HYDROGRAPHY 



53 



SOUNDINGS CHAKTED IN FEET 



Ordinarily fractions of feet are not charted but, where necessary to obtain a proper dis- 

 tribution of soundings and to show the depth curves in their proper position, a Yi-ioot fraction 

 may be used on the deeper side of the curve. One-half foot fractions may also be used to 

 keep depth curves open and to define more clearly the natural channels. 



The following table is to be used when converting tenths of feet on a survey to whole or 

 haK feet: 



Kfeet 



Survey 

 0.1 

 0.2 

 0.3' 

 0.4 

 0.5 

 0.6 

 0.7 

 0.8 

 0.9 



Whole feet 



0.0 ft. 



Kft. 



1ft. 



SOUNDINGS CHARTED IN FATHOMS (Fathoms and Feet to Eleven Fathoms) 



On all new and reconstructed charts using fathoms as depth unit, soundings shall be 

 charted in fathoms and feet for depths less than 11 fathoms, thus: 82. 



On charts constructed prior to 1948, soundings were expressed in fathoms and quarters to 

 7 fathoms, then in fathoms and halves to 8 fathoms. Fractions were not used for depths 

 greater than 8 fathoms except adjacent to the 10-fathom curves, where, in flat bottom, 10}^- 

 fathom soundings were used to avoid displacement of the curve. When extensive hydrographic 

 revisions are made to these charts, consideration should be given to changing the sounding 

 units to fathoms and feet in depths less than 11 fathoms as outUned above. Often it is more 

 practical to retain the fathoms and quarters units, carrying quarters to 11 fathoms in the 

 revised area. 



When soundings in whole feet or fathoms and feet on an original survey by this Bureau or 

 in feet and tenths on a Corps of Engineers survey, are to be charted in fathoms and fractions 

 of fathoms, the feet remaining after converting into whole fathoms (6 feet equals one fathom) 

 shall be converted to fractions of fathoms in accordance with the following tables: 



Feet and tenths 

 0.0 to 0.9 



1.0 to 2.4 

 2.5 to 4.0 



4.1 to 5.1 

 5.5 to 5.9 



Feet and tenths 

 0.0 to 1.9 

 2.0 to 4.9 

 5.0 to 5.9 



Feet and tenths 

 0.0 to 4.9 

 5.0 to 5.9 



% fathoms 

 

 % 

 % 

 % 

 1 



Yi fathoms 

 



V2 

 1 



Integral fathoms 

 

 1 



