Naval Weapons of World War One: Guns, Torpedoes, Mines and ASW Weapons of All Nations

NAVAL WEAPONS

OF WORLD WAR ONE

NAVAL WEAPONS

OF WORLD WAR ONE

Guns, Torpedoes, Mines and

ASW Weapons of All Nations

AN ILLUSTRATED DIRECTORY

NORMAN FRIEDMAN

Seaforth

P U B L I S H I N G

In memory of John Campbell

FRONTISPIECE: The forward turret of HMAS Australia, one of three modified

Invincibles which retained the 12in/45 guns but had the two wing guns spread

more widely for better broadside fire. Initially an upgunned design (E) with

12in/50s was chosen for the 1907/8 programme, but by March 1908 the design

showed the earlier 12in/45, and the connection with the earlier series of designs

had been abandoned (the ‘new Invincible’ offered to the Board in March 1908 was

Design A). The approval of Design E presumably accounts for the widespread

belief that these ships had 12in/50 guns.

Copyright © Norman Friedman 2011

First published in Great Britain in 2011 by

Seaforth Publishing

An imprint of Pen & Sword Books Ltd

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www.seaforthpublishing.com

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A CIP data record for this book is available from the British Library

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CONTENTS

GLOSSARY AND ABBREVIATIONS

ACKNOWLEDGEMENTS

INTRODUCTION

Units of Measurement

PART I: GUNS

Introduction

I/1: British Guns

I/2: German Guns

I/3: US Guns

I/4: French Guns

I/5: Italian Guns

I/6: Russian Guns

I/7: Japanese Guns

I/8: Austrian Guns

I/9: Spanish Guns

I/10: Swedish Guns

I/11: Other Navies’ Guns

PART II: TORPEDOES

Introduction

II/1: British Torpedoes

II/2: German Torpedoes

II/3: US Torpedoes

II/4: French Torpedoes

II/5: Italian Torpedoes

II/6: Russian Torpedoes

II/7: Japanese Torpedoes

II/8: Austrian Torpedoes

II/9: Swedish Torpedoes

II/10: Other Navies’ Torpedoes

PART III: MINES

Introduction

III/1: British Mines

III/2: German Mines

III/3: US Mines

III/4: French Mines

III/5: Italian Mines

III/6: Russian Mines

III/7: Japanese Mines

III/8: Austrian Mines

III/9: Swedish Mines

III/10: Other Navies’ Mines

PART IV: ASW WEAPONS

Introduction

IV/1: British ASW Weapons

IV/2: German ASW Weapons

IV/3: US ASW Weapons

IV/4: French ASW Weapons

IV/5: Italian ASW Weapons

IV/6: Russian ASW Weapons

IV/7: Austrian ASW Weapons

SOURCES

INDEX OF SHIPS

GLOSSARY AND ABBREVIATIONS

AA = anti-aircraft

ADM = Admiral

AMC = Armed Merchant Cruiser

AP = armour-piercing

APC = Armour-Piercing Capped (shell)

ASW = anti-submarine warfare

BAG = Ballon-Abwehr Geschütze (‘anti-balloon gun’)

BAK = Ballonabwehrkanone (‘anti-balloon cannon’)

BIR = Board on Industrial Research

BL = breech-loading

BuOrd = Bureau of Ordnance (US)

CCP = Capped Common Pointed (shell)

Cdr = Commander

CI = cast iron

CINO = Chief Inspector of Naval Ordnance

CIW = Chief Inspector, Woolwich

CNO = Chief of Naval Operations (US)

Col = Colonel

COW = Coventry Ordnance Works

CPC = Common Armour-Piercing Capped (shell)

crh = calibre radius head

CSOF = Chief Superintendent RGF (q.v.)

CSP = Chillingworth Smokeless Powder

DAMS = Defensively-Armed Merchant Ship

DCB = Distance-Controlled Boat

DCT = Director Control Tower

DGD = Director Gunnery Division

DNA&T = Director of Naval Artillery and Torpedoes

DNC = Director of Naval Construction

DNI = Director of Naval Intelligence

DNO = Director of Naval Ordnance

DNP = dinitrophenyl

DOD = Director of Operations Division

DrL = Drilling Lafette (‘twin mount’)

DTD = Director Trade Division

DTM = Director Torpedoes and Mines

EOC = Elswick Ordnance Company

FY = financial year

GDT = gyro director training

HA = high angle

HCP = hand-controlled power (gear)

HE = high explosive

K = Kanone (i.e. BL gun)

KC = Krupp Cemented (armour)

KMK = Kurze Marine Kanone (‘short naval gun’)

KNC = Krupp Non-Cemented (armour)

Lt = Lieutenant

MGen = Major-General

ML = Motor Launch

ML = muzzle-loading

MLR = muzzle-loading rifle

MP = Mittelpivotlafette (‘centre pivot mount’)

MTK = Morskoi Tekhnicheskii Komitet (‘Naval Technical Committee’)

NGF = Naval Gun Factory (US)

NMM = National Maritime Museum, London

ONI = Office of Naval Intelligence (US)

OpNav = Office of Operations (US)

PDH = Portable Directional Hydrophones pdr(s) = pounder(s)

PGS = Portable General Service (hydrophone set)

QF = quick-firing

QFC = quick-firing converted

RADM = Rear Admiral

RAF = Royal Air Force

RAN = Royal Australian Navy

RAOAZ = Stock Society of Ordnance Plants (Russian acronym)

RCF = Royal Carriage Factory

RF = rapid fire (i.e QF gun: US)

RFC = Royal Flying Corps

RGF = Royal Gun Factory

RHA = Royal Horse Artillery

RKL = Ringkanone

RNAS = Royal Naval Air Service

RP = rohr-pulver (‘tube powder’, i.e. German equivalent of Cordite)

SA = semi-automatic

SAP = semi armour-piercing

SAPC = semi armour-piercing capped (shell)

SC = solventless cordite

SF = submerged fire (pistol)

SK= Schnellade-Kanone (‘fast-loading gun’, i.e. QF)

SL = side lug (torpedo)

STCAN = Service Technique Construction et Armes Navales

TAG = Torpedoabwehrkanone (‘anti-torpedo-boat cannon’)

TR = tiro rapido (i.e. QF)

TW = Torpedo Werkstatte (German Navy Torpedo Factory)

