Page:Popular Science Monthly Volume 90.djvu/565

 Popular Science Monthly

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��plainly enough. When even. the periscope will betray her, which it does partly on account of its wake, she must dive com- pletely and become absolutely blind. Hence, the periscope has been fittingly called the "e^-e" of the submarine. It is a telescope built so that you can see around a corner or over a wall of earth or

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��Above: What one sees in look- ing through the periscope "eye" of a United States submarine

��The commander of a submarine looking through a periscope at the outside worid from under-sea

��) Underwood and Underwood. N. T.

��water. There are as many kinds of per- iscopes, almost, as there are styles in hats. Each boat in all navies carries at least two periscopes, one for the commanding officer and one for the helmsman or second officer.

The One-Man Submarine

Henry Ford's proposal to build cheap one-man submarines has once more focused attention on an idea that has always fas- cinated inventors. But no one who is at all familiar with submarines believes in the one-man type. In a letter to the Popular Science Monthly, Simon Lake, our fore- most submarine inventor, disposes of the question in this fashion:

��"A number of one-man submarines have been built, but they have never proven to be of much value because they had such a short radius of action and low speed. The modern Whitehead torpedo is something over 1 8 feet in length and i8 inches in diameter, and it requires a good sized vessel to carry otie of these within the hull. If carried outside the hull, which has been done in some cases, the torpedo offers much additional resistance to a small craft and thus tends further to reduce its speed.

"We prepared a number of one-man boats, which our engineers designate 'pickle-boats,' but they were very disappointing as to the speed it was possible to get out of them."

This was not written of the Ford plan, but on the subject in general.

Ford's idea of building one-man boats very cheaply is ridiculed by naval men. The engine necessary to obtain high speed would have to be as light as an aeroplane motor, and aeroplane motors cost about $5,000 each.

Thomas Orchard Lisle, a prominent marine engi- neer, punctures the Ford idea very effectively when he points out what are its limitations:

"Mr. Ford proposes to drive this submarine with the same engine that is used in his automobiles, of which, I believe the maximum horse- power is forty under the best conditions. This would give a small boat, say twenty feet long, a submerged speed of not more than eight knots; that is if an internal combus- tion engine could run when the boat is submerged. So imagine the futility of chas- ing a thirty-knot battle cruiser with an eight-knot submarine."

Mr. Ford has not considered among other things, the difhculty of supplying air to the engine and to the solitary constituent of the crew, nor the disposal of the exhaust gases, so that they may not betray the boat in a soda-water wake, nor the utter impossi- bility of operating such a boat in a rough sea.

In their mine-layers the Germans have developed a new and ingenious type of sub- marine. One of the mine-layers was cap- tured by the British last year, and the details of her construction have been given out by her captors. She is about no feet long, and 1 1 feet beam, and she displaces

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