Page 21 preliminary 1341 



Careful study and planning will result in a logical sequence of operations so that 

 each phase of the work accomplished will give as much information as practicable on 

 whicli to base the subsequent phases of the work. A project so planned will be com- 

 pleted without waste of time or effort and without any of the essential work having 

 been omitted or neglected. 



1341. Priority of Operations 



The project instructions may call for priority in certain phases of the operations 

 and these must be planned for completion at as early a date as practicable. 



The nature of combined operations is such that the effective accomplishment of 

 certain phases of the work will depend on the prior accomplishment of others. If no 

 triangulation exists in the area, it will probably be necessary to plan and execute a 

 complete new scheme to control the other operations. It is necessary that the work 

 be planned so that the triangulation will always be in advance of other operations. 

 If the size of the project is such that the work will continue for several years, efficient 

 planning will provide for the accomplishment of triangulation sufficiently in advance 

 so that control will be available at the start of each season for the first topographic and 

 hydrographic surveys. 



The topographic surveys, which serve to locate the control stations for the hydro- 

 graphic surveys, should always be planned so that the hydrographic parties will not 

 be delayed waiting for control to be established. 



Where unknown dangers to navigation are likely to exist in the area, the harbors 

 and anchorages should be surveyed in advance of the time they may be needed by the 

 survey vessel. The inshore surveys should be carried to a depth in which it is safe for 

 the larger vessel to operate. 



1342. Parallel Progress of Operations 



Except for the priority described in 1341, it is desirable that all classes of work 

 be completed to the same general limit at the end of each season. It is inefficient to 

 have topographic surveys completed at the end of a season too far in advance of the 

 hydrographic operations, because signals are likely to be destroyed before the next 

 season. Even where signals have not been built but the stations merely marked, it 

 would be necessary to go over the same ground the next season in order to build them, 



1343. Incomplete Sheets 



The work should be planned, if practicable, so that any topographic or hydrographic 

 sheet begun will be completed during that season, barring unforeseen circumstances. 

 The results of the field operations are not available for charting until the surveys have 

 been verified and reviewed in the Washington Office and it is usually not practicable 

 to do this for a sheet partly completed. 



All necessary development and investigation of shoals should be kept up to date 

 as they are revealed through the regular system of sounding lines. During the early 

 part of a season, it is essential to do this for reasons of economy in operations, otherwise 

 the party is likely to find such work not conveniently located to be undertaken economi- 

 cally in connection with the other operations. During the latter part of the season, 

 this procedure is quite important in order to avoid closing the season with incomplete 

 surveys. 



