1

The

was taken in these ships in the disposition of the armour.
belt was 9 in. only, but it was carried up to the main deck for a
total depth of 15 ft. The length of the citadel was 250 ft., or
about two-thirds the length. The protective deck between bar-
bettes was run level across at the middle line, but sloped down to

the bottom of the armour at the side, as shown in Fig. 130. This deck was 3 in. on the flat and 4 in. on the slope. In this arrangement of armour the influence of the larger nature of quick-firing

guns is seen. The protection at the waterline is not sufficient to keep out the heaviest projectiles. It is, however, backed up by the 4-in. sloping deck (which is about equivalent to 5 in.

"MAJESTIC

-FORMIDABLE.

- BULWARK

"DUNCAN.

--KING EDWARD VID

FIG. 131.-Sections at side of battle-ships. C., Compound; N., Nickel; H., Harvey; K.C., Krupp cemented.
CANOPUS.
ROYAL SOVEREIGN.

horizontally), so that before the vitals of the ship are reached a penetration equivalent to about 23 in. of wrought iron is necessary. Although this does not compare well with the 30 in., say, in the Royal Sovereign, yet it is certain that a ship will be most difficult to hit at the waterline, and it was considered better to give up absolute protection at the waterline in order to obtain a larger area of good protection, because of the development of the large quick-firing guns. The ends of the ship are not protected by vertical armour, but have underwater decks 2 in. thick. In some of the later ships of this class the barbettes are circular, and not pear shaped as Fig. 129, owing to a change of the type of gun mounting.

A point worth noting in connection with a narrow belt (as in Fig. 132) is the fact that when deeply loaded, or damaged so that sinkage takes place, the top of the belt may possibly be at or below the waterline, and the advantage of a thick belt is then lost. Another point is that ships increase their draught as time goes on (about an inch yearly), owing to alterations and additions, so that the value of the belt gets less and less during the course of years, unless steps are taken to reduce the draught.

Krupp Armour.-The Harvey process of manufacturing armour was soon superseded by the Krupp process. The steel for this process has a high tensile strength, approaching 50 tons per square inch, and contains small proportions of nickel, chromium, and manganese. Plates above 4 in. are cemented, and are termed K.C., or Krupp cemented. Plates 4 in. and below are not cemented,

these are termed K.N.C., or Krupp non-cemented. For K.C. plates the cementation is carried out in a similar manner to that of the Harvey process, but in the final face hardening the plate is not heated bodily as in the Harvey process, but the heat is graduated from the face to the back. After heating the face is placed under the cold water douche.

L

For K.N.C. plates the composition of the steel is similar, but the plate is water cooled without previous cementation. These plates are about equal in resisting power to Harvey plates, i.c. have a figure of merit of about 21. K.C. plates have a figure of merit about 2.3 to 2.5. In some few cases a higher figure of merit, approaching 3, has been obtained.

(An exhaustive summary of the armour question year by year is given in Lord Brassey's Naval Annual. See also the supplements to Captain OrdeBrowne's "Armour and its Attack by Artillery.")

Armour Bulkhead.--In the case of a thwartship armour bulkhead to a ship with a sloping protective deck as Majestic and following ships, it is necessary to pay attention to the thickness of this bulkhead where the middle deck does not come behind. Fig. 133 shows the after armour bulkhead of a battle-ship with 7-in. side armour. The armour protecting the barbette gun

mountings is 11 in. and 10 in. At the points marked B there is no deck behind the armour, and a shot striking there would have direct access to the vitals of the ship. Accordingly, the lower bulkhead plates shown are made 10 in., considerably thicker than the ordinary side armour.

"Canopus" Class (1897).-The vessels of this class are six in number (Canopus, Albion, Glory, Ocean, Goliath, Vengeance). They are 390 ft. long and 12,950 tons. The belt armour is 6 in. only, and there are two protective decks, the lower one being 2 in. and the upper one, the main deck, being 1 in. The citadel is 227 ft. long, and the forward end of the ship is protected with 2 in., worked on a double thickness of plating. The belt is closed in with armour bulkheads at each end, and the barbettes are circular, having a maximum thickness of 12 in. The lower decks, forward and aft, are 2 in. A section of the side amidships of this class is given in Fig. 131.

"Formidable" Class.-The next type of ship laid down (1898) was the Formidable class (Formidable, Implacable, Irresistible). These ships are 400 ft. long and 15,000 tons. They are protected similarly to the Majestic, with 9-in. armour, but the main deck is made 1 in., and the middle deck 2 in. on the flat and 3 in. on the slopes (see Fig. 131 for section at side). The lower decks at ends are 2 in. forward, 2 in. aft, and the side forward has 2 in., worked on a double thickness of plating. The side plating aft is increased to a total thickness of 1 in. The barbettes have a maximum thickness of 12 in.

"Bulwark.”—The five later ships of Formidable class (Bulwark, London, Venerable, Queen, Prince of Wales) (1899) are of the same dimensions and displacement as the Formidable, but the armour is arranged differently at the forward end. The forward armour bulkhead is dispensed with, and the side armour is carried forward from the 9 in. side in steps of 7 in., 5 in., and 3 in., and right forward we have 2 in. worked on a double thickness of skin plating. The main deck is 2 in. over the citadel, and is worked to the stem, where it is 1 in. thick. The middle deck in way of citadel is 1 in. on the flat, 2 in. on the slopes. The lower deck forward is 1 in., and where it slopes to meet the middle deck before the forward barbette it is 2 in. The lower deck aft is 2 in. The side plating aft is increased to a total thickness of 13 in. The whole arrangement is similar to that of the Duncan (Fig. 134).

"Duncan" Class (1899).—The six vessels of this class (Duncan, Cornwallis, Exmouth, Russell, Albemarle, Montagu) are 405 ft. long and 14,000 tons. They were specially designed for high speed, viz.—

19 knots on 8 hours' trial, 18,000 I.H.P.

In consequence of this, these ships had less displacement and a finer form than Formidable, in order to avoid excessive I.H.P., and the armament being the same as in that ship, the weight available for protection would only allow a 7-in. belt to be worked. This belt is reduced in thickness to the forward end, as shown in Fig. 134. Aft the plating is doubled, and on the flush surface thus obtained 20-lb. (1⁄2 in.) nickel steel is worked. The decks are as follows:

Main deck: 2 in. between barbettes to 1 in. right forward.
Middle deck: 1 in. uniform between barbettes.