The Gunnery Pocket Book - Part 2 (2024)

GENERAL.

175. The object of this chapter is to give all the information that is required by an officer or man in his ordinary duties on board with respect to:-

Detailed information regarding the construction and methods of working of the various stores has not been included. If such information is required the various text-books on the subject must be studied.

This chapter should be read in conjunction with the other chapters, certain portions of which are repeated here to make this chapter as self-contained as possible.

GUNS.

176. The simplest form of gun is a strong steel tube into which is placed a projectile; the gun is rifled to impart spin so that the projectile may be rotated and so kept steady in the air. In order to propel the projectile out of the muzzle a charge is placed in the gun behind the projectile; the space occupied by the charge is called the chamber, and the rear end of the chamber is closed with a breech block. Arrangements are made so that the charge can be ignited, with the consequent formation of a large volume of gas, in the chamber behind the projectile; the pressure thus created propels the projectile from the gun.

Guns are divided into two classes, according to the method adopted to make the breech end gas-tight.

First, B.L. (breech loading) guns, in which the breech is made gas-tight by an elastic pad (called the obturator) carried on the face of the breech block. When the charge is ignited, this pad is forced back against the breech block and made to expand outwards against the inside of the chamber, completely sealing the breech during the moment of firing.

Second, Q.F. (quick firing) guns, in which the breech end is made gas-tight by a brass case (known as the Q.F. cartridge case), in which the charge is carried. When the gun is fired, the cartridge case expands and seals the breech end.

EXPLOSIVES.

177. An explosive is a substance which, on being given a suitable initiation, is rapidly converted into a large volume of hot gases.

Explosives are used in Naval gunnery for two purposes.

Firstly, for the cartridge placed behind the projectile in the gun. When the gun is fired the cartridge is ignited, and the large volume of gas produced hurls the projectile out of the gun at a speed of over 2,750 feet per second (nearly 2,000 miles per hour). This type of explosive is known as a "propellant".

The only difference between a disruptive and a propellant is the speed at whichgas is produced when they are ignited. Disruptives explode almost instantaneously. Propellants burn comparatively slowly and regularly.

Cordite is the propellant chiefly used in Naval guns. It is a mixture of nitroglycerine and nitro-cellulose with a stabiliser or preservative. It is pressed intovarious shapes which have a brown hornlike appearance and, in the case of tubularcordite, into sticks not unlike macaroni.

The sticks are pressed in various thicknesses, and each size is given a three-figure number, which is its approximate diameter in thousandths of an inch. Forinstance, size 280 means that the stick is .28-inch in diameter, size 070 that it is.07 inch in diameter. All the cordite of any one size produced by the corditefactory in a certain period is blended together and given a lot number, which remainswith that cordite throughout its life, thus enabling its behaviour to be observed.

Flashless cordite has a whitish appearance and is usually supplied in theslotted-tube form and is described in terms of exterior and interior diameters ofthe tube in thousandths of an inch, e.g., S.T. 164-048 means that the slotted tubeis .164 inch external and .048 inch internal diameter.

Another form of propellant is called " N.H." or " non-hygroscopic ". Thisis a plain nitro-cellulose propellant and contains no nitro-glycerine. It is suppliedin short lengths about .1 inch long and is usually " multi-tubular ", i.e., each pieceis pierced with seven holes longitudinally.

N.H. is described by the " web " size, e.g., N.H. 050 means that the thicknessof the web between the holes or tubes is .05 inch.

178. High explosives or "disruptives", are used for filling shells and aircraftbombs (and also mines and torpedo war-heads, etc., which do not come within thescope of this book). When properly initiated, they are instantly converted intogas with great violence, the process being called detonation. In order toassist the transmission of the impulse from the fuze to the filling, an exploderis fitted under the fuze which acts as a booster. The exploder consists of a smallquantity of some high explosive which is more sensitive and therefore more readilyaffected by the fuze unit than is the main bursting charge of the shell. Thecomposition of the exploder depends on whether the fuze gives a combustive ordetonative impulse, i.e., whether the shell filling is required to "explode" or"detonate".

The high explosives used in the Naval Service as shell fillings are: R.D.X.,T.N.T., shellite and lyddite (or picric acid).

The following high explosives are in use in the Naval Service as explodersand fillings for caps, fuzes and gaines: T.N.T., picric acid, C.E. (compositionexploding), fulminate of mercury, lead azide and picric powder. Caps, fuzes andgaines are described later.

Gunpowder, one of the earliest explosives, was originally used both as a propellant and as a shell filling. Though now superseded in these two functions, itis still used in the Naval Service for many purposes, such as bursters in shrapneland star-shell, and in tubes, igniters, primers, fuzes, blank charges and fireworks,all of which are described later.

CARTRIDGES.

179. For safety, convenience, and rapidity of loading, the cordite charges forguns are placed in silk cloth bags, or cylindrical metal cases, and are then known ascartridges.

180. These cartridges consist of a number of cordite sticks, tied together in abundle with silk thread, and sewn up in a silk cloth bag. They are made upcontaining a whole charge, two-thirds, one-third, one-quarter or one-sixth of acharge, according to the size of the gun and the method of loading employed.When firing in action, cartridges are loaded to make up the "full charge". Inpeace-time full-calibre (as opposed to sub-calibre) practices, "reduced charges" are generally used for the large guns as they do not wear out the gun so much. Reduced charges are normally three-quarters or two-thirds of a full charge.

To facilitate igniting the cordite, igniters may be employed on cartridges forB.L. guns. The igniter consists of gunpowder in a red balloon bag, sewn over one or both ends of the cartridge. Gunpowder catches fire more readily thancordite, and the duty of the igniter is to ensure that the flash from the tube (seeunder " Tubes ", paras. 186-189) sets the cordite alight. The igniter, by itsinflammable nature, is a potential source of danger in action; therefore, to reducethis danger, those cartridges which have igniters and are made up in fractions offull charges do not have an igniter on each fraction, but two per full charge. B.L.cartridges must be put into the gun with the red igniter end to the rear and asclose as possible to the breech block of the gun. Special care is necessary incordite handing rooms to ensure that where igniters are fitted the cartridges areplaced in the hoists the right way round.

