Popular Science Moiit/ily 



229 



Another feature of the cargo-carrjing 

 boat is the pro\ision of wheels whicii 

 enable the craft to travel on the bed of 

 the ocean, rivers and the like. Mr. Lake 

 was the first to use what may be called 

 "automobile submarines." Indeed his 

 first \cnturc in the submarine field was 

 the Argonaut, which ran on the bottom 

 of Chesapeake Bay. The wheels are of 

 great service in following a dredged 



rather in oil engines suitable for sub- 

 marine purposes, lies somewhere in the 

 neighborhood of two hundred horse- 

 power per cylinder. The Germans arc 

 now building submarine torpedo boats 

 about two hundred and twenty- feet 

 long, propelled by twin-screw engines 

 aggregating two thousand, four hundred 

 horse-power and giving a surface speed 

 of seventeen knots. A submarine some- 





Longitudinal Section 



Carry $1,000,000 Worth of Chemicals 



tight cylindrical tanks. The quarters for the crew, the engine 

 room, etc., are contained in a water-tight cylindrical inner hull. 

 When the vessel is to submerge, the entire space between the 

 inner and outer hulls is flooded with sea water; when the 

 vessel is to travel on the surface, the water is pumped out. 

 The submarine boat has wheels, so that it can travel along 

 the bottom of a dredged channel — a method of propul- 

 sion which Mr. Lake has successfully employed. This huge 

 submarine would be about 350 to 400 feet long. It 

 would be not a submarine but a submersible ship 



channel. In some experiments which 

 Mr. Lake performed for the Russian 

 Government at Libau, some years ago, 

 he was able to pick his way out of a 

 harbor much more easily than com- 

 petitors of his, simply by running along 

 the bottom of a dredgecl channel. 



There is no inherent difficulty- in build- 

 ing a cargo-carrying submarine, even 

 though it be four hundred feet long. But 

 there is great difficulty in obtaining en- 

 gines which will drive it. 



The practical limit of size as yet at- 

 tained in big submarine engines, or 



what bigger, requiring three thousand, 

 six hundred horse-power to develop a 

 surface speed that will enable her to be 

 of any practical use will need three 

 engines with si.x cylinders each. Now, 

 for a \-essel four hundred feet long a very 

 powerful set of propelling machines will 

 be required. Oil engines are out of the 

 question. Steam engines must be em- 

 ployed. And the use of steam engines 

 means the sol\-ing of the- very difficult 

 problem of insulating the generating 

 apparatus so that the crew will not be 

 parboiled. 



