CHAPTER VIII 



SOUNDING 

 Boat Sounding — Ship Sounding — Searching for Vigias. 



Import- It is difficult to say that any one step in the construction of a 



Sounding, chart is more important than another, as each is necessary 



for the completion of the whole, and an error anywhere may 



cause a disaster ; but if any particular item is to be picked 



out, perhaps the sounding should rank in the highest place. 



The operation of sounding is the least pleasant part of a 

 marine surveyor's work, especially when the weather is against 

 liim, and the sounding uninteresting — that is, where the 

 depths are regular, and there is no excitement in the way 

 of discovering and working out shoals and reefs ; but the 

 notion that it is therefore ah^ays to be relegated to the juniors 

 of a survey is not only hard upon them, but may introduce 

 errors into the very part of the chart which, as Ave have already 

 said, is the most directly important. 



As soon as the points are down — i.e., plotted — the sounding 

 can be commenced ; but, as before remarked, on an intricate 

 piece of coast it is better if the coast-line is put in first. 

 Ordinary The ordinary main plan of sounding is thus. The boat 

 Sounding, proceeds in straight lines in a direction, of a length, and at 

 distances previously decided on, with a man in the bow con- 

 stantly sounding. Every so many soundings, as the case may 

 be, the officer takes angles \vdth a sextant to fix the position 

 of the boat, always doing this at the beginning and ending of 

 every line. 



It is evident that this main plan may be largely varied in its 

 details. 



In the first place rises the question as to whether it is better 

 to plot fixes, and enter soundings on the sheet, regularly, in 



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