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m-s riwc R-D f i81t/ / :, / I+ ./A (. L/NAVY DEPARTMENT, BUREAU OF ORDNANCE, WASHINGTON, D.C. OP 1002 CHANGE ITo ail holders of Ordnance Pamphlet 1002 (1st. Rev,) (1stev )!nsert change; write n cover Change I entered

-4 I2 September 13QLtApproved by The Chief of The Bureau of Ordnance --- -.A

is changed OS follows: AND AMMUNITION

1 e c i ;,s:;i:'ications changed from C~~NF'Ij)EI'iTTAL,o RESTRICTED. Clasrifioat ion is now marketla. CJIJI.. z!J?Ii:,I,n the cover and every page cf lJa!lll)r,iet;hl:; ,ouLd be cl!:,nged,o ?Q'1'1~lC'.1L

JJ~STFIBUTION- - - - - - _ --Heque -t,c: for :idritionaI opies of OP 1002 (1st Revision), Change 1 should be submitted on NAV(JXE0rrn : !rRDNI,NCll:UBLICATIONS AND FORMS REQJJISITION, o the nearest Ordnance Publications ?Jlc;tribu? f~rlenter: Navy Yard, Wash. 25, D.C.; Adak, Alaska; Pearl Harbor, T.H.; Mare I::l;intC2,lif'.11 piritll anto, New Hebrides; Exeter, England;Brisbane,Australia'. Disi i~JUtiOn Cent.i:rrn;i ii r!,?.dtireSC?Sshould be obtained from List!Onnof the Standard Navy Di::tribut,ion,irt, 1from _ ,e ever:+:ide of NAVORD FORM 1.star,cl:-d L ~Jl.:;t~itJUtiOn List No. 262 co, e' c;li. ILless therwise noted..1. 'I) :, :, I, , k, 1;3. h, c, h, k, n, v. 'i 2;5 : I,lJ'J';,ui

I. Y, :I , u+' x, ee. ( 0 p i es> h:, . :i i, j, i,'1: 6P;dI:t &STS G, K, Q, S, Z, kAj, hhP. , )/I oijiei:),, n (IO)

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BUREAU Of6iibNANCEWASHIN GTON 25, D. C.

To all holders of Ordnance Pamphlet 1002 (1st Rev.)insert change; write on cover Chan ge 2 insertedApproved by The Chief of The Bureau of Ordnance1 Page Page 1

ORDNANCE PAMPHLET 1002 (1st Rev,)is changed as follows: 7:2 ROCKET LAUNCHERS, MK 20,MK 22, AND AMMUNITION,

i On page 4, a dd th e following referen ce:OP 1437 . . . . . . . . . . . . . . . . . . . Range Table for 7.2 InchShipboard Rockets

>On page 58, add th e following note u nder 712 assem blies:

Ran ge Table d ata for 7:2 assem blies given in OP 1437 sup ersede th ecorresponding data given in this table.

DISTRIBUTIONRequest s for ad ditional copies of OP 1002 (1st Rev.) Cha nge 2 should be s ubmit ted on NAVORD FORM 1ORDNANCE PUBLICATIONS AND FORMS REQUISITION, to the nea rest Ordna nce Publications DistributiokCent er: Navy Yard, Wash. 25, D.C.; Adak, Alaska; Mare Island, Calif,; Gua mIslan d, Ma rian as; P ear l Ha rbor,T.H.; Manus Island, Admiralty Islands, Distribution Center ma iling addresses should be obtained from List1Onn of the Standa rd Navy Distribution List, or from the reverse side of NAVORD FORM 1.Standa rd Navy Distribution List N o. 28 (C) and 31 (R)2 copies u nless oth erwise noted.1. a, e, g-i, k, 12. a*, c, h, k, n3.* c(l), k, o, z, bb, kk , mm , nn , w(3), ww-yy, bbb;B3. LIONS, CUBSF.: k z bb k k m m, nn, ww-yy, bbb5. b (Londbn only)6. a7. f, h-k, u*, x, ee;. (5 copies ), b, c, j, p, s. b, h*, i, j, 1, n (SPE CIAL LISTS G, K, Q, S, Z, AA, GG, NH), hh10. i, .j, t, qq, ss10. (25 copies), nn11. a (BuShips, CNO, ComdtMa rCorps)12. a, b (Revision 1)13. c(3), (4), (6)14. a, q, s.* Applicable add ressees.

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/i WESlRiCTED NAVY DEPARTMENTBUREAU OF ORDNANCEWASHINGTON25,D.C.

To all holders of Ordna nce Pam phlet 1002 (let Rev)insert change; write on cover Change 3 insertedApproved by The Chief of the Bureau

OIUINUCE AWHLET1002 (let Rev)is changed a8 follows:

OP 1002 (let Rev) CHANGE 315 November EJL~

Acting Chief UJ Bureau 1 P a g e P a g e 17!2 ROCKET AmCmH s, - 20,MARK 2 ANDAHHUNITIOP

1. Insert Change 3 inetru ctlon sheet between Chan ge 2 instruction sheet a nd tltlo page.2. P8ge 33. Cancel lnf ormatian in lae t para graph under NOTE.3. Page 34. Cancel informa tion continu ed from page 33 and the two para graph0 above theheading Safety Featuree.4. Page 35. Cancel heaiing Handling an d the para graph below the heading.

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CONF I DE NT I ALRDNANCE PAMPHLET No. 1002FIRST REVISION

72 ROCKET AUNCHERS,ARK20,MARK22 AND AMMUNITION

DESCRIPTION AND OPERATION

30 NOVEMBER 1943

This publication is CONFIDENTIAL and will be handled in accordancewith Article 76, United States Navy Regulations, 1920

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NAVY DEPARTMENTBUREAU OF ORDNANCE

WASHIN GTON, D. C.

CONFIDENTIAL 30 November 1943

ORDNANCE PAMPHLET NO. 1002, FIRST REVISION7.2 ROCKET LAUNCHERS, MARK 20, MARK 2FL,AND AMMUNITION

1. Ordnan ce Pam phlet No. 1002, First Revision, describes the operation and use of the7.2 Rocket Launchers, Mark 20 and Mark 22, the contr ol panels, t he equipment, and theam mu-nition used with these launchers. This pam phlet is made in loose leaf form with th e intent iontha t when n ew Marks and Mods. of 7 .2 Launchers and Ammunitionthe data t hereon can be readily added as additional chapters.

ther efor are approved,

2. This pamphlet is intended for use by officers for t heassigned t o operate and mainta in the equipment.

instru ction of men who may be

3. This pamphlet supersedes 0. P. 1002 dated August 1942, Ordnan ce Circular Let tersA69-43, G4-42, an d G13-43, which s hould be dest royed by burn ing in th e pres ence of a com-missioned officer. Other publications on these and related equipment s are listed on page 4 ofthis Ordnance Pamphlet.

4. This publication is CONFIDENTIAL and should be han dled in accordan ce with thecurrent edition of the Registered Publication Manual and Article 76, U. S. Navy Regulations,1920.

W. H. P. BLANDY,Rear Adm ira l , U . S . Na vy , I

C h i e f o f t h e B u r e a u o f Or d n a n c e .

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7 .2 ROCKET AUNCHERS 0. P. 1002

REFERENCES TOEXISTING PUBLICATIONS

The following pu blicat ions, pert ainin g t o Lau nch-ers, Mark 20 and Mar k 22, and accessories, may be ofinterest to personnel responsible for launcher instal-lations.

0. P. No. 1017 Pr ojector Char ge Fuzes (Restr icted) August 1943.0. S. No. 2759 Specifications for the Installation and Test of Pr o-

jector, Mar k 20. (Restricted .)0. S . No. 2963 Specifications for the Insta llation and Test of Pr o-

jector, Mar k 22. (Restr icted.)Ordalt No. 1383 Pr ojector, Mark 20, Installation of Watert ight

Safety Plug and Rewiring of Control Pan el.(Restricted.)

Ordalt No. 1435 Pr ojector, Mark 20, Instr uctions for Stiffening th ePr ojector Ways. (Restr icted.)

Ordalt No. 1803 Control Pan el, Mar k 2, for Launchers, Mark 20 and22---Replacement with Control P anel, Mark 3, Mods.2 or 3.

Ordalt No. 1836 7 .2 Launchers, Mark 20 and Mark 22, Installationof New Type Knife E dges.

Ordalt No. 1952 7.2 Rocket Launchers, Mark 20 and Mark 22,Installation of Watert ight Electrical Wiring.

BuOrd. Conf. Circular Letter No. A4-43, dated J an. 1943.BuOr d. Circular Lett er No. A31-43, dat ed 1 May 1943.BuOrd. Conf. Circular Letter No. A50-43, dated 25 Ju ne 1943.BuOrd. Order N o. 47-43, dated 8 Ju ly 1943.Cominch Tentat ive Instr uctions, P rojector Char ge, Mark 20 and Mark 22 (Mouse-trap)(confidential).

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CONTENTS 0. P. 1002Page

REFERENCES TO EXISTING PUBLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Chapt er 17.2 ROCKET LAUNCHER, MARK 20 .......................................... 9

INTRODUCTION. ............................................................ 9DESCRIPTION ............................................................... 137.2 ROC KET LAUNC HER ............................................. 13INSTALLATION ....................................................... 15ELECTRICAL CO NTROLS ................................................ 17FIRING PANELS ........................................................ 21

Chapter 27.2 ROCKET AMMUNITION AND FUZES .................................. 25

AMMUNITION ............................................................. 257.2 ROC KET. ................................................................ 25BODY ................................................................ 25MO TOR .............................................................. 27PROPELLANT COMPONENTS ......................................... 27

FUZE SEAT LINERS .................................................... 29FUZES ...................................................................... 31U. S. N. NOSE FUZE, MARK 131 (AND MODS.) ................................. 33GENERAL ............................................................. 33OPERATION .......................................................... 33SAFETY FEATURES ..................................................... 34HANDLING .......................................................... 35SPECIAL PRECAUTIONS ................................................ 35U. S. N. NOSE FUZE, MARK 135 (AND MODS.). ............................... 37GENERAL ............................................................. 37OPERATION .......................................................... 37

SAFETY FEATURES .................................................... 38

CONFIDENTIAL 5

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7 .2 ROCKET AUNCHERS 0. P. 1002Page

