A Treatise On The Principles And Practice Of Dock Engineering

CONSTRUCTIVE PLANT. 115 are generally either round with a pivoted handle, or square with a hinged bottom. Lewis bars and clips, for the lifting of masonry and concrete blocks, are of various designs. In the former case, the hold is obtained either by turning the bar through an angle or by wedging it. In the latter case, the tension in the chain causes a closing of the jaws, and the block cannot be released until the chain is slackened. A number of them are illustrated in figs. 71-76. Constructive Plant at Keyltam Dock Works. As an example of the variety and amount of plant required for dealing with dock work on a large scale, a statement of the plant used at Keyham Dockyard Extension Works is quoted from Mr. Whately Eliot’s paper on the subject : —* “ The works occupy ground to the extent of 113 acres, of which 35 acres are situated above high water mark, being chiefly land which has been reclaimed, in former years, from that part of the Tamar called the Hamoaze. The remainder of the area, 78 acres in extent, is the foreshore of mud from high water line to about low water of spring tides, the range of tide being 15J feet. The works compose a tidal basin of 10 acres and a closed basin of 35^ acres, divided by a space about 900 feet in width, in which there will be three large graving docks and an entrance lock. The whole of the river front of the site is enclosed, during construction, by a cofferdam, to exclude the tidal and river water. This cofferdam is more than a mile in length.” List or Plant. Ten vertical boilers, ....................... Six 40-H.P. winding engines, .... Six 20-H.P. „ „.... Two 40-H.P. fixed ,,.... Three 25-H.P. portable ,, .... Seven 20-H.P. „ ,,.... Four 18-H.P. ,, „.... Pour 15-inch cylinder locomotives, 6-wheeled, Four 12-inch ,, ,, 4 ,, Pour 10-inch ,, „ 4 ,, Two 9-inch ,, ,, 4 ,, Used for hauling waggons and mud scoops. Used for dynamos, pumps, sawmills, and other purposes, in the yard. Used in conveying materials from landing jetties and to various parts of works. Eight 10-ton steam cranes, Two 7-ton ,, „ Thirty-seven 5-ton steam cranes, r Used in landing goods at jetties, lift- ing materials from the trenches, lowering concrete and masonry into the trenches and setting masonry, and various other purposes. Pour of the 10-ton cranes are fitted to be worked as steam navvies. * Min. Proc. I. Mech. E., and Engineering, 28th July, 1899.