Broadly speaking, the protected cruiser is less than thirty years old. The oldest vessel classed as a cruiser to be found in Brassey is the English Iris, of 3730 tons, launched in 1877. Brassey does not give any deck thickness for the Iris. The Champion, of 2380 tons, launched in 1878, is however, said to have a thickness of protective deck of 1 1/2 inches.
Owing to the comparatively recent origin of the type, the navy lists of to-day contain practically all the protected cruisers that have been built, except those that have been lost by stranding or otherwise. This being the case, I have taken the last Brassey (for 1903) and prepared Table I, showing, for Great Britain, France, Germany, Russia, the United States and Italy, the name and displacement of protected cruisers launched each year since 1877. I have taken as protected cruisers all vessels classed by Brassey as cruisers. From the data in Table I, I have prepared Fig. 1, which shows graphically the tonnage of protected cruisers launched each year for the six navies referred to. Fig. 1 extends from 1876 to the end of 1902, the ordinates showing, in each case, the total tonnage of cruising ships launched during the year, which still existed in 1903.
The notable feature of Fig. 1 is the sudden cessation of launching protected cruisers, which began about 1898. This is attributable, of course, to the development of the armored cruiser.
Fig. 2 refers only to British ships. It repeats the data for the protected cruisers of this nation in Fig. 1, and gives similar data for the English battleships and armored cruisers. It will be seen that there was no halt in the construction of battleships in England about 1898, but the cessation in building cruisers was accompanied by the rapid development of the armored cruiser.
The armored cruiser, in Great Britain, according to classification, is about twenty years old, and in 1887 this nation had over 50,000 tons of them afloat. These cruisers, however (although in any classification, they must be classed as armored cruisers), are not very close to the modern conception of these vessels. They consist of the Imperieuse and Warspite, originally designed with sails and with a maximum speed of about 17 knots only, and a half-dozen vessels of the Orlando class, of 5600 tons displacement and 18 knots trial speed. The real development of the type in England dates to the early 9o's, the first armored cruiser, in the modern acceptation of the term, being probably the French vessel Dupuy de Lome, launched in 1890. The cause of the obsolescence, so to speak, of the protected cruiser type is not far to seek. With the development of high explosive shell and the marked increase in the muzzle velocity of naval guns, the value of the protective deck, which, at best, protected the armament and gunners not at all, was almost entirely nullified. The Bureau of Ordnance, for instance, says, with reference to the protective deck:
"The Bureau believes that no plate can be manufactured that will resist an attack at a striking velocity at all approaching the muzzle velocities obtained to-day, when the shot is delivered at an angle approximating that at which the plate would probably be struck in service."
The ground in this connection appears to be well covered by M. De Lanessan, Member of the Chamber of Deputies, and late Minister of Marine in France, in his book "La Programme Maritime," 1900-1906, as translated in the Journal of the Royal United Service Institution of England. M. De Lanessan writes:
CRUISERS.
"The second category of large ships in all modern navies are those which came under the general classification of cruisers.
"Their leading feature should be the predominance of speed and radius of action over offensive power and protection.
"In the earlier history of modern cruisers such an importance was attached to speed, that everything, even radius of action, was sacrificed to it. It was an epoch when the dimensions of the ships were diminished of set purpose in order to have a larger number of the same type, it being considered that the number of units was of greater importance than their power.
PROTECTED CRUISERS.
"This period was marked by the construction in every navy, but more particularly in ours, where the idea originated, of ships with displacements of from 1500 to 2000 tons, in which every effort was made to attain the highest speed, which could be reached at that time, but at the sacrifice of every other quality, owing to their small displacement. Their offensive power was represented by a small number of medium-sized and small-calibre guns, with two or three torpedo discharges for use against battleships if any opportunities presented themselves. The only protection was afforded by a thin steel armor deck, which extended the whole length of the ships at the waterline, below which was the machinery. The radius of action was necessarily limited, owing to the small size of the ships. We have no hesitation in saying that these cruisers have two grave defects. In the first place, their protection and armament are now recognized to be far too weak. In the second place, experience has shown that the speed for which everything else has been sacrificed was a merely nominal one, since it fell off very rapidly when the ship had to struggle against ever so little a sea. One knows to-day, as the result of experience, that no fast cruisers of less than 4000 tons displacement can hope to maintain, in spite of the sea, a speed anything like that attained at her trials.
"These larger displacements were adopted as soon as the necessity for them was clearly demonstrated; but the only protection for these fast cruisers continued to be an armored deck, and coffer-dams running along the side above this deck. The economy realized, however, by the weights which represented protection, served to increase the offensive power, particularly in the matter of Q. F. guns of a medium calibre.
