THE SUBMARINE Ho AT, 721 



to discover a metal that will be noncorro.sive, nonmagnetic, of lighter 

 Aveig-ht. and yet of greater strength. It is to be hoi)ed a petroleum 

 motor can be substituted for the gasoline engine for surface work. 

 There are other weaknesses of the submarine which the engineer in 

 part will 3"et overcome. 



Neither the marine engineer nor the naval architect perceives anj^- 

 thing mysterious in either the design, equipment, or operation of the 

 boat. The few men who operate these boats can not attach any sub- 

 stantial value to the craft by ascribing some tactical attri))utes to their 

 use. In general, the boat is a parabolic spindle with a conning tower, 

 the hatch of which can be hermetically sealed. This spindle contains 

 a gasoline engine for surface work, and a storage battery for sub- 

 merged operations. There are ballast tanks which can be rapidly 

 filled and emptied, and by manipulating the ingress or egress of water 

 into these tanks the ])uo3'ancy is destroyed or secured. Such a craft 

 nuist necessarily have limitations. It has been the effort of inventors 

 to overcome weaknesses rather than revolutionize the design in the 

 effort to extend the held of operation of this possible w^eapon of Avar. 



BOATS OF THE DIVING TYPE HAVE LITTLE LONGITUDINAL STABILITY. 



On boats of the diving type but little advance has been made in 

 securing increased stability. Where a boat is designed to dive like a 

 porpoise, it is practically impossible to secure longitudinal stability. 

 When the craft is in condition for diving, the center of gravity must 

 be near the center of buoyancy, otherwise the influence of the hori- 

 zontal rudders would not affect the boat. With an exceedingly well- 

 skilled and resourceful man at the steering wheel, with a well-trained 

 and efficient crew, and w ith favorable conditions as to wind and sea, a 

 boat of the diving type can submerge and rise with considerable suc- 

 cess and certainty. Where such favorable conditions do not exist, it 

 is extremelv improbable that the boat can steer a desired course, or 

 that she will be fully under the control of the operator. A submarine 

 boat of this type will undoubtedly be thrown off her course by the 

 effect of currents, tides, or waves, in case she has not sufficient speed 

 to overcome the strength of strong local eddies. In the absence of a 

 guiding medium, such a l)oat simply gropes al)out. In conmienting 

 upon this weakness of the submarine boat, Captain Mahan writes: 



"I should be interested to see some demonstration that the su))ma- 

 rine boat will not find a practically insuperal>lc difficulty in discerning 

 her prey — in seeking it, I should rather say." 



ENDURANCE OF CREW AN IMPORTANT FACTOR. 



It should ever be remembered that the actual limit of the operations 



of the submarine boat is a limit of endurance of the crew. The skilled 



artificer in charge of the motor can not escape breathing, at least u 



small portion, of the products of combustion when the gasoline engine 



SM 1901 46 



