much miscellaneous information of value to the mariner, especially the stranger. Although they contain additional facts which cannot be shown on the charts, they are not at all intended to supersede the latter; the mariner should in general rely on the charts. The sailing directions can be less readily corrected than the charts, and in all cases where they differ the charts are to be taken as the guide.

The most extensive series of sailing directions is that published by the British Admiralty, comprising fifty-six volumes and including all the navigable regions of the world. In the United States the Coast and Geodetic Survey publishes ten volumes of coast pilots for the Atlantic, Gulf, and Pacific coasts, Porto Rico, and southeastern Alaska, and eight volumes of sailing directions for Alaska and the Philippine Islands. The United States Hydrographic Office publishes sixteen volumes of sailing directions for various parts of the world.

Notices to Mariners are published at frequent intervals, giving all important corrections, which should be at once applied by hand to the charts, such as rocks or shoals discovered and lights and buoys established or moved. New charts, new editions, and canceled charts are also announced.

These notices should be carefully examined and the necessary corrections made on all charts of the sets in use on the vessel. A chart should be considered as a growing rather than a finished instrument, and constant watchfulness is required to see that it is kept up to date. Neglect of this may cause shipwreck, as the following instance shows. Report came to Manila in 1904 that there was a low sand islet lying off the very poorly charted northeast coast of Samar; this information was promptly published in the local Notice to Mariners. About a month later a small steamer was sent to land some native constabulary on that coast. The captain failed to obtain or observe this notice, and approached the coast before daylight on a course which led directly across the sand islet. The vessel was driven far up on the sand, where it still lies.

In the United States, weekly Notices to Mariners are published by the Department of Commerce and Labor for the coasts under the jurisdiction of the United States, and by the Navy Department for all regions. These notices are distributed free and can be obtained from chart agents and consular officers. In Great Britain the notices are published at frequent intervals by the Hydrographic Office, and practically all countries issuing charts also issue such notices. Information as to important changes in lights and other announcements of navigational interest are also sometimes printed in the marine columns of newspapers and in nautical periodicals.

Tide Tables. Brief information as to the time and height of the tide is usually for convenience given on the face of the chart. More complete information is published in the Tide Tables, with which every navigator should be provided. "The Tide Tables for United States and foreign ports," published annually in advance by the United States Coast and Geodetic Survey, give complete predictions of the time and height of high and low water for each day of the year for 70 of the principal ports of the world, and the tidal differences from some principal port for 3000 subordinate ports. The other leading nations also publish annual tide tables; those of the British government are entitled "Tide Tables for British and Irish ports, and also the times of high water for the principal places on the globe."

Light and buoy lists. Brief information as to all artificial aids to navigation is shown on the charts. Every vessel should also have on board the latest official light and buoy lists, which give a more detailed description than can be placed on the charts.

Light and buoy lists for the coasts of the United States are published annually by the Light-House Board. The United States Hydrographic Office publishes a "List of Lights of the World" (excepting the United States), in three volumes.

The British Hydrographic Office publishes eight volumes of Lists of Lights, and these are corrected annually.

Chart catalogues are published in connection with all series of charts. They give the particulars and price of each chart published, and are usually arranged in geographical order, with both alphabetical and numerical indexes, for convenience in finding charts either by position, name, or number.

Charts for special purposes. There are various special charts published for the benefit of mariners, although not intended for direct use in plotting the course of a vessel or in locating its position. Some of the more important of these are mentioned below.

Gnomonic charts are intended solely for laying down the great circle or shortest practicable courses between points, for which purpose they are very convenient. Their use has already been described. The United States Hydrographic Office publishes six such charts, for the North Atlantic, South Atlantic, Pacific, North Pacific, South Pacific, and Indian Oceans.

Current charts are published by the British Hydrographic Office for the various oceans; these usually show the average ocean currents, but for the Atlantic there are monthly and for the Pacific quarterly current charts.

Magnetic variation charts are published by both the United States and British governments. They show on a mercator chart of the world the isogonic lines, or lines along which the variation of the needle from true north is the same. The lines are drawn for each degree of variation. The annual change in the variation is also indicated.

Other magnetic charts are published showing the lines of equal magnetic dip, horizontal magnetic force, and vertical magnetic force.

Meteorological ocean charts are published by several governments, including the United States, Great Britain, and Germany, and give the average weather conditions, winds, fogs, currents, ice, tracks of storms, and other information. "Pilot charts" of the North Atlantic and North Pacific Oceans are issued by the United States Hydrographic Office about the first of each month, and give "a forecast of the weather for the ensuing and a review of that for the preceding month, together with all obtainable information as to the most available sailing and steam routes, dangers to navigation, ice, fog, derelicts, etc., and any additional information that may be received of value to navigation." Mariners in all parts of the world have joined in contributing the information which has been used in compiling these pilot charts.

Track charts are published by the British and United States governments. That of the latter is entitled "Track and distance chart of the world, showing the routes traversed by full-powered steamers between the principal ports of the world, and the corresponding distances."

Telegraph charts are published showing the "telegraphic connections afforded by the submarine cables and the principal overland telegraph lines."

Index charts are outline plans showing the area covered by each chart of a series, and furnish a convenient means of finding a chart of any desired region or of selecting the most suitable chart for any purpose. These index charts are published either in sets, showing all the charts of a series, or are bound into the chart catalogues.

Star charts are included in navigational series, and are conveniently arranged for use on shipboard in identifying the brighter stars. The United States Hydrographic Office publishes two, constellations of the northern and of the southern hemispheres.

Explanatory sheets are published in connection with various series of charts, giving explanations of the symbols and abbreviations used and of other important features. In the United States the Coast and Geodetic Survey has issued a small pamphlet, "Notes on the use of charts," which contains explanations of its chart symbols, and the Hydrographic Office has published "A manual of conventional symbols and abbreviations in use on the official charts of the principal maritime nations."