VADM = Vice Admiral

VCP = Vavasseur Centre Pivot (mounting)

ACKNOWLEDGEMENTS

This book could not have been written without considerable assistance. I would like to thank, first, Cherry Campbell, who made the surviving parts of her late brother’s manuscript available to me. W R Jurens drew several turrets specially for this book. Erwin Sieche, formerly editor of the Austrian journal Marine Gestern, Heute, provided his collection of transcribed Austro-Hungarian manuals for various guns, as well as other vital data. Stephen McLaughlin provided a great deal of Russian data and translated several articles from Russian. John A Roberts provided invaluable material from his collection of photographs and manuals. Ian Buxton generously allowed me to reproduce gun mounting drawings from his history of British monitors. As in my previous book on naval fire control, Naval Firepower, I have benefitted greatly from British official documents provided by Dr Nicholas Lambert and by Dr Jon Sumida. Christopher C Wright, editor of Warship International, generously provided material from his collection. Cdr Erminio Bagnasco and Dr Maurizio Brescia provided Italian photographs, and Achille Rastelli and Col. Filippo Cappellano provided some of the Italian gun data. Sivart Gustafsson, a volunteer at the Bofors archive, found vital data there. Capt Per Islander RSwN (ret) also provided Swedish data, and he obtained permission for me to use several official Swedish drawings he had previously published. Kent Crawford, who has long been interested in guns, was helpful in several ways, particularly in disentangling some German guns. I am also very grateful to Chris Carlson and to Christoph Kluxen for assistance with German data. Others whose assistance I much appreciate were A D Baker III, Alexandre Sheldon-Dupleix, Raymond Cheung, Dr Josef Strazcek, Wolfgang Legien, Richard Worth, Peter Schupita, Steve Roberts, Ray L Bean and Ted Hooton. I hope that the result justifies the assistance of all those who have helped.

This book is based largely on archival sources. For access to them, I would like to thank Jennie Wraight, the Admiralty Librarian, and Jeremy Michel and Andrew Choong of the Brass Foundry outstation of the National Maritime Museum, as well as the staff of the old Caird Library at the National Maritime Museum (which held the museum’s collection of Armstrong and Vickers handbooks and some other related material), the staffs of the Public Record Office, the US National Archives (both downtown and at College Park), the French Ministry of Defence archive at Vincennes, and the French DGA archive at Châtellerault. Dr Evelyn Cherpak very kindly helped me at her unique archive at the US Naval War College. This archive was particularly important because during the period of interest the war college functioned, in effect, as the think-tank of the US Navy in conjunction with its educational role. I am also grateful to the staff of the US Navy Department Library, which holds considerable operational and technical data relevant to this project.

Above all it would have been impossible to research and write this book without the continued loving support and encouragement of my wife Rhea. I particularly appreciate some of her advice and her strong encouragement to persist in some parts of this project which initially seemed impossible.

A Note on Illustrations

Many of the illustrations in this book are copies of original documents or plates from weapons manuals which are both valuable and difficult of access. The conditions under which copies have to be made often prevent perfect reproduction, so some blemishes like fold lines and occasional distortion have had to be accepted. Nevertheless, these are better representations of complex weapons – especially gun mountings – than photographs, so they have been preferred even when less than ideal.

INTRODUCTION

When World War I began in 1914, the world’s navies were just beginning to assimilate the latest products of a continuous technological revolution. It had only been a decade since the new weapons, in an even more primitive form, were first tested during the Russo-Japanese War: fast-firing heavy guns and independent (contact) mines. The new long-range torpedoes had never been tested, and guns and fire control were far more developed than they had been in 1904. Ocean-going submarines were entirely new. By 1918 the weapons with which World War II would be fought all existed, although aircraft were still primitive. The main exception in World War II practices was the rise of dive-bombing, and of course World War I was radarless.

The pace of weapon development during World War I was set by the industrial effort involved in making new weapons. It was relatively difficult to make entirely new guns, so nearly all the guns listed in Part I either existed before the war or were close to completion in 1914. The British 18in gun is the main exception. Torpedo development required considerable effort, but new torpedoes appeared in wartime. Mines and ASW weapons were developed and produced far more quickly, on a time-scale that now seems unbelievable.

Where possible, I have tried to explain why navies chose the weapons they did, in terms of the tactics they adopted and the tactics new kinds of weapons made possible. The main tactical discussions are in the gunnery sections, because in 1914–18 fleet tactics were built largely (though hardly completely) around guns. I have not described ASW tactics, because that subject would deserve a massive book in itself. Nor have I described the nascent subject of air defence in any detail, although it was certainly of vital interest to World War I navies.

The key point to remember is that fleet tactics combined two rather different weapons, the gun and the torpedo. It was generally accepted that gunfire was a cumulative weapon; as late as 1913 the Royal Navy expected it to take many minutes of fire to knock out a modern battleship. Even then the ship probably would not sink. It is true that two Russian battleships were sunk at Tsushima by shellfire, but their fate could be traced to more or less incidental issues such as excessive use of flammable paint and large expanses of unarmoured side which could be smashed in. It can also be argued that this view retained its validity. The three spectacular battlecruiser explosions at Jutland might seem to show the opposite. However, for many years it has been clear that they were due more to horribly flawed British magazine practices than to the inherently devastating effect of shells penetrating their armour. In recent years this point has become even clearer, because it has become obvious that the magazine practices were far worse than had been imagined. After the war, the British believed that a ship with properly-handled magazines could survive any single hit – the destruction of HMS Hood being horrifying evidence that something was still wrong.

Torpedoes and mines were a very different proposition. In 1914 no navy believed that it had satisfactory underwater protection. It seemed that a single mine or torpedo explosion could sink, or at the least severely damage, even the largest ship. During the Russo-Japanese War primitive contact mines had sunk one Russian and two Japanese battleships, and had disabled others; we now know that Japanese drifting mines sank a second Russian battleship (at the time most thought she had been sunk by torpedoes). Mines were probably the single worst surprise of the Russo-Japanese War. After the war many navies converted cruisers for minelaying and began to develop contact mines both for defensive and for offensive purposes (some had done so before the war).