U. S. N. NO SE FUZE, MARK 140 ............................................. 39GENERAL ............................................................ 39THE MECHANISM ..................................................... 41EXPLOSIVE C OMPONENTS ............................................ 41OPERATION .......................................................... 41SAFETY FEATURES .................................................... 42ARMED FUZES ........................................................ 42INSTALLING IN ROCKET.............................................. 43POINTS TO CHECK ................................................... 437".2 ROCKET ASSEMBLY SHEET. ...................................... 44SERVICING ........................................................... 46PACKING AND MARKING ............................................ 46

Chapter 3OPERATION AND MAINTENANCE 7.2 ROCKET LAUNCHER, MARK 20. 47

OPERATION ................................................................ 47STOWAGE AND ASSEMBLY .......................................... 47LOA DING AND FIRING ............................................... 48SAFETY PRECAUTIONS ................................................ 49MAINTENANCE ...................................................... 52TACTICAL OPERATION ............................................... 52Chapter 4

PERFORMANCE DATA OF 7.2 ROCKET LAUNCHER, MARK 20.. . . . e.. 53PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Chapter 5COGNIZANCECOGNIZANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Chapter 67.2 ROCKET LAUNCHER, MARK 22 ......................................... 63

INTRODUCTION .......................................................... . ... 63DEFINITION ........................................................... 63USE................................................................ . ... 63DESCRIPTION ................................................................ 657".2 ROCKET LAUNCHER. ............................................ 65INSTALLATION ....................................................... 67ELECTRICAL CONTROLS ............................................... 69CONTROL PANELS ................................... . ................ 71

6 CONFIDENTIAL

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CONTENTS 0. P. 1002. Page

Chapter 7OPERATION AND MAINTENANCE 7.2 ROCKET LAUNCHER, MARK 22.. . 75

OPERATION ................................................................. 75LOADING AND FIRING .............................................. 75SAFETY PRECAUTIONS ................................................. 76MAINTENANCE ........................................... ............ 77ROCKET PERFORMANCE ................... ..N......... ..O ............ 77

Chapter 8COGNIZANCECOGNIZANCE ............................ ....... .a,............, ............. 79

Chapter 92.5 ROCKET LAUNCHER AND 2.5 ROCKETS FOR LAUNCHERS,MARKS2oAND 22................................................... 81

INTRODUCTION .............................................................. 81DEFINITION ........................................................... 81USE.................................................................... 81AMMUNITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ......................... 83THE 2".5 ROCKET ........................................................... 83GENERAL ............................................................ 83INSTALLATION .............................. . ......................... 83BODY ................................................................. 83MOTOR .............................................................. 83PROPELLANT COMPONENTS .......................................... 83OPERATION ................................................................ 84LOADING AND FIRING .................... .......................... 84SAFETY PRECAUTIONS ................................................ 85COGNIZANCE ........................................................ 85DISTRIBUTION ............................................................... 87

CONFIDENTIAL

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FIG. I. 7 " . 2 ROCKET LAUNCHER, MARK 2 0 , LOADED, READYFOR FIRINGCONFIDENTIAL

INSI ALLING IN KUCKt I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

POINTS TO CHECK.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 o RACKET ACCFAARI CUFFT ;I

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INTRODUCTION 0. P. 1002Chapt er 1

7 .2 ROCKET AUNCHER, ARK20

DEFINITION 9he 7.2 Rocket Laer, Mark 20 (formerly known as theMap) is a set of steel wazsu pport ing an d firing 7.2Rockets. This launcher was also form erly known as the Pro-jector Mark 20, and many name plates ar e so marked.The designation Control Pan el was changed to Firing Panelsubsequent. to the preparation of this Ordnance Pamphlet.CONFIDENTIAL 9

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10

LAUNCHER INFOLDED AND RAISEDPOSITIONS

The launchers can be folded, lashed down and locked to thedeck when not in use. When ra ised for firing, th ey ar e fixedin elevat ion and azimuth, the salvo being fired with th e shipheading on the gun tra in order bear ing and at the propervalue of range.

LOCATION OFLAUNCHERSON FOREDECK

Ordinarily two launchers are mounted on the foredeck, oneport and one star board, arr anged symmetr ically about thecent er line of t:he boat and facing forwa rd. Each launcherfires 4 rockets in a salvo. Firin g is electrical and is cont rolledfrom the bridge.

7 . 2 ROCKETSThe rockets fired from t he Launcher, Mark 20, are 7.2 in

diam eter and 35.0 long. The body is filled with a bout 30pounds of explosive. The rocket is equipped with an impact-firing fuze and is propelled thr ough the air by the burning ofthe powder in the motor.

CONFlDENTlAl

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INTRODUCTION 0. P. 1002

RANGE OF ROCKETSA small boat, using t wo laun chers, can fire a salvo of 8 rocketsapproximat ely 300 yards forward.

PATTERN OF FIREThe ways of the laun cher are spread apar t at the ends, fan-

wise, so tha t the 8 rockets strike the water in a stra ight lineabout 83 yards long at right angles to the center line of theboat.

CONFIDENTIAL 11

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A.- STOWED POSITION

RETAINERS\

RETAINER HANDLE e-d .

ELECTRICAL CONTAC TS

DEFLECTOR PLATE =-..,

DEFLECTOR -

DECK PLATE

ANG LE IRON STIFFENER ADDEDq BY ORDA LT 1435 DATED l-14-43

r -% WAYS

!UTCH

FIG. 2. 7 . 2 ROCKET LAUNCHER, MARK 2 0

12 CONFIDENTIAL

r 1BASE

FOUNDATION

RAISED POSITION

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DESCRIPTION 0. P. 1002

7.2 ROCKET LAUNCHER, MARK 20

The laun cher consists of ways welded together to mak e a rigidunit wh ich is hinged to th e base which in tur n is fastened to th edeck structure. When erected, the ways are supported by acrutch which also is hinged to th e base an d locks in place withtwo levers. The ways themselves consist of sections of steelplate bent up to make r ails in which the rockets ride. The thr eeinside sections ar e made broad an d wedge-sha ped, one piece thu sserving as comm on rail for two adjacent rockets. A spread ofone par t in 40 is mad e between ways to give the requir ed spacingof shots. A set of retr actable reta iners is provided to keep therockets from being washed out of place in a heavy sea. Theseretainers are raised manua lly and pinned in place after the waysare loaded. They do not inter fere with the firing. In firing, anintense blast of hot gases is ejected from the nozzles of th e rocketmotors for several feet. Unless the deck and nearby structuresar e protected, th ey ar e likely to be scorched considerably. Todivert th e direct blast at th e base of the projector, heavy steeldeflectors ar e provided and a $-inch steel plate 24.0 long laidon th e deck immediately behind. For places not directly str uckby the blast, a light steel sheet is sufficient.

The launcher is designed to fold down and be lashed to th e deckwhen not in use, as shown in figure 2. When conditions requir eit, weather permitting, the launcher may be maintained elevatedand loaded. Whenever weather conditions are such that thelaun chers or the amm unition exposed on the rails would be sub-ject to dama ge or deteriorat ion, th e amm unition should beunloaded and stowed and th e rails lowered and lashed down.

CONFIDENTIAL 13

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7 .2 ROCKET AUNCHERS 0. P. 1002LAUNCHER IN STOWED POSITION

\

PORT LAUNCHER STARBOARD LAUN CHER

STEEL DECK SHEATHING FIVE WIRE/ CONNECTION BOX

STEEL SHEATHINGON BREAKWATER FIVE WIRE CABLE

READY SERVICEAMMUNITION BOXES k

PILOT HOUSE

,p SAFETY RECEPTACLE

CONTROL PANEL

FIG 3. FOREDECK INSTALLATION OF 7 . 2 ROCKET LAUNCHER,MARK 2 0CONFIDENTIAL

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~ - - R - -- - -- - ---n--* -- - ---___-- -___-._--- - -_ 1.1 1_. - ^ .l__ -m


INSTALLATIONThe laun chers ar e moun ted on the foredeck (see fig. 3) requir -

ing two clear spaces a bout 38.0 by 84.0. All wooden str uc-tu res directly aft are sheat hed with j{s-inch steel sheet a s pro-tection against blast. Extending from the launcher, in thedirect line of th e blast, a SC-inch steel floor plate about 2 feetlong is pr ovided. The flame is of sufficient intensit y to rem ovepaint from surfaces directly in line for the first 2 or 3 feet, SOfrequent repain ting of the sheat hing may be necessary.

The launchers ar e mount ed on wood or meta l founda tions SOtha t they are level ath wart ships and have a 3-5 slope fore andaft with t he high point forwar d. The two launchers ar e placed,in the folded position, on th e foredeck symmetr ically about th ecenterline of th e ship. The extrem e forwar d point of th e in-board edge of th e base of each lau ncher deviates 4 to 5 inchesfurther from the centerline than the aft end of the base. Thisdeviation is inversely proportional to the dis:ance betweenlaunchers. This placement of th e laun chers gives an appr ox-imately equal spacing to all 8 rockets.

Ready-service boxes are provided on th e foredeck, convenientto th e launchers, for read y ammun ition. Each box is water -proof an d holds 8 rounds in easily accessible racks. Additionalamm unition is stowed below decks in magazine stowage.

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7 .2 ROCKET AUNCHERS 0. P. 1002MOTOR TROUGH OF WAY

FORWARD SHROUD

UPPER ELECTRICAL CONTACT

LOWER ELECTRICAL CONTACT

o COMMON

FIG. 4. ELECTRICAL CONTACTS FOR 7 . 2 ROCKET LAUNCHER,MARK 2 016 CONFIDENTIAL

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DESCRIPTION 0. P. 1002P

ELECTRICAL CONTROLSElectrical conta ct for firing is made to the two shrouds of the

rocket motor by mean s of knife edges (see fig. 4). The lowerconta ct mounted in the deflector plate grips the inside of thegrounded rear motor shroud, which is electrically connected toone side of the igniter, and serves as a stop. The upper insulatedconta ct is mounted on a phosphor bronze spring an d bears onthe outside of the insulated forwar d shroud. Both contacts aremade of har dened stainless st eel.

CONFlDENTlAL 17

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-- --------- - - +


18

f

c ~BRANCH BOX EMTYPE

SAFETY RECEPTACLE

I WIRE CONNECTION BOXCONTROL PANELp MARK 2, MOD. 2

b SAFETY PLUG

FIG. 5. CIRCUIT SCHEMATIC FOR 7.2 ROCKET LAUNCHER,MARK 20(USING CONTROL PANEL, MARK 2, MOD. 2)

A cable with 5 active condu ctors run s from th e cont rol pan el to a 5-wire conn ection box.From this box, a cable ru ns to a branch box Type E at each launcher, and then ce to the launcher.In certain installations, the cable from th e contr ol panel passes through the deck through awat ert ight bushing t o a 5-wire conne ction box. For schematic diagrams of the circuits, seefigur es 5 an d 6.

