Assisted by the Committee on Publications of the Franklin Institute. PUBLISHED BY THE FRANKLIN INSTITUTE, AT THEIR HALL. 1857. JOURNAL OF THE FRANKLIN INSTITUTE OF THE STATE OF PENNSYLVANIA FOR THE PROMOTION OF THE MECHANIC ARTS. JULY, 1857. CIVIL ENGINEERING. The Relative Efficiency of the Screw and Paddle Wheel when applied to Vessels of Identical Form, Tonnage, and Steam Power, independent of the use of Sails.* The comparative results of the Himalaya and Atrato afford the best opportunity of testing the relative efficiency of the screw propeller and paddle wheel, and examples for exhibiting the system proposed in the Arithmetic of Naval Architecture, by which the economy of the engines Ind. H. P.X 100 can be calculated by means of the formula V2= } Mid. Sec. 3220 tons. 700 2050 560 sq. ft. 18 ft. 3 ins. 15.87 15.75 80 tons per day. The effective H. P. required for the above midship section, and rate by the formula (conceded as a standard), is 1367, and £50 per nominal H. P. taken as a basis for testing the economy of the engines, the value of the E. H. P. becomes £25 12s. per horse; and assuming 15.87 miles as her working rate, as an example, the consumption of E. H. P. is 5.4 lbs. per hour, or one ton of displacement carried one mile, by the consumption of 146 lbs. of coal, at the rate of 15.87 miles per hour. From the Lond. Artizan, April, 1857. VOL. XXXIV.-THIRD SERIES.-No. 1.-JULY, 1857. 1 |