Torpedoes played only a very small part in the Russo-Japanese War, but they were widely expected to have devastating effects in any larger conflict. It is well known that the Imperial German Navy was fascinated by underwater weapons, but it is much less well known that the Royal Navy shared that fascination and in important ways exceeded it. It seems that several of the fears expressed by Admiral Jellicoe in 1914–16 actually reflected planned or current British torpedo tactics. We now know that British surface-launched torpedoes were considerably superior to their German counterparts (a point the Germans acknowledged at the time).

To a modern reader, accounts of the tactical thinking of the period show one glaring gap. Remarkably little realistic testing was done. For example, in 1914 Admiral Jellicoe realised that the key to handling a vast fleet was to maintain a tactical plot, so that he could see what was happening even beyond the limit of visibility. That was a very modern step, analogous to the sort of tactical pictures now common in naval and other warfare. Jellicoe seems not to have tested this idea in any way prior to Jutland. He did not realise that he now depended on his deployed ships to provide his tactical picture, so relative navigation was critical (the British solved this problem after Jutland). Nor did he realise that it was necessary to maintain a fixed schedule of radio reporting, both to ensure that he did receive reports and to ensure against gross interference. The latter problem kept cropping up even much later; for example it bedevilled US fleet air defence in the 1950s. Even so, Jellicoe’s plot gave him a dramatic advantage compared to his adversary Admiral Scheer; it enabled him to keep capping the German line. The sense of confusion and surprise on board the German flagship almost certainly convinced Scheer that it would be suicidal to fight the Grand Fleet again. Apparently it had never occurred to Scheer that he would be unable to visualise the battle situation from his flagship; he had no plot of the situation (and the Germans never adopted that technique). No other navy had adopted tactical plotting, although several US naval officers at the Naval War College pointed out the need for it in 1914 (the US Navy adopted the method only after seeing it on board British ships in 1917).

This is only an example. With some important exceptions, officers seem to have assumed that navigation would always be good enough – which it was, if the object was, say, to cross the Atlantic, but not at all if the object was to reach a rendezvous in the middle of the North Sea in poor visibility, or to know the bearing of a cruiser beyond the horizon.

The British sections of this book are far more massive than those devoted to other navies because in 1914–18 the Royal Navy was by far the largest in the world, and also because British firms supplied most of the weapons used by the navies which did not make their own. The Royal Navy had also been huge long before its new rivals, the Americans, the Germans and the Japanese, began their own build-ups. In 1914 it therefore had a much larger backlog of earlier weapons. The French navy had been large for as long as the Royal Navy, but its growth was severely limited in the late nineteenth century, as French finances were stretched to provide an army large enough to match the Germans.

This book began with John Campbell. In the 1990s he wrote a manuscript of an encyclopaedia of World War I naval weapons as a companion to his well-known encyclopaedia of World War II naval weapons. Unfortunately it was not published at the time, but a few years ago it appeared that the manuscript had resurfaced and the present author was named technical editor. It turned out, however, that the only parts of the manuscript which had survived were the material on British naval guns and the material on German guns from 17cm calibre up. Mr Campbell had already published much of his account of British naval guns from 4in up in Warship.

This is not Mr Campbell’s book. I am very grateful to Mr Campbell’s surviving sister, who made his manuscript available to me. The data in the British section combine Mr Campbell’s data with that from British official sources. The data on the heavier German guns are Mr Campbell’s, but data on lighter German guns are taken from a variety of other sources. The comments on gun history are my own. All other parts of the book are my own, taken as far as has been possible from official and mainly contemporary sources.

Unlike my previous books, this one has not been footnoted. In an encyclopaedia of this kind, it is impossible to provide a source for each piece of data, but I have tried to indicate some of the key official sources and their locations.

The world’s navies developed many of the weapons and tactics they used during World War I based on experience during the Russo-Japanese War. The Russian battleship Sissoi Veliki survived about fourteen shell hits and a torpedo hit right aft (which destroyed her rudder and steering gear) at Tsushima. She was still able to steer using her engines and to proceed at slow speed (waterline hits forward had caused flooding which put pressure on her forward bulkheads, hence she could not make much speed). Her captain scuttled her when forced to surrender by two Japanese auxiliary cruisers. To many the lesson of this and other battle damage was that it was almost impossible to sink a ship using gunfire. The Russian ships which did succumb to shellfire suffered mainly from fires lit by high-explosive shells, which should not have happened had they been properly stripped before battle. Borodino seems to have been the only case of a magazine explosion caused by a shell hit. It seemed to follow that a properly-designed and -equipped armoured ship would be difficult to sink by shellfire; at the least, shellfire was likely to be a cumulative weapon. On the other hand, three battleships (one Russian, two Japanese) were sunk by moored mines, and the battleship Navarin was sunk by a drifting mine laid in her path (only the Japanese and the British knew that).

Units of Measurement

Units have been given in the form provided by the sources, to avoid errors due to translation back and forth between metric and Imperial units. In a few cases, data for metric navies were obtained from a source using Imperial units. I have generally not translated back and forth because computers and calculators are now so commonly available; but a few translations have been made (in brackets after the original data). Note that in some cases Imperial units were used for metric navies (as in the Imperial German Navy) because they were taken from intelligence or technical reports in Imperial form, or because they were taken from reference books (generally Brassey’s) in which data originally supplied in metric form had already been translated into Imperial form. It would have been misleading to translate back, due to inevitable rounding errors. Important units and equivalents are:

Weight: Imperial tons (2240lbs) are expressed as tons; metric tonnes (2205lbs, 1000kg) are denoted t.

1kg = 2.204lbs

1t = 2204.6lbs

1 ton = 1.016t

1lb = 0.4536kg

The Royal Navy used the Imperial system in which smaller units were the hundredweight (cwt, 112lbs), the quarter (32lbs), and the stone (14lbs); the weight of a gun or mounting was typically given as so many tons, so many cwt, so many qtr, so many stone, and so many lbs. A long (Imperial) ton was 20 cwt. Weights have generally been translated into pounds (lbs) and then into tons. Navies which relied on British technology generally also used Imperial units. The US Navy used Imperial pounds and tons but not, apparently, the intermediate units.