CONFIDENTIAL

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5 WIRE CONNECTON BOX

3, MOD. 2AFETY RECEPTACLE/

\ SAFETY PLUG

- BATTERY BOX

FIG 6. CIRCUIT SCHEMATIC FOR 7.2 ROCKET LAUNCHER,MARK 20(USING CONTROL PANEL, MARK 3, MOD. 2)

The cont rol pan el is locat ed on th e bridge. From th e contr ol panel, a 4-conductor cable runsto a safety plug receptacle. All connections are broken in this receptacle unless the safetyplug is in place. The safety receptacle is usually mounted on the side of the bridge st ructur ein a position protected from blast a nd at a safe distance from the laun chers.

CONFIDENTIAL 19

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7 .2 ROCKET AUNCHERS 0. P. 1002FIRING BUTTON

TH IS NAME PLATbEUSED ON CONTROLPANEL MARK 3, MOD.1AND MARK 3, MOD. 3

CONTROL PANEL MARK 3AND MARK 3, MOD. 2

TERMINAL TUBETO SAFETY PLUG(ADDED BY ORDALT1383 DATED 12-18-42)PLUG RECEPTACLE =

FIG. 7. CONTROL PANELS FOR 7 . 2 ROCKET LAUNCHERS,MARK 2 0 AND MARK 2 220 CONFIDENTIAL

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CONTROL ANELSThe types of cont rol pan els in use ar e Mar k 2, Mod. 2, th e

Mar k 3, an d Mar k 3, Mod. 2. (See fig. 7.) Th e lat ter two a reidentical in externa l a ppearan ce. The differences lie in the bat-teries u sed as sources of power and in the interna l wiring. Th eControl Panel Mark 2, Mod. 2, conta ins batt eries whereas theControl Pan el Ma rk 3, and Mark 3, Mod. 2, have power suppliedfrom ba tt eries in a separa te box locat ed either above or belowdecks. One 45-volt and one 6-volt dry bat ter y ser ve as power forthe Contr olPan el Mark 2, Mod. 2, as is shown in the wiring diagra m,Figure 8. The Control Panel Ma rk 3 operates with either one45-volt an d one 6-volt dry batt ery or one 45-volt and t wo 6-voltbatt eries as is shown in Figure 9 (A). The wiring to the panel isunchanged wheth er one or two 6-volt dry batt eries are supplied.Two 7X-volt dry batt eries are supplied with the Control PanelMar k 3, Mod. 2. The wiring of th is panel is shown in Figur e 9 (B).The batt ery box supplied with the Control Pan els Mar k 3 andMark 3, Mod. 2, should be discarded as a unit when the bat teriesare exhaust ed and replaced by a new box. Prior to discarding,the receptacle should be removed from the old box and insta lledon the new one. In case no batt ery box is available, a porta blestorage batt ery may be used for operating the launchers. Thisbatt ery should be 6-volt and preferably not less tha n 50 amper e-hour capacity. The Cont rol Pa nel Mar k 2, Mod. 2, should beopera ted only with 45-volt an d 6-volt bat ter ies, as described above.

Service experienc e nd lab orato ry tests have de mo nstratedha tthe 45-volt ba ttery origina lly supp lied w ith co ntrol pa nel Ma rk 2and with about200 c ontrol pa nelsMa rk 3 as unsuitab le ue o highinternal esistance. Ordalt No. 1803 hasbee n ssuedwhichprovidesfor the rep lac eme nt f the firing pa nelMa rk I, Mod. 2 b y the firingpa nel Mark 3, Mod. 2.

CONFIDENTIAL 21

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_.-- -- -- ---


5 WIRECONNECTON BOX

BOXTYPE

CORD CONNECT0

STARBOARD b

L - -POWER,#jPOWER._ --_-- .-. ---- --.-

CONTROL PANEL c +

FIG. 8. WIRING DIAGRAM FOR Y.2 ROCKET LAUNCHER,MARK 20(USING CONTROL PANEL, MARK 2, MOD. 2)

The operation of any of the above contr ol panels is th e same. A push button mar ked FIREfires th e odd-num bered ways and actuat es a time-delay relay which fires the even-number edways l/&XOnd later. Switches permit selection of port or star board launchers or both anda mast er switch cuts off all power. A green pilot light indicates when t he power switch is onand a red light indicates when the Safety Plug is in place in the case of the Contr ol Pan el,Mar k 2, Mod. 2.

22 CONFIDENTIAL

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-- --_-_.--__ -


BRANCH BOX5 WIRE CONNECTON BOX

BOXTYPE

FIRINGP SWITCH

SAFETYRECEPTACLE

CONTROL PANEL

0BATTERY BOX

CONTROL PANEL MARK 3. MO D. 2

FIG 9. WIRING DIAGRAM FOR 7 . 2 ROCKET LAUNCHER,MARK 2 0(USING FIRING PANEL MARK 3 OR MARK 3, MOD. 2)

On the Firing Panels, Mark 3 and Mar k 3, Mod. 2, a single light is illuminated when th eSafety Plug is in place a nd th e power switch is ON. The power switch on the panel shouldbe tur ned to ON only to ascertain if the laun chers are in a ready condition, and just priorto firing. Leaving the switch at ON unnecessarily will result in a run -down batt ery andmisfires. The indicator lights furnished with the panels are Navy t ype TS-20 (Mazda NO.64) 6-8 volt 3 c-p, bayonet candelabr a double cont act bases. If these lamps are too bright,Navy type TS-43 (Mazda No. 90) 12-16 Volt 6 c-p may be used instea d.

CONFIDENTIAl 23

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--~__---__ .---1.11

7 .2 ROCKET AUNCHERS 0. P. 1002NO SE FUZE MARK 131

FUZE PROTECTING CAP

/ YUZE PROTECTING CAP

-

FORWARD SHROUD

/

-4 72 ROCKETBODY MK. 5

7:2 R 0 CK ETBODY MK 4v b

THREADED

PREAR SHROUD

JOINT

2 i25 ROCKETMO TOR MK. 30 b

FINS

7:2 ROCKET 7:2 ROCKETEND VIEW

FIG I O. 7 . 2 ROCKET

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AMMUNITIONChapter 2

7 .2 ROCKET MMUNITIONNDFUZES

7 .2 ROCKET MMUNITION

0. P. 1002

Two genera l views of th e 7.2 Rocket amm unit ion for use withLaunchers, Mark 20 and 22, are shown in figure 10. The unit sconsist of th e body, t he motor, and the fuze. The body is 7.2inches in maximum diameter and the assembled projectile weighsabout 63 pounds. The entire unit is strea mlined and providedwith fins to give stable flight a nd a high sinking rat e in water .

The body of th e projectile is filled with appr oxima tely 30pounds of TNT or 34 pounds of TPX. An auxiliar y booste rconsisting of granular TNT is employed to detonat e this charge.

BODYThe body for 7.2 Rocket amm unit ion is a welded ste el cylin-drical case, with a relatively flat nose section and a conical tailfairing. It is provided with an opening in the nose section toreceive the fuze seat liner and the fuze. Originally the body wasdesigned for nose filling an d the fuze seat liner was screwed intothe nose. Later designs provide for filling thr ough the rear andthe fuze seat liner in these bodies is integral with the body.

The body, Mark 4, and motor, Mark 3, are assembled by screw-ing the motor into the th readed cone bushing of the body. Thenewer body (Mark 5) with integral fuze seat liner uses a connectorclosure into which an adapt er is screwed which, in tur n, a ccom-modates the motor. The design of this body not only perm itsof pouring of the high explosive thr ough the rear opening but a lsopermits the use of a larger m otor when t he adapter is omitted,th us allowing other ap plications of th is body.

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_____ _._-_ -_--__--- -----. -

7 .2 ROCKET AUNCHERS 0. P. 1002FRONT CLOSURE DISC

/--------i / /I

IGNITER

INSULATED WIRES c -==-/

SECTION A-

PERSPECTIVE OF POWDER GRAIN

INSULATON

MACHINE

GRID

INSULATED WIRE

INSULATED WASHER

NO ZZLE CLOSURE DISC DESICCANT BAG

FIG. 11. DIAGRAMMATIC SKETCH OF ROCKET MOTOR(SHOWING DETAILS OF TYPICAL PROPELLANT ASSEMBLAGE)

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AMMUNITION 0. P. 1002

MOTORThe motor consists of a steel tube ha ving an outside diameter of

2.25 inches, 4 radial fins and a cylindrical shroud surr ounding thefins (see fig. 11). The forwar d end of the motor tube is externallythr eaded for assembly with the body. The fins ar e inclined 10relative to the tube axis. This design is intended to impartrota tion to th e rocket a nd to cancel rudder ing effects whichwould disturb t he under water tra jectory.

PROPELLANT COMPONENTSThe propellant components are conta ined in the motor. A

typical assem bly of th e componen ts is shown in figure 11. Themain component is a single grain of solventless extruded b&stitepowder. At the forwar d end of this powder grain is located anigniter which consists of an electrical squib lea ding int o a char geof black powder. Two electr ical wires ar e run from the motorshrouds thr ough a central perforat ion in the powder grain to theigniter. When the electrical circuit is closed, the igniter burns,igniting t he propellant grain which burns u niformly on all sur-faces a t a pressur e of 800 to 2,300 pounds per squar e inch, depend-ing upon temper atu re. The gases evolved are forced out thr oughthe nozzle at high velocity and, by their rea ction on the motor,propel the unit forward. The propulsion does not depen d onany inter action with the air or upon th e shields st ruck by theblast, so no recoil problem exists. It is this feature which makesthe use of such equipment possible on relatively light boats.The burning continu es for about 0.4 second at normal tempera -tur e, while the rocket tra vels about 33 feet. After this period,no further propulsion occurs and the rocket is in free flight.

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7-U. S. N. NOSE FUZE, MARK 1 3 1

30

U.S.Na NOSE FUZE- MARK 131

SAFETY PIN MUSTBE IN POSITION

U. S. NOSE FUZE, MARK 1 3 5FIG 13

ClNFlDENTlAL

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FUZE SEAT LINERS(See fig. 12). A th rea ded opening is provided in th e 7.2

Rocket body, Mark 4, into which the fuze seat liner is screwed.The fuze seat liner is thr eaded externa lly to fit this thr eadedopening in the body hea d and is thr eaded interna lly to fit thefuze threads. A formed, light meta l extension or liner perma-nent ly fixed to the fuze seat liner head forms the cavity for thefuze and auxiliary booster. The fuze seat liner flange is providedwith hooks for engaging the fuze cap when t he Mark 131 fuze isused. This fuze cap is intended to protect the propeller vanes ofthe Mark 131 fuze and should r emain in place until the rocket isloaded on the launcher way.

