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 433
and F G, lips of the dredge, 2| feet long. H, holes to wliich bag is laced. 11, perforations in the canvas bag. K K, swab bar. Ti, bar of dredge mouth, 6 inches. 2G—2 404 HYDROGRAPHICAL SURVF.YING [chap, xviii. The hawser is weighted with about 60 pounds, at 5 fathomsfrom the dredge. On a sandy… … The Dredge. aAAay, if caught ; or even one large swab at the end of a rope,weighted 2 feet above it to keep it down. These are especiallyuseful on coral banks, where a regular dredge may very likelybe lost. To dredge, turn the ship away from the wind or current, anddrop the dredge from aft A\ith…
Hydrographic surveying · Nautical charts
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