Russia had its own units, including the pood (for weight) and the British inch. Thus Vickers gun designs for Russia are recognisable because weights were translated into poods. Russian data are given in metric terms because the references used date from the period after the Revolution, when the Soviets adopted the metric system. It seemed unwise The great surprise of World War I was that battle fleets which fought for command of the seas could not, themselves, affect the submarines which could evade them. It turned out, however; that command of the sea (on the surface) by the Royal Navy and its allies made it possible to conduct an effective anti-submarine campaign using craft which could not have survived had the German High Seas Fleet been free to operate. Another surprise was that submarines often fought on the surface, partly because torpedoes were both expensive and sometimes unreliable. Photographed after the surrender, UC-97 shows her UTOF 10.5cm/45 gun.

to translate back into pre-Revolutionary units, because that would risk further errors.

Length:

1m = 3.2809ft or 1.0936yds

100mm (10cm) = 3.937in

1mm = 0.03937in

1 nautical mile = 6080ft, but in gunnery it is typically 2000yds

1ft = 0.30479m

1in = 2.54cm

Note that the German Imperial Navy often measured distance in hm (units of 100m, so that a km was 10hm). The Russians often used the cable, a tenth of a nautical mile, hence very nearly 200yds (and often equated to 200yds).

Pressure:

1000kg/cm² = 6.35 tons/in²= 14,223lb/in²

1000atm (atmospheres) = 0.656 tons/in²

1 ton/in² = 152.38 atmospheres = 157.49kg/cm²

PART I: GUNS

The Brazilian battleship Minas Gerais was built in Britain by Armstrong, one of the first two export dreadnoughts (she was ordered in 1906). She is shown as modernised at the New York Navy Yard in 1918 for potential employment with the Grand Fleet. Note the rather elaborate windows in the sighting hoods visible above No. I turret (the centre hood was for the turret officer as well as the trainer; the side hoods were for the two gunlayers). Modernisation included increasing maximum elevation to 23°, which presumably accounts for the large gun ports. Visible around the bridge (note the glass windows) are US-style Venturis to deflect wind, a feature evident in US destroyers of this era and in the torpedo defence control stations of US battleships modified during World War I. The vertical cylinders were directors for the torpedo defence battery, installed at this time. Not visible is another major improvement, a US-supplied Ford Rangekeeper (analogue computer) for the ship’s main battery. Export was permitted specifically because of World War I (the Argentines, who declined to have their two battleships modernised at this time, had to fight to get Rangekeepers for them after the war). Note also the range dial below the foretop, a standard fitting at this time.

INTRODUCTION

Navies considered guns, particularly heavy ones, the arbiters of future naval warfare. The guns in this section are arranged in descending calibre. For each calibre, they are arranged by date, the oldest coming first, to give some idea of gun evolution. The extent of data varies from section to section because different navies kept very different records. Gun length is given in two or three forms: overall, the length of the bore (breech face to muzzle) and rifled length. Lengths are given in calibres (as well as units of length) in order to make comparisons more meaningful.

Where possible, notes are provided on the structure of the gun. The problem was to resist the intense internal pressure of the gun with the lightest possible structure. Pressure distribution changed as powder changed. The powder of the 1880s was black powder (gunpowder), an explosive providing a brief, powerful impulse. The gun was heavily stressed near its breech, but the shell received little pressure as it proceeded up the barrel. Guns were made relatively short because most of the time the shell spent in the barrel it was decelerating due to friction as its driving band bit into the rifling. From the mid-1880s onwards slower-burning powders were introduced. Now the pressure continued as the shell travelled down the barrel, so it made sense to give the gun a longer barrel because the shell kept accelerating. It was still important to reinforce the breech end of the gun, but now the barrel also had to be reinforced, because it was subject to considerable pressure. The barrel was also stressed by the shell itself, as it forced its way through the rifling towards the muzzle.

Guns consisted of an inner (A) tube surrounded by reinforcing tubes and hoops, their letters indicating how far they were from the A tube. Many navies placed liners inside the main A tube; a gun which wore out its rifling could more easily be repaired by having its thin liner replaced. The British adopted wire-winding, which had been invented by an American in 1855. The wire was wound, under great tension, between tubes. Areas over which wire had been wound were subject to uniform stress, but only in the radial (outward-pointing) direction. Opponents of wire-winding claimed that these guns had lengthwise weaknesses and tended to droop. The British claimed that wire-wound guns were inherently lighter than built-up ones (using only tubes and hoops). That seems to have been true about 1905, but not about 1914 (note the comparison between different Italian 15 in guns at that time). Much depended on metallurgy; Krupp seems to have been particularly successful.

The revolution in heavy guns can be traced partly to better ammunition handling coupled with a retreat from extreme calibres; in effect, muzzle velocity was substituted for projectile weight. Very crudely, to punch through armour, a shell imparts enough energy to shatter it. Its energy is proportional to its weight and to the square of the shell’s velocity when it hits. Another factor is the time during which the energy is imparted (typically measured by the ratio of shell diameter to velocity). The shorter the time, the more difficult for the armour to flow (literally) so as to resist the shell. Thus a shell must be either fast or massive. If it cannot be fast, the gun firing it also has to be very heavy. On the other hand, a light shell loses velocity to air resistance more quickly than a heavier one. In 1906, for example, a British naval officer compared the French 7.6in gun to the British 7.5in. The French gun fired a lighter shell (by 15lbs) at a higher velocity (by 215ft/sec). Beyond 2000yds the heavier British shell had greater velocity. The crossover for 12in guns was 1000yds.

Conversely, the earlier black-powder guns with short barrels could not develop high velocities. The only way to generate enough energy to penetrate armour was to use a very massive projectile, which in turn required a massive gun. Handling and firing was slow; such guns could not deal with fast targets. Firing rates were once every few minutes. Speed could substitute for armour: in the 1870s the Italians built a pair of essentially unprotected, but very fast (for the time) battleships, armed with the heaviest guns in the world, Armstrong 17.7in monsters. For that matter, a ship might come very close before being hit. That made ramming a viable tactic. Very slow fire also made it logical to provide a ship with only a limited amount of armour; there was no possibility that it would be peppered with fire.

This book reflects a revolution in gun design and operation which began in the 1890s and continued up to 1914. It became possible to fire the heaviest guns surprisingly quickly, so that they, rather than quick-firing lighter weapons, could dominate naval battles. One key to faster fire was the development of quick-acting breeches, beginning with the discovery that the screw threads holding the breech in place did not have to be complete. The breech therefore did not have to be screwed into place. Instead, it could be secured with one partial turn. This is the breech of a Japanese 16in gun aboard HIJMS Nagato.The hole in the breech block was for an obturator, a pad which expanded when the gun was fired to help seal the breech. A wide variety of different linkages were developed for quick breech operation.

