170 



HYDROGRAPHIC MANUAL 



Detached determinations of the character of 

 the bottom must always be accompanied by 

 position data. 



The vessel's heading by compass must al- 

 ways be entered except when lines are being 

 run along distance arcs in launch hydrog- 

 raphy. Indicate in the space at the top of 

 the column whether a steering, standard, 

 gyro, or boat compass is being used. A course 

 change shall be entered on the line corres- 

 ponding to the time it is made. All courses 

 shall be entered in degrees clockwise from 

 north. 



5-96 Position data. — Insofar as prac- 

 ticable, all position data shall be entered in 

 the column headed "Position Control Data" 

 on the right-hand page. The first entry of 

 position data shall invariably be on the same 

 horizontal line with the corresponding time 

 on the left-hand page, followed on consecu- 

 tive lines by the remainder of the position 

 data. 



The names of the three stations of a three- 

 point fix shall be recorded vertically in the 

 left part of the column. The recorded names 

 of signals must agree with those on the boat 

 sheet. The objects shall always be recorded 

 clockwise, that is, the left object first, the 

 center object next, and the right object last 

 (see Fig. 64). The angles are recorded in 

 the right part of the column, the left and 

 right angles being recorded opposite the 

 names of the left and right objects respec- 

 tively. Where the same control stations are 

 used for successive fixes, it is not necessary 

 to repeat the names ; the word "same" or the 

 letter S, covering the three spaces occupied 

 by the fix, may be used to indicate a repeti- 

 tion, except that the names must be recorded 

 at the top of each page. All station names 

 must be entered if any station in the fix is 

 changed. 



Supplemental angles, cuts, or check angles 

 are entered in the same column below the fix 

 and the names of the objects are entered on 

 the same line. The name of the left object 

 is recorded first. Detached positions are fre- 

 quently recorded without a sounding as when 

 locating rocks or signals. All such positions 



shall be assigned a number and recorded in 

 the same manner as for hydrography. 



Electronic control systems furnish posi- 

 tioning data on two dials, one for each ground 

 station. The dials shall always be read and 

 recorded from left to right, and the readings 

 correctly related to the shore stations. When 

 Shoran is used, the left dial is for the "rate" 

 station, and the right is for the "drift" 

 station. A flip of a switch on the indicator 

 can reverse the two stations and a change 

 of this kind must be recorded. EPI cannot 

 be changed at the ship, but changes can be 

 made at the shore stations to reverse the 

 stations on the controller-indicator. In Ray- 

 dist, the "red" station distance readings 

 always appear on the left-hand phasemeter 

 dial. 



Rubber stamps are available for use in 

 the sounding record to record position data 

 furnished by the various electronic control 

 systems. It is usually more convenient to 

 record the data in a double column, each one 

 headed by the station name. Both distances 

 are recorded on the same line (Fig. 65) 

 and as they are read from left to right on the 

 instrument. 



Calibration and other corrections must 

 be applied to electronic position data, and 

 several spaces between positions should be 

 left for this purpose. If sextant fixes, cuts, 

 or bearings are observed at the position, the 

 data should be recorded in the remarks col- 

 umn and referenced to the position. 



5-97 Remarks column. — All additional in- 

 formation required for the proper under- 

 standing and correct plotting of the work, 

 for which provision is not made in other 

 columns, shall be entered in the remarks 

 column. Abbreviations (see 5-87) may be 

 used for many entries. Where notes are too 

 long to be entered in the remarks column, 

 the sequence of recording may be interrupted 

 to record a note the entire width of a page. 

 As a rule, all notes should be entered at the 

 time the event described occurs. The hy- 

 drographer should initial expanatory notes 

 which he enters in the record. 



A great number of miscellaneous entries 

 are required, too numerous to be discussed 



