Editor’s Note: The following article was published in the July-August 1914 edition of the Journal of the United States Artillery, Vol. 42, No. 1.
While the idea of protecting ships of war by means of armor plate is not of so recent conception as may be generally supposed, its practical application, like that of many inventive designs, was delayed until long after the first trial; and armored ships, as we know them, date from about the middle of the 19th century.
Prior to the 16th century, the wooden sides of the ships were depended upon for protection against hostile missiles, and, with the advent of guns and their increase in power, the thickness of the sides of the vessels increased.
The Great Michael which was built by James the Fourth of Scotland, who was killed at Flodden in 1513, was 240 feet in length and 56 feet in breadth, but, as the sides of the ship were 10 feet in thickness, the interior breadth was only 36 feet.
While this great thickness was given to the sides of the vessel for the purpose of protection, it scarcely entitles the Great Michael to be classified as an armored vessel, and the first of these does not appear until 1530.
One of the largest ships of that time, belonging to the fleet of the Knights of St. John, was covered entirely with lead and was said to be successful in keeping out all the shot of the period. The practice of using lead armor does not, however, seem to have become general.
The question of the application of armor to ships of war for the purpose of protection from an enemy's fire, caused but little concern until the beginning of the 19th century, although the French had designed floating batteries in 1782 with a novel means of protection. These vessels, which the French employed in their attack upon Gibraltar, were covered with junk, rawhide, and timber to the thickness of seven feet, and had bombproofing over the decks.
Unfortunately for the French, this armor-plating was combustible and the ships were easily set on fire with red-hot shot. Still the French seemed to like the idea of floating batteries, for similar vessels were again used some 70 years later by them in the Crimea.
The earliest recorded proposal to employ iron armor for war vessels seems to have been made in England by Sir William Congreve in 1805. In 1812 John Stevens, of New Jersey, designed a ship with a battery protected by inclined armor. In 1814, a bomb-proof vessel was patented by Thomas Gregg of Pennsylvania.
The Stevens family continued to work on the subject of iron armor and had, by 1841, determined by actual experiment, the penetrative powers of the projectiles of the day against wrought iron. In 1842 R.L. Stevens, began the construction of an iron-armored ship which was never completed. In 1845 M. Dupuy de Lome designed armored frigate.
In 1814 the first war steamer ever built, the Fulton, was launched and demonstrated the possibilities of steam in the construction of navies. This ship was designed by Robert Fulton and called by him the Demologos. She was essentially a floating battery, the precursor of the Monitor, with two 100-pdr. guns on pivot mountings and with a ram-shaped bow.
She was driven by a steam paddle in the center of the ship, and was armored with wood so thick that it was proof against the shot of the time. The Demologos, upon being launched, became known as the Fulton the First and was considered the Dreadnought of the day. She attained a speed of 3-1/2 knots, but was not completed in time to demonstrate her possibilities in the war.
By 1822 shell guns had been adopted and the question of protection to ships became more important than it had been before. General Paixham, the inventor of the shell gun (canon obusier), himself suggested that the only reply to shell was armor. The necessity for armor becoming more and more apparent, experiments were begun about 1827 in England, France and the United States, with a view to the determination of the resisting powers of iron and its possibility of use for protection of ships.
Iron, for structural purposes, was developed rapidly, but in ship construction wood continued to be used almost to the exclusion of iron, until the middle of the century; and even in 1850 there were constructors who declared that iron was unsuitable for ships.
With the introduction of steam, however, ships increased rapidly in size and wood became unsuitable, because of the greater stresses to which the larger ships were subjected. The local strength and stiffness of a wooden ship was great, but the structural strength was considerably less than that of the iron vessel. Iron was, therefore, practically forced upon ship designers.
It is of record that an iron boat, intended apparently for passenger service, was built and launched on the River Foss in Yorkshire in 1777, and during all the latter part of the century iron was, according to report, used in the construction of canal boats and barges. The first iron steam boat in the United States, of which there is definite record, was the Aaron Manby, built in 1820. The U.S.S. Wolverine (ex-Michigan) built in 1842, was the first iron warship in our service, and is still in use (out of commission) on the Great Lakes.
