Hydrographical surveying : a description of means and methods employed in constructing marine charts (1920)
Wharton, W. J. L. (William James Lloyd), 1843-1905, Field, Arthur Mostyn, 1855- · London : J. Murray · leaf 457
refore, noticeable, except on a very large scale ofplotting. The roller (see Fig. 92), with both towing lines attached, ishoisted out with a burton, on a slip toggle; the shij) is startedat slowest speed, and the roller is lowered from one lower boomby its bridle, the opposite bridle being eased… … Fig. 92. and the counterpoise must be put over as soon as possible,in order to keep the wire taut all the time. When the roller is towing in place, a leadsman is stationedto read the depths shown on the depth-wire; and is ordered tohail them at even numbers of seconds apart, as desired—aboutevery…
Hydrographic surveying · Nautical charts
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