The fuze seat liner is an integral part of the 7.2 Rocket body,Mark 5. -

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72 ROCKET AUNCHERS 0. P. 1002BOOSTER PELLET

LEAD-INaLOAb \ PBOOSTER CASEP STOP PIN

DETONATOR \ jLEAD-IN-DISC \

JI SECTION A-A /i/FIRING PISPRING

FIRING PIWEIGHT

1 SEALING COLLARb2i, SEALING IWASHER - > fz

ARMING SCREW---o SPRING PLATE

VANE SHEAR WIRE

I aARMING VANE HUB \LOCKING PINS

Y/P FUZE BODYSHUTTER SPRIN

SHUTTER/ STdP PIN

DETONAT

SECTION B-BSLEEVE STOPFIRING PIN SLEEVESLEEVE SPRING3 BALLSRETAINING RING

a P GASKETB * SET-BACK COLLAR::%!

FUZE-PLUG

-- - -- ------,

SAFETY PINSET SCREW

n ARMING VANE A UNARMED POSITION

FIG. 14. U. S. N. NOSE FUZE, MARK 1 3 132 CONFIDENTIAL

G

3R

-.I

I

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FUZES 0. P. 1002U. S. N. NOSE FUZE, MARK 131 (AND MODS.)GENERAL

The Nose Fuze, Mark 131, in general a count erpar t of the British Fuze No. 420, except tha tthe collar sh ear wire is omitted, is illustrat ed in Figure 14.

NOTE. The Nose Fuze, Mark 131, is identical in appear ance to the Fuze, Mark 136, whichis used in the projectile charge, except tha t the nose of Nose Fuze, Mark 131, is painted red.The Nose F uze, Mark 136, has a collar shear wire and since the set back in rockets is notsufficient to shear this wire, it should never be used in rockets.

Arming the fuze is accomplished after t he fuze strikes the water and has sunk to between10 and 15 feet below t he surface. Seven complete revolutions of the arming vanes ar e requiredfor complet e ar ming, alt hough it will probably be sufficient ly ar med t o fire on side impactafter only 4 complet e revolutions of th e vane.

Detona tion of th e fuze is accomplishe d by impact , eith er direct, oblique, or glancing, on animmersed object after the rocket has sunk beyond the arming distance of between 10 and 15 feet.

Generally, the fuze will not operat e on striking and sinking into soft sea bott oms.

OPERATIONThe fuzes a re issued with the tagged safety pin in place. This pin passes thr ough the

arming screw, fuze plug, and set-back collar and should remain in place until a fter the fuzzedrockets have been positioned on the launcher ways, a t which time it should be removed.The fuze caps should rem ain in place on fuzed r ockets at all tim es ---until just before firing-to avoid dama ge to fuzes by handling or by exposure to weather .

Prior to firing from t he launcher, the arming vane is prevented from rota ting by theset-back collar which engages locking pins in the arming vane hub and the plug. Thesepins fit in a slot in the set-back collar and positively lock t he arming vane until set-backforce causes th e set-back collar to move backward on the plug. The vane is further securedagainst rotat ion by a vane shear wire which fixes the arm ing vane hub directly to the fuze plug.

When t he rocket is fired from th e launcher, the set-back collar m oves rear ward due toits inertia and is reta ined in this rearward position by a small spring plate which dr ops behindthe fuze plug pin.

NOTE.- When131 , and mod$be retracted

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72 ROCKET AUNCHERS 0. P. 1002rema ins, it is tr ue, but this could$e severedbow, and the fize ar med by sub$$bent spray.

by heavy impa& p,f-. ea water coming over th eI+$er such sba%onditions, th e set-back collar

should not be ret ra cted un til just .before firing, i~S $&l weat tier or with st ickyjcollar s. If thefuze is not fired, th e collai shouldbe repla ced. . I ,. l ! iAfter the &t-back collarhas moved r earwa rd, th e arm ing vane is restr icted, again&t rota-tion, dur ing air flight,, by the vane shear wire.I Upon striking th e water , the tbr$u e impoyd onthe vane by the water ! action shears the vane shear wire, allowing the:vane to r&Ate hs the char gesinks. As the %ane:rotafes, th e arm ing scre& moves fo&ard, alpowing th$ w$ght, togitherwith the associated firing pin, f&ng pin locking ballb, firing p in spfing an d firing pin sleevi, toalso move forwa rd un d& th e influence of th e compr essed sleeve spring.! This action pl@esth e weight in its arm ed!position, free to oscillate about its base, and allow&he detonat or shut terto spring int o a? arqed pos&on in alignment with the firing pin. As the firing pin sleevemoves forwar d, khe 4 stops z/re released, and moved inward by their springs. These, detentsprevent th e firing pin from bking forced agairist t he detonat or by rotat ion of th e arm ing vaneand screw in the r&efse direction when una rming an/inadvert ently ar medfuze by han d in z$neffort to render it isafe to handle.

,: :

With th e fuze$qth e ax-me4 cond+ion described a&&e, an y blow which will cause the weigh?to iosci)late abouC iis .base will\ perm it th eirelea se o!!the firing pin from tfe locking balls q

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FUZES 0. P. 1002

SPECIAL PRECAUTIONSNo at tempt should be made to remove arm ed or part ially arm ed fuzes from rockets under

any circumsta nces. The rocket a nd the fuze should be disposed of together.In installing or removing this fuze in or from a rocket, do not grasp the fuze by the arm ing

vane or use a pipe wrench or any other tool on the plug, set-back collar, or arm ing vane. Ifthis precaution is not followed, the plug may be unscrewed or the arm ing vane tur ned, ther ebyarm ing t he fuze. Only the special spanner wrench which ha s been placed on the ships launcherallowance list (spare pa rt s) should be used for insta lling or rem oving th e fuze. This wrenchfits the outer pair of holes in the fuze body, and not th e holes in the fuze plug. There is onrecord a serious accident caused by the use of improper tools.

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7 .2 ROCKET AUNCHERS t P. lU2P POST

SHUTTER

SHUTTER SPRING

SHUTTER SPRING CAP

/ DETONATOR

DETENT SPRING

DETENT SPRING CAP

SECTION A -A

LEAD-I N-LOAD

LEAD-I N-DISC

HOUSING

FIRING PIN

SET-BACK COLLAR

3 BALLS

WEIGHT

NO SE PLATE

DIAPH RAG M

SAFETY PIN

BOOSTER PELLET

BOOSTER CUP

RETAINING RING

LOCATNG PIN

FIRING PIN SPRING

BODY

BELL CRANK

BELL CRANK PIN

GASKET

NOSE CAP

DIAPHRAG M BUTTON NUT d b DIAPHRAGM BUTTON

FIG. 15. U. S. N. NOSE FUZE, MARK 1 3 5 AND MARK 1 3 5 , MOD. 1( H . . . F U Z E )

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U. S. N. NOSE FUZE, MARK 135 (AND MODS.)GENERAL

The Nose Fuze, Ma rk 135, is illustrated in figure 15. This fuze was former ly designatedH. I. R. fuze. The fuze is of th e hydrost at ic ar ming, impa ct firing, rocket type.

OPERATIONArming the fuze is accomplished by pressur e of water enter ing the cavity in the nose of

the fuze thr ough two f:G-inch holes from which a safety pin has been previously withdrawn.The water pressure builds up against a prestr essed phosphor bronze diaphr agm. At a certainvalue of pressure, the diaphragm pops, behaving like the bott om of an oil can and operat estwo bell cranks, releasing the detonat or shut ter and freeing the weight, thu s arming the fuze.Upon impa ct or jarr ing, th e weight is displaced, freeing t he firing pin locking balls. Thefiring pin spring th en forces th e firing pin point into the lead azide detonator. The detonatorinitiates the lead-in which fires the tet ryl booster pellet which in tur n detonates the auxiliarybooster and the main filler.

The fuze normally arms under a stat ic pressure equal to approximately 30 feet of water .At the high velocity with which the rocket strikes the water when actually fired, a dynamicpressure is built u p on the head immediat ely after t he impact, causing the fuze to arm at adept h of 15 to 20 feet. This effect would not occur on a rocket mer ely dr opped overboard oron one which fell considerably short of the normal operat ing ran ge. In these cases, thevelocity in the water would not be sufficient to cause ar ming before a 30-ft. depth had beenreached.

After th e fuze is ar med, it will fire if th e weight is jar red off, relea sing 3 ste el balls whichhold the firing pin. A sudden decelerat ion, for example when the rocket st rikes h ead-on,pulls the weight forwar d, first forcing the balls inward against the force of the firing pin springand then releasing them . A glancing hit causes t he weight to roll about a point on the edgewhere it is supported against the body and releases th e balls. The sensitivity to forwar d andsidewise impacts is about equal, sponding to about a&inch drop in air on the end of awood post. The fuze will fire on an under-water surface inclined at a;uch as 7S from normal(head-on). Th us a hit within less tha n a foot of the extrem e outline of a submarine hull issufficient to actuat e the arm ed fuze.

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7 .2 ROCKET AUNCHERS 0. P. 1002-. . SAFETY FEATURES /

Safety against dropping or jolts is guar ant eed by th e fact that th e bell crank s h old th eweight positively in place until th ey ha ve been forced out by th e diaphr agm. Their symmetry

I

is such tha t sidewise blows tend to move one bell crank out and move th e other in. The inter-locking butt on on the diaphra gm prevent s th eir moving indepen dently. Similar ly, effects ofshakin g ar e cancelled out by th e opposing action of th e bell crank s. In shipping and handling,positive safety is provided by a safety pin which passes t hr ough a hole in th e nose cap and locksth e diaphr agm in th e safe position. If this wire is pulled out just before th e rocket is fired, itserves also to clean out t he ports t hrough which water enters the nose cap.

Since th e diaphra gm is fairly heavy and completely support ed in the collapsed position,th e fuze will rema in operat ive at depths in excess of 600 feet. The unit is sealed against ,penetr at ion of wat er by th e gasket action of th e edge of th e diaphr agm clamp ed between th e jnose cap and the body, supplement ed by a coat of crater compound . This seal also preventspenetr ation of moisture to th e moving part s in storage.

