PRINCIPLES OF NAVAL ENGINEERING 



to becoming the major prime mover for naval 

 ships. 



With the advent of the steam turbine, the 

 problem of reconciling the speed of the prime 

 mover and the speed of the propeller became 

 critical. The turbine operates most efficiently 

 at high speed, and the propeller operates most 

 efficiently at low speed. The obvious solution 

 was to use reduction gears between the shaft 

 of the prime mover and the shaft of the pro- 

 peller; and, basically, this is the solution that 

 was adopted and that is still in use on naval 

 ships today. However, other solutions are pos- 

 sible; and one— the use of turboelectric drive- 

 was tried out on a fairly large scale. 



During World War I, the collier Jupiter (later 

 converted to the aircraft carrier Langley ) was 

 fitted with turboelectric drive. The high speed 

 turbines drove generators which were electri- 

 cally connected to low speed motors. The "big 

 five" battleships— the Maryland , the Colorado , 

 the West Virginia , the California , and the 

 Tennessee — were all built with turboelectric 

 drive. Ultimately, however, starting with the 

 modernization of the Navy in 1934, the turbo- 

 electric drive gave way to the geared-turbine 



drive; and today there are relatively few ships 

 of the Navy that have turboelectric drive. 



The period just before, during, and after 

 World War II saw increasing improvement and 

 refinement of the geared-turbine propulsion 

 plant. One of the most notable developments 

 of this period was the increase in operating 

 steam pressures— from 400 psi to 600 psi and 

 finally, on some ships, to 1200 psi. Other im- 

 provements included reduction in the size and 

 weight of machinery and the use of a variety 

 of new alloys for high pressure and high tem- 

 perature service. 



Although the development of naval surface 

 ships, unlike the development of submarines, 

 has been largely dependent upon the develop- 

 ment of steam machinery, we should not over- 

 look the importance of an alternate line of 

 work— namely, the development of internal com- 

 bustion engines. In the application of diesel 

 engines to ship propulsion, Europe was con- 

 siderably more advanced than the United States; 

 as late as 1932, in fact, the United States was 

 in the embarrassing position of having to buy 

 German plans for diesel submarine engines. A 

 concerted effort was made during the 1930's 



^FIO 



PROPELLER SHAFT 



SATURATED 

 STEAM 

 BOILERS 



SUPERHEATER 

 BOILER 



MAIN STEAM LINE 



147.5 



Figure 1-5.— Propulsion plant of the Wampanog. 



10 



