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enable a coal-bucket to be run along to bring the coal from any upper bunker to any desired lower bunker. The coal-bucket is shown in Fig. 120, and has one side hinged and a sloping bottom. The bucket would be brought up to the trunk and the catch released, and the contents dropped into the lower bunkers. The rail has to be made portable in way of the watertight bulkheads to allow the door to close. Most of these are horizontal sliding doors worked from the main deck, but in the after bunkers they are ordinary hinged doors.

In recent cruisers the wing bulkhead and the divisional bulkhead in the upper bunkers has been dispensed with (see Fig. 23). This considerably increases the coal capacity, and makes the operations of coaling very much simpler.

Care is taken in all coal-bunkers to screen the watertight doors from the pressure of the coal, so that the doors may close and open even if the bunker is full of coal. A specimen screen is shown in Fig. 120. Two side plates support a sloping top plate, and these keep the coal from the door. When the door is free from coal the side plates can be hinged back, and the top plate hinged up out of the way. Screens are also provided, as shown, to the doors in the upper bunkers.

We have seen in Chapter X. the necessity for the efficient ventilation of coal-bunkers and the provision made for the same. It is also necessary to provide means for ascertaining what the temperature is in the body of the coal. For this purpose temperature tubes are placed as shown. For the lower bunkers the temperature tubes are approached from the ammunition passage, for the upper bunkers from deck plates on the main deck. The temperature has to be noted at frequent intervals.

CHAPTER XIII. .

ARMOUR AND DECK PROTECTION.

THE three methods of attack which a war-ship may have to withstand are ramming, torpedo- or mine-attack, and gun-fire. The two former would cause damage principally at and below the waterline, and the only protection that can be afforded is the extensive watertight subdivision. For protection against gun-fire, armour plates are provided over as large a portion of the ship as possible. These armour plates are, in most cases, backed up by coal and thick decks. The parts not protected by armour are minutely subdivided in the neighbourhood of the waterline in order to localize damage as far as possible. Thick decks, both above and below water, are also largely employed for purposes of protection.

A large proportion of the weight set aside for protection in modern ships is necessary for the protection of the armament. Thus in a recent battle-ship the total weight provided for protection was 4335 tons, and this is divided as follows:

:

Armour and deck protection to hull for the preservation of buoyancy and stability, 2875 tons.

Protection to armament, as barbettes and casemates (not including gun shields), 1460 tons.

This shows that, in this case, about one-third the available weight was devoted to the protection of the armament and twothirds to the ship.

It is proposed to trace briefly the history of the subject from the Warrior until the present time, taking typical ships. The dates given refer to the year in which the ships were laid down.

"Warrior.”—The first large vessel provided with armour protection in this country was the Warrior (1859). This ship was built of iron, and was 380 ft. long, and 9200 tons displacement. The armour was 4 in. thick, and extended, as shown in Fig 121, for a length of 218 ft. and a depth of 22 ft. This 4-in.

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armour was the thickest that could then be produced, and experiments carried out at the time showed that it was sufficient to withstand the guns then in use. The armour was of wrought iron, and this material was used for protection right up to the Inflexible (1874). Owing, however, to the continuous development of gun power the thickness and disposition of the armour in subsequent ships underwent considerable modifications. One serious disadvantage in the Warrior was the unprotected state of the ends and the rudderhead. This was remedied in subsequent ships.

"Minotaur."-This ship (1861) was larger than the Warrior, being 400 ft. long and 10,690 tons, the extra size being necessitated by the increase of the thickness of armour to 5 in. amidships (Fig. 122); and the provision of 3-in. armour at the ends.

Bellerophon" (1864).-The next step was the production of a shorter and handier ship, the Bellerophon, which was 300 ft. long and 7550 tons. There was a complete belt at the waterline (Fig. 123), 6 in. thick amidships, tapering at the ends as shown. Above the belt for a length of 94 ft. amidships there was an armoured battery of 6-in. armour.

"Temeraire."-The above type of ship with a complete belt and a battery amidships continued until the Temeraire (1873), in which ship the belt was 11 in. maximum thickness, with a battery 8 in. thick (Fig. 124). In this ship we also find 8-in. and 10-in. redoubts towards the ends for mounting the heavy guns. The Temeraire was 285 ft. long and 8540 tons.

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"Devastation "

(1869).-This was a

FIG. 125.-H.M.S. Devastation.

special type of ship in which sails were abandoned and twin screws adopted. She had low freeboard (Figs. 125 and 125A), and was 285 ft. long and 9320 tons. The belt, 12 in. thick amidships, was continued to the ends 8 in. thick. Above this belt there was a central breastwork 153 ft. long, 10 in. thick along the sides, and

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