APPENDIX NO. 1.EXPLOSIVES.
The latest adopted explosive for submarine mines is trinitrotoluol, also called trotol. The commercial names for this explosive are trinol, trotyl, and triton.
Wet guncotton is used extensively for submarine mines and in emergency other commercial high explosives may be employed, preferably dynamite.
Trotolis a fine crystalline yellow powder, much resembling brown sugar. It is manufactured by nitrating toluol. It is very insensitive to shock or friction, insoluble in water, very stable in storage, and very powerful when detonated. Its melting point is about 81° C., its ignition point is about 197° C., its specific gravity in powdered form is about 1.55; it has no dangerous chemical action on metals.
The priming charge is a fuse can full of crystalline trotol.
Trotol is supplied in wooden boxes doubly lined with wax paper, each box containing about 50 pounds of explosive. The date of receipt at the post and the name of the explosive shall be painted on each box. The boxes should be stored in tiers with the marked end out, the bottom tier resting on skids. The explosive is not dangerous to handle, but the same care should be observed in storing and handling as with other high explosives. It should be stored in a perfectly dry place, preferably in a magazine. If it is impracticable to store in a magazine, the explosive may be stored in the driest place available where it is protected thoroughly from all fire risks. If from any cause the boxes of explosive are wet and there is reasonable assurance that the interior has become wet, a box should be selected and opened. If the interior is wet, a full report of the circumstances shall be made to the War Department. Boxes should be opened and the contents dried in open air out of the direct rays of the sun.
Trotol may be stored with wet guncotton, explosive D, and dynamite.
Inspection at posts will be limited to seeing that the rules for storage and care are strictly observed. Technical inspections will be made, when required, by the Ordnance Department.
Wet guncottonin the form of compressed cakes is supplied in boxes lined with zinc, the lid being screwed down upon a rubber gasket so as to prevent the loss of water by evaporation. Each box contains 100 pounds of dry guncotton. In the lid is a small flush cap which screws down upon a rubber washer and closes a tube communicating with the interior of the box. Upon each box there is painted by the manufacturer the net and total weights. Shipping regulations require that guncotton should be wet with water so that the water is 20 per cent of the weight of guncotton and water. This is too much water for full detonation, and the guncotton upon receipt at a post should be dried out so that the weight of water is from 12 to 15 per cent of that of the dry guncotton. The guncotton is dried by opening the box and pyramiding the guncotton on the lid and in the box so that there will be free circulation of air between the cakes. The use of an electric fan in this connection will ordinarily materially facilitate the operation. By weighing pilot cakes it may be determined when the proper amount of water has evaporated. The guncotton is then repacked, lid screwed down, and the weight chalked upon the end of the box. The guncotton should be placed while drying so that it is not in the sunlight and should be handled with clean cotton or rubber gloves.
In addition to the regular monthly inspection the boxes are reweighed quarterly under the supervision of the officer responsible for submarine mine explosive, and the gross weight so found chalked upon the end. Should any box show any decided decrease in weight the screw cap in the lid is removed, enough fresh water, preferably distilled or rain water, added to bring it up to its original weight, and the screw cap replaced.
Magazines in which guncotton is stored should not be allowed to attain a temperature as high as 100° F. for any length of time.
Guncotton which is kept wet may deteriorate after long storage, but will not become dangerous.
Wet guncotton can not be ignited by a flame, but gradually smoulders away as the outer portions in contact with the flame become dried.
A brownish or reddish shade is sometimes seen in cakes of guncotton. This is due to the presence of iron in the wash water and does not indicate decomposition.
When storing guncotton in the magazine the piles of boxes should be made so as to give free circulation of air and the greatest convenience in handling consistent with the capacity of the magazine.
In the event of damage to any case, which may cause loss of water by evaporation, the contents shall be removed at once, repacked in a guncotton box which has been washed with soda solution, the proper amount of water added to the contents, and the box closed. The gross weight shall be marked on the case. In repacking avoid as much as possible handling the cakes with the bare hands. This is for the protection of the guncotton from oil or acid of any kind. Clean cotton or rubber gloves are suitable covering for the hands when engaged on this work.
If for any reason the cases are subjected to dampness sufficient to cause unusual deterioration of the cases, they should be removed from the magazine and dried, out of the direct rays of the sun.
Guncotton containing 12 or 15 per cent of moisture may be stored with explosive D, trotol, and dynamite, but never with dry guncotton.