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FUZES 0. P. 1002

FIG. 16. u. S. N.GENERAL

- _-SAFETY

TO BE REMBEFORE FI

^ I --__ -

PfNOVEDRING

NOSE FUZE, MARK 140

The Nose Fuze, Mar k 140, is a hydrost at ic ar ming, impa ct-firing fuze.Arming occurs under a stat ic pressure of approximat ely 30 feet of water; however, at the

high velocity with which the rocket strikes the water , dynam ic pressure is built up on the headso tha t the fuze arms at depths of from 8 to 15 feet.The fuze will function on impa ct with a solid object such as a subma rine deck or a wooden

deck grating.

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7 .2 ROCKET AUNCHERS 0. P. 1002/ MAGAZINE BOOSTER,

LEAD-IN DISCSTRIKER RING

BELL CRANK

FIRING PIN SPRING

I,/ RELEASING SPRING BUTTONPIVOT

2 LOCK SCREW1 DIAPHRAGMDIAPHRAGM NUT -1

DETENT --___SHUTTER ____-

SHUTTER SPRINGS -

SECTION X-X SECTION X-X(UNARMED POSITION) (ARMED POSITION)

FIG. 17. U. S. N. NOSE FUZE, MARK 1 4 0

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FUZES 0. P. 1002U. S. N. NOSE FUZE, MARK 140THE MECHANISMThe mechanism is conta ined in the fuze body. A nose cap with two water intak e portsis screwed in the upper end of the body and covered with a fuze protective cup. A phosphor-bronze diaphr agm is set in the upper end of the body against a diaphragm seat. This dia-phragm is prestr essed and so clamped at the rim that a stat ic pr essure of from 12 to 15 poundsper square inch is required to push it inward. A button, in which two bell cranks are engaged,is secured by a nut in the diaphragm, so tha t inverting the diaphragm will work against thebell cranks. The nut t o which the butt on is secured is so shaped tha t it will anchor the dia-phragm to the nose cap when a safety wire is inserted thr ough the water inta ke ports of thenose cap. The bell cran ks are affixed by pins to slots in the hea d in which they can be pivoted.On each bell crank th ere is a projection from which h ooks exten d upwar d and downward. Asafety r ing is loosely fitt ed on the hub of the head. The head fits tightly on the fuze base andis secured by a press fit.

The fuze base houses th e firing pin, firing pin sprin g, and locking balls. The striker ringand the firing sleeve which mainta ins the lockin, u balls in place ar e set around the base. Thedetonat or shut ter under spring pressur e is fitt ed in a groove in the fuze base. A lead-in discis housed between the shut ter and the booster. A boost er ma gazine encloses th e fuze cavity.

EXPLOSIVE COMPONENTSThe explosive component s consist of:

(1) Detonator- -Housed in shut ter.(2) Boost er lead-in-Housed in disc.(3) Boost er- Approximately 30 gram s (1 .l) ounce tet ryl Housed m booste r cap.

OPERATIONARMING. After the fuze has been assembled in the nose of the rocket, the safety wire

is removed. When the rocket enters the water, the pressure of the water which enters th eintak e ports of the nose cap and the dynamic pressur e built up by the motion of the rocketthr ough the water act .on the diaphragm tending to push it inward. When t he rocket h asreached a depth of from 8 to 15 feet the diaphragm pops or is inverted, behaving like thebottom of an oil can. This diaphragm action moves t he two bell cranks out of engagementwith the shut ter and the firing sleeve, thereby arm ing the fuze. The shutter operating underspring pressur e slides to a position where t he detonat or is aligned with t he firing pin and boosterlead-in wher e it is locked by sprin g det ent s. The firing sleeve is also free and can now bedislodged by impa ct with a solid object.

At the time th e rocket is fired, th e set-back force a nd air pressur e acting on the diaphragmtend to arm the fuze prema tur ely. However, the freely moving safety ring is held in engage-ment with the hooks on the bell cranks by the set-back force to prevent such prematu rearming.

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-c__--__-I -_- _.._-_- -- --~-

7 .2 ROCKET AUNCHERS 0. P. 1002When wa ter impact occurs, prema tur e arm ing is also prevented by the momentar y engage-

men t of grooves in th e firing sleeve wit h t he hooks on th e bell cran ks.FIRING : Th e fuze functions upon im pact with a solid object. It is designed so tha t itis not likely t o function on impa ct with soft objects such as mud dy bottoms. It will function

however on impact with wood gratings on the decks of submarines. When the impact occurs,inertia forces the firing sleeve forwar d, ther eby releasing the locking balls. The balls areejected by th e force of th e firing pin which is und er press ur e of its compr essed sprin g. Th efiring pin, now free, is moved forwa rd und er t he force of its compr essed sprin g, st rikes th edetonator and sets off the explosive tra in.

A glancing blow causes t he loosely fitting str iker r ing to move sidewise cammin g th efiring sleeve forward, releasing the locking balls and thus permitting the fuze to function,

The sideways sensit ivity is appr oxima tely one-fourt h of th e nose sensit ivity.

SAFETY FEATURESDETONATOR SAFETY: This fuze is detonator safe. In the una rmed position, the

detonat or is out of alignment with the booster charges. Should the detonator function pre-mat urely, the force of the detonation would be dissipated thr ough an opening in the bodyawa y from the explosive component s.

INSTALLED IN ROCKET: Wh en the fuze is installed in the rocket, the fuze is in theunar med position. Arming will not occur until pressure pops the diaphragm. Pressur e of12 to 15 pounds per squar e inch is required to operate the diaphragm. After the fuze hasbeen arm ed, it will not funct ion unt il the locking balls are freed by impa ct of th e fuze wit hsome solid object.

DURING SHIPPING AND STOWAGE: Additiona l safety is provided dur ing shippingand stowage by a safety wire inserted thr ough the water int ake ports. The safety wire posi-tively locks the diaphragm butt on tothe nose cap, ther eby prevent ing the diaphragm frommoving inward an d accidentally arm ing the fuze. The removal of the wire serves to cleanthe water inta ke ports.

DROP SAFETY: The fuze has a large dome-shaped steel cup fitt ed over the exposed endwith wat er ent ry an d spanner wrench holes around its sides. The s ole pur pose of th is fuzeprotect ive cup is to preven t functioning of th e fuze if a round is accidenta lly dropped on itsnose.

ARMED FUZESFrom an examination of the exterior of the fuze, it is impossible to tell whether or not the

fuze is arm ed. However, when th is fuze is arm ed, it is impossible to reinsert the safety wirethr ough the wat er inta ke ports in the nose cap. If the fuze is unar med, the safety wire canbe reinsert ed all the way through the nose cap.

42 CONFIDENTIAL

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FUZES 0. P. 1002INSTALLING IN ROCKET

INSTRUCTIONS:(1) Remove the shipping plug from the rocket and inspect the fuze seatliner. Clean if necessary.69 Remove the fuze from its conta iner and examine it for defects, p a r -

ticularly as to the gasket. Check the freedom of movement of the safetyring. This is accomplish ed by tu rn ing th e fuze alt ern at ely nose-downand nose up. The ring should be heard to click with each movement .The last click sh ould be hear d when the fuze is tur ned to the nose-upposition. In this position the ring engages the hooks on the bell cran ks.

(3) Screw th e fuze securely in the nose of the rocket using a spanner wrenchin th e openings provided. The spann er wrench fits the holes in the sideof th e fuze prote ctive cup. Insure t hat the gasket is properly in positionso tha t t he connection of the fuze with th e rocket will be water tight.Seepage of water past the gasket may resu lt in the malfunctioning of thefuze. Before inserting the fuze the thr eads should be given a light coatof petrolatum or any available mineral grease. Also, th e safet y wir eshould be coat ed with a light coat of grease in order t o keep moisture fromenter ing into the fuze.

(4) Remove the sa fety wire from the wat er intak e ports in the nose of thefuzc prior to firing the charge.

(5) Do not remove the fuze protective cup from t he fuze. This cup is apart of the Mark 140 fuze and should not be confused with t he fuze capused t o protect, fuzes and which is a part of the projectile body.

POINTS TO CHECK:The following points should be checked dur ing t he inst allat ion of th e

fuze in the rocket:(1) That the fuze seat liner into which the fuze is to be screwed is clean

an d free of foreign subst an ces.(2) That the two 2.0 length auxiliary boosters are in place in the rocket.(3)(4)(5)(6)

That the safety ring moves freely.That the fuze gasket is properly in position.That the fuze is securely seated in the rocket.That the safety wire ha s be en emo ved .

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------ - - - - -- .-.--- - --

7 .2 ROCKET AUNCHERS 0. P. 1002ASSEMBLY SHEET

7.2 AND 2.5 ROCKET AMMUNITIONFOR SHIPBOARD USE

COMPLETEROUNDMARK No.

2

101201 Drill 60

t 2102

6106206

789

109209

1015

-

ROCKET BODY COMPONENTSUSE OFROUND

NOMINALROUND ROCKET BODY LINER FILLERWT. (LBS.)Size Mark Mod. Dwg. No. Dwg. No. TYW

--

Service 60--Target 60

7.2 1--7.2 1--

Lane Wells SK99440 TN TLane Wells SK99440 Plaster

7.2 1-- Lan e Wells SK99440 PlasterSer vice 60 7.2 3 330904 SK99440 TNT--Target 60 7.2 3-- 330904 SK99440 Pla sterDrillServiceServiceTargetDrill

60 7.2 3 330904 SK99440 Pla ster-- All65 7 .2 4 (Note 1) 329138 SK99440 TNT---- All 32870862. 5 7.2 4 (Not e 1) 329138 329292 TNT-- -ll62. 5 7.2 4 (Note 1) 329138 (Note 3) Pla ster-- All62. 5 7.2 4 (Note 1) 329138 (Note 3) Pla ster--

Ser vice 61. 4 7.2 5 330906 Int egra l TPX--Ser vice 62. 4 7ll.2 5 330906 Int egra l TPX--Ser vice 57. 5 7.2 5 . 330906 Integral TNT--Target 57. 5 7.2 5 330906 Int egral Plast er--DrillServiceService

57. 5 7.2 5 330906 Int egra l Pla ster-- -58. 5 7.2 5 330906 Int egra l TNT-- 32870863. 5 7.2 4 All 329138 329292 TNT--

Tar get 8. 8 2.5 1 All 329402 None SolidNOTE. (1) Mark 4 all mod. bodies d o not include Mar k 4a bodies.

(2) Mark 3 all mod. motors do not include Mark 3 mod. 1 motors.(3) Mark 4 plaster loaded bodies may or may not include fuze seat liner.

