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— Oil Separators Are Economical Practical Devices Perfected for Separating Oil from Bilge and Ballast Water — Oil Content Can Be Removed with Saving to Shipowner BY H. S. HELE-SHAW, L. L. D., D. Sc., F. R. S. and ALBERT BEALE, Wh. Sch. IL ON: troubled waters has a O beneficent action which has long been proverbial. That a rela- tively small amount of oil can calm a large area of sea is due to its great capacity for spreading, for a film of oil will extend unbroken to a re- markable degree of tenuity. This property has also in recent years been beneficially employed in reducing the scourge of malaria by sealing the breeding places, in pools and swamps, of the mosquitoes which carry the in-- fection. The same property, however, has still more recently forced itself upon the attention of mankind, in an aspect the reverse of beneficial. the seas by oil has become one of the most distressing features of our civil- ization, and it is to the elimination of this that we desire to direct attention. Oil pollution is due mainly to the discharge of oily ballast water by some four thousand oil-burning vessels, and to a less extent to the discharge of oily bilge water from ships of all A paper read at the summer meetings of the sixty-seventh session of the Institution of Na- val Architects, held in Belgium, June 25, 1926. MIXTURE INLET OIL WITHDRAWAL AND INSPECTION cOocKS Fig, 1—I. 8. McDoveatu’s Patent oF 1892, SV hig i INLET Pollution of WATER OUTLET types. The evil has become so great as to necessitate the earnest attention not merely of local authorities but of the governments of maritime nations. During the Great War oil-burning tonnage increased enormously, while at the same time attention to the pres- ervation of amenities was relaxed, with the result that wholesale pollu- tion of the seas passed almost unre- garded until the postwar period gave opportunity for the consideration of this matter along with other legacies of the war. Features of Oil Pollution It may be urged in extenuation of the shipowners, who in seven years of peace have still failed to eliminate oil pollution, that in the course of normal development, unprejudiced by war, the evil would probably never have arisen, as the prevention of the loss of valu- able oil would have been provided for in the natural course of sound design. Now that the trouble exists, it is unfortunate that shipowners. are sev- erely handicapped by trade depression, so that no addition to the equipment of a ship, however great the economy WATER OUTLET shown thereby, is undertaken very readily. The sea receives and cleanses so much that is unclean that it is at first unthinkable that relatively small quantities of oil can be seriously harm- ful. There are three reasons however, why oil is exceptional: first, it floats; © second, it spreads; and third, it per- sists. By its remarkable capacity for spreading (one pint of oil will form an iridescent film over an acre in extent) a relatively small quantity of oil forms an extensive film on the surface, making it unsafe for sea birds, whose wings it clogs, and pre-. venting that aeration of the water which is essential to life below the sur- face. Humanitarian considerations alone provide sufficient reason why the mil- lions of gulls and other birds around our shores should be saved from a painful and lingering death, but, in addition, the fact that gulls perform a most useful service in indicating to fishermen the presence of shoals of fish provides a further and conclusive argument for their protection. MIXTURE INLE Fic, 3—W. E, Laxe’s Patent or 1904, OIL DISCHARGE WATER OUTLET, Fie. 2.—J. Nicuavsse’s Patent oF 1903, MIXTURE INLET Fic. 4—Tue “ WATER OUTLET, ” Pirpricgur” Separator, F. Pink’s PATENT oF 1923.