"During the last fifteen years there have been built in France, England, Germany, and Italy a very large number of these so-called 'protected' cruisers, the speed of which is more or less considerable. England possesses to-day 130, France 33, and Germany 25 of this kind of vessel. As it became necessary to add to the offensive power, so little by little the displacement increased. In England, in the Powerful and her unique sister the Terrible, it rose to 14,200 tons. In France in the Guichen, we have reached 8280 tons, with a speed of 23 knots, and a ship which is the most perfect type of her class. In spite, however, of her comparatively speaking large displacement, which raised the cost of her construction to nearly 16,o0o,000 francs (640,000 l.), and the cost of maintaining her in commission to more than a million francs (40,000 l.), the Guichen and her sister the Chateaurenault are condemned by all our officers on account of their weak armament, which is composed of only two 6.4-inch Q. F. and six 5.5-inch Q. F. guns, with twelve 3-pounders."
ARMORED CRUISERS.
"Nearly every navy has now given up the construction of protected cruisers, as it is realized that a vast expense has been incurred on a class of vessels which, although they may be able to work mischief against unprotected merchant ships, are quite incapable of holding their own against any ship better protected than themselves, and may even be put hors de combat by a simple armed mail-boat. Consequently, during the last few years, all navies have striven to give at least a certain number of their cruisers a relatively speaking fair amount of protection.
"France was the country which set an example to other countries in this matter. In July, 1888, the Dupuy de Lome was laid down, a vessel where protection was afforded not only by an armored deck, but also by armor which covered her hull from end to end, to a height of some 12 feet above the waterline. Her armament was for those days a very powerful one, consisting as it did of two 7.6-inch, and six 6.4-inch Q. F. guns, with six 9- and six 3-pounders. The 7.6-inch and 6.4-inch guns were mounted in turrets protected by 5-inch armor. Unfortunately, owing to her limited displacement (6780 tons), it was not possible to give her a greater speed than 19 knots, so she cannot compete with ships of the same class, which are being laid down to-day, all of which can steam from 21 to 23 knots; her small displacement also did not allow of proper protection being given to her hull, her side armor being only 4 inches thick, which is quite insufficient even against the medium guns of similar foreign ships.
"After the Dupuy de Lome, between 1889 and 1903, we laid down five other armored cruisers with displacements varying from 4000 to 5500 tons, all of which had the same qualities and the same faults as their predecessors; especially in the matter of speed, which did not exceed 19 knots."
Fig. 1 and Fig. 2, apart from any argument, appear to me to show conclusively the general appreciation, about 1895, of the fact that vessels of the protected cruiser type were not worth the money put into them in comparison with other types. Of course, there is another side of the question, and it might be argued that the nations in question had a large number of protected cruisers and did not find it necessary to build more for a time. It is almost ten years now, however, since the laying down of protected cruisers came to a halt, and there does not appear to be much tendency to resume their construction. It may be pointed out that, since 1895, the Spanish War demonstrated very conclusively the exceeding vulnerability of the protected cruiser type. The old idea was that, in the protected cruiser, the vitals of the ship were protected by the deck. I think it will be generally admitted that experience in the Spanish War showed that protected cruisers could be practically annihilated without penetrating the deck. Since then, the advance in ordnance has seriously reduced the protection afforded by the protective deck.
It is generally admitted that there are needed types of vessels other than battleships and armored cruisers, but it would seem to be exceedingly doubtful whether the protected cruiser deserves to be reproduced at all, that is to say, a vessel in which a large amount of weight is given to deck protection and no other protection admitted, except, perhaps, shields on the guns. It seems to me, all things considered, that the true line of advance would be in the direction of abandoning the protective deck entirely and putting the weight saved into more remunerative features. There appears to be no reason why the new scout type could not do all of the work now done by the protected cruisers of the navy, and much more valuable work in time of war.
Some years ago I advocated in the Naval Institute the adoption of the steam turbine for main propelling machinery. This will shortly be tried in our service on a large scale, and if as successful as its advocates expect, will enable cruisers to be designed which will be a marked advance upon anything we now have. I should anticipate that it would be possible to design a 5000-ton vessel without a protective deck (with watertight deck only) which would reach nearly 30 knots on trial and would be able to maintain at sea, in ordinary weather, more than double the speed of a fleet of battleships. Such vessels would have no difficulty in coping with converted liners. Such a design, however, or an approximation to it, would be utterly impossible if an attempt is made to obtain deck protection. The Baltimore, which approximates 5000 tons displacement, has a weight of nearly 600 tons in her protective deck, or say 12 per cent of her displacement. A 5000-ton vessel of extreme speed would, however, require to be certainly more than half as long again as the Baltimore and should probably have 75 per cent more waterline area.