Rotoring

Idlers along the Charles River in Cambridge, Mass., last week beheld a scene out of the sepia supplements of the Sunday papers. A beamy, 35-foot Navy cutter was moving steadily by, showing neither smoke nor sail and emitting a "put-put-put" altogether too faint to be coming from a gasoline motor proportionate to the craft's size. Men on the deck were observing a smokeless stack that rose amidships, a cylinder 3 1/2 feet in diameter and 9 1/2 feet high. The stack was revolving. The vessel was a U. S. rotorship--the first.

Lieutenants Joseph M. Kiernan and W. W. Hastings, students of naval architecture at Massachusetts Institute of Technology, were the rotorists. Working with discarded materials, they had constructed a craft that differed from the original rotorship of Herr Anton Flettner of Germany (TIME, Nov. 17, Dec. 8, Mar. 2), in two respects: Where Flettner's R. S. Buckau had had two rotor cylinders, the lieutenants used but one, believing they thus avoided a detrimental interaction; where the base and top disc of the Flettner cylinder had revolved, in the U. S. design it was stationary. The motive principle was the same as Flettner's, however: the Magnus principle, that wind passing over any surface creates suction on that surface, greatest on any part of the surface that does not move with the wind. Thus, the forward surface of a rotorship's cylinder being made to move into the wind -- i. e., clockwise into a starboard wind, counterclockwise to a larboard jwind--suction is strongest on that forward surface and the ship is drawn ahead.

The Cambridge rotorists managed, with a 12-mile breeze, to proceed at 3 knots an hour. They estimated that whereas a 10 horsepower engine would have been needed to drive their craft 6 miles an hour by propeller, the rotor and a 15-mile wind would take them 7 miles an hour with an exertion, from the put-put-put-ing motor that turned the rotor, of 1 1/2 horsepower.

Simultaneous with the nativity of rotoring in the U. S., the gigantic Count von Luckner, famed German sea-raider in wartime, declared he would spend two years circling the globe in Herr Flettner's Buckau, "to make rotorships known in all countries."