A Treatise On The Principles And Practice Of Dock Engineering

RECENT PROGRESS. 5 fhips ate fo raked by the ice, that il is often a confiderable addition in the charge of refitting, if no other more material damage happens to them thereby. Wkereas the fhips kere depofited, lye always water borne, without the leaft rubbing of the ice, or any further care or charge for their prefervation, as fully appeared by the laß great froft in 1715. Skips are likewife kere more effectually fecur'd from tke peril of fire ; tkere being proper cook rooms provided on fkore, and no fire fuffered to be on board. But if neitker ftorms, nor ice, nor fire, be confidered, fhips are kere depofited at a mach lefs charge and a much greater fecurity than in the river; which any one may eafily evince, if he will calculate the wearing their cables or the charge of the chain, the frequent fhifting of the moorings, and other neceffary incidents, which do and will happen in the river, and compare them with the moderate rates wet-docking is by this work reduced to. Defcription of the Dock.—The outward gates of the wet-dock, leading to the Thames, 21foot high, and 44 foot wide, open’d to let in the fkip. Tke bafon, or gut, leading to tke great wet-dock, 44 foot wide, 150 foot long. Tke inward gates, of tke fame keigkt and breadtk with the outward, but ftronger, by reafon they bear the great weight of water in the dock, which fometimes fiows within a foot of the top of thefe gates, and is kept pent up within 4 foot thereof. The great wet-dock, wherein at good fpring tides there is feventeen foot of water, over the cell againft which the bottom of the gates fhut ; fo that it would commodioufly receive his Majefty's third-rate fhips. The dimenfions of the dock are from eaft to weft 1,070 feet; from nortk tofouth, at the weft end, 450 feet, and from north to fouth, at tke eaft end, 500 feet; fo that it would contain upwards of 120 fail of tke largeft merckant fkips, witkout tke trouble of fhifting, mooring, or unmooring any in the dock, for taking in or out any other. This dock when full at a fpring tide, contains, by a moderate computa- tion of 40 foot folid to the ton, 228,712 tons of water, being much larger than the farnous bafon of Dunkirk, or any pent water in the world. The maft crain, for taking out and fetting in mafts in fhips in the wet- dock, which anfwers the end of an hulk, with proper pils and crab for careening three or four fhips at once. Recent Progress.—To whichever of the two rival ports the honour be u located (and this is a matter of no great moment), at any rate it is apparent that the first English dock dates back no further than the commencement of thi 18th century. But what perhaps is more remarkable still, is that duiing the next hundred years, despite the enormous increase in oversea tude and the great development of lines of inland navigation, no works of note were undertaken for the extension or improvement of dock accommodation.