NAVAL WARFARE.

North Otago Times, Volume C, Issue 13147, 31 August 1914, Page 3

NAVAL WARFARE.

THE AMMUNITION USED. ' ARMOUR PIERCING SHELLS. ! In a recent article, on animunitioii - it was explained that the land artillery i! used 'principally two forms of. projectile ' j— slira'piiel for "inhn-killiiig," ami high'- !: explosive shell for the destruction of I shelters. So, too,' in the Navv, big-gu'n i projectiles fall within two classes, but j both are aimed primarily at the ships. ,! That men arc killed'is an incidental, I Individually and apart from his ship, the modern nian-of-warsnian has small {fighting value. Silence his guns, and lie |is beaten, for lie cannot charge his loneiiiy. The guns may certainly be J silenced by killing off tho crew; bill ' there arc quicker methods. Tho object jis simply to di.snhfb I jio chip as a lighti ing. machine, either by smashing lici' ' into, harnilcssncss, or by sinking her ; with >}ll her remaining power, to hurt—s: and, -"'unfortunately, with all her crew. 11These.two projectiles arc "common" I!aiid "armour-piercing" shell. Bej cause the attention is most easily lixed i 1 upon it, let, us consider the arpiour- . j piercing shell first.' r It, is a very interr csling study. The first essentials' of vj sucli ii shcli arc that it shall lie strong • enough to'"' stand the terrific shock of . striking an extremely-strong plate of i steel; and that it shall be hard enough . jto / pierce' it; thereafter is a'third cont j sidcration, that when it has pierced the '•larmour it shajl not be inert metal, but a j shall burst and do as much internal 3 damage as possible, The first big naval I j shells were made of cast-iron, and the 'first armour-piercing projectiles were |! made by the! I'alliser process. Instead s i of casting them in sand-moulds, Sir \V. 0 jPalliser had theni cast in a mould made II of iron; kept as cold as possible. The 'i j c nil ling of the, iron made the head of ii! the shell extremely hard, and the result 111 was a marked improvement. But the 0! inevitable improvement iii armour soon a j made a better shell necessary; and mod : I) | em armour-piercing shells- are made oi f special cast steel, of extreme strength, i,' forged .into shape, machined to shape, j. and hardened and toughened with as much skill and care as a razor-blade, One has only, to-study the extraordinary results of tests of shells and armour to t realise how wbnderfui these projectiles 3 are; They arc, of course, cylindrical, 1 with pointed heads'; and'only long ext perieuce has dictated the exact shape S of tlie strong yet' sharp point. The i shells are hollow, but have thick walls;

V aid'-the metal is massed iji the head, so '■ as to. give the. greatest strength, possible e to it, The'hqliow is filled with a charge, e of powerful explosive, weighing rougli--0 ly, one-thirtieth of the shell's, total •* weight, and sufficient to smash'it into s ragged, heavy, chunks, and' send them 0 flying in all directions. These' shells do e . not require fuses, though 'they are'-often 6 fitted with them, in the base.' I, ' ■! The Dapped Shell. ■' shell is ; quite' a simple thing; but it % cannot be; discussed without' special re- ? ference to its "cap." Upon the nose of all such shells' there are now fixed ® nose-pieces' of soft steel. . They fit s closely the-curve of the shell's point, * but, until recently, were thimble-shaped 1 on'the outside, so that they toolc away all appearance of sharpness. Latterly, they have been prolonged so as'to'put' j a long point to the shell, for the obvious r " reason that they: i'lius offer less resist- ,! unco., to the air, and the range, is,ini- ■(. proved. But the prolongatipiUß hollow; the business -part of the'cap consists of j, the portion actually 'surrounding the r nose of the shell, and the forward part y is simply crushed like an eggshell when, jj it strikes the target. These caps have an extraordinary offeet upon the ability of a shell. Ural at 1U very high velocity, lo pierce armoury , r Tlicy increase that ability by perhaps l_ one, fourth, though the increase is very ,'e various, and vanishes altogether unless s the velocity is high.. Many a long argu(j nient there has been as to how. it is \ - done. It'js agreed tha,t the cap has the [C effect of holding Me point of the shell .6 together when it atrikes tlfe plate, which ft otherwise -might':':., crush thb shell to ;si.pieces;. and undoubtedly, it. does give i; tlmt sxipport. The question is, how, . considering. the .weakness of the cap, d does,t-liis come about?-'" ii is more a sube. jeet for. mathematicians. tliaii for geneit ra I' readers; but i t in/iy be stated that it one very sound-lookirigi explanation , is ic that .when the' sliell' strike's,''the . cap r- offers, in ' addition to its small, resist;s ance, stretched, "an enormous ir resistaiicc'tp;:being: moved, sideways,by. d- the wedging'action of .the shell passing id- through *iti Headers- must not let tlienit- selves lie. jiicrodulous; wliciMt is-stateil ;i ith'it-> l-hV»---'ji?alfl»\laJtioi}'F■"' e-ipeft : sliow V that this', if. 'in Uir cap of a s-. large shell, -as'.much - as-. toxis per 3- square inch close to the point, of the s, shell, and on ef 1000 tons to the square t* mcjj l one -.inch- frojn.\tlie. extreme point/ d Suqh a/ pressure exerted upon the sur ly- 1 face 7 of the shell ! is obviously of value m v-. t: ;/fev.f.