Igniters for certain cartridges are protected by silk igniter covers or millboard "tear-off" discs fitted over the end of the cartridge. These must beremoved in the last place of handling, i.e., in the cordite handing room of turretswhen using main loading, or at the gun in hand-worked mountings. The rearigniter cover only need be removed. Igniters of other cartridges are protected bynon-removable igniter covers which are coloured red and are sewn both to theigniter and cartridge bag.

Most B.L. cartridges are fitted with lifting bands of tape or braid to assist intheir removal from the magazine cases. These bands are to be taken off on withdrawal of the cartridge from the case, before passing it to the ammunition hoist.

Tin Foil is introduced into every B.L. cartridge to prevent coppering ofthe bore.

On the silk cloth bag is stencilled all information concerning the cartridge,which includes:-

(i) The gun for which it is intended.
(ii) Weight of the charge.
(iii) Nature, size and lot number of cordite.
(iv) Fraction denoting size of charge, i.e., 1/4, 1/6, etc.
(v) Date of filling and monogram of filling station.
(vi) N-for Naval Service.

Cartridges for Q.F. Guns.

181. For these the bundle of cordite sticks is placed in a brass Q.F. cartridgecase. The ammunition for Q.F. guns is divided into two classes: fixed ammunition, in which the base of the projectile is secured in the mouth of the cartridgecase, and separate ammunition, where cartridge and projectile are separate.

Where N.H. propellant is used the propellant is confined to the lower partof the case by a leatherboard cup held in position by a distance piece, one end ofwhich bears on the top of the cup, and the other on the base of the shell in fixedammunition and on the lid of the case in separate ammunition.

The gunpowder necessary to ensure regular ignition of the cordite is containedeither in the magazine of the primer or in a metal igniter (see under "Primer", para. 190).

The front end of the cartridge case of separate ammunition is closed by ametal or plastic lid.

Tin foil is introduced to prevent coppering.

All information relating to the charge and cartridge case is stamped on thebase and stencilled on the base or side of the case. This information includes:-

(i) Stamped on base:-

(a) Nature and mark of gun.
(b) Mark of empty case.
(c) Monogram of manufacturer of case and date of manufacture.
(d) Marks by which the history of the case may be read.
(e) Lot No. of cordite and distinguishing letter of cordite manufacturer.

(ii) Stencilled on base or side:-

(a) Lot number of cordite.
(b) Mark of cartridge.
(c) Monogram of filling station and date of filling.

Drill Cartridges.

182. To enable loading drills to be carried out, drill cartridges are supplied,having approximately the same weight and outside dimensions as the cartridgesthey represent. Those for B.L. guns are either wood covered with raw hide, orlengths of rope covered with canvas. Those for Q.F. guns, both fixed and separate, are usually made of wood with brass facings.

Blank Cartridges.

183. Blank cartridges, filled with gunpowder, and designed to make a greatdeal of noise and smoke, are supplied for saluting purposes and signalling. Blankcartridges for B.L. guns are enclosed in silk cloth bags, and are only suppliedwhen specially required.

Blank cartridges for Q.F. guns are contained in Q.F. cartridge cases. Theyare usually supplied to ships in their component parts to be made up on boardas required.

No projectile is used with a blank cartridge.

As gunpowder is easily ignited, blank charges should be treated very cautiously,and never exposed to a possibility of a spark or smouldering matter. They areusually stowed in a separate magazine or shell room, or with small armammunition.

184. All information is stencilled on the B.L. cartridge and on the bag of theQ.F. charge. This information includes:-

(i) Mark of cartridge.
(ii) Contractor's initials or recognised trade mark.
(iii) Nature of gun.

(iv) Weight of charge.
(v) Class of powder.
(vi) N-for Naval Service.
(vii) Initials or monogram of filling station.
(viii) Date of filling.

The word "BLANK" is stamped or stencilled across the base of Q.F.cartridges supplied for such use.

Precautions to be observed.

185. On all occasions of withdrawing a blank cartridge from a B.L. gun itis to be passed overboard.

Before firing blank charges from a B.L. gun, the cartridge is to be kept in aClarkson's case or waterproof duck bag and is not to be uncovered until the borehas been inspected.

TUBES AND PRIMERS.

186. B.L. cartridges are fired by tubes placed in the vent of the breech, whileQ.F. cartridges are fired by primers screwed into the base of the cartridge case.

Tubes.

187. To distinguish them from other types of tube, they are known as tubes,vent.

Tubes, vent, consist of a means of ignition and a magazine of powder pelletsand loose powder contained in a small brass case. The powder pellets, whenignited, fly, burning, into the igniter (where fitted) of the B.L. cartridge andignite it. Tubes are of two types, electric and percussion.

Electric tubes are fired by an electric current passing through an electric lock.When this current is switched on, by the gunlayer or director-layer pressing histrigger, it flows along a thin iridio-platinum wire " bridge " surrounded byexplosive inside the tube. The bridge fuses almost instantaneously, and ignitesthe explosive and the powder pellets in the tube magazine. Owing to the frailtyof the bridge, electric tubes must be handled with care; otherwise the bridgemay be broken and the tube missfire. Electric tubes are usually balanced by amegger before firing to confirm that they are electrically correct. Their resistanceshould lie between 0.9 and 1.1 ohms. Electric tubes which have missfired (i.e.,which have been reported as "tube not fired") should be set aside for examination.

Percussion tubes are fired by the blow of the striker of a percussion lock.The striker, when it flies forward, hits the tube striker at the rear end of the tubeand fires the cap of the tube. A flash from the cap ignites the powder pellets inthe tube magazine. Percussion tubes must be handled with the greatest care, asan accidental blow on the cap may cause the tube to fire. Percussion tubes whichhave been struck, as indicated by a dent in the centre of the striker of the tube,but have not fired, are dangerous and should be thrown overboard as soon aspossible.

