A Treatise On The Principles And Practice Of Harbour Engineering

HARBOUR DESIGN 15 and other obstructions. These précautions, however, appertain to the province of military engineering. Commercial Harbours.—Passing on to special aspects of Commercial Harbours, we may describe them as a class forming most important appanages to ports. They are, in fact, the great termini of the highways of the sea. Their province is the accommodation of the mercantile marine during the operations of loading and discharging cargoes, and for the transaction of trade. Thus, in addition to the obviously fundamental needs of accessibility and accommodation already discussed, we meet with the more special requirements of Quays and Sheds, and also of Inner Basins and Repairing Docks. Fig. 8. —New York Harbour. Commercial harbours are to be found in a variety of situations: upon the seacoast, at the mouths of rivers, inside sheltered estuaries, and even some considerable distance inland along the banks of rivers and canals. They require more shelter than that which suffices for simple purposes of refuge. It is indispensable to the conditions of modern trade that there should be the least possible delay in the reception and despatch of vessels ; hence everything must be done to ensure continuity of operations, and for this purpose protected quays are a first considération. Coastal Harbours présent most difficulty in regard to this point. The mere protection afforded by a breakwater is not sufficient to impart that tranquillity which is essential to the loading and unloading of ships. There are, of course, cases like that of Zeebrugge (fig. 2) where a single mole built