The use of metal in the construction of merchant and passenger vessels developed much more rapidly than in naval construction, because of the slower increase in size of naval vessels. However, by about the middle of the 19th century iron had been definitely adopted and the navies of the world were continuing with ships of metal that struggle for supremacy which had begun with ships of wood.
In 1840 the British Admiralty conducted experiments to test the action of shot against iron plates backed by various substances, and it was concluded that iron was a poor material for ships of war.
In 1842 armor experiments were conducted with iron plates made by riveting together plates three-eighths of an inch in thickness to a total thickness of six inches. These plates did not successfully resist 8-inch guns or heavy 32-pdrs. at 400 yards; so some modifications were introduced and further experiments made in 1850.
This laminated armor was never reported on favorably; and general opinion, at about this time, was somewhat against armor. The French, however, formed a more favorable opinion of iron armor than did the other nations, and, in 1853, they constructed five floating batteries which carried four inches of iron armor.
These ships were almost totally unmanageable because of their bad lines, and their speed never exceeded four knots. They were of light draft and carried 18 50-pdr. guns with a crew of 320. It was intended that they should be able to use either sail or steam; but, when it was discovered that they refused absolutely to proceed under sail, the masts were removed and pole masts substituted.
Notwithstanding their many defects, three of them were sent to the Crimea, and it is reported that it was necessary to provide transports to carry their guns for them. Having arrived safely, they joined a large fleet in the attack on Kinburn on Oct. 17, 1855, and, by steaming in close to the fortifications, the floating batteries were enabled to silence the batteries in the course of a four-hour engagement without material injury to themselves.
It was no doubt the success of the floating batteries in this attack, which led the French to adopt armor plating for their ships of war; and so it is the French who are to be credited with having produced the first sea-going iron-clad, La Gloire, and, with her, that contest between gun and armor which has not yet ended; for improved kinds of guns and armor are still being sought and experimented with.
La Gloire, together with the Normandie, the Invincible, and the Couronne, were laid down in 1858; but scarcely were their frames up before England replied by laying down the Warrior, the Black Prince, the Defence, and the Resistance. By 1862 all the naval powers of the world had taken notice of the new naval developments.
Italy had begun the Formidable in 1860; Russia, the Petropalovski in 1861; and the United States, the New Ironsides, the Galena, and the Monitor in 1861. At this same time Spain, Austria, Denmark, and the Confederate States also had iron-clad ships either afloat or under construction.
While the European ships were, for the most part, modifications of existing types, the American ships were constructed from new designs, or railway iron and the like was attached to existing vessels.
The Monitor was a distinct novelty, not only because it was built entirely of iron, but also because it was the first of the turret ships. The battle between the Monitor and the Virginia (ex-Merrimack), being the first encounter between armored vessels, may be said to have opened the modern armor-clad epoch, for it demonstrated definitely that the wooden war vessel already belonged to the past and that armor was a factor which would have to be considered in all naval deigns of the future.
The credit of introducing the monitor type of vessel comes to the United States only because the presence of the Virginia in the Confederate Navy made necessary the rapid design and construction of the Monitor. While Ericsson was designing his vessel, Captain Cowper-Coles was designing the Rolfe Krake for Denmark. Coles proposed a turret ship which was to carry seven or nine center-line turrets, each containing two guns which were to recoil up a slope and return automatically to position.
It is improbable that either Ericsson or Coles used the other's ideas, as has been charged, for neither invented the idea of turrets. Turret-ships seem to have been proposed in the 16th century, and pivot guns had long been used. Ericsson’s turret revolved on a spindle; while that of Coles revolved on a series of rollers and was, therefore, more practical.
The advance in gun construction began at practically the same time as the advance in ship and armor construction. A wire-wound gun was proposed in the United States in 1850 by Dr. Woodbridge and in England by Mr. Longridge, C.E.; in the same year, 1855, Mr. Mallett, in England, advocated a built-up cannon. While the manufacture of armor plates progressed rapidly from the first, the improvements in gun powder forced a continually increasing thickness of the plates.