188. Tubes are made in three sizes: 1-in., electric, and .5-in. and .4-in.electric or percussion:-

(i) 1-in. tubes are used in certain B.L. guns the cartridges for whichare not fitted with an igniter.
(ii) .5-in. tubes are used in all other B.L. guns in the service, exceptas in (iii).
(iii) .4-in. tubes are now only used in 6-in. Marks VII and XI guns.

189. Tubes can be identified as follows:-

(i) Electric tubes are left plain and smooth. Electric tubes for some gunshave a raised contact piece in the head, and are fired by strikerlesslocks; they are called "S" tubes. The others have a small sunkdisc in the head, where the striker makes contact.
(ii) Percussion tubes have four notches cut out of the rim of the head.
(iii) Drill tubes are blackened and have four longitudinal indents impressedon the body. The heads are milled.

Tubes are packed ten in a flat tin box, sealed by a soldered tear-off band. Whenthis seal is broken, the date is to be recorded on the tin and the contents relegatedfor testing purposes only after one week (one month during war). Tubes are stowedin a special locker in the gunner's store room. Lockers are fitted near the guns fora ready-use supply of tubes in action.

Primers.

190. Primers screw into the bases of Q.F. cartridges and provide the meansof firing them. Three types are used:-

(i) Percussion.
(ii) Electric.
(iii) Electric and Percussion.

Percussion primers consist of a powder magazine and a percussion cap contained in a metal holder. They are fired by a blow from a striker which hits andignites the cap; flash from the cap passes into and ignites the contents of themagazine of the primer.

Electric primers are similar in operation to an electric tube, and are fired byelectricity.

Electric and percussion primers may be fired either by percussion or byelectricity.

Primers screw in flush with the base of the cartridge case, and are protectedby a clip, which must be removed before loading. Special keys are provided forremoving the primers after the cartridge has been fired.

AMMUNITION PACKAGES.

191. Cartridges are supplied to ships packed in aluminium alloy, steel orbrass cases, or in steel or wooden boxes. Some of the latter have a tinned platelining. The cases and boxes stow in magazines on board in such a manner that,so far as possible, their contents can be removed while they remain in their stowage.Boxes, however, may be carried with their contents to the place where they arerequired. (See also para. 245.)

Ammunition cases and boxes are made air-tight and water-tight by the useof luting (a sort of non-drying putty), and rubber or dermatine (a form of rubber)rings at the lid joint.

Cases and boxes containing cordite cartridges are "sealed" before beingsupplied to a ship, so that it will at once be apparent if anyone has opened ortampered with the lid of a case. The sealing is generally effected by sticking a

192. The cases and boxes most generally encountered are:-

All cases and boxes containing ammunition should be handled with care toavoid injuring their contents. Rough usage of cases and boxes causes them to losetheir air tightness, with detriment to their contents. It may well occasion hangfires, missfires, or even premature explosion, and jamming of the lids which causesloss of time in opening cases, a common result of rough usage.

COLOURING OF AMMUNITION PACKAGES.

193. Except as stated below, all packages containing ammunition and fireworks are painted a stone colour.

" Packages painted the following colours contain stores as shown:-

Magazine cases made of aluminium-silicon alloy.
Boxes for warheads and projectiles.
Galvanised steel packages.

One end of some cylindrical cases is painted blue to show that that end ispermanently closed.

The following band markings will be found:-

194. To assist in the rapid identification of the type of projectile, all fixedammunition packages are marked with a coloured bar on the lid or on the sidebearing the label:-

Details of the contents of a package are stencilled on the outside of the box,and are also indicated on the contents label affixed to the outside of the package(except for cases, magazine).

A.S.A. boxes have coloured labels stuck on the outside so that their contentscan quickly be recognised.

Boxes containing star-shell have a star-shaped piece of brass screwed to thelid to enable the contents to be identified in the dark by sense of touch.

All packages containing explosives are marked with a government explosivesgroup label in red with a white numeral indicating to which group the contentsbelong for stowage purposes.

PROJECTILES.

195. There are various kinds of projectiles, whose design depends on thefunction they are required to fulfil. They can, however, be divided into threemain groups:-

(i) Piercing shell.
(ii) H.E. shell.
(iii) Miscellaneous projectiles.

Piercing and H.E. shell, which are designed to do as much damage as possibleto the enemy, are steel cases filled with disruptive explosives. The filling isdetonated or exploded by a fuze screwed into the base or nose of the shell.Between the fuze and main filling is placed a small quantity of fairly sensitiveexplosive termed an " exploder " (see para. 178).

Piercing Shell.

196. These shells are designed to perforate thick armour at battle ranges,and to burst effectively when inside. To achieve this the shells are made with thickheads and walls, and consequently carry only a small amount of explosive. Inmodern shell, to assist perforation a penetrative cap of hard steel secured overthe nose of the shell, is generally employed, the letter "C," for capped, beingadded to the title of the shell.

Sometimes light steel domes are fitted on the cap or nose of the shell to bringit to the best shape for flight through the air. These are called ballistic caps,and in no way assist the actual perforation. The suffix "B.C." is sometimes usedto indicate the presence of a ballistic cap.

Fuzes of all piercing shell are fitted in the base, where they can be best protected from damage during penetration.

197. The following types of piercing shell are supplied to the NavalService:-

H.E. Shell.

198. These are designed to burst with great shattering effect on unarmouredtargets, but have little or no penetration. They contain the largest possiblebursting charge consistent with the shell having the necessary strength

Miscellaneous Projectiles.

199. The characteristics of other types of shell which are likely to be metwith are as follows:-

(vii) Drill Shell of wood and Dummy Shell of wood covered with a tan hideare supplied for loading drill at the guns. Drill at the loading teacheris carried out with practice projectiles. Drill shell of iron (or practiceprojectiles) are also supplied for pusher hoists or Fuze Setting Drill,and are marked NOT TO BE LOADED IN GUN.

SUPPLY AND CARE OF PROJECTILES.

200. Projectiles 5.25 inch and above, except star shell, are supplied in bulk.Projectiles 4.7 inch and below, and star shell of all calibres, are packed in boxeswhich are returned to the depot after the shells have been stowed in the bins.Capstan-headed grabs are supplied for embarking and disembarking shell 8-inchand above. Quick-action grabs, as used in shell rooms, are never to be used forembarking or disembarking shell.

