CHAP. VI.] RUNNING SURVEY 175 



A running survey must be roughly plotted, and everything 

 sketched in, as we go on, putting down position after position 

 by course and distance, and cutting in the objects we choose 

 for marks, giving them names by which to recognise them, 

 and to record in the sounding book. Assistants should be 

 told off for separate duties — one to look after the sounding ; 

 another to sketch in the coast-line and hills between each 

 object chosen, on another sheet or sheets of paper ; the chief 

 and some assistants getting the angles ; one writing down ; 

 another plotting the stations and drawing the lines to the 

 points, so as to see what angles are A\anted at the next station 

 to objects already chosen, and how far on the next station 

 should be. Bearings should be taken of all prominent points 

 in transit, and patent log noted. 



At each position, as laid down by course and distance, com- 

 mence plotting by laying down the bearing of the object we 

 have selected for zero for the round of angles. From this the 

 other angles can then be laid down. 



It follows that a bearing must be obtained, as a necessity, 

 from each position. This should be taken to the zero 

 selected. 



At each fix the most important angles and those that 

 change most rapidly should be the first to be observed. If a 

 distant object is connected by angles with other objects at the 

 moment of the fix, it is recommended to take the bearing of 

 the former, because its bearing will change more slowly than 

 that of the others, and thus allows more time to decide on the 

 exact bearing than can be the case when an object is changing 

 its bearing more rapidly due to the sliip's movement. 



Distant hills are a great help in a running survey, as, when mils of 

 replotting from the astronomical positions, if these hills can ^^®** 

 be fixed by bearings (true or compass) from them, the angles 

 taken to the hills, at a position now and then, may possibly 

 be used as fixes, which may be plotted by station pointer, 

 and so get intermediate positions independent of the patent 

 log positions, which are so liable to error by the action of 

 currents. 



A running survey will nearly always have to be replotted, 

 as the astronomical positions and those by patent log will 

 never agree. 



