Page 57 preliminary 173 



in depths greaier than a thousand fathoms if the vessel is properly equipped (see 283), 

 but ordinarily they will not be needed unless depths considerably less than this are 

 found during the preliminary investigation. 



A complete and separate report of each investigation made shall be forwarded 

 to the Washington Office at the earliest opportunity. The report should give the 

 latitude and longitude of the least depth found and should include all of the sounding 

 and control data, and a discussion of the methods of control used. 



If a danger to navigation is discovered it must be reported immediately by radio 

 (see 8522). 



173. Erroneous Soundings on the Chart 



En route to and from the project area, or when navigating in the vicinity thereof, 

 every opportunity should be utilized to verify the charted soundings, especially in 

 areas in which the charted data are known to have been based on reconnaissance or 

 inadequate surveys. Where an erroneous sounding is discovered, or where the general 

 depths obtained differ materially from those charted, a full report of the facts shall 

 be made to the Washington Office. 



174. Aids to Navigation 



Survey vessels should verify all aids to navigation along their routes or in the areas 

 adjacent to their project, when practicable. The verification should consist of (a) a- 

 check of the charted position, (b) whether a lighted aid is burning, and (c) a comparison 

 of the actual characteristics with those charted and listed in the Light List. 



En route it will sometimes be practicable to verify only the lightships and offshore 

 buoys, but in the immediate vicinity of the project area the positions of all aids to 

 navigation, which have not been previously located by this Bureau, should be verified, 

 if practicable. 



When a lighted aid is found extinguished, immediate report should be made to the 

 Commander of the nearest United States Coast Guard District. When a floating aid 

 is discovered out of position, a report should be m.ade both to the Coast Guard Com- 

 mander and to the Washington Office. Where a fixed aid is found incorrectly charted 

 either as to position or characteristics, a report should be made to the Washington 

 Office, giving the correct position and the method by which it was determined. (See 

 also 383 and 853 L) 



175. Coast Pilot Data 



Advantage should be taken of all calls at ports and passages between ports to verify 

 the information contained in the latest edition of the Coast Pilot for the area. If the 

 information is correct but should be supplemented, the necessary data should be 

 obtained (see 912 and 916) and reported to the Washington Office at the earliest 

 opportunity. 



176. Field Examinations 



When surveys of a minor nature are made outside of the project area, for which no 

 specific instructions are written, they are considered Jield examinations. These are 

 intended for revision only and are not registered in the archives as original survey 

 sheets, but should be as adequately controlled as surveys called for by specific instruc- 

 tions. A field examination may consist of such items as (a) a resurvey by planetable of 

 a point extended by accretion, (6) a planetable survey to locate a new pier or determine 



465382—44 6 



