Putnam, G. R. (George Rockwell), b. 1865 · New York, J. Wiley & Sons; [etc.] · leaf 64
FIG. 15. THE SIGSBEE SOUNDING MACHINE ON A SURVEYING VESSEL. (45) … Hydrography 49 angles on survey signals or by angles from the shore.The ordinary method of sounding is to cast a lead froma boat and read the depth when the lead touches bottomand the line is vertical, and make note of the nature ofthe bottom. There is a systematic spacing between thecasts of the…
Nautical charts
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