FUEL OIL IN STEAM NAVIGATION Dr. George Otis Smith, Director of the U. S. Geological Sur vey, in an address before the American Iron and Steel Institute, May, 1920, states that the requirements of the American Navy and the'new Merchant Marine present a priority demand on fuel oil. Dr. Smith said: "Admiral Griffin, the chief of the Bureau of Steam Engineering of the United States Navy, informs me that the oil-burning vessels ready for service aggregate more than 6,000,000 horsepower and that other vessels under construc tion will bring this total up to nearly 9,000,000 horsepower. The navy now needs 8 million barrels of fuel oil a year, yet this figure is small compared with the requirements of the Shipping Board, which are stated by Mr. Paul Foley, its Director of Operations, as 40 million barrels for 1920 and 60 million for 1921. If the American flag is to fly on the seven seas the motive power to carry it must be assured, and here is one demand for fuel oil which alone equals the present output of our refineries for about four months. Surely no American with vision wishes to con template even the possibility of a shortage of fuel oil that would endanger the immediate availability of these battleships, cruisers, and destroyers or interfere with the successful operation of the passenger and freight steamers in the construction of which our Nation has invested so many million." All of the advantages inherent in oil burning on shore are applicable to its use in steam navigation. On an equivalent bunker weight the higher calorific value of fuel oil as compared to coal increases the ship radius of action by 50 percent. A ton of coal occupies 43 cubic feet, while a ton of oil occupies 36 cubic feet, and, consequently, with equivalent bunker space the ship's radius of action is increased 80 percent and this advantage can be greatly increased by carrying fuel oil in double bottom tanks. Ship Building and Shipping Record states that during the war it was found possible to utilize the double bottom for storing oil without any great alterations. But there are stringent rules laid down by the registration societies and the Board of Trade which must be conformed with. The flash point of oil fuel is not to be less than 150° F., according to the former, while the latter require a minimum of 175° F. in the case of passenger vessels. Any double-bottom, peak, or deep ballast tank which is able to pass the ordinary watertightness tests can be used. Owing,. however, to the spacing of rivets, they will probably not be oiltight, but if steps are taken to deal with any leakage which may occur, they can be accepted. To limit the wash from side to side the center
line division must be reasonably oiltight, but it is sufficient merely to close the drainage holes by bolted plates. Lloyds re quire that the tanks should stand a head of water to the top of the filling pipes, the load waterline, or 12 ft., whichever the greatest. Special attention is required for all the piping and pumping ar rangements, with the intention of preventing oil from finding an entrance into the machinery space, and draining the compart ments as completely as possible. Coal bunkers will usually be found unsuitable in construction ; it is, however, suggested that electric welding might be used with advantage. Both the B. 0. T. and Lloyds require that special precautions be taken for dealing with leakage; the double bottom must be sheathing, with ceiling standing on grounds at least 2 in. above the tank top, and bulk heads must be closely sparred to prevent cargo from touching the plating and to allow leakage to drain freely to the gutters and wells. Oil must not be stored in a compartment adjacent to crew or passengers, and cofferdams must be fitted between oil and fresh-water tanks. Thus, although the details require careful treatment, the difficulties of conversion of existing ships are not great. From experience gained during the war, it is found that on no occasion has the cargo been deleteriously affected if the details have been thus considered." The ability to force boilers with oil-fired furnaces to 50 per cent above normal rating without a great strain on the personnel is a decided advantage, and the quickness with which an oil burning ship can get under way is a very important point in its favor for naval use. The U. S. Shipping Board, in announcing that 636 of the 720 vessels now under construction for the Emergency Fleet Corporation will burn oil fuel, justify their abandonment of coal as follows : 1. Less bunker space required, a barrel of oil being equal to one ton of coal, and occupying four-sevenths of the space. 2. Oil can be carried in spaces, e. g., the double bottom, not avail able for cargo. 3. Cargo can be carried where coal is now. 4. Greater despatch in bunkering, of special advantage in view of the shortage of ships. 5. No labor or machinery required to handle ashes. 6. No stoking, reducing the number of crew and labor costs. 7. Uniform pressure is easily maintained, insuring a steady speed, and reducing boiler depreciation due to uneven temperature.