Empty cases, before being placed in storage, must be washed thoroughly to remove all traces of guncotton.
For a charge of wet guncotton, the priming charge is dry guncotton. This may be either of crumbled guncotton or cakes made to fit the fuse can. The compressed primer cakes are supplied wet and bored with holes to receive the fuses and the loading wire.
Should the supply of guncotton primers become exhausted fresh ones may be prepared as follows: Two blocks of soft pine are used, one 3 inches square, the other circular and 2.9 inches in diameter. A cake of wet guncotton is clamped between these blocks. Using a fine joiners’ saw and the circular block as a gauge, a cylinder is sawed from the cake. The cylinder is then smoothed down with a rasp. Four of these are prepared for each charge and in each one of them a hole about ⁹/₁₆ inch in diameter is bored. While boring the hole the cake must be tightly clamped between two pine blocks to prevent it from splitting; to insure that all the holes will be in alignment it is advisable that the upper wooden block be provided with a ⁹/₁₆-inch hole and be thick enough to enable this hole to serve as a guide for the bit. The boring is done with the ordinary bit, which must be sharp, so as to cut clean.It is not safe to saw or bore a dry guncotton cake.
It is essential that the guncotton primer be thoroughly dry. The primers may be dried by exposure to the air or by means of drying ovens supplied especially for the purpose. To air-dry a primer, it is placed on edge upon a shelf of wire gauze or netting which is hung up indoors where there is a free circulation of dry warm air. Drying should continue until weighings on two successive days show no appreciable loss. This may require a week or more.
In drying with an oven the cakes are laid on edge on the shelves and the temperature of the oven is kept at about 100° F.; it should not exceed 104° F. The heat is provided by means of a bank of lamps placed under the hood and the current of warm air regulated by the size of the lamp bank and the openings in the top of the oven. Under no circumstances must an open flame be used as a source of heat. The drying in this case also is continued until successive weighings of samples show no appreciable loss.
Whenever it is necessary to dry more than 50 pounds of guncotton primers for immediate use the guncotton should be placed in the drying oven and exposed to the action of an electric fan placed about 4 feet in front of the open door until the moisture content is reduced toabout 6 per cent, when the drying should be completed by the use of the bank of lamps as described in the preceding paragraph.
In each case, to test the dryness of the primers, take a cake and split it in four or five pieces and detonate each separately with a fuse.
It has been determined that about 5 per cent of water is the maximum content for unconfined guncotton capable of detonation by a Du Pont No. 30 fuse.
Priming charges are not to be prepared until just previous to the time they are to be used in loading. When the primers have been dried, they should be kept in well-sealed jars unless they are to be used very soon after drying, in which case they will be stored in assembled fuse cans; when thus stored the assembled fuse cans should be kept in a cool, dry, and secure room away from other explosives. If, however, the primers are to be stored for any length of time, two strips of blue litmus paper are inserted between the cakes, which are inspected from time to time. If the litmus paper shows decided redness, it should be removed and fresh strips inserted. If these strips turn red in a few hours, the primers should be thoroughly wet with fresh water. In general, the period of storage will be short and no particular examination of the dry guncotton will be required.
Dry guncotton should be handled as little as possible, to prevent crumbling and scattering of guncotton dust. Finely divided guncotton is difficult to remove by brushing and if allowed to collect about a room may give serious trouble by flashing should a portion become ignited. This dust may be removed with a damp sponge or cloth.
Dry guncotton which is not used as contemplated shall be rewet with the proper amount of water and repacked.
Samples of each lot of guncotton issued to the service are preserved in the laboratory of the Ordnance Department for chemical test. These retained samples are subjected regularly to technical inspection and test by that department to determine their condition as to stability. This will insure the detection of lots that are deteriorating and their removal from the posts or their destruction before they have deteriorated to such an extent that they become dangerous.
Dynamite.—Dynamite cartridges are packed ordinarily in sawdust in wooden boxes. Each cartridge is wrapped in paraffin paper. The cartridges are arranged in the box so that when they are transported all cartridges will lie on their sides and never on their ends. Usually the amount of explosive in a single package will not exceed 50 pounds.
The boxes must never be allowed to stand so that the cartridges will be vertical.
Like other nitroglycerin, dynamite freezes at about 40° F., and in its frozen condition is, under ordinary circumstances, less liable to explosion from detonation or percussion than when thawed, but more susceptible to explosion by simple ignition. Should any of the nitroglycerin be exuded, the dynamite cartridges are much more sensitive to explosion by a blow.
