815 HYDROGRAPHIC MANUAL PaGE 766 



has not been made in other columns. Abbreviations (8111) can be used for many- 

 routine entries. 



Among the entries which recur frequently are the following: 



(a) The latitude and longitude shall be entered at the first position of each day's work, at the 

 beginning of a system of contiguous lines, at each detached sounding in a new locality, and at the 

 beginning of a line in a locality different from the last previous recorded position. Use rubber Stamp 

 No; 39, Line Begins (fig. 180). 



(b) The words "line begins" and "line ends," or their abbreviations, are to be used at the begin- 

 ning and end of adjacent lines, in accordance with 3454, where soundings around the turns are not 

 recorded or are not intended to be used on the smooth sheet. The words "line turns" should be entered 



in the "Remarks" column only when a turn is 

 made in a continuous line of soundings. 



(c) The abbreviation "L. T. L." or "L. T. R." 

 shall be entered after the entrv "line ends" to in- 



No. 39 LINE BEGINS 



FIGURE 180.-Facsimile of Line Begins stamp. dicate the direction the vessel turns to proceed to 



an adjacent line. 



(d) Changes affecting any of the information given at the beginning of the day's work (see 813). 



(e) Notation of a change in locality of work or a change of sheet, including the ship's run (in 

 nautical miles). 



(/) Distance (in meters) and direction of features in the water area, such as aids to navigation, 

 rocks, breakers, and shoals, where passed close by. Indicate if the distance is estimated (do not scale 

 distances from sheet for this purpose). If depression angles are recorded, record the height of eye also. 

 (See 3353.) Indicate whether the object has been previously located or whether the data entered 

 are to be used to locate it. (See also 363.) 



(g) Estimated distances (in meters) to the high-water line, to the low-water line, to reef lines, 

 to kelp, etc., from the nearest recorded position (see 3122 and 754). Explanatory' notes in regard to 

 any areas not completely surveyed. 



(h) Complete notes relative to methods used in revising the high-water line or topography and 

 any data which do not properly belong in other columns. (See 3244, 381, and 753.) 



(i) Notation of all changes in speed (3461). Note any sounding lines started from a stand- 

 still (3451). 



ij) Measurements or estimates of heights of exposed rocks, if not previously well determined 

 (3244 and 363), and estimated depths over rocks, shoals, and areas, which cannot be sounded over 

 (364). Such elevations and depths shall be referred to the water level, and the time of observation 

 shall be entered in the "Time" column; they should never refer to a plane of reference. 



(k) The time spent in examining a shoal by drift soundings, or otherwise, where systematic lines 

 are not run (3312(e) and 3666). 



(/) Complete and comprehensive notes regarding the examination of shoals shall be given, 

 including the method of search used; a statement as to whether or not bottom was visible; apparent 

 size of the top and base of shoal; kind of bottom; presence or absence of kelp or grass; least depth 

 found; and such additional information to enable the reviewer to determine whether or not the exami- 

 nation was adequate. (See 3312(e) and 3666.) 



(m) The reason for the correction or rejection of any recorded data. Any entry which appears 

 unlikely by reference to other recorded data shall be verified immediately, the entry checkmarked (V) 

 and notation made in the "Remarks" column that it was verified immediately after having been 

 recorded. 



(n) Notation of any visual echo-sounding instrument which is not operated or attended 

 continuously (3415). 



(o) Mention of any current encountered, 

 (p) The reason for missed soundings (3542). 



iq) A record of any marine growth encountered, its length, thickness, and whether it is visible 

 on the surface of the water. Note the value as an indication of danger of any kelp encountered (7864). 

 (r) Wrecks, wreckage, and obstructions should be described (365). 

 (s) Explanation of any time not spent in sounding. 

 (t) Notation of a change from one method of sounding to another. 