The development of these very heavy guns was tied to some extent to the development of breeches. The problem was to seal the gun breech so that the gas produced by the powder propelled the shell instead of escaping. The British had adopted Armstrong’s breech-loaders in the 1850s, but the problem was so difficult that they failed repeatedly, and the British turned back to muzzle-loaders, which had no such problem (they had others). Other navies persevered with breeches, the usual solution being a threaded screw plus a mushroom-like obturator to help seal it when the powder was set off. Early breechloaders fired very slowly, because the breech had to be unscrewed for each shot. The French seem to have been the first to realise that the threads did not have to be complete. If they were interrupted – if sectors of the breech were left blank – the breech could be shoved into place and then sealed with a single partial turn. Guns differed in just how this was done, and hence in how many (and how large) the movements involved were. The gun typically incorporated a carrier onto which the breech turned when it was withdrawn from the gun. Several manufacturers offered single-motion breeches.

Beginning in the 1870s, small guns began to use metal cartridge cases. When the gun fired, the gas of the powder expanded its cartridge case, sealing the breech. Once the cartridge case cooled, it contracted, and could be extracted. There was no need to clean out the usual residue of the bagged charge. The British called such guns quick-firing (QF). Naval QF guns began to appear in the 1880s. At the Yalu (1894) Japanese cruisers armed with QF guns devastated Chinese battleships armed with much heavier but much slower-firing guns. The QF gun seemed to be an equaliser; a cruiser armed with it could smash the large unprotected area of a battleship. That possibility did not last long, because about the same time lightweight armour, which could be spread over more of a ship’s side, appeared (Harveyised and Krupp Cemented [KC]).

Krupp adapted the QF idea to heavy guns. Instead of a threaded breech, in the 1860s the company had tried a pair of wedges which could move horizontally across the bore of the gun. The pressure of the powder explosion was expected to press the wedges into each other and thus to seal the breech. The mechanism was inherently weak, and in 1867 trials it did poorly against a British muzzle-loader. The company introduced built-up guns (‘mantle-ring’ types in which a mantle [jacket] was shrunk over the breech to reinforce it) in the 1870s. The introduction of cartridge cases was the great step forward, and Krupp’s innovation was to apply this QF concept to heavy guns, beginning with a 9.4in cannon. Given cartridge cases, it could use a breech much less robust than the screws used in foreign navies. Krupp called its cartridge guns Schnellade-Kanone (SK), the German equivalent of QF. Its lighter guns used vertical wedge breech blocks, but in all cases the idea was the same: since the cartridge case sealed the breech, there was no need for any elaborate breech structure.

As it happened, most QF guns retained interrupted-screw breeches. They fired rapidly because cartridge cases were easier to handle than the usual powder bags, and because it was easier to extract them in order to prepare a gun for the next round. Breeches could also be lighter, because they did not have to withstand the previous heavy forces. However, it could be argued that a conventional (breech-loading [BL] in British parlance) gun with an efficient breech could fire about as quickly. That was why the Royal Navy switched back from QF to BL 6in guns. For the British, the advantage of cartridge cases was entirely in ease of handling, and during World War I British destroyers were rearmed with QF rather than BL 4in guns (the 4.7in was BL only because it took longer to design a QF gun and its specialised cartridge cases).

The new QF guns and also the newer heavy guns benefited from a new kind of slow-burning powder. The first brown powders (Rottweil cocoa and Westphalian brown powder) appeared about 1881. With much the same constituents as black powder, they were reformulated to burn more completely and thus yield more energy. With the adoption of these powders, the Royal Navy jumped from its 16- to 18-calibre muzzle-loaders to a new generation of 30-calibre guns. Slower-burning powder made longer guns with lighter projectiles worthwhile for heavy guns. It became possible to fire even the heaviest guns much more rapidly.

Rapid fire would have been pointless had the target quickly been obscured by the kind of smoke black or brown powder produced. Thus rapid-firing guns were associated with a new smokeless (actually reduced-smoke) powder. The French were the first to produce smokeless powder by combining two explosives, nitroglycerine and nitro-cellulose (gun-cotton) with a plasticiser and a stabiliser (hence they were called double-based). Because these powders were considerably more energetic than brown powder, they were used for all naval guns, even those not firing very quickly. The British version, adopted about 1890, was Cordite. Unfortunately nitroglycerine made the new powders quite unstable, at least at first. They could, for example, deteriorate badly when warm. The roll-call of ships destroyed was remarkable. Cases were the Japanese Mikasa (10 September 1905), the French Una (12 March 1907), the French Liberté (25 September 1911), the German cruiser Karlsruhe (approaching Trinidad, 4 November 1914), the British Bulwark (26 November 1914), the Italian Benedetto Brin (27 September 1915), the Italian battleship Leonardo da Vinci (2 August 1916), the Russian battleship Imperatritsa Maria (21 October 1916), the British cruiser Natal (30/31 December 1916), the Japanese cruiser Tsukuba (14 January 1917), the British battleship Vanguard (9 July 1917) and the Japanese battleship Kawachi (12 July 1918). Because they happened before World War I, the French battleship disasters received particular attention, and the French were forced to reformulate their ‘poudre B’. Apparently unstable powder did not account for the loss of USS Maine in 1898 (a spontaneous coal fire apparently cooked off her powder).

The German equivalent to Cordite was RP (rohr-pulver, or tube-powder, because it was formed into small tubes). It impressed observers during World War I because it burned rather than exploding when exposed to fire, as was very spectacularly demonstrated when German battlecruisers survived severe turret hits at Dogger Bank and at Jutland. It is not clear to what extent this was a matter more of the use of cartridge cases than of what was inside. Note that the cruiser Karlsruhe was almost certainly the victim of a spontaneous magazine explosion. The British obtained samples (RP C/12, i.e., the 1912 version of RP) on board German capital ships interned at Scapa Flow in 1919. In 1927, based partly on their analysis of RP C/12, they introduced a new more stable solventless Cordite (SC), which had a somewhat reduced energy content (94 per cent), and burned at a slightly lower temperature (3090°K vs. 3215°K).

