Principles of naval engineering - Historic Naval Ships Association

PRINCIPLES OF NAVAL ENGINEERINGFigure 12-28.— Cruising turbine.147,102maintained on the glands when the turbine is inoperation, and the gland packing must be keptin good condition. An adequate supply of watermust be maintained for the makeup feed tankso that air will not be drawn into the condenser.A combatant ship operates most of the timeat speeds far below maximum. At cruisingspeeds, only a fraction of turbine capacity isrequired. At low speeds, economy is obtainedby one of the following methods: (1) by usingcruising turbines which are designed to operateeconomically at speeds up to about 18 knots,(2) by using cruising stages in the high pressureturbine, and (3) by using turbines whichare designed so that they can be operated inseries.On ships that have a cruising turbine, thecruising combination should be used for allunderway operations requiring speeds of lessthan 18 knots. The officer of the watch (orthe petty officer of the watch) should obtainpermission from the OOD to operate on cruisingcombination whenever possible.To prevent casualties to cruising turbines,the protective devices (sentinel valve, directreadingthermometer, crossover valve lock,and thermal alarm) should be checked continuously.In order to be a good engineering officer ofthe watch, he must acquaint himself with allstanding orders and operating instructions forhis ship. These are made up for each ship and342