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HYDROGRAPHIC MANUAL 



Page 716 



A. SMOOTH-SHEET SOUNDINGS 



Where the depth unit on a hydrographic smooth sheet is feet, all soundings are in 

 ntegral feet (and occasionally half feet) . Where the depth unit is fathoms, all soundings 

 are in integral fathoms or fathoms and decimals. To accomplish this a conversion 

 from the unit of the depths in the Sovniding Records is frequently necessary. This 

 shall be done in accordance with the following rules which are also illustrated in figure 

 162: 



(1) Where the same depth unit is used on the smooth sheet as in the Sounding Record, but in 

 integers on the sheet, any partial units shall be converted into whole units by changing 0.75 or more 

 into the next greater integral unit, and changing decimals below 0.75 into the next lesser integral 

 unit (e. g., 2.75 to 3.75 feet = 3 feet; 12.75 to 13.75 fathoms=13 fathoms). 



(2) Where as in (1) the depth unit is the same but the soundings are to be plotted in fathoms and 

 tenths, partial units shall be converted by changing 0.075 or more into the next greater decimal unit, 

 and less than 0.075 into the next lesser unit (e. g., 2.575 to 2.675=2.6 fathoms). 



(3) Where as in (1) the depth unit is the same but the soundings are to be plotted in half units, 

 then 0.25 to 0.75 shall become K, and 0.75 to 1.25 shall become 1 (e. g., 3.25 to 3.75 feet=3Kfeet; 

 3.75 to 4.25 feet = 4 feet). 



(4) Where the reduced soundings in the Sounding Record are in a different unit from that to be 

 used on the smooth sheet, they shall first be converted to their equivalent values in the smooth-sheet 

 unit and then apply rule (1) or (2), as the case may require to obtain the values for plotting. 



Table 26 illustrates the application of these rules: 



B. CHARTED SOUNDINGS 



llie soundings on the published nautical charts are either in (a) integral feet, (6) 

 integral fathoms, (c) fathoms and half fathoms, or (d) fathoms and quarter fa thorns; — 

 but, these charted soundings are from smooth sheets on which the soundings may appear 

 in (a) integral feet, (6) feet and half feet, (c) integral fathoms, or (d) fathoms and tenths 

 of fathoms. 



