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The Gunnery Pocket Book , B.R. 224/45, 1945 was created near the end of WW II and therefore represents the peak of British WW II gunnery. This edition has a few small corrections and updates that were added by hand in 1949 that are reflected in the text.

B.R. 224/45 THE

GUNNERY

POCKET BOOK 1945 ADMIRALTY, S.W.1.

GUNNERY BRANCH. A



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ADMIRALTY, S.W.1.

19th June, 1945. G. 6450/43. B.R. 224/45-The Gunnery Pocket Book, 1945, having been approved by My Lords Commissioners of the Admiralty is hereby promulgated for information and guidance. B.R. 224-The Gunnery Pocket Book, dated 1932 and reprint of 1938, and B.R. 154-The Ammunition Pocket Book, 1935, are hereby superseded and all copies should be disposed of in accordance with the instructions in B.R.1-B.R. Catalogue. By Command of Their Lordships, To Flag Officers and Commanding

Officers of H.M.

Ships and Vessels concerned.



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CONTENTS Page List of Abbreviations Used in Gunnery x Introduction Paras. Objects of the book-Possibilities of the gunnery career-steps in the gunnery career-advancement-recommendations-training 1 CHAPTER I Gunnery in Ships General-A 6-inch cruiser, "Mauritius" class 20 A "Dido" class cruiser-A typical destroyer 32 CHAPTER II The Ship's Company Part played in fighting the ship 41 CHAPTER III Naval Guns How a gun is fired-Construction of the gun barrel-Rifling-Problem of recoil 45 Breech mechanisms-Summary of safety arrangements-The B.L. mechanism 51 The Q.F. mechanism-Care and cleaning 59 CHAPTER IV Hand Worked Mountings Principles of mountings-Pedestal mountings-Central pivot mountings-Cradles-Trunnions-H.A. mountings-Recoil arrangements-Run-out arrangements-Intensifiers-Elevating gear-Training gear-Loading tray 85 The 4.7-inch Q.F. Mark IX** gun on the C.P. Mark XVIII mounting 111 The 4-inch Q.F. Mark XVI* gun on the H.A. Twin Mark XIX mounting 117 Maintenance of mountings 122 CHAPTER V Power Worked Mountings General-Liquid used in hydraulic systems-Pipes and joints-Types of valves-Leathers-Pressure supply-Hydraulic machines 130 6-inch B.L. Mark XXIII gun on Triple Mark XXIII mounting 149 5.25-inch Q.F. Mark I gun on H.A./L.A. Twin Mark II mounting 159 Upkeep of machinery 171



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CHAPTER VI Ammunition Paras. General-Guns-Explosives 175 Cartridges-Tubes and primers-Ammunition packages-Colouring of ammunition packages-Projectiles-Supply and care of projectiles-Tracers and Igniters-Colouring and marking on projectiles-Fuzes-Fuzing of shell-Gaines 179 Aircraft bombs-safety arrangements-supply and fuzing-markings 212 Small arms ammunition-Rifle grenades-Fireworks supplied for Naval service-Fireworks supplied for use in aircraft-Firework boxes-Line-throwing guns-Line-carrying rockets 216 Magazines and shell rooms-Ammunitioning ship 240 CHAPTER VII Low Angle Firing SECTION 1-THE DIRECTOR SYSTEM Reasons for a director system-Allowances to be made in director firing for elevation and for training 256 For Elevation.-Dip-Differences in muzzle velocity and temperature of charge at each gun-Tilt-Displacement 260 For Training.-Convergence -Drift 267 Summary of corrections 270 The director sight-the "P" sight-The gun receivers, elevation and training-Firing arrangements 271 Electrical transmission and lining up-step by step-synchronous-magslip, indicator and power 284 Director laying and training-practical working of a director sight 292 Errors in director firing due to roll and pitch of ship-due to roll, firing on the beam-due to roll, firing on the bow 295 SECTION 2- THE FIRE CONTROL PROBLEM AND ITS SOLUTION Target indication-Obtaining the correct range-Obtaining the correct line of fire-Summary of the fire control problem 297 Admiralty Fire Control Clock 304 Typical modern Fire Control Table 312 The fire control team-Composition of the team-Organization for night action-Standard methods of passing orders-Method of using telephones-Positions of controlling and methods of firing the guns-Gun-layer's control 318



