WHEN GERHARD MERCATOR made his first chart of the world in 1569, and gave to civilization the Mercator projection, he placed on that chart a prophetic inscription: “God willing, we will give more and greater information on this diagram . .”
To give more and greater information on their charts, which are indeed the keys for unlocking the ocean passages to commerce, has been the constant endeavor of the hydrographic offices of the great maritime nations of the world. So well has this effort been realized that accurate hydro- graphic charts are taken for granted, and even mariners are little aware of the data, research, computations, and compilations forming the keel upon which the complete and elaborate system of maritime security is built. Accurate navigational charts, sailing directions, light lists, notices to mariners, pilot charts, storm warnings, mine warnings, ice reports, radio aids, manuals, and navigational tables are all needed to make an ocean voyage safe and expeditious. These necessary publications are produced in all of the great maritime countries by the hydrographic offices of their respective governments. So vital to maritime security are such data that, by mutual agreement between nations, this information is freely exchanged and made universally available to all in the interest of safe navigation at sea.
In the United States, marine surveying and chart production is divided between the Coast and Geodetic Survey, the Army, and the Navy. The Coast and Geodetic Survey is charged with the surveying and charting of the coastal waters of the United States and its possessions. The Army surveys and charts the Great Lakes and certain inland waters. The Navy, through the Hydrographic Office, conducts surveys beyond the limits of the United States and in foreign waters, by agreement with the foreign governments concerned. The Navy also surveys and charts domestic waters, when required for special naval purposes. The Hydrographic Office is authorized to construct aviation charts for the ever growing needs of military and civilian aviation.
To arrive at an understanding of the various steps in the collection, compilation, and distribution of aids to navigation, it is well to commence with the mission of the Hydrographic Office:
To collect, digest, and issue timely information calculated to afford the maximum possible navigational safety and facilities to ships on the seas and to aircraft operated over the sea routes.
Although the Hydrographic Office, when first founded in 1830, was limited largely to issuing timely information in the form of nautical charts, the impetus given to the study of oceanography, hydrography, meteorology and to surveying expeditions by Wilkes and Maury was such that pilot charts and books of sailing directions made their appearance and soon became widely sought after by all mariners. Through Maury’s efforts, an international conference was arranged at Brussels in 1853, resulting in a uniform system for collecting information concerning winds, currents, magnetic phenomena, and other material valuable to the mariner.
The pioneer work of these early naval officers was placed on a more official basis in 1866 by statutes of Congress, which provided that:
There shall be a Hydrographic Office attached to the Bureau of Navigation in the Navy Department, for the improvement of the means for navigating safely the vessels of the Navy and of the Mercantile Marine, by providing, under the authority of the Secretary of the Navy, accurate and cheap nautical charts, sailing directions, navigators, and manuals of instructions for the use of all vessels of the United States, and for the benefit and use of navigators generally.
The Secretary of the Navy is authorized to cause to be prepared, at the Hydrographic Office in the Navy Department, maps, charts, and nautical books relating to and required in navigation, and to publish and to furnish them to navigators at the cost of printing and paper, and to purchase the plates and copyrights of such existing maps, charts, navigators’ sailing directions, and instructions as he may consider necessary, and when he may deem it expedient to do so, and under such regulations and instructions as he may prescribe.
It will be noted that the mission of the Hydrographic Office and the laws under which it operates are broad, and that its obligation to the Mercantile Marine is extensive. In view of these directives every effort has been made to co-operate to the fullest extent in furnishing information to the Merchant Marine, as well as to the Navy. In return the Merchant Marine is the main agency through which the Hydro- graphic Office acquires the necessary information to keep its charts up to date, and to act as a clearing-house for information of dangers to navigation, vital alike to the Navy and to other maritime interests. Through an extensive system of co-operative observers the Merchant Marine furnishes information in exchange for pilot charts, notices to mariners, the hydro- graphic bulletin, the daily memorandum, and radio broadcasts of immediate dangers to navigation. Foreign hydrographic offices freely exchange their notices to mariners, sailing directions, and other useful information with the U. S. Hydrographic Office, and this information, together with data received from the co-operative merchant marine observers, is then digested, compiled, and issued.
Nautical charts are constructed of material from two sources; original surveys and existing information in the form of foreign charts and other nautical data. In conformity with the policy of the great maritime powers to survey the exterritorial waters in the vicinity of the smaller nations who are not prepared to carry on this work, the United States has been engaged in surveying and charting the Caribbean and Central American waters. These areas are of great commercial importance to the United States, and accurate charts for vessels of our Merchant Marine engaged in Central American trade are a necessity.
The Navy maintains at present two surveying vessels, the Hannibal and the Nokomis, manned by naval personnel with the addition of three civilian hydrographic engineers in each vessel. The past two years have been devoted to the area in the Pacific to the westward of the Gulf of Panama, including the Gulf of Nicoya, and to the coast of Colombia, in the vicinity of Cartagena and Barranquilla. The north coast of Panama, Chiriqui Lagoon, the east coast of Costa Rica, and the Colombian coast from Cartagena to Santa Marta have also been surveyed.
Upon the completion of the survey work in any particular area, the data obtained are forwarded to the Hydrographic Office where a chart manufacturing plant is maintained for constructing and printing the finished chart. A distribution division of the Hydrographic Office receives the finished chart and, from this main distribution point and from the agents of the Hydrographic Office in the principal United States seaports, charts and other data are sent to the mariner.