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0. P. 1002

I ROCKET MOTOR COMPONENTS I BALLISTIC DATAMark

BOOSTERROCKET MOTOR

Needed Mark Mod. Dwg. No.

1 1 2r.25 I 1 I I 330905I None 2fl.25 I 1 I I 330905None 2!.25 I 1 I I 330905

1 1 1 2.25 1 3 1 1 1 329932None 2.25 3 1 329932None 2lj.25 3 1 329932

All=1 2ll.25 3 (Note 2)d 329932--- All

1 1 2lj.25 3 (Note 2) 329932All

None 2.25 3 (Note 2) 329932None 2.25 3 (Note 2) 329932

All1 1 2.25 3 (Note 2) 329932All2 2 2ll.25 3 (Note 2) 329932-_ All1 1 2ll.25 3 (Note 2) 329932

AllNone 2ll.25 3 (Note 2) 329932 2.25 /one I 3 / (N:e! 2) / 329932

All2 2 2ll.25 3 (Note 2) 329932

All2 2 2.25 3 (Note 2) 329932

I None I 1.25 1 1 1 1 329403 4 None 8 8

-_.-- -.-.-

.-

GRAIN FUZE Curve No. Column No.

Mark Mark Page 54 Page 58

135 1 11 None 1 1

None None1 135 1 11 None 1 1

None None---2 135 2 23 1 131 / 3 1 33 1 None 1 3 1 3

None None3 131 4 43 140 3 3

10 131 5 510 None 5 5

None None10 140 6 6

3 140 7 7

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SERVICINGUSE OF LUBRICANTS: Fuze surfaces that might become ru stedor corr oded should be given a light coat of petrolatu m or minera l grease.Before installing in th e projectile fuze thr eads should be given a light coatof grease.

DISASSEMBLY: No disassem bly of th is fuze is au th orized.REPORTS OF MALFUNCTIONINGS: Reports of malfunc-tionings or any difficulties encountered with this fuze should be report edto the Bureau of Ordna nce. The report should conta in th e lot num ber,a complete detailed h istory and all pertin ent informa tion concerning th efuze.

PACKING AND MARKINGPACKING: One fuze is packed in a sealed cylindrical meta l con-tainer . Twenty-four fuzes in conta iners are packed in a wooden ship-ping box.

MARKING: The fuze is mar ked with ma rk, mod., and lot num ber,the date of man ufacture and the loading activity. The conta iner andshipping box are mar ked with mar k number, lot num ber, num ber of fuzesconta ined within, name of man ufacturer , year of man ufacture, ordernum ber, and th e inspectors initials.

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__- -I-_ -

OPERATION 0. P. 1002Chapt er 3

OPERATIONAND MAINTENANCE7 .2 ROCKET AUNCHER, ARK20

STOWAGE AND ASSEMBLYThe 7.2 Rockets are issued to ships in three units: Bodies (with auxiliary boosters

installed), rocket motors, and fuzes. They are to be stowed in magazines with bodies a ndmotors assembled, uncrat ed and unfuzed, and may be sta cked on top of each other not to exceedten high. Separa tors should be used between the motors to keep the shrouds slightly apar t.The above is in conformity with existing stowage facilities.

Fuzes ar e issued in boxes of 24 each. Except in rea dy s ervice st owage, fuzes are not to beassembled in the ammu nition or stowed in magazines with the ammu nition. In ships whereit is impracticable to provide separa te magazine stowage for the fuzes, it is acceptable to pro-vide stowage in water tight lockers, topside.

In assembling the motor to the body care must be exercised to avoid cross thr eading.It will be necessary to employ stra p wr enches in order t o drive th e motor thr eads fully homeinto the body thr eads. The auxiliary booster, tubular cardboard spacer, shipping plug, andfuze cap are installed in the body when sh ipped. Prior t o inserting the nose fuze, remove thefuze cap, shipping plug, and tubular cardboard spacer from th e nose of the body and make cer-tain t hat the correct number and correct mar k of auxiliary boosters are in place (see page 3 1 ),and that the fuze hole threads are undamaged. Before inserting the fuze the thr eads should begiven a light coat of grease petrolatum or any available mineral grease, such as water pumpgrease, bear ing grease, or cup grease. After the fuze has been inserted in the nose of the bodyand screwed down it should be set up sufficiently tight on its gasket to insure a watert ight sealThe special wren ch pr ovided must be used for th is pur pose. Atten tion is invited to 0. P. 1017

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_... - .-_-. .- --___-______-_ _

7 .2 ROCKET AUNCHERS 0 . P . 1 0 0 2and BuOrd Circular Letter No. A5043 covering this subject. When th e Mark 131 fuze isused the fuze cap should be put on again after t he fuze has been installed, and should be keptin place un til just before firing. Nose plugs and fuze caps should be tur ned in to th e nextissuing depot.

Rockets should not be fuzed until just before th ey are put into th e read y-service boxes.Excessive read y box temp erat ur es should be avoided by any mean s at han d. Fu ze caps onrockets in read y service boxes should be rem oved at frequent inter vals for inspection of th efuze and to rem ove any moistur e which may have accumu lated und er the cover. Fuzes shouldbe covered with a light coat of petrolatu m or minera l grease on th e exposed surfaces toavoidrust or corrosion. Before screwing th e fuze in th e body the thr eads should be covered witha light coat of grease.

LOADING AND FIRINGExact loading and firing procedure is covered in publications un der the cognizance of

Headquarters, Comman der in Chief, United States Fleet.In general, 4 to 6 loaders plus a gun capta in will be used. To prepa re a laun cher for firing,

two loaders lift the rails or ways and swing the crutch up in place, locking it with t he latchesprovided. B fore loading, the gun cap tain of the launcher crew must have the safety plug in hispossession. Two loaders are sta tioned at th e read y boxes. They rem ove th e rockets fromthe ready boxes a nd pass them to 2 other loaders who are stationed at the launchers. The twoloaders, last ment ioned, load th e rockets in th e ways of th e launchers. In loading the rockets,one hand is placed between th e fins of th e tail ring and t he oth er han d grasps th e nose of th erocket. The rocket is th en laid in th e way about 6 inches a bove its norma l position and pusheddown into th e conta cts. Care must be taken that th e motor shrouds seat properly and that t hevanes do not interfere with th e rear contact. If th e rocket sh ould accidentally be dropped th etwo motor sh rouds may short together and make a misfire possible.

When all the ways are loaded, the retainers are swung up and pinned in place, and th ecrew takes firing stations. These positions ar e chosen in such a way tha t all entr an ces to th eforedeck ar e guar ded and the guard s protected out of line of blast of th e launchers. The guncaptain takes station at the safety receptacle and inserts t he safety plug at a command fromthe bridge. To prepa re for firing, the connin g officer thr ows th e switch ma rked POWERon the Control Pan el, Mar k 2, Mod. 2, th e red safety indicator lights u p when th e safety plugis insert ed in the receptacle, and the green indicator when th e power switch is tur ned ON.On th e Control Pan el, Mark 3, Mod. 2, the red indicator lights when th e safety plug is inplace and the power switched ON. The power switch should be kept at OFF except to

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OPERATION 0 . P . 1 0 0 2check for readines s or to fire. To fire both launchers, the switches mar ked port and star -board ar e th rown to th e ON position. When the proper ran ge is reached, the conningofficer pr esses t he firing button at the next instant tha t t he ship is on even keel. The firingbutt on should be kept depressed until all the rockets have gone; unless t he batt ery is in goodcondition, ther e may be a relatively large interval between the firing of the halves of a salvo.As soon a s the salvo is gone , the safety plug must be remove d and the pow er switch ope ned. The laun-chers can t hen be reloaded.

The ready boxes ar e replenished from storage as soon a s possible, in any time a vailablebetween salvos. It should be noted t hat certain rockets have safety shorting wires shortingthe connection in the motor. These wires ar e to be clipped off close t o th e ter mina ls beforethe rockets are placed in the ready boxes. With am munition of present and future issue, asafety clip will be used inst ead of wires. This clip must be removed after th e amm unitionhas been loaded on the ways.

SAFETY PRECAUTIONSIt should be emphasized tha t all rocket amm unition must be trea ted with care. Rocket

motors should not be needlessly exposed to the direct rays of the sun or to any tempera tur e inexcess of tha t print ed on the motor tube, as such exposure may resu lt in the rocket motorblowing up on the launcher when t he rocket is fired. Under no circumsta nces are rockets tobe fired when they have been subjected to a temper at ure in excess of the safe firing limitat ionsuntil they have been allowed to retu rn t o a temper atu re within the safe limits. Ammunitionwhich has been exposed to excessive temper at ures (temperat ures in excess of the upper limitor less tha n t he lower limit printed on the tube) should be maint ained within the safe firinglimits for at least 6 hours before use. Every effort should be made to mainta in amm unitionin ready s ervice within the safe temper at ure firing limits a t all times.

Since, at present , the propellant is sealed into the motor tube by means of closure discsand asphalt paint, it is not possible to conduct visual or surveillance tests of any kind. Th edevelopment of surveillance tests for ballistite is at present being undert aken and when a properprocedure has been worked out it will be made the subject of a publication. Under no circum-stan ce is the propellant to be removed from the motor of any rocket. Any rocket motors onhan d in which t he closur e disc or discs have become loosened mus t n ot be fired. They must bedisposed of either by tur ning in to an ammu nition depot or, if this is not practicable, by dump-ing into deep water.

It is obvious tha t it is dangerous to stay directly in front of a launcher while it is loaded orbeing loaded. It is mo re da ngerous, howe ver, to stay directly behind the launc her under the same

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7.2 ROCKET AUNCHERS 0 . P . 1 0 0 2circumstances. The blast tha t is emitted from the nozzle (rear) end is intensely hot and th egases travel at a rat e of between six and seven thousan d feet per second. Small slivers ofburning powder may be blown out of the nozzle, and these ar e very difficult to extinguish.Extreme ca ution must be taken to ma ke sure that no one is directly in front of or direc tly to the rear of aloaded launcher or one that is being loaded . Loading should always be done in such a man nertha t the loader and a ny member of the crew a re well to one side of the path tha t th e projectileor the blast would tak e in case a rocket should be fired eith er accidentally or intent ionally.Carelessness in this respect has resulted in fatal casualties.