While soft iron had been adopted for the armor for ships, experiments continued with this and with laminated armor, hard iron, and, later, chilled iron, steel, and the plate-upon-plate system. In 1861 various backings such as timber, cork, India-rubber, layers of wire, etc., were tried and it was concluded that, “while the hard materials improved the resisting power of the armor, they led to its being more injured by cracking, and to the giving way of fastenings.”
At about this same time, a Special Committee on Iron (British) came to the following conclusions:
1. That steel and steely iron are bad materials for armor, while soft iron is best.
2. That corrugations and bosses, designed to break shot on impact, are undesirable.
3. That plates should be large as practicable.
4. That hard backing supported the plates at the expense of the bolts, whose functions are not only to hold the plates on but also to resist vibration and prevent buckling.
5. That tonguing and grooving of plates tend to spread injury from plate to plate, and are bad.
6. That the effect of shot on plates is not proportional to the momentum of the former, but to the energy.
The advantages of a hard pointed projectile with which to attack the soft armor soon became apparent, and Sir William Palliser introduced an ogival-pointed chilled-iron shot. His projectiles were first tried at Shoeburyness in the autumn of 1863.
In 1864 steel plates made their first appearance, plates supplied by the Thames Company, Brown & Co., the Parkgate Company, and Petin & Gaudet, being unsuccessfully tested in Russia in this year.
With the adoption of armor protection for ships of war, all the principal nations of the world, with the exception of the United States, began the construction of armor-clad navies with a feverish activity, which continued until the eighties. Up to 1875 the contest between gun and armor had wrought iron armor on one side and cast iron projectiles on the other.
There had been no material improvement in the manufacture of projectiles since the introduction of rifled cannon other than that (noted above) caused by chilling the ogive in casting. Neither had there been any essential improvement in the manufacture of armor-plate; so the steadily increasing power and caliber of the gun had forced a continually increasing thickness of armor-plates.
The climax was reached in 1876 when the Inflexible, a ship of 11,800 tons, was given 24 inches of armor amidships. In this ship an outer thickness of 12-inch armor-plate was backed with 11 inches of teak, behind which was another 12-inch armor-plate backed with 6 inches of teak. Inside all this were two thicknesses of 1-inch iron plating.
As the weight of armor to be carried by ships could not be increased indefinitely, an improved kind of armor with which the gun might be successfully opposed became necessary. The Italians seem to have been the first to recognize this, for they began a series of experiments at Spezia in 1876 upon several forms of target, with their attention especially directed to steel.
The steel employed tended to shatter upon impact of the projectile; but it was noted that projectiles which passed completely through wrought iron plates were stopped by the steel plates. As a result, the Italians fitted the Dandolo and the Duilio with armor belts consisting of 21.65 inches of solid steel. These were the first ships to carry steel armor.
These experiments gave added stimulus to the investigation of steel for armor; and, from this date, experiments were conducted under the conviction that wrought iron would be replaced sooner or later by steel in some form. Mr. George Wilson, of the Cammel Company, patented a compound armor in 1876 which was to compete with the all steel armor. This armor consisted of a steel face welded to a wrought iron back and offered the advantages of a hard surface and a tough body.
Experiments in 1877 with plates consisting of 5 inches of steel united to 4 inches of wrought iron showed this compound armor to be superior to wrought iron plates, and further experiments showed that best results with compound armor were obtained when the steel constituted about one-third of the plate.
Naturally, a contest between the all-steel and the compound armor resulted, and the compound armor seemed at first to have the advantage; but, with the introduction of the steel shell a little later, the advantage turned to the steel plate.
The compound plate was produced mainly in England and the steel plate mainly in France, and rivalry between these plates continued until the Annapolis and Ochta experiments of 1890. At these trails the superiority of the steel plate was demonstrated beyond a doubt; but both plates were found to be inferior to a new nickel-steel plate which had just appeared.
