Page:Popular Science Monthly Volume 92.djvu/261

 Popular Science Monthly

��245

��25 Miles

��18 i Miles

��14 Miles

��IO4 Miles

��0~ ^

Position Wo 3 Carqo.^subina;:^ rine bridge 15 Ft. above water

��8 Miles

��5| Miles

��Horiion 65 Miles

��Position No 2 Cargo subma- rine bridge 5 Ft. above water

��^-

Position No I _ Carqo subz.- marine per- iscope 15 Ft. above water

��Military submarine

lying in wait for approach- ing vessels; periscope 15 Ft. above water Submerged speed -10 knots

��and Keeps the Big Ship in View While She Is Herself Unseen

��direct course than if slie were intercepting a fast Mauretania. Assume that this approaching slow- speed craft had no solid opaque portion extending over fifteen feet above the surface of the water, as in the case of the cargo submarine shown in posi- tion 3. She would pass the waiting submarine below the horizon, and the intervening round of the sea surface would prevent the submarine from seeing her. She would pass by unseen and in safety. In the various positions here shown, the submarine is assumed to have a submerged speed of ten knots. It is evident that practically one hundred per cent safety would be secured, could

land. I can see no sense in building million dollar ships, loading them with several million dollars worth of cargo and sending them out to be sacrificed, when absolute immunity from attack can be secured at an additional first cost of not over two hundred and fifty thousand dollars per ship, or about eight per cent of the value of the ship and cargo (less than the present immense insurance rate on one voyage to England). For a supposedly inventive and progressive people, we are

�� ���Area of der-.qsi

��'ai 1"'' *^6a of possible >

���/ interception

��Diagram position No a cargo submarine. 5peed lo Knots

Without Danger of Being Torpedoed

in position No. 3. This increases the danger area to about three hundred and thirty square miles, about three times the danger area shown in position No. 1. But as the area to be covered by the military submarine on the high seas far from land is also much greater, the real danger would be propior- tionately less than the lower visibility in a more thickly infested zone might lead one to suppose.

��cargo-carrying submarines cross the ocean and remain invisible during the entire journey. This is, of course, impossible, because there is no means of supplying sufficient power for long under-water voyages without drawing on the upper air. But the diagram shows that a cargo-carrying sub- marine running awash, with her periscope and air-intakes alone above the water line, may ap- proach within about five and three-quarter miles of any waiting military submarine without danger of being seen; for her betraying wake would be far, far below the horizon of the most watchful, ruthless enemy submarine afloat.

curiously prejudiced. Here are the Ger- mans with their reputation for stolidity and slow-thinking successfully attacking very much the same problem with a boldness and an imagination which they themselves attribute to Americans. And we — we seem to be paralyzed by a con- servatism inherited from our English ancestors.

The truth is -that the submarine is a

mystery to our shipping men. It takes a

combination of liberal-mindedness and

special knowledge to set a fleet

of merchant submarines afloat.

Despite the example of the

Deutschland, despite the enor-

\ mous profits which that ves-


 * ,~l~ sel admittedly made for her

'" / owners, we still go on building

/ surface ships, many of which

must inevitably succumb to

German submarines.

When our shipping men and our naval authorities realize the importance of invisibility and learn that the submarine is the least visible of all vessels, perhaps the rational solution of the problem here advocated will be attempted. The only effort at present used to secure invisibility is to be

�� �