A Treatise On The Principles And Practice Of Harbour Engineering

HARBOUR DESIGN. 35 a difficult and uncertain operation ; (2) that the covering arm will be costly on account of the strength required to resist a broadside attack; (3) that the arm will favour the travel of littoral drift, and lead to shoaling in the neigh- bourhood of the new entrance ; and (4) that the latter will be navigable with difficulty in a heavy sea. None of these objections, however, can be held to possess sufficient force to overrule the conclusion carefully arrived at, that the existing arrangement is unsatisfactory and no longer maintainable. They possess no insuperable drawback in themselves, and the scheme is undoubtedly the best modification which can be devised in the light of local expérience. For much of his information respecting the Port and its history, the author is indebted to the courtesy of Mr F. J. E. Spring, C.I.E., the chair- man and engineer of the Harbour Commissioners. The following interesting observations are direct from the pen of that gentleman :— “ Madras Harbour makes no pretence of offering, nor, owing to its situa- tion, can ever pretend to offer, shelter to shipping in very severe weather. For, though the artificial breakwaters are finished at a height of 12 or 14 feet above sea level, they cannot, at that height, shelter the sides of modern steamers from winds, the force of which may avail to break the mooring chains. There are in the harbour nine berths for large steamers, with permanent bow and stern buoys, the bow buoy chain being 3| inches diameter and the stern buoy chain 2^ inches diameter. But in heavy winds the vessel’s own stern lines sometimes break; accordingly, the moorings are so arranged that each vessel may swing round clear of every other vessel and of the breakwaters. “The breakwaters, however, very greatly mitigate the roughness of the water within the harbour, and so enable the barges and lighters locally in use —of from 2 to 10 tons burden only—to carry cargo in all weathers between ship and shore. The water is not, however, always smooth enough—that is, from twenty to thirty days in the year it may not be smooth enough—to allow ships to lie alongside jetties. “It is in view of obtaining smooth enough water within the harbour for ships to lie alongside permanent jetties that the scheme of harbour improve- ment, now in hand and to cost some £375,000, has been initiated. The scheme in question is expected to be completed by the year 1911, and it will then be time enough to consider whether the volume of trade is likely to be such as to warrant the expenditure of perhaps £200,000 more involved in the erection of permanent jetties for ships’ use. Madras is not, and probably never will be, a terminal port, where ships can discharge and take in full cargoes. By far the greater number of vessels touching there either have only a few hundred tons to put out and take in, or discharge full cargoes and go elsewhere for return cargoes; or, again, corne from other ports for whole or part cargoes. Few vessels, therefore, seem likely to need the convenience of quays erected at an expense which must put a permanent burden on the trade of the port and a fairly heavy tax on the tonnage of goods using such