Tesla and the Electric Propulsion of Ships

In a recent number of the "Century Magazine" an article by Mr. Nikola Tesla was printed, in which some statements were made that drew caustic comment from our contemporary, "Marine Engineering." In the July number of the latter magazine the editor refers to the article as the "handiwork of a cerebrose individual - a bombastical genius who has illumined unknown fields of imaginative science with his intellectual searchlight and is willing to permit the gaping world of ignorance or complaisance to peep in and wonder, the credulous editor drawing the curtain. This dazzling contribution to modern unscientific research," he continues, "reads like nothing so much as an essay on Christian Science, so profound is it in the ambiguous nothingness whereby it leads through the intricacies of incoherency into the climax of absolute asininity." The particular statements made by Mr. Tesla which most aroused the editor of "Marine Engineering" were:

"Steamers and trains are still being propelled by direct application of steam power to shafts and axles. A much greater percentage of the heat energy of the fuel I could be transformed in motive energy by using in place of the adopted marine engines and locomotives, dynamos driven by specially-designed high-pressure steam engines or gas engines, and by utilizing the electricity generated for the propulsion. A gain of from 50 to 100 per cent in the effective energy derived from the coal could be secured in this manner. In ocean steamers such an improvement would be particularly desirable as it would do away with noise and increase materially the speed and carrying capacity of the liners."

In the same issue of "Marine Engineering" also appears an article by Prof. W. F. Durand commenting upon Mr. Tesla's reckless statement. Mr. Durand argues, and of course soundly, that any especially efficient prime mover which can be used to drive an electric generator can also be used to drive a propeller direct so that interposing a generator and motor between the prime mover and the propeller shaft would be a gratuitous waste of energy. Mr. Durand further points out that the addition of an electrical equipment in the case of a liner having 25,000 horse-power of driving machinery would result in a loss of about one-third of the freight-carrying capacity of the ship, besides the loss of about 2500 horse-power due to the two transformations of energy, entailing a reduction in speed from half to three-quarters of a knot. "The increase of carrying capacity referred to at the close of the quotation," says Mr. Durand, "would be, therefore, of a character not likely to commend itself to the stockholders or board of directors."