Page:Popular Science Monthly Volume 90.djvu/567

 Popular Science Monthly

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��about 200 tons. In other words she is not more than one third as big as an ordinary sea-going, commerce-destroying German submarine.

A mine-lajfe,E carries no guns or torpedoes — nothing but mines confined in t>vos in incHned tubes at the bow. The mines are released from the conning-tower. Each mine has a sinker which carries it swiftly down away from the submarine. As the mine sinks, hinged legs are forced out by springs, the legs lying flat on the bot- tom of the sea. The mine itself is at- tached to the sinker or anchor by means of a chain. Soon after the sinker strikes the bottom the mine floats up. A device called a hydrostatic valve regulates the height of the mine above the anchor, so that whether it be high or low tide the mine will always be at the right dead level.

Although Britan- nia still rules the waves quite as com- pletely as she did in the days of Drake and Nelson, the sub- marine has unques- tionably made her more cautious. The English Grand Fleet emerges only when it has a prospect of fighting, and then only when it is preceded by a cordon of torpedo boat destroN'ers, which keep an eye out for German submarines, and a squadron of mine-sweepers and trawlers which fish out mines planted by submarine mine layers and which net any submerged submarine in the course. When the battle fleet is safely out in the open sea it must keep moving. The blockading squadron, too, must not venture too close to German shores, and it, too, must move always.

Naval officers are by no means agreed what type of submarine the United States should adopt. While some pin their faith to the big, German sea-going tyjje and

���An aeroplane can detect a submarine under water. It is, therefore, one of the most formidable of enemies

��Others boldly advocate the fleet submarine, even though no one knows how to obtain the engines to drive it, others recommend a comparatively small coast-defence type. In view of our present conflict with Germany, every American wonders what we would do if the British fleet were not engaged in corking up their German dread- noughts? Considering our Uvo enormous coast lines, our pos- sessions in Alaska, the Philippines and the Hawaiian Is- lands, some of our officers think that we need not only coast defence sub- marines (the 800- ton type with a surface speed of 17 knots, able to remain at sea for three weeks) but something much more formidable. Thus, Captain W.L. Rogers agrees that if our main fleet is destroyed, coast de- fence submarines cannot prevent an enemy from landing, because they cannot know when and where an attack will be made, and they cannot escape drags and nets forever. What we need, ac- cording to him, are fleet submarines — vessels which will be able to keep at sea with scouts and bat- tleships, which will have a surface speed of at least twenty-five knots.

This problem of building a submarine which is able to keep pace with a fleet of battleships and battle cruisers, is so difficult of solution that some naval authorities despair of seeing it solved at all. At present no submarine, even of 1200 or 1500 tons, can be equipped with sufficiently powerful machinery to make the required twenty-five knots necessary to keep up with a battle-ship squadron. On the other hand, small submarines cannot act for months at a time with the main fleet per- haps a thousand miles from a base. They have neither the speed nor the endurance.

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