Big Gun Monitors

Design, Construction, and Operations 1914-1945

Ian Buxton

• Publisher: Seaforth Publishing
• Year: 2008
• ISBN:
  9781783469116
• Topic: Histoire
• Subtopic: Histoire de l'armée et de la marine

"Extremely well researched... a total account of the design, building, service, refits, and fates of the big gun monitors built for WW1 and WW2." —Malcolm Wright, author of British and Commonwealth Warship Camouflage of WWII In the history of naval warfare probably no type of ship has provided more firepower per ton than the monitor—indeed they were little more than a huge gun mounting fitted on a simple, self-propelled raft. Designed and built rapidly to fulfil an urgent need for heavy shore-bombardment during World War I, they were top secret in conception, and largely forgotten when the short-lived requirement was over. Nevertheless, they were important ships, which played a significant role in many Great War campaigns and drove many of the advances in long-range gunnery later applied to the battle fleet. Indeed, their value was rediscovered during the Second World War when a final class was built. Monitors were largely ignored by naval historians until Ian Buxton produced the first edition of this book in 1978. Although published privately, this became an established classic and copies of the first edition are now almost unobtainable, so this new edition will be welcomed by many. It has been completely revised, extended and redesigned to a generous large format which allows material deleted from the original edition for lack of space to be restored. "This book looks in detail at the technical and economic aspects of the 42 monitors built, and is, without a doubt, the definitive work on the subject." —Ships Monthly "Ian Buxton's work has set the standard in celebrating these big gun ships... It makes an invaluable contribution to the study of naval and land operations." —Warships International

Taken in March 1941, this shows Roberts awaiting her 15in turret. The battleship fitting out is Duke of York and the destroyer Piorun (ex-Nerissa). The only significant change visible in the Clydebank shipyard in the intervening quarter of a century is the addition of the large tower crane to cover the upper end of the longest slipway on which the Queens were built, although the cantilever crane has been strengthened to 200 tons. (JOHN BROWN)

CHAPTER 1

The Origins of the British Monitor

‘MONITOR — one who admonishes another as to his conduct’

Shorter Oxford English Dictionary

In a letter to Gustavus V. Fox, Assistant Secretary of the United States Navy during the American Civil War, the Swedish engineer John Ericsson claimed of his new design of ironclad ship:¹

The impregnable and aggressive character of this structure will admonish the leaders of the Southern Rebellion that the batteries on the banks of their rivers will no longer present barriers to the entrance of the Union forces. The iron-clad intruder will thus prove a severe monitor to those leaders. … On these and many similar grounds, I propose to name the new battery Monitor.

The wooden ships of the Federal forces had been unable to overcome the batteries guarding the way to the Confederate strongholds above Hampton Roads, Virginia. Construction of Ericsson’s ironclad began in October 1861, and she was completed just in time to counter the destruction that the newly converted Confederate ironclad Virginia (ex-Merrimack) had been wreaking among the blockading Federal ships. The 987-ton ship was named uss Monitor, her principal features being a powerful armament of two 11in smooth-bore muzzle-loading guns in a rotating armoured turret, a well protected low-freeboard hull presenting a very small target, and no rig or sails, as she relied entirely on steam propulsion to provide her modest 6kts speed. The inconclusive action between the Monitor and Virginia on 9 March 1862 has been recounted many times; neither ship was seriously damaged owing to the protective value of their iron plates. Such a radically new design of fighting ship had a significant influence on warship development, making obsolete at a stroke virtually all the vulnerable wooden sailing vessels whose design had changed little over the centuries; although it must be recognised that the trend towards iron-cladding and the turret was already apparent in contemporary European designs, Warrior having been completed in 1861.

The use of special ships to attack well-defended targets has a long history. Both the British and French used bomb vessels at the end of the seventeenth century to bombard forts, as at Tripoli, Algiers and Genoa in 1682-84. From time to time, bomb and mortar vessels continued to be used as required for coast offence purposes. The first serious attempt to ally this type of vessel with the new developments of steam propulsion and iron protection occurred during the Crimean War. In July 1854 French Emperor Napoleon III ordered ten ironclad floating batteries to be constructed which could be used against the Russian Crimean and Baltic forts. Five vessels were built in Britain and five in France, each of about 1,600 tons, mounting sixteen 68pdr or 50pdr muzzle-loading guns. Four-inch wrought iron plating covered the sides of their hulls, and they could steam at about 4kts.