The introduction of the compound and the steel armor gave the plate the advantage over the gun, and investigations were conducted with a view to the determination of the best material for projectiles. One series of experiments was conducted by the British Admiralty of 1877 with chilled iron projectiles of various kinds, steel projectiles, and projectiles with steel bodies and chilled iron heads. Among other things, they recommend:
• That all battering projectiles should have heads struck with a radius of 2 diameters.
• That the question of a delay-action fuse to be used with guncotton be further investigated.
• That a certain proportion of forged steel shells be issued.
• That cast steel shells be not adopted unless greatly improved.
In this same test was tried a wrought iron cap on the point of the projectile. This was brought about by the fact that it had been discovered that a steel faced armor plate lost its power of breaking up chilled shot when a 2-1/2-inch wrought iron plate was placed over the face of steel plate. Captain English and General Inglis thought a cap would serve the same purpose as the iron plate. The effect of the first shot encouraged further investigation, but further trial showed that “no advantage was gained by a cap.”
Other experiments were carried on by all the manufacturers of projectiles. Krupp, Hadfield, Holtzer, Armstrong, Firth, and others tested cast steel, forged steel, specially treated steel, and steel alloys, until the Holtzer works advanced a chrome-steel projectile which was successful against the new armor. With a chrome-steel projectile, Holtzer in France and Hadfield in England became most prominent as projectile manufacturers.
The projectile having again gained the ascendancy, it became necessary to effect the destruction of the chrome-steel projectile; so the plate manufacturers began to increase the hardness of the face of the plates. Captain Tressider, R.E., patented a method of face hardening in 1887, which was first applied to the compound armor. In 1889 Schneider introduced nickel into steel; and in 1891 or 1892 the St. Chamond works used nickel steel with a small percentage of chromium.
The armor which was adopted for replacing the steel and the compound armor was a face-hardened nickel-steel armor introduced by Mr. H.A. Harvey, of the Harvey Steel Works of Newark, N.J. This is the armor mentioned above as having been tested at the Annapolis trials. These trials led to further tests at Indian Head, and the results were so successful that Harveyized nickel steel armor-plate was adopted for warships.
The United States Navy at this time was in its infancy, so far as modern navies were concerned. Little interest had been taken in the development of the Navy after the close of the Civil War. As though satisfied with the production of the first monitor, this country allowed the Navy to decay for twenty years, with the result that, in 1880, there was not a really seaworthy seagoing warship belonging to the Navy, while practically, all the ships owned were sailing vessels.
All other countries had definitely discarded sailing war vessels long before this; so, as a naval power, the United States stood near the foot of the list. In 1880 the country appeared to awaken to its naval needs and interest in naval development was soon apparent.
Our modern navy then dates from the early eighties, that is, from about the time of the development of steel in naval construction. Our first ships, the Dolphin, the Boston, the Atlanta, and the Chicago, laid down in 1883, were given steel hulls. From this time on the United States continued to lay down ships and to strengthen the Navy, until, in the early nineties, it began to be recognized as a naval power.
The Monterey (1891) and the Indiana class (1893) were the first ships to carry Harvey armor. The Spanish-American War brought the Navy not only to the attention of the world, but, what is more important, to the attention of the American people; and since then the United States has forged rapidly to the front as a naval power.
In 1893 Krupp introduced a face-hardened armor, nickel chrome steel with special heat treatment, which soon superseded the Harvey armor. This armor, known as Krupp Cemented (K.C.), was adopted by German on the Kaiser Wilhelm II in 1897. By 1901, this new armor had been adopted by all the naval powers, and now practically all the principal armor of all the navies of the world is Krupp Cemented.
In regard to recent improvements in armor very little has been made public. Several new kinds of armor or methods of manufacture have recently been reported, and it may be that K.C. armor will soon be discarded, as have all preceding kinds.
The Schaumann plate, recently invented, consists of a light steel plate backed by a plate of duralumin. The two are welded together at various points, but not solidly. The new plate is lighter than steel and it is stated that the inventor expects to equal the best Krupp plate with 25 to 30 percent less weight.
Another new plate is the Simpson, which consists of a hard tool steel plate and a tough steel plate welded together, with a sheet of copper between, giving a weld which is practically invisible, the welded plates being molecularly continuous.