It is important that dynamite cartridges be kept dry. If exposed to a moist atmosphere, there is a tendency of the water, condensed from the air on all exposed surfaces, to displace the nitroglycerin.
The cases should be raised from the floor on skids and the floor underneath covered with clean sawdust. The sawdust should be removed from time to time, the old sawdust being burned in the open air.
Rubber gloves should be worn in handling this explosive, or in the absence of rubber gloves cover the hands with grease and wear cotton gloves. This is for the protection of the skin from the injurious effect of nitroglycerin.
Dynamite may be stored with wet guncotton, explosive D, and trotol.
Date of receipt at post shall be marked on each box.
The priming charge for dynamite is a pound of loose dynamite contained in a small bag which fits easily into the fuse can. In filling the bag rubber gloves must be worn. To insert the fuses the bag is opened and the fuses embedded in the explosive, the choke being tied around the fuse wires.
At the monthly inspection all boxes shall be examined to see if they are dry. If not dry, all shall be exposed to the dry air out of the direct rays of the sun.
The principal source of danger from dynamite is in the exudation of the nitroglycerin. Exudation is indicated by the presence of small white, oily, lustrous globules of liquid, either among the particles of dynamite or on the packages. If such globules are discovered, they may be identified positively as nitroglycerin by absorbing a drop in a piece of unglazed paper, which should be placed on an anvil or other piece of metal, and striking it a sharp blow with a hammer. If it be nitroglycerin, an explosion will occur. Another test is to set fire to the paper, and if the liquid be nitroglycerin it will burn with a crackling noise and a greenish-yellow flame.
If exuded nitroglycerin has stained floors or other material not readily destroyed, the nitroglycerin may be decomposed and rendered harmless by washing with “sulphur solution.” This solution may be made by boiling 50 pounds of lime in a barrel of water and adding powdered sulphur until the solution will take up no more. This will require about 20 pounds of sulphur. The resulting bright orange-colored solution should be filtered and only the filtrate used. A suitable filter for this purpose is a piece of thin cheese-cloth. Sodium carbonate may be used in the place of lime.
Dynamite may be destroyed by burning in small quantities at a time. Slit the cartridge with a knife, spread out the contents over some straw or shavings, and ignite carefully. Do not attempt to burn frozen dynamite.
Mine fuses.—These are regular commercial electric fuses, extra quality, and each contains about 25 grains of mercury fulminate. Fuses are supplied in pasteboard boxes containing 50 each, pasteboard boxes being shipped in suitable wooden boxes. They are supplied with long leads which are cut to proper length when the mines are loaded.They must not be stored with other explosives.
Loading mines.—In loading mines the following precautions are observed:
(a) Funnels are used to cover the screw threads.(b) Trotol is poured through the funnels.(c) Cakes of guncotton or packages of dynamite are passed through the funnels by hand.(d) The screw threads are wiped carefully before the compound plug is inserted.(e) Pieces of canvas or paulins should be spread upon the floor of the loading room. After the loading has been completed the canvas should be removed and thoroughly cleaned. The floor of the loading room should be scrubbed and all refuse destroyed.
(a) Funnels are used to cover the screw threads.
(b) Trotol is poured through the funnels.
(c) Cakes of guncotton or packages of dynamite are passed through the funnels by hand.
(d) The screw threads are wiped carefully before the compound plug is inserted.
(e) Pieces of canvas or paulins should be spread upon the floor of the loading room. After the loading has been completed the canvas should be removed and thoroughly cleaned. The floor of the loading room should be scrubbed and all refuse destroyed.
Unloading mines.—Mines charged with trotol or wet guncotton may be unloaded without danger; the compound plug being unscrewed, the cakes of wet guncotton are removed by hand, repacked in the original boxes, a little fresh water added, and the boxes closed. If loaded with trotol, the charge is poured out into the boxes, which are then closed. Trotol should be inspected carefully when removed from the case, and if there is indication that any of it has undergone a change while the mine was loaded, a report should be made to the War Department.
In unloading mines charged with dynamite too many precautions can not be taken. The mine should be held either in an opening in a raft or behind an earthen traverse and the compound plug removed by some arrangement which may be operated from a safe distance. If the mine has been planted for some time the recovered dynamite is usually destroyed. Sometimes the interior of the mine case may be found coated with an extremely thin film of exuded nitroglycerin. This film may be destroyed by filling and thoroughly rinsing the case with “sulphur solution.”