All rocket launchers are equipped with safety plugs and r ecepta cles. These receptaclesar e installed on an externa l bulkhead, in sight of the launcher and at a safe distance ther efrom,and ar e part of th e electrical firing circuit. The safety plug is at all times to be in th epossession or under the contr ol of a part icular person, whose r esponsibility it shall be to seetha t t he safety plug is not installed in the receptacle unt il the launcher is in all other respectsready to be fired, and is removed immediately after firing. The safety plug shall be removedby the person charged with its care before a loaded or part ially loaded launcher with the plug inplace is approached by any oth er person. All personnel must be instru cted not to load anylauncher or to approach any loaded lau ncher unt il it has been made absolutely certain tha t th esafety plug is in the possession of the crew member charged with its care. Fatal casualtieshave resulted from failure to observe the necessary precautions.

Tests of Fring circ uits o f launc hers, Mark s 20 and 22, when they involve personnel being in theimme diate vicinity of the launchers shall not be co nduc ted until all rock ets have been removed fromthe launchers and the imme diate vicinity of the launchers or stored in the ready -service box. Subse-quent to the co mp letion of such tests, the rock ets may be reloade d on the launchers only at the order ofan individual at the launchers who has bee n mad e responsible for the load ing ope ration and is inac tual p hysical possession of the safety plug.

The safety precaution in th e preceding para graph shall be posted conspicuously andpersonnel concerned frequently and th oroughly instr ucted and drilled in it.

The projectiles should be kept free from rust , and th e unpa inted surfaces protected withgrea se. The condit ion of th e insula tion should be periodically inspected , but no electricaltests should be made because of the danger of setting off the electric primer. It is importanttha t it be stored and ha ndled in such a way as to avoid bending of th e tail rings, since distortionof th ese rings may cause misfires du e to lack of cont act in the launcher, and will also have aserious effect on th e under water tr ajectory.

It may sometimes happen tha t a misfire occurs and one or more rockets in a salvo willremain on the ways. No one is to be allowed on th e forecastle for at least 10 minut es aftersuch a misfire. B fore approac hing the launcher, which should be done from one side if possible,mak e sure that the safety plug has been remo ved from the safety recep tac le. If inspection then re-veals tha t t he closure disc in the nozzle has not been blown out, it is probable tha t the igniter

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OPERATION 0 . P . 1 0 0 2did not fire because of electrical difficulties. Th e contacts should be checked and connectionsinspected. If the rockets have been subjected to sea spra y while in the launcher, it may betha t shortin g has been caused by salt bridges which h ave form ed on th e cont acts. These caneasily be rem oved by washing down with water . The stream of water must n ot be directed atthe nozzle closure disc, a s it may loosen th e disc.

Note tha t if a misfire is due to a short circuit, two rockets may r emain on th e ways, sincethe cont acts ar e conn ected in para llel pairs. For exam ple, if all th e even- or odd-num beredrockets ar e misfired, examine th e delay-relay in th e cont rol panel. If any obvious defects arefound, they are to be repaired and the firing repeated. In case the same rocket again fails tofire, and inspection reveals no obvious defects, rem ove th e round from th e laun cher, replaceth e safety wire in the fuze, and rem ove the fuze from t he projectile. After replacing th e short-ing wire or shorting clip, unscrew the motor from th e rocket body, properly tag it so as to showthe chara cter of malfunctioning, the num ber of days the round had been on th e ways, thenum ber of immediat ely previous successful firings from the same ways, or any other rem ark swhich may aid in determ ining th e cause of misfire. Then turn in the motor to the nearestamm unition depot for tra ns-shipment to th e Naval Mine Depot, Yorkt own, Va., for inspection.All the foregoing rules apply to tar get pra ctice or test firings. In actual combat against t heenemy, t he time int erval may be short ened at th e discretion of th e comma nding officer, but insuch ca se every precaution shall be taken that personnel remain c lear of the area which exp erience hasshown to be dang erous bec ause of burning pow der ga ses. The misfired rounds shall be dropped over-board, after t he fuze safety wire has been replaced. It is not inten ded to prevent efforts tofire the rocket by repeating the normal firing procedure as the time taken to repeat the firingcycle a nd possibly clear th e lau ncher of misfire, is sma ll.

Because of the fact tha t th e fuze rema ins arm ed once it has been arm ed, un fired rocketsar e not t o be fished up out of th e water . They do not necessarily fire on sand bott om.

Since small pieces of solid propellant may be ejected dur ing firing and rema in on th e deckprecaut ions should be tak en to avoid fire hazar ds. After firing the laun cher, th e decks sh ouldbe thoroughly hosed down and all such powder fragment s washed overboard , as th ey ar e highlyinflammable.

It is of the utmost importan ce that naked lights, matches, or other flame producing apparatu sshall never be allowed in th e vicinity wher e this amm unition is present . The pr esence of blackpowder in th e igniter ma kes this amm unition highly susceptible to ignition. Before perform-ing any work which m ay cause either an abnormally high tempera ture or an intense localheat in a magazine or stora ge place where r ocket amm unition is kept or in an adjacent com-partm ent, the ammun ition must be removed to safe storage. Because of the presen ce of blackpowder in th e igniters of rocket type ammu nition separa te storage sh ould be provided wherepracticable. Stora ge in magazines should not be made except in accorda nce with appr ovedplans.

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__-____ --________-- ---- .-

Y.2 ROCKET AUNCHERS 0 . P . 1 0 0 2MAI NTE NANCE

The laun cher units should be kept paint ed and free from ru st, dirt and accumu lationsof salt. The electrical system should be examined at frequent intervals to insure tha t thebatt eries, firing panel, contacts, safety plug and receptacle and wiring are in satisfactory con-dition. U d er no condition should the electrical system be chec ked when rocke ts are on thelauncher rails or when in an expo sed co ndition in the imme diate vicinity of the launcher. A simpletest of the electrical system is outlined below:

(a) With all switches in the OFF position measur e t he voltage at the batt ery.(b) With th e launcher unloaded place the power switch at ON and the starboard (or upper)

switch at ON. Insert the safety plug into its receptacle. Measure the voltage bet ween thehot knife edge cont act and ground. A reading a ppreciably less tha n tha t obtained under(a) indicates a short circluit or low resistan ce part s, which should be found and corrected.If both voltage readings (a) and (b) are substant ially the same, connect a suitable resistan cebetween the knife edge cont act and ground; a convenient resistan ce consists of a 6-volt 21cl, or 32 cp au tomobile type lamp, passin g about 4 and 6 am peres, resp ectively. Such alamp should light up fairly brightly; a quick check with a voltm eter should show at least 3volts across t he lamp. To avoid run ning th e batt ery down th ese tests should be of as shortdura tion as possible.

(c) Repeat (b) with power switch at ON; and the port (or lower) switch at ON.(d) All ter mina l tu bes, glands, boxes, fittings, etc., exposed to salt spray should be kept

tight, gaskets a nd packing being used as necessary. Unless this is done water may ent er intoone of the electric cables, which will act as a hose, providing a channel whereby water maypass int o conn ection boxes, etc., both above a nd below decks.

(e) Remove the covers of all boxes at frequent intervals. If moisture is present ascertainand remove means of entr y. Wash out the box with fresh water and dry.

(f) Do not use ordinary paint on the knife edge conta ct assembly, part icularly on theinsulation. If necessary use an appr oved insulating varnish; in general th e application ofvarnish will not mat erially improve performance.

(g) Salt bridges m ay form on ex,posed par ts causing short circuits and misfires. In gen-eral, a th orough hosing with fresh, or even sea water, should remove them .

Each ship may carry a spare safety plug and one spare batt ery. Additional batt eriesmay be obtained from tender s or Navy Yards.

If ice forms on the launchers, including the conta cts, it must be completely removedbefore firing. If loaded, care m ust be tak en to insur e tha t the rockets are not frozen t o theways. Extr eme care must be tak en tha t th e fuzes are not arm ed dur ing th e de-icing process,part icularly when using a hose.

TACTICAL OPERdTlONTactical employment of th e launcher, Mark 20, including th e several corrections which

must be determ ined and included in th e proper firing ran ge, will be found in a publicationissued by Headqua rter s, Comma nder in Chief, United Sta tes Fleet.

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PERFORMANCE 0 . P . 1 0 0 2Chapter 4

PERFORMANCEATAOF7 .2 ROCKET AUNCHER, ARK20

As has been previously ment ioned, the propellant grain burnswith an almost consta nt pressure for several tent hs of a second.The value of the pressur e depends on temper atu re, varyingfrom about 800 pounds per square inch at 10" F., nd 1,500pounds per square inch at 70 F., o 2,300 pounds per squa reinch at 120 F. Since the motor tube is test ed to 5,000 poundsper square inch, ample safety factor is provided. The time ofburning depends inversely on the temper atu re, varying from0.7 econds to 0.2 seconds.

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7 .2 ROCKET AUNCHERS 0 . P . 1 0 0 2

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PERFORMANCE 0 . P . 1 0 0 2A graph, figure 18, shows the relationship between ran ge and propellant

temperature. The variation of velocity and range with temper at ure dependson a num ber of factors. At low tem pera tu re, th e effective velocity of th e gasescaping from the nozzle is lowered because of the lower burning pressure.Also, more energy must be used to heat t he powder mass to the burning temper -at ur e, leaving less for propulsion. Fur ther ,the acceleration distance is great erat low tem perat ure, resulting in more curvat ure in this part of the tr ajectoryand hence in shorter ran ge. The combination of these effects r esults in adecrea se in velocity of about 10 percen t, in ra nge of about 20 percent , in goingfrom 70 F. to loo F. At elevated temper atu res, decrease in mechanical str engthof the powder results in an increased loss of powder in unburn ed form, pra c-tically compensating for effects tending to increase the ran ge. Thus the rangeis sensibly const an t from 70 F. to 120 F. Because of th e rela tively lowvelocities, the ranges will only be about 3 percent shorter tha n those calculatedfor vacuum.

A ra nge corr ection for complet e round a ssemblies which d iffer in weightfrom th e nominal round weight of page 44, ma y be ma de by th e following ru le:The percentage change in ran ge is twice the percenta ge change in weight,and in the opposite direction, i. e., an increase in weight causes a decrease inrange and vice versa.

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DEPTH-FEET

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PERFORMANCE 0 . P . 1 0 0 2Since the point of application of thr ust of the rocket motor is behind the center of gravity

of the charge, th ere may be some tendency to veer off course when t he accelerat ion continu esbeyond the launcher. For this reason, the latera l dispersion of shots from a given way maydepend quite mar kedly on the burning time, and hence on the tempera tur e. For example, at120 F., about one-fifth of th e burn ing occurs on th e ways an d th e lat era l dispersion is appr ox-imately 2 yards in 300. At normal temper atu res, one-tent h of the burning is on the ways andthe dispersion is approximately 4 yards. At 10 F., the fraction is one-thirt eenth and thedispersion approximately 12 yards. The dispersion in ran ge, on the other hand, is nearlyconsta nt, about 6 yards in 300? since at 49 quadran t angle, th e ran ge is not sensitive to theangle of the tra jectory at the end of burning.