When handling projectiles, care should be taken:-

(i) That driving bands are not damaged. (Rope grommets are provided,to protect them.)
(ii) That caps are not subjected to any strain.
(iii) That markings are not obliterated.
(iv) That heavy shell are slung slightly nose heavy.
(v) That star shell are not subjected to rough usage or dropped. A drop oftwo feet on to its base may be sufficient to render a star shell unserviceable.

TRACERS AND IGNITERS.

201. To enable the flight of the projectile to be seen, a tracer may be fittedinto the base. A tracer consists of a small tube or disc filled with tracer composition, which is ignited when the gun fires.

The igniter is a device to ensure self-destruction of the shell if the fuze hasnot operated by a given time.

The tracer and igniter is a similar device combining the functions of tracer andself destruction.

COLOURING AND MARKING ON PROJECTILES. Plate 19.

202. In order that they may readily be distinguished, types of projectile arepainted differently (see Plate 19).

The bodies of shell are painted:-

The points or caps of shell are painted the same colour as the body, with thefollowing exceptions:-

(i) Old Method.

(ii) Present Method.

(G. 6619/46.-A.F.P. P.75147.

The letter "S" on a white circle denotes that the shell is fitted with a smokebox (present method).

The method of painting target smoke shell is best seen from Plate 19.

Stencilled on the shell are the calibre of gun from which it is to be fired, thedate and place of filling the shell, and particulars of the exploder and the fuze,and game or tracer if fitted.

The gas check cover plate or disc tracer of base fuzed shell and the screwedring which holds the cover plate in position are coloured to indicate what fuze isfitted.

FUZES.

204. Fuzes screw into the nose or base of shell, and are used to start theexplosion or detonation of the bursting charge in the shell. They fall into threemain groups:-

(i) Percussion (D.A. and base).
(ii) Time (Combustion and Mechanical).
(iii) Time and Percussion.

Fuzes contain a detonator, i.e., a small quantity of sensitive high explosiveand a magazine.

Percussion Direct Action Fuzes.

205. These are the simplest kind of fuze. They screw into the noses of H.E.shell and burst them on impact. When the fuze hits the target, a striker in itsnose is forced into the detonator which fires and detonates the fuze magazine,and thence the exploder and the shell filling. There are two main types of thisfuze, direct action (D.A.) and direct action impact (D.A.I.). D.A. fuzes are verysensitive and are used for bombardment and in 2-pdr. shell. D.A.I. fuzes requirea harder blow to cause them to work and are used in H.E. shell which is fired atships.

The larger D.A. and D.A.I. fuzes have caps to protect them from accidentaldamage, spray, and moisture during transport and stowage. These fuzes areprepared for firing by removing the caps in the following manner:-

If a fuze is prepared for firing and then not fired, the cap and pin, where fitted,should be replaced, except in No. 44, Mark X and later fuzes. In No. 44 MarkX and later fuzes, and in fuzes where the pin is difficult to replace the fuze shouldbe carefully removed from the shell and thrown overboard.

H.E. shell for low angle work are supplied already fuzed to small ships. Forlarger ships the fuzes are supplied separate from the shell, the hole in the nose of

If nose-fuzed shell are to be left for more than a few hours on the weather deck,those fuzes which are not fitted with watertight caps are protected from damp byrubber covers or kit plasters which fit over them.

Percussion Base Fuzes.

206. Piercing shell, which are required to perforate armour before bursting,are fitted with base fuzes which are not damaged by the passage of the shell throughthe armour. The action of the fuze is started when the shell strikes, but the burstdoes not occur until a fraction of a second later, when the shell has got well insidethe enemy ship.

Base fuzes are supplied screwed into their shell. Normally no preparationis required. Care must be taken not to damage them with the point of anothershell. Base fuzes must never be removed on board.

Time Fuzes.

207. These are supplied for H.E. shell to be fired at aircraft, and for star shellH.A. practice, and target smoke shell. There are two types, powder burning andmechanical. In the powder-burning fuze, a powder train is started burning bythe action of a detonator when the shell is fired. By revolving a ring the effectivelength of the train can be so adjusted that the projectile will burst in the air at anydesired interval after leaving the gun. In the mechanical fuze, revolving thedome similarly causes the fuze to fire after the desired interval. Both types offuze are "set" by revolving to the required setting immediately before loadingthe shell into the gun.

The setting must never be zero or very close to zero, as this may have the effectof bursting the shell whilst the gun and crew are still within the danger zone.

Some time fuzes have, in addition, a percussion arrangement that causes theshell to burst on impact if it strikes anything before the time fuze works. Thesefuzes are called time-and-percussion fuzes, and are used mainly with shrapnel.Time mechanical fuzes will also cause the shell to burst on impact with substantialtargets.

The fuzes used in the ammunition for close range A.A. weapons must not beconfused with time-and-percussion fuzes. The fuze in this case is a D.A. fuze. Aself-destroying element, operating after a fixed length of time, is fitted inside theshell to prevent it returning to earth intact and possibly causing injury to a friendlyparty.

Most time fuzes have a cap as a protection. The cap must be removedbefore the fuze can be set and should immediately be replaced if the fuze is notgoing to be fired.

208. In addition, the following fuzes have safety pins which must be removedbefore loading: Nos. 65a, 81, 92, 93, 181 and 192. These pins are on no accountto be replaced. If the pin has been withdrawn and the shell is not required forimmediate use, the fuze is to be carefully removed from the shell and thrownoverboard.

Time and time-and-percussion fuzes are always supplied to ships separately insuitable packages. The shell are fuzed with them on the outbreak of war, or whenrequired in peace-time. If the shell are going to remain fuzed on the weatherdeck for more than a few hours, the fuzes, if not fitted with water-tight caps,should be protected by rubber covers or kit plasters.

If a time or time-and-percussion fuze has been set and is then not fired, it isreset to SAFE usually indicated by a small red triangle a little beyond the highest

Safety Arrangements of Fuzes.