Hadfield has produced a cast steel plate which has been very successfully tested, and the use of these plates seems to be becoming more and more general.
However, the quality of armor in general use has not greatly improved since 1897, while, on the other hand, guns have enormously improved at the same time that there has been improvement in the projectile itself, as well as that due to the adoption of the cap shortly after the Russian trials in 1894.
With the introduction of the 13.5 and the 14-inch guns in the last year or so it may be said that the gun has again attained, superiority over the armor; so, according, to all precedent, we should see a new or improved armor adopted in the course of the next few years.
In this continuing struggle between the gun and the armor there have been many changes and modifications in the construction of the ships themselves. The change to steel permitted a lighter construction, giving a decrease in the dead weight and an increase in the allowable weight for armor and armament. Improvements in the methods of manufacture since that date have permitted of many improvements in the details of construction.
In types of ships there has been a great change. The old wooden sailing ship carried a battery arranged for broadside fire, while the battleship of today is prepared for heavy end-on as well as broadside fire. The intermediate armament came into being on armored ships and passed away, battleships of today carrying only big guns and some torpedo defense guns.
The old line-of-battle ships were high sided and from this type we jumped to the monitor with practically no freeboard. The battleships and battle-cruisers of today have worked back to the high freeboard and its elevated gun platform, which permits the use of the guns in a seaway and gives greater stability to the ship.
In size also there has been a marked increase since the beginning of the modern era. Warships increased very gradually but continuously in size from the 1400 tons of the French floating batteries to the 12,000 tons of the pre-Dreadnoughts. Since then they have increased very rapidly to the 30,000 tons of today, with 40,000 tons proposed, with the result that battleships launched ten years ago have today but little value. As the Panama Canal can accommodate battleships up to 43,000 tons only, that would seem to be the present limit in size, at least for the United States.
The Dreadnought, which marked the beginning of the rapid increase in size of warships, is about the only epoch-making development in naval science originating in Great Britain, but it opened a new era in ship design for the navies of the world. This ship was based on the design of "the ideal ship for the British Navy," published in 1903 by Colonel Cuniberti, Constructor to the Italian Navy.
The ship, whose design had been declined by the Italian Navy because it was too ambitious for that power, was to be of 17,000 tons displacement and was to combine in itself the offensive and defensive powers of two or three battleships.
The idea was not taken seriously, until, in the Russo-Japanese War, it was announced that the battleships Aki and Satsuma, which had been laid down, were to be more or less on the lines of Colonel Cuniberti's design. At the same time it was announced that the United States had started the South Carolina and the Michigan, each carrying four two-gun center-line turrets.
Both of these ideas were public property before the Dreadnought was laid down, but she was built with such rapidity that she was completed before any other vessel of the type, and her building was shrouded in so much mystery that she received considerably more advertising than did the other vessels.
Japan and the United States are obviously entitled to a great share of the credit for originating the Dreadnought movement. The South Carolina type, all big guns on the center line, all bearing on either side, was a distinct novelty. No secrecy whatever was observed about them and the United States is probably the first nation that definitely adopted the all-big-gun idea.
The Dreadnought idea spread rapidly, each nation striving to out-do the others by increasing the size and armament of each vessel laid down. This has resulted in a type known as the super-Dreadnought which surpasses the Dreadnought as much as that vessel surpassed its immediate predecessors. …
Thus it is seen that the battleship, from its earliest days, has been increasing in size and in its offensive and defensive powers, until today we have colossal 30,000-ton super-Dreadnoughts which were undreamed of fifteen years ago. What the future holds in store in the line of naval development only the future can tell.
There is at present a vague feeling among the younger element in the Navy that the days of the battleship are numbered, and that further development will be along other lines. This idea has appeared on previous occasions, but its present advocates point to the recent developments in the submarine, in the torpedo, and in aerial navigation.
It remains to be seen, however, whether the battleship will retain dominion over the sea or whether it is doomed to disappear, future wars being decided in the air or beneath the surface of the waters.