Chapter 10- PROPULSION BOILERS 



BOILER CASUALTY CONTROL 



There are many fireroom casualties which 

 require a knowledge of preventive measures 

 and corrective measures. Some are major, some 

 are minor; but all can be serious. In the event 

 of a casualty, the principal doctrine to be im- 

 pressed upon operating personnel is the preven- 

 tion of additional or major casualties. Under 

 normal operating conditions, the safety of per- 

 sonnel and machinery should be given first 

 consideration. Therefore, it is necessary to 

 know instantly and accurately what to do for 

 each casualty. Stopping to find out exactly what 

 must be done for each casualty could mean loss 

 of life, extensive damage to machinery, and even 

 complete failure of the engineering plant. A 

 fundamental principle of engineering casualty 

 control is split-plant operation. The purpose of 

 split-plant design is to minimize the damage 

 that might result from any one casualty which 

 affects propulsion power, steering, and elec- 

 trical power generation. 



Although speed in controlling a casualty is 

 essential, action should never be taken without 

 accurate information; otherwise the casualty 

 may be mishandled, and further damage to the 

 machinery may result. Cross-connecting and 

 intact engineering plant with a partly damaged 

 one must be delayed until it is certain that such 

 action will not jeopardize the intact one. 



Cross-connecting valves are provided for 

 the main and auxiliary steam systems and other 

 engineering systems so that any boiler or group 

 of boilers, either forward or aft, may supply 

 steam to each engineroom. These systems are 

 discussed in chapter 9 of this manual showing 

 the construction of the split-plant design on 

 some types of ships. 



The discussion of fireroom casualties in this 

 chapter is intended to give you an overall view 

 of how casualties should be handled. For further 

 information on casualty control, study the Naval 

 Ships Technical Manual , Chapter 9880, and the 

 casualty control instructions issued for each 

 type of ship. 



Most of the casualties discussed in this 

 chapter are usually treated in a step-by-step 

 procedure, but it is beyond the scope of this 

 chapter to give each step in handling each 

 casualty. In the step-by-step procedure one 

 step is performed, then another, then another, 

 and so forth. In handling actual casualties, 

 however, this step-by-step approach will proba- 

 bly have to be modified. Different circumstances 



may require a different sequence of steps for 

 control of a casualty. Also, in handling real 

 casualties several steps will have to be per- 

 formed at the same time. For example, main 

 control must be notified of any casualty to the 

 boilers or to associated equipment. If "Notify 

 main control" is listed as the third step in 

 controlling a particular casualty, does this mean 

 that the main control is not notified until the 

 first two steps have been completed? Not at 

 all. Notifying main control is a step that can 

 usually be taken at the same time other steps 

 are being taken. It is probably helpful to learn 

 the steps for controlling casualties in the order 

 in which they are given; but do not overlook 

 the fact that the steps may have to be performed 

 simultaneously. 



FEED WATER CASUALTIES 



Casualties in the control of water level in- 

 clude low water, high water, feed pump casual- 

 ties, loss of feed suction, and low feed pressure. 

 These casualties are some of the most serious 

 ones. 



Low water is one of the most serious of 

 all fireroom casualties. Low water may be 

 caused by failure of the feed pumps, ruptures 

 in the feed discharge line, defective check 

 valves, low water in the feed tank, or other 

 defects. 



However, the most frequent cause of low 

 water is inattention on the part of the checkman 

 and the PO in charge of the watch, or the di- 

 version of their attention to other duties. The 

 checkman's sole responsibility is to keep the 

 water in the boiler at a proper level. 



Low water is extremely damaging to the 

 boiler and may endanger the lives of fireroom 

 personnel. When the furnace is hot and there 

 is insufficient water to absorbthe heat, the heat- 

 ing surfaces are likely to be distorted, the 

 brickwork damaged, and the boiler casing warped 

 by the excessive heat. In addition, serious steam 

 and water leaks may occur as a result of low 

 water. 



Disappearance of the water level from the 

 water gage glasses must be treated as a casualty 

 requiring the immediate securing of the boiler! 



It should be noted that when the water level 

 falls low enough to uncover portions of the 

 tubes, the heat transfer surface is reduced. As 

 a rule, therefore, the steam pressure will drop. 

 Ordinarily a drop in steam pressure is the 

 result of an increased demand for steam, and 



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