changed, however, in special cases where the shape of the land so requires or where long custom to the contrary has with good reason prevailed. If the north can not be shown toward the top, it should preferably lie toward the left. The north line shall be simple in design, in accordance with the example on the Boston map. Show both true and magnetic north. The long dimension of the map shall preferably be from left to right rather than from top to bottom.

14-34. Title and lettering. The title shall be placed in the lower right-hand corner, unless the shape of the map prevents. Use only plain vertical letters of open type, as these reduce better. Lines should be of uniform thickness; use no faint lines in lettering. Title should preferably be done in Roman type; see Plate No. 14-8 for example.

14-35. Coordinates 200 feet apart in either direction shall be indicated in faint lines on each map. These should preferably be parallel in direction to the edges of the sheet. The border line may be divided into 100-foot segments. Number the columns of squares at the top or bottom of sheet, or both, and designate the rows, at either or both ends, by letter, so that letter and number may be used to identify any given square on the map. If the plot is so laid out on the map that the coordinate lines would be more useful if at an angle with the edges of the sheet, such an arrangement may be adopted.

14-36. Size of sheets. The size of the sheet shall preferably conform to the bureau standard, viz, 29 by 35 inches (27 by 33 inches between margins); or it may be 29 by 52 inches (27 by 50 inches. between margins). Every yard map should be placed on sheets of these sizes unless the shape of the plot to be shown and the scale, in special cases, may make larger sheets obligatory.

14-37. Scales. The standard scale shall be 100 feet to the inch, but a scale of 200 feet to the inch is permissible where the map would otherwise be too large. A scale of 50 feet to the inch may be used in special cases of small areas where the map may still be contained on the standard size sheet. Scales other than these shall not be used, unless specifically approved in advance by the bureau.

14-38. Water front. All piers, as mapped, should be distinctly numbered or lettered, and the depth of water at each side of each pier designated, either by contours or soundings, or by general note covering limiting depth. There should be shown the pierhead and

bulkhead lines last approved by the War Department. Fixed cranes, shear legs, and derricks, where they occur, should be shown and their reach and capacity indicated.

14–39. Shore structures. Buildings, as mapped, should be neatly diagonal-hatched for existing structures, with the assigned number shown in the center of each, and the floor elevation in the lower right-hand corner, where practicable. Buildings under construction should be shown in dotted lines and left without the hatching, but should show the assigned number and main-floor elevation. It is not necessary that the use of the building be noted, except in the list of buildings. Structures (other than buildings) which are not assigned numbers, or which do not appear in legend, should be titled.

14-40. List of buildings shall be incorporated with map, and shall show the following: Number of the building, its location by coordinate lines, department, shop, or office occupying same, and the purpose for which used.

14-41. Datum plane. Note on the plan the datum plane to which soundings and contours are referred. State range of tides and note highest and lowest recorded abnormal tides or flood levels.

14-42. Key plan. Where several plans are required to show the entire station, a key plan on a small scale shall occupy the first sheet, or it may be shown on one of the larger scale sheets if space is available.

14-43. Location plan. Where space permits, a small scale plan, indicating the location of the yard or station with reference to the nearest city, to railways, to the ship channel, or to other approaches, shall be shown on the map.

14-44. Other topographic maps. Whenever survey maps of areas adjoining the station proper are made, but not included in the annual report map, prints of such maps shall be furnished for the bureau's files.

SUBSURFACE MAPS.

14-45. Conditions necessitating original subsurface surveys. Prior to 1911 there existed few complete record plans showing the size, location, and condition of the various subsurface systems that had been installed from time to time in the various navy

yards. This condition naturally followed from the fact that the several yard departments, each with a practically independent organization, had directed the installation of underground structures without reference to similar work of the others. The condition at that time was little short of chaotic, and when new structures were installed or repairs to old ones undertaken, great confusion, delay, and expense resulted from the lack of information as to existing underground structures. In many instances test pits had to be sunk, and sometimes whole street intersections were laid bare in order to determine a possible location for a new underground line; frequently obstructions were not discovered until trenches for new work were opened.

14-46. Execution of original surveys. In 1911 the bureau authorized a comprehensive subsurface survey at the navy yard, New York. This involved a complete resurvey of the yard, including the location of all structures above and below the surface, by the rectangular coordinate method. Upon the completion of this first subsurface survey, the bureau arranged for making similar surveys at other navy yards. On account of the highly technical character of the undertaking, special survey parties, under expert supervision, were organized for the initial surveys. After initial completion of these valuable records for any yard, public works officers were required to keep them up to date with their regular force, following a routine system of plotting extensions and alterations.