209. In addition to the caps and pins mentioned above, all fuzes have internalsafety arrangements to prevent their functioning accidentally during transportor stowage. The chamber pressure, shock of discharge, and rotation, " arm "the fuze when it leaves the gun, so that it may function correctly at the end of itsflight.

FUZING OF SHELL.

210. The regulations concerning this are laid down in N.M. and E.R. Detaileddirections are given in the Handbook on Ammunition (B.R.932/45).

The most important points to remember are:-

GAINES.

211. A gaine is a small magazine of sensitive high explosive which is placedbetween time fuzes (except No. 211, which has the gaine incorporated in it) andthe exploders of the shell in which they are fitted. Its object is to step up theexplosion of the fuze so as to produce detonation of the shell filling. Shell fittedwith gaines are also used occasionally with D.A. fuzes, for bombardment.

AIRCRAFT BOMBS.

212. Bombs at present in use can be divided into 7 groups:-

The main filling of H.E. bombs is detonated by similar means to thoseemployed in shell, i.e., by an exploder which in turn is ignited by a detonator. Thedetonator is initiated by means of a pistol. In some bombs the detonator and pistolmechanism are combined in one unit termed a fuze. In either case when a bomb is

(i) A.P. Bombs-2,000 lb.
These bombs are designed for use against heavily armoured targets and aremade of steel. They contain a comparatively small charge in relation to the totalweight. Detonation is initiated by a fuze in the tail.

S.A.P. Bombs-500 lb. and 250 lb.
These bombs are designed for use' against lightly armoured targets. Theyare made of steel and contain a comparatively small charge. Earlier types arefitted with a tail fuze, and the latest type with a tail pistol and detonator, givingthe required delay.

(ii) G.P. 250 lb. and M.C. Bombs, 500 lb.
These bombs, as the name implies, are used to attack a variety of targets.They rely chiefly on blast effect to cause damage and have a relatively large charge.They are fitted for nose (instantaneous) or tail (delay) fuzing, and use a pistol anddetonator in both cases.

(iii) A/S Bombs, 100 lb.
These bombs are used against submarines, and also against certain targetswhere a large blast effect is required. They have a relatively large charge,and are fitted for a tail pistol and detonator. (Earlier types were fitted for a nosefuze.)

(iv) Anti-Personnel Bombs, 40 lb. G.P. and 20 lb. Fragmentation.
These bombs are designed to give a large number of small fragments on burstingand are fitted with a nose pistol and detonator only. Otherwise they are generallysimilar to the larger G.P. bombs.

(v) Incendiary Bombs, 25 lb. and 30 lb.
The 25 lb. incendiary bomb consists of a metal case containing seven magnesium and thermite firepots which are ejected at 4-second intervals by means ofsmall explosive charges.The 30 lb. incendiary bomb contains an incendiary filling which is ignited andspread by means of an exploder contained in a nose fuze.

(vi) Practice Bombs. 8 1/2 lb., 10 lb. and 11 1/2 lb.
These bombs contain either a smoke flame or a flash composition; smokefor day and flame or flash for night use respectively. On impact a small detonator-burster is ignited by means of a pistol which is an integral part of the bomb.

(vii) Drill Bombs.
These may be of any of the above types differing only in that the filling isinert.

Safety Arrangements.

213. Bomb pistols and fuzes are fitted with safety arrangements to preventdetonation of a bomb before it is required for use or in the event of a crash orpremature release. The safety arrangements take the following forms:-

Supply and Fuzing.

214. Bombs of 100 lb. and above are supplied unboxed, their tail unitsand nose pistols being in separate containers. Tail pistols are usuallysupplied in position in the bomb. Smaller bombs are supplied boxed with pistolsin position. Detonators and fuzes are supplied in separate boxes.

Fuzing is carried out in accordance with N.M. and E.R. Article 249.

Markings. Plate 20.

215. Stencil markings on bombs give the following information:-

(i) Nomenclature and mark.
(ii) The monogram of filling station or trade mark of filling contractor.
(iii) The date of filling.
(iv) The lot number of filling.

Coloured markings are as follows:-

(i) H.E. bombs are coloured green (old supply were yellow).
(ii) A red band round the nose denotes Filled.
(iii) A white band contiguous to the red band denotes S.A.P.
(iv) A white band either side of the red band denotes A.P.
(v) A plain green band denotes T.N.T. filling. T.N.T. is stencilled on ornear the band.
(vi) A plain green band with a numeral above and a fraction below indicatesan amatol filling of low grade.
(vii) A criss-cross green band with a fraction below denotes an amatol fillingof high grade.
(viii) Incendiary bombs are painted dull red.
(ix) Practice bombs are painted white. Two green bands on the tail denote"filled with smoke composition "; two black bands on the tail and ared band on the body denote" filled with flash composition."
(x) Drill bombs are painted black with yellow band.

Note. In (v) and (vi), new supply, the green band is of a lighter shade than thebody colour.

SMALL ARMS AMMUNITION.

216. The term Small Arms Ammunition includes ammunition for aimingrifles, machine guns, aircraft guns, rifles and pistols of 1 inch or less calibre.

Various types are supplied. Except for 20 m.m. Oerlikon the type is indicatedby letters preceding the mark number stamped on the base of the cartridge. Theinterpretation of the letters is as follows:-

Letters after the mark of a cartridge are an indication of the nature of thepropellant, e.g., Cartridge, S.A. .5 inch W Mark I Z. has an armour piercingbullet and a nitrocellulose propellant. Similarly, the letter T in place of Z wouldindicate a black powder propellant, and absence of a final letter a cordite filling.

(i) 1 inch Aiming Rifle Ammunition is fired from aiming rifles, whichfit into parent guns. It is manufactured either for electric or percussion firing.

(ii) 20 m.m. Ammunition of various types is fired from 20 m.m. automaticguns such as the Oerlikon and Hispano. It fires by percussion and is supplied inbulk. The different types are distinguished by the colour of the shell.