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SECTION 3-THE PRINCIPLES OF RADAR, OPTICAL RANGEFINDERS AND INCLINOMETERS Paras. Radar-nature of Radar-uses of Radar-limitations of Radar-Radar operators 349 Optical rangefinders-use of rangefinders 354 Principles of the coincidence rangefinder 356 Focus-magnification or power-taking a range-types of field-astigmatizers-light filters 357 L.A. ranging-halving error-mean adjustment error or coincidence error 363 Inclinometers 371 Maintenance of rangefinders and inclinometers 372 SECTION 4-THE GUN Gunsights-trainer's free sight-Parts of a sight-Types of sights-Corrections required at a sight-Maintenance of gun sights-Telescopes 373 Gunlaying and training-when following director-when using gunsights-point of aim-recognition of targets 395 Firing arrangements-local firing-gunlayer's firing-quarters' firing 400 General principles underlying drill at the gun 401 The gun's crew at a destroyer's gun-composition of crew 403 Action drill-action drill common to all forms of fire-action drill for low angle fire 405 Defence and cruising stations at the gun 408 CHAPTER VIII High Angle Firing Outline of the control system-the problem-principles of deflection 415 H.A.C.S., fuze prediction 427 Fuze keeping clock, fuze prediction 432 The high angle fire control team 436 Air defence of the ship-barrage firing-A.B.U. firing. T.I.U. 446 Drill at the high angle guns 449 CHAPTER IX Close Range A.A. Gunnery Necessity for simple control-Close range guns' crews-Close range guns sights - Eyeshooting and Aircraft recognition -type of attack 455 The Pom-Pom director Mark IV-The 2-pounder Mark VIII gun on Mark VII mounting-The Oerlikon 471



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CHAPTER X Look-outs and Optical Instruments Paras. Look-outs-Care of binoculars-How to adjust binoculars-How to use binoculars-Typical look-out organisation-Duties of lookouts-Reporting-Recognition 495 CHAPTER XI Organisation of a Ship's Company Degrees of readiness in war-time-Alarm signals-Food and sanitation -Spare gear-Casualties 510 CHAPTER XII Damage Control Closing doors-Abandoning compartments-Fire-Prevention of fire in a ship Magazines-Flooding and spraying-Correcting heel and trim-Counter flooding-Damage control communications-General 525 CHAPTER XIII General Maintenance of the Armament in War Cold weather-Muzzle covers 545 CHAPTER XIV Notes on Boarding Parties 555 CHAPTER XV Gunnery Practices Types of practice firings-Training close range guns' crews-precautions during practice firings-Records and recorders-stop watches-notes for recorders 560 CHAPTER XVI Saluting Guns Nature and number of guns used-Single ship procedure-Fleet procedure 580 APPENDIX I. Page Particulars of Armament and Fittings supplied for Service Boats 196 APPENDIX II. List of Bugle Calls. 202



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DIAGRAMS Paras. 1. 4.7 inch Q.F. Mark IX** Gun on C.P. Mark XVIII Mounting 111-6 2. 4 inch Q.F. Mark XVI* Guns on Twin H.A. Mark XIX Mounting 117-21 3. " U," "Hat" and " L " Leathers 139-40 4. Illustrating Angle of Dip 260-1 5. M.V. and Temperature Corrector at Elevation Receiver 262-3 6. Tilt Corrector 264-5 7. Illustrating Displacement 266 8. Illustrating Convergence 267-8 9. Typical Arrangement of D.C.T. Crew 255, 271 9a. Gyro Director Sight, Type H Mark I 255, 271 10. Fig. I Elevation Receiver Type " E.M." Mark I 276-8 Fig. II Training Receiver Type "D" Mark IV 279-80 11. Director Layer's and Gunlayer's Firing Circuits 281-3 12. Range and Deflection Step by Step Receiver, Counterdrum Type 285 13. Fig. I Step by Step Transmission 285-6 Fig. II Synchronous Transmission 287-8 14. Principle of Hunter Mechanism 289 15. Fig. I Indicator Magslip Transmission 290 Fig. II Power Magslip Transmission-Three Element System 291 16. Captain's Sight and Open Face Indicator 24,297 17. Admiralty Fire Control Clock Mark I-Plan of Top 304-11 18. The Measurement of Inclination 305-6 19. Typical Modern Fire Control Table 312-7 20. The Low Angle Fire Control Team 318-28 21. The Principle of Optical Rangefinding 356, 360 22. Figs. I and II Heightfinder Cut 360 23. Halving Error in Rangefinders "Erect Image Field" 368 23A. Halving Error in Rangefinders-Inverted Image Field 368 24. Inclinometer Type S.F.13 371 25. Typical Geared Sight-4.7 inch Mark XVIII Mounting 375 26. Parts of a Gun Sight 380 27. Principles of Deflection 421-4 28. Deflection Screen-H.A.C.S. Mark IV 425-6 29. Typical Range Plot-H.A.C.S. 427-31 30. Fuze Keeping Clock Mark II 432-5 31. The High Angle Fire Control Team 436-45 32. Eyeshooting Sights 460-4 33. Pom-Pom Director Mark IV 471-2 34. 2-pdr. Pom-Pom Mark VII Mounting 473-5 35. 20 mm. Oerlikon Gun 476-91 36. Binoculars Pattern 1900A 496-7 37. Air Lookout (A.L.O.) Position 500