In cold weather, due to slower bur ning time of propellant grain, a str ong cross windcauses notable deflection errors. For exam ple, at 25 F., a 20 mile per hour cross wind producesa 25 yard deflection into t he wind. At 70 F. or higher , th e corr esponding err or is 5 yards orless. The error int o th e wind is proportiona l to th e cross ra nge componen t of wind velocity.

It is recognized tha t pitch affects the range since the ways a re in a displaced position andthe charges ha ve an upward or downward component depending on the direction of the pitch.However, the amount of this variat ion in ran ge is not sufficient to make corrections worth -while. Also th e roll of the ship results in an err or in tra in. Thus firing should be done whenthe ship is on an even keel. Another quant ity which h as a bearing on the tr ajectory of therocket is the forwar d speed of the boat.

In the first 2 or 3 feet after striking the water, the rocket continu es on its formerpath , but with a large deceleration of the order of 50 to 100 times gravity. In about 30 feetof tra vel, th e rocket is brought to a vertical course and proceeds downward with its termina lvelocity of 22 to 25 ft./set . To rea ch 100 foot depth ta kes 12.5 seconds, including 8 secondsflight in air. (See fig. 19.) In order to keep th e rocket on course under water , it is givena spin by the vanes on the motor. Near t he end of the air tra jectory, the rockets mak e aboutfour revolut ions per second an d one revolution in 40 feet. Just under t he surface, the rateof spin is appr oxima tely one tu rn in 6 feet, probably decreas ing to about one in 12 atgreater depths.

Until further notic e is given, this amm unition must not be used if the prope llanttemp erature is higher than 1 2 0 " F., or low er than 1 0 " F. At temperatures highertha n 120 F., burning of the propellant grain is greatly accelerat ed with adangerous increase in pressur e. At temper atu res lower tha n 10 F., burningmay be incomplete and large unburned pieces of powder may be ejected fromthe nozzle. Also misfires may result.

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------


I/- -Io>

.4

f

-I.

IIT

II

. .\

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PERFORMANCE 0 . P . 1 0 0 2

ROCKETS APPROXIMATELY11.8 YARDS APARTON LANDING

SPREAD-YARDS40 20 0 20 40I I I

300

280

260

240

220

200

180 v)n%

160 > iGf140 M

120

10080

60

40

20

FIG. 2 0 . P AT T E RN OF F I RE

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0

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COGNIZANCE 0 . P . 1 0 0 2Chapter 5

COGNIZANCE

The Bur eau of Ordn an ce will supply a nd ret ain cognizance over th e following item s ofequipment :

A 7.2 Rocket La un cher, Mark 20.B Contr ol pan el, Mar k 2, Mod. 2, or Mar k 3 or Mar k 3, Mod. 2, or cont rol

panel, Mark 7, when furnished.C Safety plug and receptacle.D Wiring from laun cher to bran ch box E type,E Ammunition and fuzes.F Fuze wrenches.G Batteries.

The Burea u of Ships will supply an d ret ain cognizan ce over the following item s of equip-ment :

A Foundations for the launchers, including means for securing t he launchersthereto.

B All steel sheathing or other mat erial used for deck protection.C Watert ight meta llic st owage lockers for ready-service ammu nition.D Magazine stowage for fuze cont ain ers.E Magazine stowage for assem bled rockets (unfuzed).F All wiring and electrical appurt enances (except safety plug and receptacle)for connecting the launchers to the contr ol panel.G Such communication or signal facilities as may be aut horized in order that t he

firing stat ion may maintain proper contact with personnel at the launchers.

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RETAIIHANDL

RETAIN

UPPER WAYS Q, LOWER WAYS

JTCHES

BAS E

DEFLECTORS k/

FIG. II. 7.2 ROCKET LAUNCHER, MARK 22, LOADED, READYFOR FIRING

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INTRODUCTION 0 . P . 1 0 0 2Chapter 6

7 .2 ROCKET AUNCHER, ARK22

DEFINITIONThe 7.2 Rocket Lau ncher , Mark 22, is a rocket-laun ching de-

vice similar to th e lau ncher, Mark 20, but consist ing of two hingedsets of steel ways instead of one set, as is the case with t he Mark 20.

This launcher was formerly known as the Projector, Mark 22,and many name plates are so marked.

The designat ion Control Pan el was changed to Firing Pan elsubsequent to the prepara tion of this ordnance pamphlet.

USEThe lau ncher, Mark 22, is used exactly the sam e as the Mark

20. Ea ch la uncher , Mar k 22, fires 8 rockets in a salvo.

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/----------- ..-.---.- -____I --__I__ -----------------:2 ROCKET AUNCHERS

UPPER WAYS

LOWER WAY:

BASE\

FIG. 21. 7.2 ROCKET LAUNCHER, MARK 22, IN STOWEDPOSITION

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--~-

DESCRIPTION 0 . P . 1 0 0 2l

7.2 ROCKET LAUNCHER, MARK 22The lau ncher consist s of 2 sets of ste el ways. Ea ch set of ways is

hinged to the base frame a nd is independently supported in the raisedposition by its own crutch. The ways thems elves consist of sections ofsteel plate bent u p to make rails in which the rockets ride. The threeinside sections are made broad and wedge-shaped, one piece thu s servingas common way for two adjacent rockets. A spread of one part in 40is made between ways to give the required spacing of shots. A set ofretr actible reta iners is provided for each set of 4 ways to keep th e rocketsfrom being wa shed out of place. In general, t he same protection againstblast must be provided as is provided for the Launcher, Mark 20. Itshould be noted tha t the deck plat e is not a part of the launcher, Mark 22as it is with th e Launcher, Mark 20.

The launcher is designed to fold down and be lashed to the deck whennot in use, as shown in figure 22. When conditions require it, weath erpermitt ing, the launcher may be maint ained elevated and loaded. When-ever weath er conditions are such tha t th e launchers or the ammu nitionexposed on the rails would be subject to dama ge or deterioration, theammu nition should be unloaded and stowed and the rails lowered andlashed down.

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PORT LAUNCHER,

LAUNCHER IN STOWED POSITION\

66

_J,PILOT HOUSE d -N I

I 1 0

FIVE WIREH CONNECTION BOX

FIVE WIRE CABLE

2 SAFETY RECEPTACLE

/

CONTROL PANEL

FIG. 23. FOREDECK INSTALLATION OF 7 . 2 ROCKETLAUNCHER, MARK 22

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DESCRIPTION 0 . P . 1 0 0 2

INSTALLATIONFor mounting the launchers, two clear spaces about 42 inches

by 108 inches ar e requ ired on th e foredeck. A 16-inch or lessportion of the forward end of the lower launcher ways ma y be cutoff only if insta llation requ ires it. The sa me type of blast deflectorplates are used for the Launcher, Mark 22, as have been describedon Page 15. In addition, the portion of the deck between theupper and lower set of ways and immediately behind the upper setof ways is sheat hed against blasts.

The launchers are mounted on wood or meta l foundations sotha t they ar e level ath wartsh ips and have a 3-5 slope fore andaft with the high point forwar d. The two launchers are placed,in th e folded position, on th e fored eck symmet rically about th ecenterline of the ship. The extreme forwar d point of the inboardedge of th e base of each la uncher deviat es 5>/, to 6% inchesfurther ,from the center line tha n th e aft end of the base. Thisdeviation is inversely proportional to the dista nce betweenlaunchers. This placement of the launchers gives an approxi-mat ely equal spacing to all eight rockets.

Ready-ser vice boxes are provided on th e fored eck, convenien tto the launchers, for ready ammun ition. Each box holds therounds in easily accessible racks and is watert ight. Additionalamm unition may be stowed below decks in magazine stowage.

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-.- -_- -- -

7 .2 ROCKET AUNCHERS 0 . P . 1 0 0 2MOTOR TROUGH OF WAY

INSULATON

UPPER ELECTRICA L CONTACT

\ LOWER ELECTRICAL CONTACT

FIG. 24. ELECTRICAL CONTACTS FOR 7.2 ROCKET LAUNCHER,MARK 2268 CONFIDENTIAL

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ELECTRICAL CONTROLSFiring is electr ical and is cont rolled from th e bridge.Electrical cont act for firing is mad e t o th e motor shrouds of th e rocket

by mean s of knife edges as in Laun cher, Mark 20. The lower cont actmount ed in th e deflector plate grips the inside of th e grounded rear motorshr oud which is electr ically conn ected to one side of th e igniter andserves as a stop. The upper in sulated cont act is mount ed on a phosphor-bronze spr ing and bears on th e outside of th e forwar d shr oud. Bothcont acts ar e made of ha rdened stainless st eel.

The wirin g to the safety plug is th e same as described for th e Laun cher,Mark 20. The safety plug is ca rried by the gun ca ptain and it is his responsi-bility to see that the plug is not inserted in the safety rece pta cle until allpersonnel is off the foredec k, after the launche rs ha ve been load ed.

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FIRING BUTTON

THIS NAME PLiTEUSED O N FIRINGPANEL MA RK 3, MO D. 1AND MARK 3, MO D. 3

CO NTROL PANEL MA RK 3AND MA RK 3, MOD. 2

FIG. 25. CONTROL PANEL FOR 7.2 ROCKET LAUNCHER,MARK 22

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FIRING PANELSThe Cont rol Pa nels, Mar k 3, Mod. 1, or Mar k 3, Mod. 3, ar e usedwith th e Launcher, Mark 22. The Control Panel, Mark 3, Mod. 1 utilizes

one 45-volt an d two 6-volt dry bat ter ies. (The 45-volt bat ter y is nowknown t o be unsu ita ble). The Cont rol Pa nel, Mar k 3, Mod. 3 ut ilizestwo 7%-volt dry bat ter ies. Contr ol Pa nels, Mar k 3, Mod. 1 and Mar k3, Mod. 3 are identical to the Control Panels, Mark 3 and Mark 3, Mod.2, respectively, except tha t the nam e-plate is changed. In the ControlPan els, Mark 3 and Mark 3, Mod. 2, the plate reads Port-Power-Sta r-board. In th e Contr ol Pa nels, Mar k 3, Mod. 1 an d Mark 3, Mod. 3, th eplat e rea ds Upper -Power-Lower. (See fig. 25.)

When the switch marked UPPE R is operated and the proj

OP 1002 7.2 Rkt

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