ENGINEERING PROGRESS IN THE U. S. NAVY. 



By Captain C. W. Dyson, U. S. N. 



[Read at the twentieth general meeting of the Society of Naval Architects and Marine Engineers, held in 



New York, November 21 and 22, 191 2.] 



In preparing an article under the heading of "Engineering Progress in 

 the U. S. Navy," the ground to be covered is of such large extent that, in 

 the greater part, nothing but the merest notice of improvements can be 

 given, and only the most important points of progress will be detailed. The 

 first and most important point of all, as reacting upon the general efficiency 

 of the Navy as a reliable and economical fighting force, is the — 



CHOICE OF PROPELLING MACHINERY FOR HEAVY VESSELS OF MODERATE 



SPEED. 



In the selection of the type of machinery to be used in the above class of 

 vessels, the following points must be taken into consideration : — 



(c) General character of the service which the vessel will be called upon 

 to perform ; whether she must keep the sea for long periods, cruising at speeds 

 very much lower than her maximum speeds, or whether she will be called 

 upon for very little slow cruising, but shall be held in readiness for dashes at 

 high speed from a base to any threatened point. 



(b) Greatest economy realized at the conditions under which she will 

 be called upon to operate. This point is important, not only from the point 

 of financial saving in reduced fuel cost, but in the greater ease of fuel supply 

 due to the decreased demands. 



(c) Fuel capacity entailed by the demands of the service to which the 

 vessel may be subjected. 



(d) Ease of up-keep of the machinery, and degree to which the vessel, 

 so far as machinery repairs are concerned, can be made self-supporting. 



(e) Reliability of machinery when driven at high powers. 



(/) Minimum weight and space required for the propelling machinery. 



(g) Efficient propellers for maneuvering. 



(h) Minimum of vibration of hull due to machinery in operation. 



(i) Effect of vertical position of center of gravity of the machinery upon 

 the time of roll of the vessel, in fixing the quality of the vessel as a gun 

 platform. 



