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 459
hich carries the depth-line block, the continuous and even rattling of the tripper pass-ing successively over the battens on each section of the rollercan easily be distinguished—the sound ceasing directly thespeed of the ship is increased sufficiently for the roller to towclear of the bottom, and… … CHAP. XX.] ROLLER SOUNDING 431 the roller to wing-handle. They require to be carefullymeasured, and to have marks tucked into them, to showwhen the roller is towing at the required position, according tothe calculations derived from the ships measurements. It is advisable to have two marks in each…
Hydrographic surveying · Nautical charts
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