1. GENERAL REQUIREMENTS 



11 



If work is done by more than one unit in 

 the area covered by the sheet, a temporary 

 number shall be assigned to each volume. 

 After completion of all work on the sheet, 

 the records of each vessel shall be jrrouped 

 in proper order, the various groups com- 

 bined, and the complete set of records shall 

 be numbered consecutively and permanently. 

 The field number and the registry number 

 of the hydrog-raphic survey shall be clearly 

 marked in pencil on the cover label of each 

 volume. 



On ships which use a magnetic compass 

 for hydrography the deviation table for the 

 steering compass shall be entered on page 1 

 of each set of records, and in the proper 

 record (with reference to date) if changed 

 during the course of the survey. This is not 

 necessary for launches and small boats using 

 portable compasses. 



An index of all objects such as signals, 

 survey buoys, aids to navigation, landmarks 

 for charts, rocks, and breakers, the positions 

 of which have been located by sextant an- 

 gles, shall be entered as follows : if a separate 

 volume contains all such data, the index shall 

 be entered on Page 2 of that volume; if the 

 data are interspersed through the sounding 

 records, the index shall be entered on Page 2 

 of Volume I, giving the volume and page 

 numbers on which are recorded all data for 

 the location of any given station or object. 



A separate index of special hydrographic 

 information such as currents, tide rips, over- 

 falls, bottom samples, and calibrations of 

 electronic equipment shall be entered on Page 

 2 of Volume I. 



Certain information should be recorded 

 at the beginning of each day's work, includ- 

 ing names of personnel engaged in the opera- 

 tion, instruments in use to control the sur- 

 vey and to obtain soundings, data ralative 

 to adjustment of instruments, bar check and 

 other calibrations, if any, and notes on state 

 of weather, wind, and sea. Changes of per- 

 sonnel or instruments should be noted when 

 they occur. 



The heading on each page should be filled 

 in completely. Rubber stamps may be used 

 for some of the required entries. 



The statistics for each day's work shall 

 be entered at the end of each day. The 

 sextants and clock used shall be verified 

 and the fact noted. The processing stamp 

 shall be impressed at the end of each day's 

 work and the location of the tide gage for 

 control of the hydrography shall be entered. 



In the remarks column shall be entered 

 all additional information required for the 

 proper understanding and correct plotting 

 of the work, including the following: 



(a) Record the latitude and longitude of 

 the beginning and ending of each line; or 

 distance and direction from a nearby signal. 



(b) Record the latitude and longitude of 

 detached positions on rocks, shoals, etc. 



(c) When the sounding line passes close 

 to any important feature such as islets, piers, 

 rocks awash, breakers, buoys, etc., a bearing 

 and estimated distance to the feature should 

 be noted. 



(d) Record changes in speed of the sound- 

 ing vessel, or variation in echo sounder op- 

 erations including phase, gain, or other 

 adjustments. 



(e) Limits of kelp or grass, existence of 

 tide rips, or swirls, changes in wind direction 

 and velocity should be noted. 



(f) Full explanation must be given of all 

 corrections, rejections and omissions in the 

 record. 



(g) Changes in personnel, procedures, or 

 equipment shall be noted at the time the 

 change is made. 



Erasures shall not be made in the record 

 at any time, all corrections being made by 

 crossing out the incorrect entry. 



Standard time shall be used in all hydro- 

 graphic recording and the standard meridian 

 shall be noted at the head of the "Time" 

 column at the beginning of each day's work. 

 Time shall be recorded by numbering the 

 hours consecutively from 0" (midnight) to 

 23 (11p.m.). 



1-33 Sounding interval. — Nearly all 

 sounding are obtained by echo sounders 

 which record a continuous profile of the 

 bottom. Soundings are scaled from the 

 graph at intervals which are determined 



