Two Centuries of Shipbuilding by the Scotts at Greenock

Table V

Size and Fighting Qualities of British Battleships of Different Periods

Name.	Date of Completion.	Displacement.	Side Armour.	Speed.	Total Weight of Shot in One Round.	Collective Energy at Muzzle of One Round.
		tons	in.	knots	lb.	foot-tons
Warrior	1861	9,210	4-1/2-in. wrought iron	14-1/2	3800	61,476
Hercules	1868	8,680	9-in. to 6-in. wrought iron	14	5400	70,200
Alexandra	1877	9,490	12-in. to 6-in. wrought iron	15	5426	71,400
Inflexible	1881	11,880	24-in. to 16-in. wrought iron	13	6936	123,120
Benbow	1888	10,600	18-in. compound	16.75	4600	135,560
Royal Sovereign	1892	14,150	18-in. and 5-in. compound	17.5	5800	159,610
Barfleur	1894	10,500	12-in. compound	18.5	2450	67,670
Canopus	1900	12,950	6-in. hardened steel	18.25	4600	178,720
Prince of Wales	1902	15,000	9-in. super-hardened steel	18.25	4600	194,400
King Edward VII.	1904	16,350	9-in. super-hardened steel	18.50	5920	270,040
Lord Nelson	1905	16,500	10-in. super-hardened steel	18.50	7960	413,900

As to the machinery made by the Scotts for these battleships, the Barfleur had three-cylinder, triple-expansion twin-screw engines, to run at 108 revolutions, and to develop 13,000 indicated horse-power. On her trials the power was 13,163 indicated horse-power. There are eight single-ended, return-tube, cylindrical boilers, working at 155 lb. pressure. Other details are given in the Table on page 53.

The engines of the Canopus are illustrated on page 49 by a drawing taken from a Paper read at the Institution of Civil Engineers, by Sir John Durston and Admiral H. J. Oram.64 This was the first type of British battleship fitted with water-tube boilers. She was followed soon after by the Prince of Wales.65

The Argyll, which was built and engined by the Scotts, and the Defence, which is being built in one of the Royal Dockyards, and is having its machinery constructed by the Scotts, signalise progress in cruiser design. The hardening of armour, increasing its resistance, permits of a reduction in weight for a given measure of protection, so that it has been possible to effectively defend the modern cruiser, while at the same time giving an enormously increased gun-power and a speed far in excess of that possible ten years ago. The Argyll is a vessel of 10,850 tons displacement, being 450 ft. long, 68 ft. 6 in. beam, and having a draught of 25 ft.; while the Defence is a vessel of 14,600 tons displacement, having a length of 490 ft., a beam of 74 ft. 6 in., and a draught of 26 ft. In both ships the greater part of the broadside, from 5 ft. below the water-line to the upper deck, is armoured, and a very large proportion of the area thus clad has 6-in. hardened plates.

In the late ‘nineties it was assumed that quick-firing artillery was best suited to the work of a cruiser, and thus the 6-in. gun was exclusively adopted. But since then Naval strategists have developed their ideas as to the function of armoured cruisers, and now anticipate their use in the line of battle; so that not only has the defensive quality been improved, but the offensive power has been materially increased. In the Defence, and the other ships of the class, the 6-in. gun has been entirely discarded in favour of an installation of 9.2-in. and 7.5-in. weapons. Owing to the perfection of the hydraulic and electric mountings, little has been forfeited in respect of rapidity of fire, while much has been gained in the striking energy at a given range of each projectile. Thus, while the 6-in. gun five years ago had an energy equal to penetrating 6 in. of wrought iron at 3000 yards’ range, the 7.5-in. weapon now may perforate 6-3/4 in., and the 9.2-in. gun 9 in. of the hardest armour at corresponding range. The total weight of projectiles fired from the present-day cruiser in a minute is double, and the muzzle energy quadruple, the results attained by the cruisers designed at the close of the nineteenth century.66

The modern cruisers steam at 23 knots, the power of the machinery in the Argyll being 21,000 indicated horse-power, and in the Defence 27,000 indicated horse-power. The machinery of the Argyll, which is typical, consists of four sets of triple-expansion engines, arranged in separate watertight compartments. The diameters of the cylinders are: high-pressure, 41-1/2 in.; intermediate-pressure, 65-1/2 in.; and the two low-pressure, each 73-1/2 in., all having a stroke of 42 in. At full power, developed with 138 revolutions, the piston speed is 966 ft. per minute. The cylinders are fitted with liners, and are steam-jacketed; forged steel is used for the liners of the high- and intermediate-pressure cylinders, and cast-iron for those of the low-pressure cylinders. The cylinder covers and pistons are of cast steel, the latter being of conical form. The high- and intermediate-pressure cylinders have piston valves, and the low-pressure cylinders flat valves. The cylinders are supported at the front by eight forged-steel columns, and at the rear by four cast-iron columns formed with guide-faces, and one forged steel column. The crankshaft is in four pieces, the high- and intermediate-pressure parts being interchangeable with each other, and the two low-pressure parts with one another. The shafts are hollow, and three-bladed propellers of manganese bronze are fitted to each. The condensers are entirely separate, and independent air pumps are fitted.

The Argyll had a combination of six cylindrical and sixteen water-tube boilers, but in the later ships, including the Defence, the boilers are entirely of the water-tube type. The working pressure of the boiler is 275 lb., reduced at the engines to 250 lb. The trials of the Argyll were carried through most satisfactorily,67 and the vessel, under the new Admiralty conditions, was completed for commission by the builders. The fact that this armoured cruiser was so completed at the builder’s yard is of itself evidence of the capacity and efficiency of the plant.