(iii) .5 inch Ammunition is fired from Vickers and Browning machine guns.It fires by percussion and is supplied in bulk and in articulated belts. Care shouldbe taken that this ammunition is fired only from guns for which it is intended.Types now available are Ball, Tracer, A.P., S.A.P., S.A.P. Tracer, Incendiaryand Drill.

(iv) .303 inch and .30 inch Ammunition is fired from machine guns,including aircraft machine guns, and rifles. It fires by percussion. The cartridgesare supplied in chargers, bandoliers, strips, articulated belts, and in bulk. Ammunition is not to be fired from synchronised aircraft machine guns more thanfourteen days after the box has been opened and the rounds " exposed "; thisperiod may be extended to forty days if such ammunition has been exposed andsubsequently kept in airtight lockers. Types now available are Drill, Blank,Dummy, Ball, Armour Piercing, and various sub-types of Tracer and Incendiary.

(v) .45 inch Ammunition is fired from the Thompson sub-machine gun.

(vi) .455 inch Revolver Ammunition is fired from the Webley Revolver(Pistol, revolver, No. 1). It is supplied in packets of six (828 rounds in box,A.S.A. 1/2 N., H.3).

(viii) .22 inch Ammunition is fired from Service rifles and pistols that havebeen tubed to fire this small cartridge. Unique amongst percussion-fired cartridges, it is fired by a blow on the rim of the base instead of in the centre. Thedesignation R.F. means rim-fire. It is supplied in boxes of 100 (10,000 roundsin case, powder, M.L. quarter).

RIFLE GRENADES.

217. The No. 36M grenade, the only one likely to be encountered, consistsof a Mill's bomb, to the bottom of which a gas check plate has been screwed.The grenade is projected by a special blank cartridge, out of a 2 1/2 inch discharger,which can be fixed to the muzzle of a rifle; the latter is specially strengthenedfor the purpose. The special blank ballistite cartridge is blackened for half its lengthfrom the mouth, which is not crimped. No other cartridge is to be used.

Outside the grenade is a striker lever. Before it is projected, one end of thislever holds the striker against its spring away from the detonator, while the otherend of the lever is kept into the side of the grenade by a retaining pin. Whenthe grenade has been loaded into the discharger, this retaining pin is removed;the striker lever is then held against the grenade by the wall of the discharger.

218. On firing, the striker lever is no longer restrained by the wall of thedischarger, and is thrown off by the striker travelling downward under the actionof its spring. The striker fires a cap, which ignites a length of safety fuze in thegrenade. The safety fuze burns for four or seven seconds before firing the detonatorwhich detonates the filling. If for some reason the grenade is not projected, eitherfrom the discharger or by hand, the pin retaining the safety lever must be replacedbefore the safety lever is released either from the side of the discharger or the hand.Should the safety lever be released inadvertently, there must be no hesitation inthrowing the grenade clear, or serious injury, possibly death, will result to anyonenearby.

Detonators for grenades are issued separately and are provided with instructionsfor fitting them to the grenades.

FIREWORKS.

219. The fireworks supplied to the Service are:-

In addition the following are for use by aircraft:-

FIREWORKS SUPPLIED FOR NAVAL SERVICE.

Signal Rockets.

220. Rockets are employed for signalling and display.

Rockets on board are fired from a rocket machine by means of a copper friction

The friction tube is a small copper cylinder in which fits a friction bar. Whenthe bar is pulled out smartly the tube fires and its flash ignites the composition inthe base of the rocket.

Rockets are fired from a boat by means of a rocket upright, a portfire orslow match being employed to ignite the rocket.

At the end of its flight the rocket bursts, and throws out a number of whitestars. The rocket supplied to the Service is:-

Rocket, Signal, 1 lb., Service, with red, green, or white stars.

Line-carrying Rockets. (see para. 239.)

Rockets, Target Practice.

221. These are ignited by friction match and safety fuze: 'they eject a paperor cotton red parachute as an aiming mark for A.A. practices.Short Lights.

222. Short Lights burn with a white light for about two minutes, and areused for signalling and illuminating purposes. They are supplied fitted with ahandle, which has an igniter plug in the bottom like a large match. To ignitethe light, tear off the cap, pull out the plug, and draw its primed end lightly acrossthe top of the light in an upward direction. Hold the light so that it points awayfrom the body and with the back to the wind.

Portfires.

223. Portfires are brown paper cylinders filled with composition, and areused for lighting rockets or setting fire to anything They burn for about 10minutes and normally cannot be put out by water. They can be lit by short lightor slow match, and put out by cutting off the burning end.

Slow Match.

224. Slow Match is hemp soaked in saltpetre. It is generally used for keepinga light burning, as in a boat. It burns at a rate of one yard in eight hours. A yardweighs about 1/4 lb.

Signal Cartridges.

225. Signal Cartridges (1 inch) are fired from a special pistol and are used forsignalling at night and by day at limited distances. When fired, a star is shot ashort distance into the air, and burns red, green or white as it travels. Wherepracticable the pistol should be fixed to a bracket or otherwise secured, and firedby a lanyard.

The cartridge which contains the star is made of metal or cardboard, andthe end is closed by a paper disc of the same colour as the star. In the dark thecolours may be recognised by feeling the rim at the base of the cartridge:-

Red is milled.
Green is smooth.
White is half milled and half smooth.

A useful mnemonic is to associate the colours of road-crossing lights, viz., Redthe way is barred, Green the way is clear, and White is halfway between the othertwo.

To fire a signal cartridge, open the pistol by pressing down on the catch on theside. Insert the cartridge and close the pistol. If the pistol is not held in aholder, it should be lashed to a boathook or an oar. Before pressing the trigger,the head should be turned away. The pistol should be pointed about 60 degreesin the air to windward.

Magnesium Flares.

226. Magnesium Flares are of two types:-

(i) Flare illuminating white, Type 26. Fired by friction.
(ii) Flare illuminating white, Type 26E. Fired by an electric current (anordinary service torch battery will do).

