5. HYDROGRAPHY 



171 



individually, but the following list illus- 

 trates the variety of information which 

 should be recorded : 



(a) The latitude and longitude of the first 

 position at the beginning of the first line of 

 the day's work, of each detached position, 

 and of the beginning of a line in a locality 

 different from the last position shall be noted. 

 Rubber Stamp No. 39 may be used (Fig. 67). 

 A scaled distance and direction from a 

 nearby signal may be used in lieu of the 

 latitude and longitude of the position. 



(b) The abbreviations LTLA or LTRA 

 shall be entered when the line turns left or 

 right about to an adjacent line and LR, line 

 resumes, at the first position of the new 

 line. 



(c) Note any changes affecting the in- 

 formation given at the beginning of the 

 day's work, as personnel, instruments, 

 weather, etc. 



(d) Distance (in meters) and direction 

 of features in the water area, such as aids 

 to navigation, rocks, breakers, kelp, etc., 

 shall be noted and referenced to the time 

 of passing. Indicate whether the distance is 

 estimated, whether the object has been pre- 

 viously located, or whether the data recorded 

 are to be used to locate it. 



(e) Note estimated distances to the high- 

 water line, low-water line, reef lines, etc., 

 from the nearest recorded position. 



(f ) Note all changes in speed of the sound- 

 ing vessel. Note any sounding line started 

 from a standstill and the time of reaching 

 sounding speed (see 5-58) . 



(g) Indicate the scale or phase being used 

 in echo sounding and all scale changes as 

 they occur. When shoal and deep water echo 

 sounders are used alternately, each change 

 shall be recorded. 



(h) Enter notes concerning the correct 

 operation of the echo sounder. Frequent 

 checks on the 808 tachometer are required 



LINE BEGINS 



L«t 



^1- J20.£ .^„, 7/ SZ.JZ 



Figure 67. — Facsimile of hydrographic stamp No. 39. 



and shall be noted in the record. The note 

 "MRV," meaning "middle reed vibrating" 

 should be used to indicate the correct opera- 

 tion of this instrument. Adjustments of 

 of stylus length should be noted. The fre- 

 quency meter reading on an EDO-255 echo 

 sounder should be recorded at frequent 

 intervals. 



(i) All pertinent information received 

 from shore stations shall be recorded with 

 proper reference to time, such as time com- 

 parisons, changes in equipment, orientation 

 of Shoran reflectors, etc. 



(j) Shoran and EPI zero check observa- 

 tions should be entered in this column. 



(k) Enter measurements or estimates of 

 heights of exposed rocks, and estimated 

 depths over submerged features which cannot 

 be sounded over. 



(1) Complete and comprehensive notes re- 

 garding the examination of shoals shall be 

 recorded, including the method of search 

 used, a statement as to whether or not the 

 bottom was visible, kind of bottom, presence 

 or absence of kelp or grass, least depths 

 found, and any additional information which 

 will assist the reviewer to determine whether 

 or not the examination is adequate. 



(m) Each marked feature in the presur- 

 vey review must be examined and the re- 

 sults noted as in (1). The item should be 

 identified by number or latitude and longi- 

 tude. The note shall include a statement as 

 to the amount of time spent in making the 

 investigation. A recommendation to delete 

 the feature from the chart must be supported 

 by the reasons therefore (see 1-5). 



5-98 Information at end of day's work. — 



At the end of the day's work certain entries 

 are required to complete the record. Most 

 of this information can be entered in the 

 spaces provided in rubber stamps. A bar 

 check or leadline comparison is required and 

 the data entered under rubber Stamp No. 35 

 (see 5-93). 



The time of arrival at the anchorage or 

 headquarters and the distance run shall be 

 entered in Stamp No. 34. 



A verification of the correct adjustment 



