PRINCIPLES OF NAVAL ENGINEERING 



concentration of toxic vapors; personnel should 

 be kept away from such areas. 



Hot air may be blown over a contaminated 

 surface to decontaminate it. Steam, especially 

 high pressure steam, is also a useful decon- 

 taminating agent; the steam hydrolyzes and 

 evaporates chemical agents and flushes them 

 from the surfaces. Chemical decontamination 

 may also be accomplished by sealing off porous 

 surfaces to prevent the absorption of chemical 

 agents or to prevent volatilization of agents al- 

 ready on the surface. 



Decontamination can also be effected by 

 physically removing the toxic agents from the 

 contaminated surfaces. This can be done by 

 washing or flushing the surfaces with water, 

 steam, or various solvents. Figure 4-11 shows 

 a decontamination party hosing down a gun mount 

 in order to physically remove toxic agents. 



DAMAGE CONTROL PRECAUTIONS 



The urgent nature of damage control oper- 

 ations can lead to a dangerous neglect of neces- 

 sary safety precautions. Driven by the need to 

 act rapidly, men sometimes take chances they 

 would not even consider taking in less hazardous 

 situations. This is unfortunate, since there are 

 few areas in which safety precautions are as 

 important as they are in damage control. Failure 

 to observe safety precautions can lead— and, in 

 fact, has led— to the loss of ships. 



Because damage control includes so many 

 operations and involves the use of so many 

 items of equipment, it is not feasible to list all 

 the detailed precautions that must be observed. 

 Some of the basic precautions that apply to 

 practically all damage control work are noted 

 briefly in the following paragraphs. 



No one should be allowed to take any action 

 to control fires, flooding, or other damage until 

 the situation has been investigated and analyzed. 

 Although speed is essential for effective damage 

 control, correct action is even more important. 



The extent of damage must not be under- 

 estimated. It is always necessary to remember 

 that hidden damage may be even more severe 

 than visible damage. Very real dangers may 

 exist from damage which is not giving imme- 

 diate trouble. For example, small holes at or 

 just above the waterline may appear to be rela- 

 tively minor; but they have been known to sink 

 a ship. 



It is extremely dangerous to assume that 

 damage has been permanently controUedmerely 

 because fires have been put out, leaks plugged, 

 and compartments dewatered. Fires may flare 

 up again, plugs may work out of holes, and 

 compartments may spring new leaks. Constant 

 checking is required for quite some time after 

 the damage appears to be controlled. 



Doors, hatches, and other accesses should 

 be kept open only as long as necessary while 

 repairs are being made. Wartime records of 

 naval ships show many cases of progressive 

 flooding which were the direct result of failure 

 to close doors or hatches. 



No person should attempt to be a one-man 

 damage control organization. All damage must 

 be reported to damage control central or to a 

 repair party before any individual action is 

 taken. The damage control organization is the 

 key to successful damage control. Separate, 

 uncoordinated actions by individual men may 

 actually do more harm than good. 



Many actions taken to control damage can 

 have a definite effect on ship's characteristics 

 such as watertight integrity, stability, and 

 weight and moment. The dangers involved in 

 pumping large quantities of water into the ship 

 to combat fires should be obvious. Less obvious, 

 perhaps, is the fact that the repair of structural 

 damage may also affect the ship's character- 

 istics. For example, the addition of high or off- 

 center weight produces the same general effect 

 as high or off-center solid flooding. 



While most repairs made in action would not 

 amount to much in terms of weight shifts or 

 additions, it is possible that a number of rela- 

 tively small changes could add up sufficiently 

 to endanger an already damaged and unstable 

 ship. The only way to control this kind of hazard 

 is by making sure that all damage control per- 

 sonnel report fully and accurately to damage 

 control central. Ship stability problems are 

 worked out in damage control central, but the 

 information must come from repair personnel. 



In all aspects of damage control, it is im- 

 portant to make full use of all available devices 

 for the detection of hazards. Several types of 

 instruments are available on most ships for 

 detecting dangerous concentrations of explosive, 

 flammable, toxic, or asphyxiating gases. Per- 

 sonnel should be trained to use these devices 

 before entering potentially hazardous compart- 

 ments or spaces. 



82 