Given the new powders, navies moved towards long 12in battleship guns (the main exception was the German Navy, which preferred 1 lin weapons). Lighter shells and a new generation of breech mechanisms made for dramatically faster firing. The typical rate for 12in guns rose from once every 4 or 5 minutes (about 1895) to once a minute by 1902 (for the latest Mk IX gun, according to British official war game rules). About 1900 the new British-built Japanese battleship Mikasa claimed a round every 40 seconds. There was hope of two rounds a minute from the latest Vickers 12in mountings. The huge 16.25 in was credited with one round every four minutes and the 13.5 in of the late 1880s with 0.4 rounds per minute. The Germans apparently favoured smaller calibres (9.4in and 1 lin) specifically to gain higher rates of fire, up to two rounds per minute. Higher velocities meant flatter trajectories and better hitting rates. According to the 1902 British war game rules, at battle range (1000yds) the 12in/45 could hit a target with an average of 420lbs per minute, compared to 200lbs for the 16.25in gun firing a shell about twice as heavy. This roughly two to one ratio held for greater ranges.

The screw threads were needed to close a breech against the pressure of the gas created when the gun was fired. The alternative was to enclose the charge in a cartridge case, usually brass, which expanded when the gun fired to seal the breech. The Germans and Austrians adopted cartridge cases for all their guns. Given a cartridge case, the breech could be much simpler This German 15cm gun from the battlecruiser Goeben (the Turkish Yavuz), on display in the Turkish naval museum at Istanbul, shows a typical German horizontal sliding breech, in this case in the closed position (the rounded section at left is the port through which the gun would be loaded with the breech open). (AUTHOR)

Muzzle velocity data given in this book are not strictly comparable on a navy-to-navy basis because different navies calibrated their guns for different standard temperatures (range tables gave coefficients to be used at different temperatures). The standards were: Royal Navy 80°F (26.7°C); Germany (and Russia and Austria-Hungary), 59°F (15°C); United States, 90°F (32.2°C); Japan, 69.8° F (21°C); France, 68°F (20°C); and Italy, 89.6°F (32°C). As an approximation, at the standard British temperature a German gun would fire at about 9m/sec (30ft/sec) greater muzzle velocity, and a US gun would fire at about 20ft/sec (6m/sec) lower muzzle velocity.

Shells were designated AP (armour-piercing), SAP (Semi-Armour-Piercing), Common, HE and Shrapnel. AP shells had small (and sometimes no) bursting charges, and were initially intended to penetrate armour relatively intact and to do their damage by creating lethal splinters and by smashing the interior of a ship. By 1900 such shells had base fuses intended to burst them only after they had penetrated armour and reached the interior of a ship (they often did not always work as intended, and many British AP shells exploded on contact at Jutland). By way of contrast, Common shells were filled with black powder, which would detonate when they struck a ship’s structure. Unlike AP, they could destroy the unarmoured parts of a ship. HE was a Common shell filled with a more powerful explosive, such as the British Lyddite or the French Melinite (in both cases, picric acid) or TNT. AP shells might have the same filling, but in much smaller quantity, typically 2.5 to 3.5 per cent of their weight rather than 12 to 15 per cent. SAP was a compromise between AP and Common with an ability to penetrate about half its calibre of armour with a larger explosive charge than HE. Shrapnel was a time-fused shell filled with steel balls, intended mainly to kill personnel. Anti-aircraft shells were time-fused HE, the fuse being set for estimated target range (taking altitude into account). Anti-ship HE was typically nose-fused, to burst on hitting light structure. That could be dangerous; an explosion on board the sinking battleship HMS Audacious in 1914 was attributed to an HE shell falling out of a shell rack onto its nose.

The principal AP shell-makers in Britain (in order of importance) were Hadfield, Firth, Vickers, Elswick, and Cammell. German AP shells were made by Krupp, and US shells by Midvale.

During the nineteenth and early twentieth centuries improvements in guns and in shells themselves competed with improvements in armour. By the late 1880s AP shells were generally made of forged steel, the manufacturing process for which created a cavity (which might or might not be filled with explosive). Further improvements included changes in the composition of the steel. In 1894 the Russian Admiral Makarov introduced soft steel caps which fitted over the pointed end of the shell. It was later estimated that a cap increased penetration by about 15 per cent, provided that striking velocity did not fall below about 1600–1800ft/sec, and also provided that the shell did not strike at an angle greater than 15°. In 1908 it was claimed that the cap lost all effectiveness for angles beyond 25–30°, but World War I German shells were certainly effective at considerable angles, and all major navies later developed shells effective at long range (i.e., at considerable angles of fall).

The Royal Navy designated its capped AP shells APC. It also developed a Capped Common Pointed (CCP) shell and a Common (Armour-Piercing Capped (CPC) shell, the latter comparable to SAPC shells in other navies. The CPC shell was cast (not forged) in alloy steel, with a hardened point and a soft cap. Typically it was base-fused and filled with a mixture of pebble and black powder. It was expected to penetrate about half its calibre in armour (thicker armour would burst the filling). CPC had a filling of about 7 to 9.5 per cent of shell weight, compared to about 12.5 to 15 per cent for HE (which was filled with Lyddite or TNT, much more explosive than powder). Note that the Russians considered that their experience at Tsushima showed that Japanese HE shells had been much more effective than their own APC, which penetrated as designed but did not disable ships (it helped that their ships had large unprotected upper works and were filled with flammable material). They therefore greatly increased the explosive content of their AP shells, which were probably closer to the British CPC in concept. Note that the United States and France (and Germany for 28cm guns) limited capital ships to APC; other navies also carried HE and SAP of various kinds.

As for the fillings, the British claimed that Lyddite generated fumes and concussion which would stun and confuse a ship’s personnel. At the end of World War I, the US Navy used about a quarter of the cavities of some of its AP shells for tear gas or a similar irritant. No World War I navy produced a true gas shell, containing the sort of gas used on the Western Front, but gas shells were much discussed after the war (at one time the US Navy view was that a capital ship, once gassed, could not be decontaminated in any useful time, and might as well be scuttled).