14-47. Resumption of surveys after World War. During the World War period the subsurface surveys were suspended, as the personnel was required for other work in connection with the rapid expansion of the naval shore establishment. After the war the survey parties were reorganized, in order to make original surveys, where required, and to record the changed physical aspects resulting from war-time construction at yards previously surveyed.

14-48. Request for survey party's services. Yards and stations requiring original surveys, or extensive revision of old surveys, should so advise the bureau in order that arrangements may be made for having the organized survey party perform the work.

14-49. Importance and purpose of records. The bureau desires to impress upon commanding officers of all shore stations, and all other officers concerned, the very great importance of having

available at all times reliable record plans of all structures above and below ground. This end can be attained only by adopting a constant and definite procedure for controlling and making street excavation; for planning and directing the installation of new underground structures; for collecting and recording all information obtainable from street openings made for any cause; and for the preparation, correction, and custody of the official subsurface and other record plans. The purposes served by proper record maps of underground structures are (a) to facilitate both maintenance and operation; (b) to enable prompt and intelligent action to be taken in emergencies; and (c), in planning alterations or new work, to eliminate any avoidable interference with existing structures.

14-50. Where surveys are necessary. Surveys as hereinafter described are necessary at all navy yards, naval stations, and other activities, where the existing records of underground structures are incomplete or unreliable; subsurface maps are required where such structures are so extensive or complicated that they can not be shown without confusion on the annual report map or other similar topographical map.

14-51. Methods prescribed for initial surveys and routine corrections. For the information and guidance of all concerned, the instructions in succeeding paragraphs are given, indicating the proper procedure and methods for making an initial subsurface survey, and also for securing and recording data which are obtainable in the regular course of events. In order to secure the necessary uniformity of practice, these methods shall be followed for new surveys to such extent as local conditions permit; and at stations where subsurface surveys have already been established, the sectional records shall be kept up to date as herein described.

14-52. Data to be recorded. All data pertaining to subsurface systems and structures should be obtained and recorded, and later plotted on the sectional maps described in paragraphs 14-55 (c) and 14-63, in such manner that the maps shall give existing information as to structures and at the same time may be available for the recording of new or additional data pertaining thereto. There should be combined with the subsurface survey a topographical survey showing boundaries, building lines, railroad tracks, curbs, hydrants, and other surface conditions.

14-53. Sources of information. For proper plotting and recording, information should be obtained from

(a) Existing navy-yard surveys, plans, and graphic records pertaining to subsurface structures; field books, notebooks, or other similar records.

(b) Actual field location and examination of manholes, and also of street openings and test pits.

(c) Notes or oral information from yard foremen or employees, where necessary to supplement information from the sources indicated in (a) and (b); such information, however, should be entered in pencil on the sectional maps, and not made permanent until actually verified.

in so

14-54. Methods of securing information. As the first step in a subsurface survey is to secure the data referred to in subparagraph (a) above, a study should be made of yard surveys, maps, and field books; notes should first be made of the useful data contained therein and then indexed according to sectional areas of the sheets previously laid out. The information indicated in subparagraph (b) above should be obtained in the field in the course of the new survey, far as existing manholes are concerned. Street openings or test pits for the sole purpose of gaining information should not be made unless absolutely necessary, as such openings are expensive and may be seriously obstructive. During the progress of the survey, however, there will normally be many occasions when it will be necessary to open streets for new work, repair work, and other purposes, and considerable data can be obtained from these openings if proper arrangements are made for securing and recording the necessary observations. To this end it is of primary importance that the commandant issue orders forbidding the opening of streets, except by the public works department and in accordance with an established routine. When it becomes necessary to make an opening for repair or construction purposes, written application on a prescribed form should be made to the public works officer by the foreman or other supervisor in charge of the work, stating the exact location, the approximate date, and the purpose of the proposed opening. This permit, after approval, should be returned to the foreman, who will in turn forward it to the head of the subsurface survey party or yard instrumentman for use in collecting appropriate information. This routine should be habitually followed even after the original survey has been completed, in order that draftsmen assigned to the correction and plotting of subsurface records may have the information necessary for keeping these records up to date. Where an opening is required in case of emergency, the foreman concerned

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