The internal organization of the Hydro- graphic Office is quite similar to that of any large enterprise which produces and distributes its own products, maintaining its own research and manufacturing departments. The Hydrographic Office is administered by the Hydrographer, a Captain in the Navy. The personnel consists of 17 line officers of the Navy, whose duties are largely of an executive nature and 176 civilian employees, including scientists, cartographical engineers, engravers, photographers, surveyors, and the clerical staff.
The work of the office is divided among the following major divisions: Administration; Maritime Security; Chart Construction; Air Navagation; Research, and Distribution.
It is believed that a brief description of the various steps in the construction of nautical charts, both from the original naval surveys and from compilation of other charts, will be of interest:
Preparatory to constructing a chart from an original survey, the data from the survey vessel reach the Hydrographic Office in the form of smooth sheets, accompanied by all the necessary records from which they were plotted by the personnel in the field. These include records and computations of triangulation, geodetic positions, azimuth, soundings, magnetic and tidal observations, and aerial photographs from which the topography shown on the smooth sheets has been reduced.
As the smooth sheets of a survey are generally plotted on a larger scale than that which will be used in the chart to be constructed and include more soundings and other details than will appear on the finished chart, a careful selection of the chart features to be reproduced is required. In order to assist in this work, it is usual to photograph the smooth sheets to the reduced scale of the proposed chart and then fit the various photographic sheets together as necessary to cover the area within the boundaries decided upon for the chart. With this make-up as a basis, it is possible to visualize the distribution of the hydrographic data and better select the amount of hydrographic and topographic features appropriate to the scale of the chart, such as soundings, detail of the coast lines, and topography. After selection, these features are indicated on the original smooth sheets, usually with a colored pencil, and the smooth sheets are again photographed; this time on glass and to a scale about 2| times the scale of the proposed chart.
Meanwhile, the data with regard to the scale and the boundary of the chart have been furnished the engravers, who lay down the projection accurately on a copper plate. The engraving of the selected features upon this plate is accomplished by an ingenious device called a pantograver. This instrument permits the operator to trace the chart features with a steel point from the glass negative, thereby reproducing the same upon the copper plate through a pantograph mechanism carrying a diamond cutting point. The mechanism permits of any desired ratio between the scale of the negative and that of the copper plate.
The use of the pantograver increases the production of engraved chart plates approximately 400 per cent. Certain features, such as titles, large lettering, reef symbols, and fathom curves, are engraved by hand, as the pantograver is not adapted to this purpose.
The engraved copper plate is now treated with an acid, which etches the lines of the engraving to a depth suitable for printing, and a special copy of the chart, known as the mounted original, is printed from the plate. This print is so mounted as to retain the dimensions of the engraving and to show clear, sharp, black lines on a white background. The mounted original and not the copper plate is then used as the basis for the lithographic reproduction. Hydrographic Office charts are printed by lithography in several colors to give distinction to the various features of the chart, such as land areas, water, lights, radio aids, etc. A separate lithographic zinc plate must be made for printing each color used on the chart. The zinc plates are etched or chemically treated before going to the presses, and the chart is printed by a building-up process as the successive run for each of the zinc color plates is made. As many as 18 separate runs are necessary to produce certain aviation charts.
The compilation of a hydrographic chart from foreign charts does not, as might at first be supposed, consist of simply copying the foreign charts of the area to be charted. It involves a complex procedure of collating data from every available source concerning that area. This mass of information is investigated and checked against sailing directions, light lists, large- and small-scale foreign charts of the area, pilots, astronomical position reports, notices to mariners, and reports of the U. S. Geographic Board and the British Geographic Board giving decisions regarding names. Discrepancies between the various foreign charts of the area to be charted must be investigated and true data as to coast lines, soundings, etc., obtained.
It is readily apparent that a chart compiler must have a working knowledge of the foreign languages, symbols, and methods of chart construction used by those countries whose charts and publications are being used in the compilation process. Geographic positions are fixed, names of places are decided, soundings are brought into agreement and reduced from meters to fathoms or feet, and then generalized to give the most useful information. Part of this data is entered on working sheets photographed from the existing charts and part of it is tabulated. When this work has been completed, it is used in constructing the smooth sheets, similar to those made up from an original survey. The smooth sheets, when completed, are used by the pantograver, a hand engraver, and the draftsman in making up the plates and finally the finished chart.
All charts issued by the Division of Distribution are kept corrected to date of issue; books issued to the Navy are also kept correct to the date of issue; and books issued by direct sale or to agents are supplied with the latest supplements or other corrections. As a matter of interest, approximately 30,000 hand corrections are made on charts each week, and more than 500,000 of these corrected charts are issued annually. The average number of charts carried on the shelves is over 1,000,000. More than 32,000 nautical books and 1,400,000 periodicals were issued during the past fiscal year.
Among the more prominent scientific organizations with which the Hydrographic Office co-operates are: The Woods Hole Oceanographic Institution; The Oceanographic Laboratories of the University of Washington; The Scripps Institution of Oceanography of the University of California; and the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, D.C.
Several of these organizations have in recent years had representatives with the Navy survey vessels, assisting with the dynamic oceanographic work of the Hydrographic Office and concurrently securing data in which they have been primarily interested.
The Hydrographic Office is usually represented at the most important marine and technical conferences concerning nautical matters.
In conclusion, it will be realized from the foregoing discussion that the Hydro- graphic Office, in order to accomplish its mission, must constantly keep abreast with the scientific advancement in geodesy, hydrography, navigation, cartography, meteorology, and oceanography. Accurate charts must be produced; research in oceanography and nautical astronomy must be conducted; and accurate hydro- graphic information must be collected, compiled, and distributed to the Navy and the Mercantile Marine; for these are military and naval necessities, and vital assets to the commerce of the United States, a commerce that is an integral part of Sea Power.