During the nineteenth century it was discovered that the ideal form of a shell was an ogive, consisting of two arcs of a circle meeting at a point. The arcs could be described by the radius of the circle (in calibres); thus shells are described as 2crh, meaning two-calibre radius head. The larger the number, the longer and more pointed the shell. The French seem to have been unique in designating shells instead by the angle made by the point of the shell. For strength, an AP shell had to be relatively blunt (typically 2crh). To improve ballistic performance a thin windshield was often added ahead of the solid AP part of the shell (and its cap). The US Navy was unusual in the length of its shells, which was intended to give them higher striking velocities (hence better penetration) at longer ranges. No World War I navy adopted the common later technique of tapering the after end of the shell (boat-tailing) to reduce drag.

As an example of the effect of making the nose of the shell more pointed, according to the British 1918 range tables, at 15,000yds the shell of a 12in gun fired at 2700ft/sec retained a velocity of l421ft/sec if it was 4crh, but only 1176ft/sec if it was 2crh. The higher velocity made for a flatter trajectory, so that not only could the longer shell penetrate thicker armour, it also had a better chance of hitting. One measure of the chance of hitting was the danger space, in effect the allowable range error for a target (in the British case) 30ft high: 36yds for the 4crh shell, 26yds for the 2crh. In practice there were also random range errors (dispersion), but it remained the case that a flatter trajectory gave a better chance of hitting side armour. At very long ranges, when shells fell more steeply, the target’s deck was considerably wider than the danger space, and danger space was no longer a good measure of the chance of hitting. The US Navy used somewhat longer and heavier (870lbs rather than 850lbs) shells which retained their velocity better, so that the US wartime 12in shell fired at 2700ft/sec had a remaining velocity of 1533ft/sec at 15,000yds.

Shells were driven through the rifling of the gun by gas pressure on soft-metal driving bands near their base. The deposits left by the driving bands on the rifling (‘coppering’) were a factor in limiting the life of a gun before it had to be relined.

Of course, none of this mattered unless the shells hit, which was determined by fire control. That is a complex subject, and the reader is referred to the author’s Naval Firepower (London: Seaforth Publishing, London, and Naval Institute Press, Annapolis: 2007). Very briefly, the techniques that all navies used in 1914–18 relied on spotting to determine whether guns were properly aimed. On land, that was enough. If the first shell did not hit a stationary target, aim could be corrected until one did. At sea, both shooter and target were moving. Corrections had to be made in terms of where the target was expected to be when the shells arrived. Matters were further complicated by the firing ship’s roll and yaw.

The first approaches to predicting range so as to aim guns properly were based on the idea that, over a short time, the range would change at a constant rate. If this rate could be measured, a range clock could be set to project ahead the target’s position. The first approach to this problem was to use a device, such as the British Dumaresq or the German EU-SV, which gave a range rate based on estimated target course and speed. The next step, which was taken in the British Dreyer Table, the French Le Prieur conjugateur graphique, and in hand plots in the US and Japanese navies, was to measure the range rate by seeing how the measured range varied over time. This method had the advantage that there was no need to estimate target course and speed, but on the other hand the range rate itself was not constant. Worse, the method exaggerated the effect of a target manoeuvre, such as a zigzag; the enemy might be able to use his own range-rate device while the shooter was frustrated. The Germans in particular understood as much in 1914.

The alternative was to create a model (an analogue) of the situation, with separate elements representing shooter and target. Using this mechanical model, it was possible to read off expected target range and bearing. If they did not correspond to reality, the enemy course and speed could be adjusted. Once everything matched up, the computer could produce valid predictions until the enemy manoeuvred. Even in that case it could recover faster than a rate-based device. All major navies used this approach during World War II. It was invented by Anthony H Pollen of Britain, but his system was not adopted by the Admiralty (it was installed on board five ships for service tests). The usual explanation is that the Admiralty much preferred the simpler and less expensive Dreyer Table (Pollen’s supporters charged foul play, Dreyer being an insider by virtue of his status as a naval officer). It appears that in fact the Admiralty had decided to sponsor an alternative analogue device developed by Barr & Stroud, which depended heavily on Admiralty business for its main product, rangefinders. Money was very tight in 1912, and DNO statements that Pollen’s monopoly was anathema can easily be read as suggestions that it would be better to sponsor a competitor than to pay Pollen’s monopoly price. Unfortunately war intervened before Barr & Stroud could complete development, and after the war the Admiralty chose to develop its own computer (Admiralty Fire Control Table) using some of Pollen’s technology (among other elements). Barr & Stroud completed development but had to be content with the export market. Its system became the basis of post-war Italian and Japanese fire control and, it appears, German fire control based on an Italian prototype. In this sense Bismarck sank HMS Hood using a more sophisticated British system against a less sophisticated one – a horrible own-goal.

Although the British retained screw breech blocks for larger-calibre cartridge guns (which they called QF, quick-firers), they used sliding breech blocks for smaller ones. This Japanese ‘wet’ 8cm gun (supplied for inter-war Thai submarines), on display at the Royal Thai Navy museum, has a breech block which slides horizontally. It is a Japanese version of the British 12pdr 8 cwt gun used on board some British submarines; note the British-style recuperator cylinder over the barrel. The vertical handle worked the breech. (RAYMOND CHEUNG)

When the Admiralty dropped his system, Pollen turned to the export market. Because of the outbreak of war, sales were limited to the Russians, whose own next-generation system had failed. The US Navy grasped the importance of what Pollen had done, but it managed to pirate enough of his system (embodied in its Ford Rangekeeper) that it felt no need to buy. It did host Pollen at a wartime fire control conference, where Pollen provided the Bureau of Ordnance with some key advice. It is not, incidentally, clear that Pollen realised that a key virtue of his analogue computer was that its solution could be corrected more easily and more reliably than that of a rate-based system (he certainly did understand the limits of a rate system).

It turned out that the Dreyer Table offered more than a means of estimating range rate. British capital ships had multiple rangefinders, which often gave conflicting data. Because the Dreyer Table produced a plot of different rangefinder ranges, as well as actual spots and gun ranges, it offered a visual summary of the gunnery situation. An operator could visually average rangefinder data, for example, and he could see at a glance that one set of data were clearly in error. The bearing plot showed when targets zigzagged, hence when the fire control solution had to change. The original range rate idea was rejected altogether. After World War I, the British retained the range plot not as a means of measuring the rate, but as a means of averaging and evaluating rangefînder data. Otherwise they shifted to the new analogue technique. The new technique, as it was embodied in post-war equipment, was far more automated than the system in which the Dreyer Table had been embedded. That, much more than the technicalities of the new computer, may have been its greatest virtue. It took far less training than the earlier more manual system, and it got onto a target much more quickly. That is why the very new battleship HMS Prince of Wales performed so well when she faced the Bismarck. Pollen had certainly hoped for this sort of automation when he conceived his system about thirty years earlier, but he did not imagine contending with multiple conflicting rangefinders. For that matter, the key ability to visualise the outputs of all of a ship’s rangefinders was a rather late addition to the Dreyer Table itself.

