Popular Science Monthly 



683 



engine in order to produce that explosively- 

 rapid combustion which makes the piston 

 move up and down in its cylinder. And 

 so mechanism is provided which enables 

 the engine to inhale a measured quantity 

 of air to be mixed with a measured quantity 

 of fuel. 



Now the air within a submarine is 

 limited in quantity. When the ship is sub- 

 merged, the crew must breathe as well as 

 the engines. Moreover, there is the problem 

 of disposing of the gases exhausted by the 

 engine. They cannot be ejected into the 

 sea carelessly. They would rise to the 

 surface of the water in the form of bubbles 

 and would inevitably betray the course 

 taken by the submarine. Moreover, en- 

 gines are very hot, and the living quarters 

 in a submarine are at best none too com- 

 fortable. 



Because the air supply within a sub- 

 marine is so limited and because of the 

 very nature of the propelling engines, in- 

 ventors of submarines have had to resort 

 to the very awkward expedient of driving 

 their craft under water by means of storage 

 batteries. The batteries are heavy, cum- 

 bersome, and not always safe; they must 



J eriscopes 

 ^Operating compartment 

 Escape hatch 



be recharged at the surface — a noisy busi- 

 ness which takes from six to eight hours 

 and which imperils the safety of the 

 craft for the time being. It is said that the 

 newest German submarines can travel un- 

 der water for nearly a hundred hours. 

 That must mean a very sparing use of the' 

 stored power. According to Lieutenant 

 Hinkamp of our Navy, "the submarine of 

 the present day can operate submerged at its 

 maximum speed for about an hour. At 

 about one-third of this maximum speed, 

 she can operate practically twenty-four 

 hours." 



Is it not evident, as I maintain, that the 

 submarine, mechanically speaking, is a 

 very crude contrivance, something of which 

 mechanical engineers should be ashamed 

 rather than proud? 



Needless to say the inconvenience and 

 danger resulting from the necessity of using 

 storage batteries for sub-surface propulsion 

 have long been recognized. Inventors 

 have made many efforts to do away with 

 the storage battery entirely and to devise 

 a way of using the regular internal combus- 

 tion engines of the craft for under-water as 

 well as for surface propulsion. Here, I 

 wish to add my own contribution to the 

 solution of the problem. 



It is very evident that if the engines are 



to be used for under-water propulsion 



a large supply of air 



must be stored in 



Steering rudder 



Sufficient to Drive the Submarine under Water at High Speed and for Long Distances 



through the third coil, which is bathed by the hot 

 exhaust Rases from the explosion engine. Still under 

 pressure, but highly superheated, the oxygen passes into 

 the expansion engine where it helps to drive the vessel 

 and where it is expanded to a pressure equal to that 

 which is required to force it into the explosion engine. 

 In order that no visible wake may be left, the gases ex- 

 hausted from the explosion engine are forced out through 

 a sieve having many small holes. Thus the carbonic acid 

 gas, of which the exhaust is largely composed, is finely 



subdivided so that it can be readily absorbed by the 

 sea water. This absorption is aided by the propeller 

 which thoroughly beats up the exhaust gases with 

 large volumes of water. 



If small cruising radius and quick action alone are 

 required rather than economy, the expansion engine 

 and the three coils through which the oxygen passes 

 can all be cut out and the liquefied oxygen can be 

 forced directly into the mixing tank and mingled with 

 the proper amount of hot exhaust gases from the engine 