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ABBREVIATIONS USED IN GUNNERY. This list is not exhaustive. Certain abbreviations have been omitted, e.g., those for the greater part found on packages to which reference should be made in the appropriate handbook, particularly the Handbook on Ammunition. A. Letter usually denoting foremost centre-line turret or mounting. (A) Annealed. [ed. Letter A with a full circle around it.] A.A. Anti-aircraft. A.A.1 Anti-aircraft rating 1st class. A.A.2 Anti-aircraft rating 2nd class. A.A.3 Anti-aircraft rating 3rd class. A.A.D. Apparatus Air Defence. A.B.U. Auto Barrage Unit. A/C Aircraft. Admy. Admiralty. A.D.O. Air Defence Officer. A .D.P. Air Defence Position. A.F.C.C. Admiralty Fire Control Clock. A.F.C.T. Admiralty Fire Control Table. A. F.O. Admiralty Fleet Order. A/G. Anti Gas. A.G.O. Air Gunnery Officer. A.I.C. Action Information Centre. A .I.N.O. Assistant Inspector of Naval Ordnance. A.L.O. Air Lookout. A.M.C. Armed Merchant Cruiser. Ammn. Ammunition. A.P. Armour Piercing, Air Ministry Publication. a.p.v. Average Projectile Velocity. A.S. Angle of Sight. Admiral Superintendent. A/S. Anti-Submarine. A. S.A. Ammunition, Small Arms. A. S .0. Armament Supply Officer. Aux. Auxiliary. A.V.G.I. Auxiliary Vessel Gunnery Instructor. A.V.G.O. Auxiliary Vessel Gunnery Officer. B. Letter usually denoting second foremost centre-line turret or mounting. B.C. Ballistic Cap. B.D. Between Deck (Gun mountings). Bg. Bearing. B.H. Ballistic Height. B.H.C. Ballistic Height Correction B.L. Breech Loading. B.M. Breech Mechanism. B.P.T. Battle Practice Target. B.R. Book of Reference. B.T.U. Bearing Transmission Unit. C.A.F.O. Confidential Admiralty Fleet Order. Cal. Calibre. C.B. Confidential Book. C.B.R. Confidential Book allowed to Ratings. C.E. Composition Exploding. C.G. Captain of Gun. e.g. Centre of Gravity. Chg. Charge. C.N.F. Common Nose Fuzed. C.O. Control Officer. C.O.A. Chief Ordnance Artificer. Comd. Gnr. Commissioned Gunner. Convtd. Converted. C.O.O. Commissioned Ordnance Officer. C.O.S. Change Over Switch. C.P. Central Pivot. Calculating Position. Common Pointed. C.P.B.C. Common Pointed Ballistic Capped. C.P.C. Common Pointed Capped. C.R. Calibre Radius. Commencement of Rifling. Close Range. c.r.h. Calibre Radius Head. C.R.1 Control Rating First Class. C.R.2 Control Rating Second Class. C.R.3 Control Rating Third Class. Ctg. Cartridge. C.W.P. Wooden Packing Case. D.A. Direct Action (Delay Action occasionally). D.a. Deflection in Azimuth. D.A.I. Direct Action Impact. D.B. Dive Bombing.