It would be naive to see the calculators as the keys to successful fire control, because a ship’s fire control system embodied so much more. For example, much depended on how data were transmitted around the system, and in this the Germans and Austrians enjoyed enormous advantages because they had synchros, which transmitted data far more smoothly than the step-by-step transmitters of other navies.

For that matter, a great deal depended on rangefinders. The Germans were alone in using stereo rangefinders; all other navies used coincidence instruments ultimately based on those Barr & Stroud had introduced in about 1895. The British came to see their guns as the best rangefinders of all. After Jutland they introduced a new kind of fire control in which a quick sequence of salvoes (a ladder) was used to establish range before the Germans’ zigzag could ruin a solution. Instruments might establish roughly where the ladder would be placed, but observation of the fall of shot of the ladder would be crucial. Ironically, this was not too different from the ideas of fire control preceding all the sophistication of range rates and range clocks.

One more point is worth making. Before her action with the German Bismarck, the gunnery officer of HMS Hood remarked to a US officer that he could imagine not getting onto the target until he had fired several salvoes. He thought that would be good enough, because once his guns were on target he clearly thought he could fire so quickly, and with such effective shells, that he would win. That was not too different from what the Royal Navy believed going into World War I. Ships could likely endure so much fire that the first few minutes would not be crucial. By the 1920s it seemed that the problems which had made World War I capital ships into ‘tinderboxes’ had been solved, and the situation had reverted to that before the war – of course with much greater sophistication, and at greater range. The destruction of HMS Hood, apparently by a single salvo, was at least as great a surprise as the destruction of the three battlecruisers at Jutland.

I/I: BRITISH GUNS

Royal Navy gun requirements were framed by the Director of Naval Ordnance (DNO) under the guidance of Controller (Third Sea Lord). The Royal Navy did not make its own guns, nor did it have its own ordnance experimental organisation. However, it did have a gunnery school, HMS Excellent, which also provided vital advice on ordnance matters. Thus ordnance records include frequent references to its captain. When the Admiralty Staff was reorganised in 1917, a separate Director of Naval Artillery and Torpedoes (DNA&T) and a separate Director of Naval Gunnery Division were appointed to handle gunnery and weapons policy, in conjunction with (or in competition with) DNO.

Until 1855 a Board of Ordnance provided guns to both the army and the navy. With the abolition of the Board the army supplied the navy’s guns. There was no commercial gun industry, because countries which maintained navies generally had their own national gun foundries, and gun manufacture did not yet entail such high capital expenditures that countries could not maintain this capability. Until about 1858 heavy guns were made by Woolwich Arsenal, later the Royal Gun Factory (RGF); then there was an interval during which they were made mainly at a new factory at Elswick, and then manufacture reverted to Woolwich until 1880. By that time the warship export market was growing, and guns were developing to the point where national capability could not be maintained by many countries.

The RGF monopoly was a reaction to a decision late in the 1850s to rely for guns on a private individual, William George Armstrong, who in effect developed the first modern built-up breech-loading rifled gun. Armstrong argued that existing official gun technology was obsolete and that it was time to apply modern engineering methods. The British government built a new factory for him at Elswick, and in 1858 he was appointed Engineer of Rifled Ordnance to the War Office: he was chief of ordnance for both services. Problems with early Armstrong breech-loaders caused a reaction against him, Woolwich regaining its monopoly position. Its muzzle-loading rifles (MLRs) were adopted in 1865. Woolwich insisted on their superiority even as other navies adopted improved breech-loaders. Muzzle-loading finally showed its inadequacy in 1879 when HMS Thunderer burst a gun which had been doubleloaded. The resulting scandal brought into question the wisdom of taking guns from the army (i.e., of relying entirely on Woolwich). A new joint-service Ordnance Committee was formed in 1881; guns were bought from outside firms and from RGF. The Committee decided which designs were to be bought, based on DNO requirements. In 1908 the Ordnance Committee and Ordnance Research Board were combined as the Ordnance Board. Given the joint service arrangement, British navy and army artillery formed a common series of Mark numbers, leaving gaps in the naval series.

By 1880 it was possible to choose designs competitively, because a substantial private British heavy gun industry survived by supplying weapons to foreign buyers. The export market was dominated by the Elswick Ordnance Company (EOC), which had been founded by William George Armstrong. When the government terminated Armstrong’s contract in 1862, its terms left him with the plant it had financed. Krupp was the company’s only major rival, selling mainly to Prussia and to Russia. As the data below show, through the late nineteenth century most naval guns in the world were made by Elswick (Armstrong). Armstrong began building warships in 1867. The British government commandeered some Armstrong guns intended for Italy in 1878 and sent them to Malta for coast defence, and the Royal Navy bought some of the company’s improved 6in breech-loaders at about this time. Armstrong’s main British rival in gun design and construction was Joseph Whitworth. Armstrong acquired Whitworth in 1897, the firm being renamed Sir W.G. Armstrong Whitworth Ltd, or Armstrong Whitworth. In this book it will simply be called Armstrong.

The second major British armaments firm was Vickers, which began as a steel-maker and then acquired shipyards. Vickers received its first gun order from the British government in 1888, the first large gun being tested successfully in 1890. When the American Hiram Maxim invented the modern machine gun in 1881, he could not license it to Armstrong, as might have been natural, because at that time Armstrong’s small-calibre machine gun was the earlier Gatling gun. He therefore formed the Maxim Gun Company Ltd with Albert Vickers as chairman. In 1888 Maxim united with Nordenfelt (whose British company was formed in 1886). Besides guns, Nordenfelt was developing a submarine, two of which were built at Barrow. In the mid-1890s Vickers was still basically a steel firm with some interest in armament, but then the firm’s director decided to