Two flare stands are allowed to each small vessel supplied with flares. Instructions for firing appear on each flare. Flares can be burned either from therigging or from the special stand supplied. When the flare is burned from therigging, precautions must be taken to ensure that the molten residue does notset fire to anything on which it may fall. When burned from a stand this residuefalls into the sea. Flares burn for about 4 1/2 minutes. As they temporarily blindpersonnel in the ship burning the flares, full value is only obtained when observingvessels are present. The flares illuminate an area of water which extends for arange of about 3/4 mile, and hence any object between the observer and the flarewill be illuminated or silhouetted. The flare burning vessel should be to leeward.When flares are required for immediate use they should be kept away from heat.The packages in which flares are supplied should be kept in a cool dry place andno more should be taken out than necessary.

FIREWORKS SUPPLIED FOR USE IN AIRCRAFT.

227. A Distress Signal is ignited in the same way as a short light. Whenignited, it shows a red flare for about 10 seconds and then ejects 5 red balls like asignal cartridge at approximately five second intervals to a height of about50 feet.

Flotation Gear Actuating Cartridge when fired allows carbon dioxide toinflate the collapsible dinghy carried in aircraft. It functions by means of anelectrical circuit which is completed on immersion in salt water and which ignitesa filling of guncotton dust.

The above-mentioned fireworks are kept stowed in or near the aircraftdinghy.

228. Cartridges, 1 1/2 inch are fired from a 1 1/2 inch signal pistol in a similarmanner to the 1-inch cartridges described in para. 225 above. They include:-

229. Reconnaissance Flares have a candle power of about 750,000 and arefitted with parachutes to reduce the rate of fall to 500 ft. per minute.

231. Engine Starting Cartridges are filled with a propellant charge in the formof pellets. Five cartridges are carried in the breech of the starter in certain aero-engines and their explosion drives the piston for the first stroke.

FIREWORK BOXES.

232. Fireworks are supplied to ships in firework boxes or metal-lined cases,which are stored in the Firework Magazine, Firework Tank or Shell Room.But as fireworks may be wanted in a hurry, ready-use supplies are kept in thefollowing:-

Night signal box,
Sea-boats' boxes,
Boats' magazines and gigs' magazines.

233. The Night Signal Box is kept on or near the fore bridge. It contains:-

3 signal rockets.
1 tin of friction tubes.
18 1-inch signal cartridges, 6 of each colour.
1 pistol, signal, 1 inch.
2 short lights.

As the firing of a rocket is the signal at night for " man overboard," the rocketmachine is always kept loaded and lashed to the weather side of the bridge betweensunset and sunrise. The placing of the rocket is the duty of the Seaman Gunnerof the Watch.

234. A Sea-boat's Box is kept in each sea-boat whilst the ship is at sea. Itcontains:-

24 1-inch signal cartridges, 6 red, 6 green and 12 white.
1 pistol, signal, 1-inch.
4 short lights.

235. A Boat's Magazine forms a ready supply of ammunition and fireworksto be taken away in case of prolonged duty in a cutter or larger boat armed with3-pdr. Q.F. or .303-inch machine guns. It contains:-

204 rounds of pistol ammunition in a special pouch with a strap.
1 key for metal-lined cases.
1-1b. slow match.
2 portfires.
2 1-lb. signal rockets.
2 Short lights.

96 rounds of pistol ammunition in a pouch with strap.
1 signal rocket.
1 portfire.
1 short light.
1-lb. slow match.
1 key for metal-lined cases.

237. Power-worked boats are at all times to carry:-

18 1-inch signal cartridges, 6 of each colour.
1 pistol, signal, 1-inch.
6 short lights.

LINE-THROWING GUNS.

238. All ships are supplied with one or more of these. Older ships are suppliedwith Coston guns, but these are being replaced by rifles, M.L.E. .303-inch, (long).Both types of gun are supplied with special projectiles and blank cartridges. Thecartridge for use with the Coston gun has a diameter of nearly .5 inches, thatfor the M.L.E. .303-inch rifle is blacked all over.

The guns are fired as follows:-

LINE-CARRYING ROCKETS.

239. The Schermuly line-carrying rocket is supplied for carrying the end of aline through the air. It consists of a steel tube, filled with rocket composition,to the outside of which a short steel rod, or outrigger with a thin wire pennant, isattached; to this is secured the end of the line.

The rocket is to be fired as follows:-

(v) Hold the pistol at an elevation of about 20 degrees, and fire it pointingslightly to windward as necessary.

MAGAZINES AND SHELL ROOMS.

240. Cartridges for guns are kept in magazines. Projectiles are stowed in baysor sliding shell stowages, in shell rooms. Fixed ammunition is stowed in magazines.When required, the cartridges are passed from the magazine to the handing roomoutside, and thence to the guns. Handing rooms are not found in sloops ordestroyers. In some ships shell-handing rooms are also fitted.

241. Magazines of big ships, i.e., battleships, battle-cruisers, cruisers,aircraft carriers, and depot ships, are built as water-tight compartments andprotected from shell fire by armour. They are fitted with ventilation arrangements; magazines sited in hot positions (e.g., near machinery spaces) and alsothose in certain ships in which bare cordite charges are handled have, in addition,cooling arrangements incorporated in the ventilation system. By adjusting thevalves in the ventilation system the fan can supply fresh air direct to the magazineor alternatively recirculate the air on a closed circuit, either through or by-passingthe cooler, as desired. Magazines with cooling arrangements are fitted with long-distance thermometers, or with thermometers in tubes, called temperature tubes,which project into the magazine, so that the temperature can be taken withoutentering the magazine. When cooling arrangements are fitted the temperaturesare taken every watch. The temperatures of all magazines are taken daily andentered into the magazine log.

The principal magazines of big ships are protected from flash, such as mightoccur if a cartridge became ignited on the way to or at the gun, by flash-tight doorsand scuttles, through which the cartridge must pass on its way to the gun. Smallermagazines in big ships and magazines of small ships are not fitted with any specialflash-tight arrangements. This is to save weight and because Q.F. cartridges,which are better protected against flash than B.L. cartridges, are usually stowedin these magazines.