proven ting it 1 from being burst ito Wliatovor is Hho-explanation,-rri,. arid this "radical inertia" theory looks good^.'ciiough'onipapor—the, cappodßnoU; ■ uncloukedly makes a • ■ wonderful -yer-,, ; foriiiaiiec plaie. It lS'genVallv assumed thi),t an armour piecing shell yrill go through a hardened steel plato of thickness equal to itS'.Wn diameter, at a rango olj: about - 8(f00 yards—about > four- ( milc» i and a half.' Variations on both sides occur, soijip bliclls hayo pierced armour much tluckoj; and certain armour- 1 plates liavo, witlistoqd,! on thc' prowng grounds, pro]Gctilcf< far aljove-thoirown. } figlitingrcalibro. : It: must, liOA.rcmom-. bercd, too,-that the shell,, to do -its : best, .must strike-the : platc fairly. A - shot fiiivwhcio ncar ; 'right 1 angles means the defeat of tho plator but an cxces sive angularity.will Bend- the shell off sideways, and leave the .armour littty . worso-for tho encounter. • : "Common" Shell. . "Common" shells arc of lighter structure, and because they, have thinner walls,' they arc loiiger-'than armourpiertfing*: variety for'tho .*■ same,:' gun.!, ' Their 'internal capacity ia much larger,. aiid is filled with a high ■ explosive .ot ' tl)e lyiiilitb family; These shells ÜBuatly , carry fuses ih-the-re'arcndj' tb explode oil strikiligf the;action;of the fuse.'being; a! little delayed to allow the'shell to rdadh the iiiside of the ship..'before it bursts. ; The fuse works, on just tlie same principle as that described iii coni nection with 1 , the shrapnel shell,-but it' . has somei interestingvariations. '. One ■ never khovys,'.for instance; when a shell' , niaV be dropped in 1 handling, 1 arid tho fuse is therefore locked so that it cannot act. The, firing of the gun releases, it from.tlie locked position. In. souiO: cases there is a thin plate in the base b.f i the shell,'and the pressure of the explosion crushes it in, and so'works the' re- • i lease; In others, the locking gefir turns, , | and works bj' inertia. When tho 'sliell starts to spin in .the'rifling, the lock re- .! mains',, without for. 1 a while,■and , thus the safety devico is unscrewed. Ifi?rtia thus'plays-quite an important. , part iii projectiles; it not only fire? the. ! ,j fiises of the shrapnel and the common/ 1 '.-'shell, but it. may unlock the "trigger" :|of the fuse; and in the. annbur-piefcing ,-j sliell it plays :a' big part' in - helpingi to''I:defeat;th'e v ship's | ; The common shell •is not' available j 'against ally-thiek'ne&s of ; armour. - Tf it ; anything : beybiid its -strength^; it . j simply siiia'sh'e!ivup,' ; and the explosion;' |! if it 1 occurs 'sliip,' does'.ifom* J | paratireiy' little damage. Its function ' I is. ■ to.; ; reach the enclosed ' uuarm,loured, .spaces,, "nii'd spread, devasta-- ' j-tibn-'there.; biit ; wherever' it bursts- on : board'ship it- is' likelv to cause serious )-j dainage.' Common shell' are used'- in I naval guns, of all sizes; whereas, tho ; smaller sorts seldom fire armour piercing projectiles. Tho Guns' Charges., ' It is clearly impossible for a hardened steel shell to bo made to fit accurately the'rifling of the barrel, and a band of copper is fastened round the projectile ! near the base. It has a thin projectling ridge too big-to pas 3 through the l-gnn without heavy pressure, and ; this seizes , the and. is pressed into. II gas-tight contact' with the bore, so that ■ jno power is lost bv what the gunner , I calls'' windage;' 1 For the smaller guns ! | in the British Navy, cartridges contain- ! ing tho firing cluirgc and the shell fixed i in position 'arc used; but in the bigger ; ones the projectile and the cordite charge are separate/ All guns up to the [ Hi'n" use brass cases, but. over that sizq i the. Ii ring charge is done up in bags i'liiade of wool or'silk, which can be . trusted not- to smoulder and set fire to i t-ii'e next charge' wlien it i 3 hurriedly, i put in. It is a feature of the German 'navy that .all ammunition is in cartbridges. Tliis is necessary because the ■ ! guns have tho Ivrupp breech action, In the Briti.sh and many other navies, the \ breech is closed by a scmwcil plug, and -1 the escape of gas through tlie intei'S--.'tices is prevented by an "obturator," ' a -sort of pad held by a mushroom !• jshaped head on the front of the. breech:l lock. The heavier (he pressure due to '• the explosion the lighter tlie pad is '-'jammed against the sides of tho barrel, f aiid no gas leaks past. The Krupp action giis essentially different. Through the rear f: of the gun, and crossing the bore, is a t f j large slot, and a block slides in tlie slot, h. Wlfcii it is pulled out, the charge can i-ibe passed through, aud to close tho ci breech the block is sli,d iuto placo t' again. It is clear that an obturator d' cannot be used here, and the brass cartil; ridge takes its place, The explosion ej expands' it tightly against the sides of e; tlie chamber, and it forms: a perfect gas d j check. . [• I A few' words may be added as to the e i method of tiring- big guns. There are e! alternative w; f ays, but the. principal is f bv electricity,. In the breech-block'there, it is ; a s'mali hole, aud into this. i 3 placed o tho "printer"—a. brass case about' tho " j size of a rifle cartridge. It contains a I- charge of powder, and a somewhat intricate construction for leading a curb rent of electricity into it. Buried iu 3 i the powder is a short length of very ■ s line wire, through which the current -• palsses. The gun is aimed—in action }' it is the duty of tho gun-layers to. see 0 that it' is aimed all the time—aiid !S loaded. The word is given, the"gunner 'i presses the trigger, of a device just like a brass pistol, placed, wherever 'it is ' e handiest. 'There'is a momentary glow e in the buried scrap of 'wire. " The ; i primer shoots its-flame into the huge

parcel of- cordite—and the shell is on its' deadly way. ',. The following list shows the weights of! tlie projectiles ; and' cordite charges of the principal British naval guns, and in most cases the, speed in feet per second (f.s.) at which the shell leaves the guii:—l3.s inch, 'shell 13501b (?), cordite about :4,001b; 12 inch, 45 calibre, shell ,8501b, cordite. 3251b, 2900 f.s.; 10 inch, sHell. 5001b, cordite about 1201b; 9.2 inch, sliell 3801b, cordite 1031b, 2800 f,pi; 7.5 inch, sliell 2001b, cordite about 50lb, 2800 f.s.; 6 inch, shell' 1001b, cordite, 201b, 2750 f.s.; 4 inch, shell 451b, cordite 51b 70z,. 2100 f.s.; 4 inch, shell. 251b, cordite'3]b 9oz, 2300 f.s.; 12pounder, she'll 12ilb, cordite 31b, 2210 f.s,—'' Eyenjng Post,' Wellington, ts, , ■ ' ——.