This section is from "Scientific American Supplement Volumes 275, 286, 288, 299, 303, 312, 315, 324, 344 and 358". Also available from Amazon: Scientific American Reference Book.
We illustrate below a useful type of dredger made by Messrs. Rennie, of Blackfriars, England. The drawing almost explains itself. The machine consists of a double barge or pontoon, in which is erected a derrick. This derrick works a "spoon" dredge at the end of a lever. The spoon, as shown, is at its lowest position. It will make a forward stroke, through about one-sixth of a revolution, and will thus become filled with mud and be lifted above the surface of the water. The motion will be imparted to it by the chain and pulleys seen at outer end of the derrick jib. The jib will then be swung round over the bank on a hopper barge and its contents delivered. The requisite power is supplied by the steam engine at the end of the pontoon. Messrs. Rennie have made several of these little dredgers, which are found very useful and handy in shallow water.--The Engineer.
SINGLE BUCKET DIPPER DREDGER.
We illustrate below a dredger of simple construction, well calculated for doing useful work on shallow streams. The barge is 54 ft. long, 22 ft. beam, and 6 ft. deep. Her draught of water is under 4 ft. Built by Rose, Downs & Thompson Hull. Our drawing explains itself. It will be seen that we have here a swiveling crane and grab bucket, and that the stuff dredged can be loaded into the barge and conveyed where necessary. The lifting power of the crane is one ton, and in suitable material such a dredger can get through a great deal of work in a comparatively short time.--Engineer.
IMPROVED ONE-TON BUCKET DREDGER.