3833 HYDROGRAPHIC MANUAL PaGE 300 



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located by three-point fixes at the aids, wherever practicable; cuts are not satisfactory, 

 but where they have to be used all cuts to one aid should be taken in a short interval 

 of time so there will be less likelihood of a change in the direction of the current affect- 

 ing the position of the aid. Offshore aids to navigation beyond the visibility of shore 

 signals should be accurately located by R.A.R. if that method of control is being used 

 in the hydrographic survey. (See also 7842.) 



Wliere a marker buoy is maintained near an aid to navigation the positions of 

 both shall be determined. 



If a floating aid to navigation is found to be off station, the fact should be promptly 

 reported to the Commander of the nearest United States Coast Guard District. If 

 its station is found to be unfavorably located for the purpose for which it was intended, 

 its position and the facts should be reported to the Coast Guard and to the Washington 

 Office. The station of a floating aid is its position on the largest-scale chart of the 

 area. Any recommendations, based on the new hydrographic survey, for additional 

 aids to navigation or for more desirable stations for existing aids, should be reported 

 in writing to both offices as soon as practicable, with a photostat or tracing of the 

 boat sheet. 



Reference shall be made in the Descriptive Report to any reports which have 

 been made to the Coast Guard relative to floating aids to navigation. 



Refer to 1551 for objects which are to be located for the use of the Coast Guard. 



3833. Azimuths of Ranges 



The azimuths of all light and beacon ranges maintained by the United States 

 Coast Guard for use in navigation in the project area must be accurately determined. 

 Any that are not determined by triangulation must be determined by the topographer 

 or the hydrographer. 



The topographer shall determine azimuths of ranges by actually setting up the 

 planetable at an accurate location on each range at a considerable distance from the 

 front range, the resulting azimuth line being drawn on the sheet as a long line from 

 which the azimuth can be accurately scaled. 



Where the azimuth is determined by the hydrographic party the survey vessel shall 

 be placed on the range at a comparatively long distance from the front range where a 

 strong three-point fix and check angle can be observed. Where a check angle is im- 

 practicable, two three-point fixes at different locations on the range shall be observed. 

 The azimuth of a range established for use in crossing a bar shall be determined from a 

 position on or outside the bar. The sextant fixes must be recorded in the Sounding 

 Records and indexed. From the accurately plotted positions the azimuths of the 

 ranges are to be scaled by protractor and noted along the range Imes on the smooth 

 sheet. (See also 356.) 



3834. Nonfederal Aids to Navigation 



Aids to navigation which are established privately or by State or local governments 

 and for which the Federal Government is not responsible, shall be located by the hydro- 

 graphic party and their positions shall be shown on the smooth sheet, but the status 

 of these aids shall be made clear on the sheet and in the Descriptive Report. The 

 Descriptive Report should state the purpose of the unofficial aids to navigation and 

 the date of their establishment, the agency or person who established them, and whether 

 or not they are maintained, if these facts can be ascertained. 



