Popular Science Monthly 



DO. 



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. 



