PRINCIPLES OF NAVAL ENGINEERING 



147,102 



Figure 12-28.— Cruising turbine. 



maintained on the glands when the turbine is in 

 operation, and the gland packing must be kept 

 in good condition. An adequate supply of water 

 must be maintained for the makeup feed tank 

 so that air will not be drawn into the condenser. 

 A combatant ship operates most of the time 

 at speeds far below maximum. At cruising 

 speeds, only a fraction of turbine capacity is 

 required. At low speeds, economy is obtained 

 by one of the following methods: (1) by using 

 cruising turbines which are designed to operate 

 economically at speeds up to about 18 knots, 

 (2) by using cruising stages in the high pres- 

 sure turbine, and (3) by using turbines which 

 are designed so that they can be operated in 

 series. 



On ships that have a cruising turbine, the 

 cruising combination should be used for all 

 underway operations requiring speeds of less 

 than 18 knots. The officer of the watch (or 

 the petty officer of the watch) should obtain 

 permission from the OOD to operate on cruis- 

 ing combination whenever possible. 



To prevent casualties to cruising turbines, 

 the protective devices (sentinel valve, direct- 

 reading thermometer, crossover valve lock, 

 and thermal alarm) should be checked con- 

 tinuously. 



In order to be a good engineering officer of 

 the watch, he must acquaint himself with all 

 standing orders and operating instructions for 

 his ship. These are made up for each ship and 



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