Page 625 radio acoustic ranging 668 



box, secured to the rail in such a manner that it can be thrown overboard readily in 

 case of fire or other danger. The box should be felt lined or otherwise cushioned on 

 the bottom and all four sides to eliminate the possibility of shock. The fuse detonators 

 must be kept in the tin box in which they are supplied, with the small square of felt 

 covering them to protect them from the metal lid. Electric detonators should be 

 enclosed in a soft cloth and protected with the same care as fuse detonators. 



668. Fuse 



Standard commercial, slow burning, waterproof safety fuse is used to fire the 

 detonators in bombs used in R.A.R. It has a core of slow burning powder, either a free 

 core or a solid core, in the center of several layers of jute or similar material, the outside 

 of wliich is coated with a waterproofing compound. A number of dift'erent brands of 

 safety fuse are manufactured for use under different conditions and in different areas. 

 Most of the brands marketed on the Atlantic Coast are manufactured to burn at a rate 

 of 1 foot in 30 seconds in air, but one sold under the trade name "Clover Brand," 

 manufactured by the Ensign-Bickford Company of Simsbury, Connecticut, burns at the 

 rate of 1 foot in 40 seconds in air. The latter is the rate of burning of the brands of 

 safety fuse marketed on the Pacific Coast in 1939. 



The manufacturers of safety fuse do not guarantee the burning rate, because alti- 

 tude, weather conditions, care in handling, and other factors may affect the rate. 

 Each coil of fuse for R.A.R. bombs should be tested, preferably in water, to determine 

 the rate of burning before it is used. In water under the pressure at the depth of 

 5 fathoms, fuse will generally burn about one-third faster than in air. 



Some brands of safety fuse are especially manufactured for use in water. It 

 should be noted that, although these wiU burn in water, they will not withstand pro- 

 longed wetting, especially under pressure. The fuse that is selected for use in R.A.R. 

 should, of course, be waterproof and burn at a slow rate, and preferably it should be 

 of the solid core variety. 



Fuse should be stowed in a cool dry place, at temperatures between 45° and 75° F. 

 If a common salt shaker containing table salt is placed in the stowage place for about 72 

 hours and the salt remains dry enough to be shaken out at the end of this time, the place 

 is sufficiently dry for stowage. Fuse deteriorates with age and not more than a 2- or 

 3-month supply should be purchased at one time. It should be left in its original con- 

 tainer and should not be cut into short lengths until just before use, for if the powder 

 grains fall out of the cut ends, fighting may be diflBcult and misfires may result. 



669. Precautions in Handling Explosives 



The general methods to be used and the precautions to be observed while handling 

 explosives are described in 661 to 668 inclusive. The important DONT'S to be 

 observed for safe handling of explosives, selected from the recommendations of the 

 Institute of Makers of Explosives and amplified for special application to the use of 

 explosives in R.A.R. are listed and must be observed for safety in handling explosives 

 on board ship. 



(1) DON'T stow explosives in a wet or damp place — they should be stowed where it is clean, cool, 

 dry, and well ventilated. 



(2) DON'T stow detonators in or near a magazine or locker containing other explosives. 



(3) DON'T open cases of explosives in a magazine. 



(4) DON'T use any metal tool for opening cases containing explosives — use only wooden wedges 

 and wooden, fiber, or rubber mallets. 



465382—44 41 