During the 1860s the unprotected broadside-armed sailing vessels and wooden screw battleships of the major navies were rapidly superseded by a wide variety of steam-propelled ironclad designs. The principles of Ericsson’s Monitor found favour among the smaller powers for coast defence vessels, but low freeboard made the type unsuitable for overseas operations. Even the mighty Royal Navy embarked on building vessels suitable only for coast defence, starting with the Prince Albert in 1862. Over the next decade a motley fleet of some dozen such vessels was built. Apart from the three designed for colonial defence, these ships were almost valueless. It was strategically unsound for a major power to build coast-defence vessels. The best defence against attack or invasion was the destruction of the enemy fleet, in effect making the enemy’s own shores the defence perimeter of the British Isles. Subsequent development of armoured ships for the RN therefore concentrated on well armed, well protected vessels with a reasonable speed and capable of keeping the seas in all weathers. Such ships were necessarily large and could not be afforded in great numbers. When coast-offence vessels were needed, as at the Bombardment of Alexandria in 1882, the regular ships of the line were employed. Thus for some forty years the RN built neither coast-offence nor coast-defence vessels, although the latter remained popular with most of the smaller navies. The United States continued to build monitors up to 1903, when the last of a line of seventy-one vessels ordered was commissioned, the 3,225-ton uss Florida. Several navies also built river monitors, in effect shallow-draft armoured gunboats, but they were intended only for service on rivers like the Danube or Amur, not on the open sea.

With the outbreak of World War 1 in August 1914 the RN was committed to its first full-scale war for a century. The Grand Fleet’s role was that of neutralising the German High Seas Fleet, so enabling Britain to keep command of the seas and her overseas communications while blockading Germany. Germany’s rapid thrust on land through Belgium towards Paris had been brought to a halt by October, when the war was already showing signs of dragging on for a year or more. In addition to the main belligerents of Britain, France and Russia on the one hand, and Germany and Austria-Hungary on the other, attempts were made to persuade other nations to join either the Allied Powers or the Central Powers. At the end of October it was plain that Turkey would join the latter bloc, but Italy could not yet be persuaded to join the former.

When Lord Fisher replaced Prince Louis of Batten-berg as First Sea Lord on 30 October 1914, it was clear that some form of naval initiative would be desirable to break the impending stalemate on land and attempt to strike Germany decisively in a vulnerable spot. Winston Churchill, First Lord of the Admiralty, and Fisher had been mulling over various possibilities. Fisher had long been a proponent of a Baltic strategy, where an offensive against the Pomeranian coast could enable a landing to be made with Russian support only 90 miles from Berlin. To be successful such a scheme required the prior disablement or neutralisation of the High Seas Fleet, which otherwise could emerge from Wilhelmshaven or the Kiel Canal and wreak havoc among the invasion fleet. The shallow waters of the Baltic were easily mined, which would hamper and endanger the deep-draft big-gun ships of the RN. It would therefore be necessary to undertake the hazardous operation of seizing some form of advanced base across the North Sea in the Friesian Islands or off the Danish coast, either to force the High Seas Fleet out of its well protected base at Wilhelmshaven and enable the Grand Fleet to destroy it by battle, or to permit surface forces and submarines to blockade movements from the German bases.

The stabilisation of the Western Front on the Belgian Coast also offered opportunities for landing forces under the cover of heavy guns to turn the enemy’s flank and prevent ports such as Zeebrugge from being used as submarine bases by the Germans. Any hostilities against Turkey would probably entail an attempt to force the Dardanelles to open the direct supply route to Russia. Ships of the Grand Fleet could not be risked from their vital strategic role for such operations, while most of the older British ships had insufficiently powerful guns or were of too deep draft for working close inshore near strong shore defences. The makeshift fleet which had bombarded the Belgian Coast at the end of October (see p.95) had demonstrated the potential of coast-offence vessels, as it had been instrumental in stemming the German advance towards the French Channel ports.

All of these possibilities for coastal bombardment, some more practical than others, were at the backs of the minds of Churchill and Fisher when an important visitor called at the Admiralty on Tuesday 3 November 1914. The visitor was Charles M. Schwab, President of the Bethlehem Steel Corporation, who had left New York a fortnight earlier in the White Star liner Olympic to try to sell arms and munitions to Britain. In addition to steel and armour plate, Bethlehem manufactured ordnance as well as owning several shipyards. After some delay because the passengers on the Olympic had witnessed the sinking of the British battleship Audacious, mined off the north coast of Ulster on 27 October, Admiral Sir John Jellicoe, C-in-C of the Grand Fleet, permitted Schwab to travel to London, when he learned that Schwab had arranged to see Lord Kitchener at the War Office and that Bethlehem had submarine-building capacity available. At the Admiralty the new construction programme was discussed and agreement was reached with Schwab to build twenty submarines for Britain in the USA. That evening Schwab was asked by Churchill and Fisher if he had any other naval material which might be of use to Britain. He then disclosed that he had four twin 14in turrets nearing completion, which had been ordered for the Greek battlecruiser Salamis, then building in Germany. As the British blockade would obstruct their delivery, he was quite willing to sell them to Britain instead, together with their outfit of ammunition.