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D.C. Damage Control. Depth Charge. D.C.T. Director Control Tower. D.E. Director Elevation. Def. Deflection. D.E.M.S. Defensively Equipped Merchant Ship. Det. Detonator. Dir. Director. D.1 Lateral Deflection. D.N.P. Di-Nitro-Phenol. D.O. Director Officer. D.T. Director Training. D.v. Vertical Deflection. E.A.O. Explosives Accounting Officer. E.B.I. Enemy Bearing Indicator. E.M.F. Electro-Mechanical Firing. Exd. Examined. Expl. Exploder. F.A. Fixed Ammunition. F.C. Fire Control. Full Charge. F.C.B. Fire Control Box. F.C.T. Fire Control Table. F.D.O. Fighter Direction Officer. F.K.C. Fuze Keeping Clock. F.O.G.M.O. Fitting Out Gun Mounting Officer. F.O.G.O. Fitting Out Gunnery Officer. F.O.B. Forward Observer (Bombardment). F.O.S. Fall of Shot. f.s. Feet per Second. F.T. Field Training. F.T.P. Follow the Pointer. Fzd. Fuzed. G. Followed by a number indicates Gunpowder Grain size. G.A. Gunnery Aircraft (Radar Set). G.B. Gunnery Barrage (Radar Set). G.B.I. Gyro Bearing Indicator. G.C. Gunnery Close Range (Radar Set). G.C.O. Gunnery Control Officer. G.C.T. Gun Control Tower. G.E. Gun Elevation. G.I. Gunnery Instructor (R.M.) G.L. Gunlayer. G.L.O. Gunnery Liaison Officer. G.L.W. Gunnery Lieutenant's Writer. G.M. Gunner's Mate. Gne. GaMe. Gnr. Gunner. Gnr. † Dagger Gunner (Gunner Instructional). G.O. Gunnery Officer. G.P. Gunpowder, General Purpose. G.Q's. General Quarters. G.R. Gun Range. G.R.U. Gyro Rate Unit. G.S. Gunnery Surface (Radar Set). G.S. General Service. H.A. High Angle. H.A.C.P. High Angle Calculating Position. H.A.C.S. High Angle Control System. H.A.D.E.S. High Angle Director Eyeshooting Sight. H.A.D.T. High Angle Director Tower. H.E. High Explosive. H.E.S. High Explosive Substitute. H.G.R. Hitting Gun Range. Higher Gunnery Rating. H.O. Hostilities Only. How. Howitzer. H.S.C.T. Hot Solventless Carbamite Tubular (cordite). H.V. High Velocity. Hyd. Hydraulic. Hyg. Hygrometer. Ig. Igniter. Incl. Inclination. I.N.O. Inspector of Naval Ordnance. L.A. Low Angle. L.D.S. Local Director Sight. L.E. Lee Enfield. L.G. Lewis Gun. Large Grain (gunpowder). L.P. Low Power. L.R.1 Layer Rating First Class. L.R.2 Layer Rating Second Class. L.R.3 Layer Rating Third Class. L.S.T. Line of Sight Training. M.A.C. Main Armament Control. Mag. Magazine. M.C. Modified Cracked (Cordite). M.D. Modified (Cordite). M.D.T. Modified Tubular (Cordite).



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M.G. Machine Gun. Mk. Mark. M.L. Metal Lined. Muzzle Loading. M.P.I. Mean Point of Impact. M.T. Temporary local colloquial mark for an emptied package. Mtg. Mounting. M.V. Muzzle Velocity. N. Letter on Armament Stores for Naval Service. N.A.D. Naval Armament Depot. N.C. Nitro-Cellulose. N.C. R. Naval Cordite Regulations. N.M. & E.R. Naval Magazine and Explosive Regulations. N.O.I.O. Naval Ordnance Inspecting Officer. N.R.V. Non-Return Valve. N.T. Night Tracer. O. Marking of certain watertight doors (see Chapter 12). O.A. Ordnance Artificer. O.A.(O) Ordnance Artificer qualified in Optical Instruments. O.B.L. Ordnance, Breech Loading. Oer. Oerlikon. O.F.I. Open Face Indicator. O.M. Ordnance Mechanic. O.O.Q. Officer of Quarters. O.P. Observation Post (bombardment). Opr. Operator. O.Q.F. Ordnance, Quick Firing. Ord. Lt. Ordnance Lieutenant. O.U. Official Use (books). P. Letter signifying Pedestal type mounting.

Followed by a number may indicate a gun, or mounting on the Port side.

On a package may indicate the size of gunpowder (pebble). P.A. Picric Acid. P.A.C. Parachute and Cable. P.C.O. Principal Control Officer. Pdr. Pounder, as in 2 pdr., 3 pdr. Perc. Percussion. P.HD. Priddy's Hard. Note.-Suitable initials or monograms are used for all Armament Depots. A complete list may be found in Regulations for Naval Armament Services, Part 2, Appendix 1. Phos. Phosphorus. P.P. Picric Powder. P.P.I. Plan Position Indicator. Prac. Practice. Proj. Projectile. P.S. Powder Substitute (practice projectiles). P.S.G.I. Patrol Service Gunnery Instructor. P.S.G.L. Patrol Service Gunlayer. P.S.S.G. Patrol Service Seaman Gunner. Q Letter usually denoting third centre-line turret where more than four such turrets are fitted. Q.E. Quadrant Elevation. Q.F. Quick Firing. Q.O. Rating Qualified in Ordnance. Q.R.1. Quarters Rating First Class. Q.R.2. Quarters Rating Second Class Q.R.3. Quarters Rating Third Class. R. Repairable. R.C.1. Radar Control Rating First Class. R.C.2. Radar Control Rating Second Class. R.C.3. Radar Control Rating Third Class. Rcpr. Recuperator. Rcvr. Receiver. R.D. Research Department usually followed by a letter or figure to indicate formulae. R.D.F. Term superseded by RADAR. Red. Ch. Reduced Charge. R/E & D.U. Range to Elevation and Deflection Unit. REFLD. Refilled. REPD. Repaired. R/E.U. Range to Elevation Unit. R.F. Rangefinder. Rim Fire. RF/D. Rangefinder Director. R.G.F. Royal Gun Factory.



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