Magazines of small ships are either unprotected or protected by light armouronly. In some cases the magazine and shell room together make a water-tightcompartment, the bulkhead between magazine and shell room being flash-tightonly.

Magazines, handing rooms, and shell rooms are inspected every 24 hoursand after work, drill, or firing.

242. Points to receive special attention at inspections are:-

(i) Doors, hatches, and man-holes efficient and properly secured.
(ii) Compartments properly stowed, battens and stanchions in place.
(iii) Lids of cases and boxes on and properly secured.
(iv) Deck clean and free from dust.
(v) No cleaning gear, rags, inflammable material or other unauthorisedarticles in the compartment.
(vi) Oil from glands efficiently caught.
(vii) Flooding and spraying arrangements correct and free from leaks.
(viii) Lighting switches efficient and properly covered.
(ix). Clarkson's cases clean, empty and dry.
(x) Temperatures; these are also noted.

243. In the event of fire, the magazines and shell rooms of big ships can beflooded through pipes running directly from the ship's side. In addition, thecordite cases in the main magazines can be sprayed with salt water from the shipsfire main.

The valves operating the flooding gear can be worked from at least two positions,one close to the magazine and the other in a flooding cabinet or locker some distance away. The spraying gear can be operated from inside the magazine, fromoutside the magazine, and from the cabinet or locker.

Flooding arrangements are to be tested weekly, except when the valves aretoo numerous to be worked conveniently once a week. In this case they aredivided into groups, each group being worked in rotation so that every valve istested during the course of each month.

Valves on the spraying system are to be worked weekly or, by groups, at leastonce a month. The perforated pipes are to be blown through every two years.A thorough test of the system by the admission of water is to take place wheneverthe magazine is cleared.

The above systems are quite separate from the drenching system which in thecase of 15 inch or 14 inch turrets works off the hydraulic pressure main.

Magazines of "small" ships have no cooling plant, and usually no sprayingarrangements. Water for flooding is supplied by the fire main system.

244. To prevent unauthorised persons from entering the magazines and shellrooms, all doors and hatches which lead to these compartments are kept locked.The keys for these locks are called " Magazine Keys," and are grouped 1, 2 and 3,according to their importance. They are kept on a special key board, under thecharge of a sentry, and only officers and certain specified ratings are allowed todraw them.

The times when magazine keys are drawn from and returned to the magazinekeyboard are recorded, against signature, in the magazine log. In the log are alsorecorded magazine temperatures and results of the various inspection rounds.The sentry signs the log at the end of each watch to attest the accuracy of theentries relative to the issue and return of the keys during his watch.

Before a party goes into a magazine, all knives, matches, and anything whichmay cause sparks or fire must be left outside. To obviate any possibility ofsparks being caused by the sole of a boot striking the deck, special rubber or felt-soled shoes are always to be worn in B.L. magazines.The lights are switched on by special switches outside the magazine, and alight shows at the magazine keyboard when these switches are all off. Thesentry is thus able to check that all the lights have been switched off when thekeys are returned. Should the main lighting fail, portable electric hand lamps areused.

245. The cases in the magazine are stowed in bays, care being taken that,when possible, the lid of each case is accessible without having to remove stowagebattens. Lids of cases are removed by hand or by gunmetal keys, but must notbe taken off until the contents are actually required. In modern warships withQ.F. ammunition the cartridges are removed from the transport cases and stowedin bottle-rack stowages built into the magazine. The cartridges are kept in placeby a spring-loaded clip which takes over the edge of the base of the cartridge.A small key is supplied to lift the clip against the pressure of the spring, thusenabling the cartridge to be removed from the rack.

AMMUNITIONING SHIP.

246. The regulations regarding this are laid down in N.M. and E.R. Themore important of them are summarised below.

Before commencing to embark ammunition, all stowages are to be thoroughlycleaned; ventilation, flooding and spraying arrangements tested, and compartments dried out.

No smoking material is to be taken into the hold of the ammunition ship orlighter. Smoking is prohibited while work is going on. When work is not goingon, smoking may be permitted in places set apart and well removed from theexplosives; the latter are to be guarded by sentries.

Explosives or cases and boxes containing explosives are to be hoisted and lowered with care. Shot mats are to be used at the dumping positions. Rough usageis liable to loosen shell caps, injure driving bands, impair the flash-tight, andwater-tight properties of cases, and render tubes dangerous or inefficient.

The receipt or discharge of ammunition should never be treated as an evolution,and care should be taken not to bump cases on the deck. Cylindrical cases shouldnot be rolled. Should a box or case catch or jam in any way such that damagemay be caused, it should be set aside and carefully examined. If any damage orsuggestion of damage be found the package should be returned to an ArmamentDepot for examination.

247. Embarking or disembarking ammunition is not to be carried out in verywet weather if it can be avoided. If it cannot be avoided, protection from the wetis to be provided. Wet cases and shell are to be wiped thoroughly dry beforebeing stowed.

W/T transmission is prohibited when embarking or disembarking ammunition.

In the event of a thunderstorm, the operation of embarking or disembarkingammunition is to be suspended from the time the first thunderclap is heard untilthe storm has ceased. During this period, whips must be removed at least 6 feetfrom any explosive.

248. None other than the authorised appliances are to be used for lifting andtransporting explosives, and the proper lifting handles and beckets fitted to thecases and boxes are to be used. Where two or more beckets are fitted, two of theseare always to be used. In many ships special whips for hoisting ammunition areprovided, and are to be used; they are not to be used for any purpose other thanammunitioning. Ammunition whips are to have the standing part of the wiresecured to the drum of the winch.

Special capstan-headed grabs are supplied for hoisting shell 8 inch and above.Care must be taken that the grab is screwed properly down before lifting andthat, when removing it, it is pulled clear of the shell before "Hoist" is ordered.

249. All whips, tackles and other appliances used for embarking or disembarking ammunition are to be examined before starting work, and occasionallyafterwards, to ensure that they are sound.

Double or multi-legged, slings are not to be used for shell grabs owing to thepossibility of damage to, or the opening up of, the palms of the grabs. This maybe caused by their clashing together when being hoisted. An exception to this

250-254.