Seadrome

Although rain was beating down on Cambridge, Md., last week, men enthusiastically lugged into the Choptank River a one-ton steel model of the steel islands (seadromes) which Edward R. Armstrong of Holly Oak, Del., proposes to anchor 375 miles apart across the Atlantic. The model, 1/32 the size of intended seadromes, consists essentially of a rectangular platform. To its underside are attached hollow steel columns, each ending in a circular disk. Air in the cylinders was sufficient to keep the device floating on the Choptank and the platform several feet above the water. Speedboats dashed around the model. Their waves did not touch the platform nor did they rock it. The heavy horizontal disks at the lower ends of the hollow columns, below the depths to which the wave actions reached, counterbalanced all surface disturbances.

No surprise was his model's success to Mr. Armstrong, swarthy engineer, who since he left the Navy has been consulting engineer for the E. I. duPont de Nemours & Co. at Wilmington. For 16 years he has been experimenting and designing such a sea base having in mind ocean way stations for ships and, more lately for transoceanic aircraft. He "sold" his idea to the eminently practical duPont and General Motors financiers. They have provided him one and three quarters million dollars to build his first seadrome. Construction has already started on it. It will be called the Langley after the late Samuel Pierpont Langley, designer of the plane which, except for accidents, might have flown before the Wrights' plane did in 1903.

The Langley will have an unobstructed airplane runway 1,200 ft. long by 200 ft. wide. At the mid-sides the platform will project to give room for a hotel (with restaurant and bar), hangars, storage sheds, weather bureau, offices, hospital wards, lighthouse. Platform and buildings will be 80 ft. above calm water level. Because no Atlantic waves have ever been seen more than 45 ft. high, it is improbable that the runway ever will be awash. The buoyancy columns with their stabilizing disks will reach 160 ft. below water level. That is considerably deeper than any wave action has ever been noted.

Mr. Armstrong has long planned to anchor his first full-size seadrome midway between Manhattan and Bermuda. Studying hydrographic charts of the region he figured that there must exist a high spot on the ocean floor about where he would like it. He asked Secretary of the Navy Charles Francis Adams to send a survey ship to check his calculations. He was right. The survey showed a little plateau just 400 miles from Manhattan and 375 miles from Bermuda, in an almost direct line. It is six miles long by four miles wide and only two miles below sea level, whereas the surrounding ocean is three to four miles deep. The difference in depth means thousands of dollars of savings to Mr. Armstrong and his financiers on the 3 1/2 inch steel cable he is having laid to hold his floating island to its anchors. Those anchors are to be huge round bobbins which will dig into red clay of the submerged plateau and hold the seadrome from drifting. By next fall and before Bermuda's 1930-31-- tourist season begins Mr. Armstrong expects to have the Langley completed and anchored in place, ready to receive tourist planes and to entertain travelers on man's newest conquest of an element. As the operation of the Langley makes money, he will (and he has the money in provision to do so) construct eight similar seadromes to be strung 375 miles apart between the 35th and 40th parallels, north latitude, between Long Island and Plymouth. The 375 miles is an easy jump for any plane. Hence the project presages safe and convenient airplane passage across the ocean, direct competition with both sea ships and air ships. Flying time between the continents, Mr. Armstrong calculates, will be as low as 20 hrs.