84 HYDROGRAPHIC MANUAL PaGE 786 



The number of each package and a Hst of its contents, with a reference to the regis- 

 try number of the survey, shall be noted in the transmittal letter. A carbon copy 

 of Form 413 transmitting the records shall be included in each package. 



Records and computations destined to divisions other than the Division of Charts 

 should not be included with hydrographic data on the same copy of Form 413. 



Sounding Records and other data should be duplicated only when specifically di- 

 rected or when there is considered to be an unusual risk in the method of forwarding. 

 (See also 326 and 796.) 



84. DESCRIPTIVE REPORT 



A Descriptive Report shall be written and submitted to accompany each hydro- 

 graphic sheet. A separate Report for each sheet is preferable, but where much of the 

 information, such as control data and survey methods, is common to several sheets, as 

 in launch surveys, one Report may be submitted for two or more adjoining sheets of a 

 season's work. Where separate Reports are submitted, cross references can be utilized 

 to avoid repetition of parts of the text. 



The purpose of the Report is to supplement the smooth sheet and Sounding Re- 

 cords by information that cannot be shown graphically on the smooth sheet or to direct 

 attention to important results. It outlines the conditions under which the work was 

 done. It should be written with a view to assist the cartographers who verify and re- 

 view the survey and chart the results. It serves to index all records and reports which 

 are applicable to the survey, and to give, m concise form, information on certain stand- 

 ard subjects. The Descriptive Report should, therefore, be written with these purposes 

 in mind. General statements, as well as the detailed tabulation of self-evident data, 

 such as inshore rocks and shoals, or rocks or coral heads that are encircled by depth 

 curves, serve no purpose and should not be included. 



A daily journal should be kept by the hydrographer, in accordance with 385, as a 

 satisfactory Descriptive Report cannot be written from memory nor by an individual 

 having no personal knowledge of the field work unless he has such a carefidly prepared 

 journal. 



Notes made on the boat sheet to supplement the daily journal shall, if applicable, 

 be incorporated in the Descriptive Report. 



In surveys of large extent or of a complicated nature, it may be advisable to write 

 special reports on certain phases of the work covering the entire season or area. A cross 

 reference to each of these should be made under the proper heading of the Descriptive 

 Report. 



The Descriptive Report of a limited isolated survey should include all data, com- 

 putations, forms, etc., ordinarily mailed as separate reports, with the exception of those 

 specifically required to be submitted separately, such as coast pilot notes and landmarks 

 for charts. 



841. Sequence of Contents 



The various data which are required on separate sheets shall be arranged before and 

 after the text in the sequence described herein. 



8411. Descriptive Report Title 



Form 504, Descriptive Report, shall be used as the outside cover sheet, all of the 

 appropriate entries being made. 



