MARINE ENGINEERING. Marine engineering is that branch of the science of engineering which has to do with all ship machinery. Originally a marine en gineer was the one who designed and in stalled the propulsive machinery of the ship, in contrast to the naval architect who designed the ship itself, but now the profession of marine engineering is understood to include the designing and installation of all ship machinery, propul sion engines, boilers, propellers, reduc tion, reduction gears for turbine drives, electrical systems, refrigerating system; pumps, winches, booms, freight handling devices of all types, and control sys tems.
desire to use power for the propul sion of vessels long preceded its success ful accomplishment. There are now in existence many early plans, but most of them remained on paper, largely because a suitable engine did not exist. Paddle wheels, attached to various parts of the boat, and even screw propellers, were suggested by the early inventors. A Frenchman, Papin of Blois, about 1707 constructed and navigated with indiffer ent success a boat propelled by steam, and about seventy years later a boat de signed by the Marquis de Jouffroy oper ated on the Saone for about a year and a half. The introduction of the double-act ing steam engine by Watt in 1782 fur nished the necessary power, which had heretofore been lacking, and caused sev eral experimental steamboats to be con structed. A stern-wheeled boat built by John Fitch, which in 1788 ran from Phil adelphia to Burlington at a sustained rate of speed of over six miles per hour, may be considered the first successful applica tion of steam power to navigation, and the "Clermont," a side-wheeled boat built under the direction of Robert Fulton in 1807, which plied between New York and Albany, was the first successful com mercial application of this venture.
The side-wheel type of ocean vessel be gan to give way to screw-propelled ves sels about 1850 because, in the case of merchant vessels, the screw allowed a greater variance in depth than did the paddle wheels.
In the struggle for decrease of weight in ratio to horse power, the compound and the triple and quadruple expansion engines were introduced. Modern prac tice has displayed a distinct leaning to ward the turbine engine for steamship propulsion. In many modern ships, oil is used for fuel in place of coal, because it is more easily handled and stowed than is coal.
Because a turbine will operate econom ically only at high speed, various meth ods, such as gearing and electric dynamo motor sets, are employed to secure the proper propeller speed.
When the United States entered the Great War and determined to put ship building upon a quantity production basis, standardization of marine machin ery was found to be the only possible so lution of this phase of the problem and so, as was the case in other war indus tries, the problem of the marine engineer during the period of the war was the in crease of production rather than the im provement of design.