665 HYDROGRAPHIC MANUAL PaGE 622 



tlie suiToundiiig water; a piece of metal may be attached to this wire to increase the 

 surface area. The brass screw has two nuts, the lower of which is tightened to expand 

 the stopper and to hold it firmly in the container. A single-conductor cable is con- 

 nected to the brass screw by the upper nut, and the screw thus forms part of the con- 

 ductor to the detonator. This connection at the top of the screw must be well insulated 

 from the water. The exposed areas should be completely covered with Para-rubber 

 tape, which is then covered with ordinary rubber tape. As an added precaution, the 

 junctions of the tape with the conductor cable and the container may be sealed with 

 collodion or any other sealing compound, although this is probably unnecessary. 



This type of bomb may be weighted, if necessary, by attaching a piece of Alanila 

 line to the conductor cable about 4 feet above the bomb, the line being long enough to 

 allow the weight to hang below the bomb. The strength of the conductor cable must be 

 considered, for too heavy a weight might part the wire in some types of cable. 



665. Storage of Bombs 



Bomb containers filled with TNT should be stowed in a safe place on board and 

 receive the same care as the supply of explosives (see 666). The bomb locker should be 

 large enough to stow the number of bombs required for about one week's operations. 

 If its size is inadequate, the prepared bombs should be stowed in a locked magazine, 

 if one is available, or in a locker provided on the upper deck near the stern. 



No explosives shall be permitted on board while the ship is undergoing repairs. 

 During any extensive lay-up period, the supply of TNT, detonators, and all prepared 

 bombs should be boxed and arrangements should be made to stow them at the nearest 

 United States Army or Navy ammunition dump. Arrangements can generally be 

 made for an ammunition barge and tug to transport these supplies to the dump. If 

 the amount of explosives and the number of detonators remaining at the end of a sea- 

 son's work is small, they should be thrown overboard at sea in deep water. 



666. Trinitrotoluene (TNT) 



Trinitrotoluene, commonly called TNT, is used in making the bombs used for 

 R.A.R. It is one of the safest high explosives. It is relatively safe to handle and 

 stow on board ship, it does not readily absorb and retain moisture, it lacks any tendency 

 to form unstable compounds with metal, it is practically insoluble in water; and it 

 possesses powerful explosive properties, so that a small quantity of it will produce the 

 sound wave of high intensity required for R.A.R. Properly purified TNT, when 

 correctly stowed, remains stable for long periods of time; but it will react with alkalis, 

 such as sodium hydroxide or sodium carbonate, to form unstable sodium salts which 

 are quite sensitive. 



TNT is manufactured by various processes, all of which involve the nitration, 

 by a mixture of nitric and sulphuric acids, of toluene, a hydrocarbon derived from 

 various tars. It is a crystalline powder, resembling powdered brown sugar in appear- 

 ance, although in different grades of refinement its color and appearance vary. The 

 most refined grade, grade A, is pale yellow in color, but grade B, a less refined product, 

 contains more impurities and is darker, sometimes reddish brown in color. Both 

 grades may be obtained from the United States Navy; grade A should be used. 

 Although not quite as satisfactory, grade B may be substituted when grade A is not 

 obtainable. 