At this moment the British monitor was conceived. A supply of modern heavy ordnance was the main prerequisite for building coast-offence vessels. While hulls and machinery could be constructed quite quickly, heavy gun mountings took well over a year to build. The only source of supply in Britain would have been the requisition of mountings ordered for some of the battleships of the 1912 and 1913 new construction programmes. Any such diversion would have a serious effect on the completions that were needed to ensure an adequate margin of capital ship numbers over the High Seas Fleet. Schwab’s offer opened up the prospect of rapidly obtaining a significant coast-offence capability, so Churchill and Fisher eagerly accepted.

After the meeting the Third Sea Lord, Rear-Admiral F.C. T. Tudor, who was responsible for naval construction, immediately minuted to the Director of Naval Construction (DNC), Eustace Tennyson d’Eyncourt:²

To design immediately 2 Armoured Monitors, to be built in 4 months — each to carry 2-14in guns or equivalent. Draft 10 feet. Speed 10 knots. To have crinoline. An armoured conning tower. Armoured deck. Who could build them?

A design to satisfy these requirements was worked up very quickly, as detailed in the next chapter. It was a revolutionary design in that it owed nothing to previous ship designs, unlike the normal evolutionary process of naval architecture. By the standards of Ericsson’s original design, the British concept was not strictly a ‘monitor’, but over the intervening half-century the term could reasonably be considered as having evolved somewhat to embrace a new type which still owed something of its characteristics to the first monitor. Within the RN the description ‘monitor’ would be distinctive and unambiguous, while not giving away too much as to their expected operational role.

Over the next four months thirty-three vessels were authorised; thus, with the two vessels ordered later, the RN had by 1916 a fleet of thirty-five monitors, sixteen large and nineteen small, mounting guns from 6in to 15in calibre. Including three ex-Brazilian river gunboats and two ex-Norwegian converted coast-defence ships, a total of forty vessels saw service during World War 1. Further vessels were built exclusively for river work, the so-called China gunboats of the Insect and Fly classes but, as they were not intended primarily for bombardment operations, they are only mentioned in passing in this history of British big-gun monitors.

HMS Roberts The first monitors to be completed were simple in their essentials — a Bethlehem twin 14in turret mounted on a low hull with a tripod mast and single funnel. Unlike Abercrombie and Havelock, Roberts and Raglan had the folding midship ammunition derrick post shown, but the latter had no seaplane derrick posts aft. Later modifications included a lengthened funnel, removal of the topmast, and additional secondary armament.

CHAPTER 2

The 14in-gun Monitors

HMS

Abercrombie

—

Havelock

—

Raglan

—

Roberts

2.1 Design of the First British Monitor

Churchill and Fisher were in their element in November 1914, planning a vast new fleet of ships. The projected cruisers, destroyers and submarines were all relatively well established types, but the monitors were a totally new concept. While some of the latter’s characteristics might be similar to those of coast-defence vessels or river gunboats, neither of these types formed a suitable basis for designing seagoing vessels. The main requirements could be summarised:

(i)	Twin 14in turret to be carried on a good gun platform
(ii)	10ft shallow draft, to get close inshore
(iii)	Maximum protection against mines and torpedoes, with reasonable protection against gunfire
(iv)	Hull and machinery as simple as possible for rapid construction
(v)	Modest speed of 10kts
(vi)	Reasonable seagoing capability.

By the time Schwab returned to the Admiralty on 6 November to discuss further details of the proposed contracts, a Constructor, A.M. Worthington, had sketched out a preliminary specification of a monitor of about 6,000 tons displacement.¹ After the weekend, formal instructions were given on the 9th to a young Assistant Constructor, Charles S. Lillicrap. It was a challenging task even for a talented man who was later to become DNC himself; a totally new type of ship to be designed and built with the greatest urgency, with the formidable Fisher continually appearing in the office to hasten progress.

Unfortunately no Ship’s Cover (the file kept by DNC Department recording the design of each new class of ship) was prepared for the early monitors, probably owing to Fisher’s impatience and to the secrecy surrounding them. However, it is possible to glean something of the considerations applied in the monitor design from the calculations recorded in Lillicrap’s calculation workbooks. The turret was the heaviest single item, about 620 tons revolving weight, plus about 350 tons for ammunition and barbette armour. Such a concentrated weight would have to be placed nearly amidships to avoid problems of trim. The width of the hull would need to be about 60ft to contain the turret comfortably and its magazines. Protection spaces were to be fitted outboard, as a monitor was the ideal vessel on which to demonstrate d’Eyncourt’s newly developed design of an anti-torpedo bulge. The bulges, sometimes called blisters, were added outside the hull proper, being 15ft wide on each side, as described on p.14, The breadth of the ship would thus be about 90ft; anything wider would severely restrict the number of drydocks that coul...