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CC-1 Lexington Class Design

It will be agreed that, without exaggeration, these stupendous warships, in their combination of size, speed, and power must be considered to be the most novel and sensational ships designed for any Navy since the day of the British Dreadnought. They had the length of the largest transatlantic liners, the speed of the fastest destroyers, and the gun power of a modern battleship. Intended as fast combat scouts for the battle fleet, these large ships had a prolonged development history. Their original 1916 design was to displace 34,300 tons with a main battery of ten 14-inch guns, rather light armor, seven smokestacks with many of the boilers above the armored deck, and a speed of 35 knots. By 1919, the plans had been recast on the basis of World War I experience to produce larger ships armed with 16-inch guns, much better protection, two smokestacks with all boilers below the armored deck, and a somewhat lower speed.

The new battle-cruisers were to be 850 feet between perpendiculars and 874 feet over all; their beam was 91 feet [the definitive design increased this to 105'5"], and their draft was over thirty feet. Now 850 feet between perpendiculars is just 100 feet greater than the length between perpendiculars of the famous Lusitania, and it is exactly equal to the length between perpendiculars of the Hamburg-American liner Imperator.

In view of these figures it was surprising and very significant to learn that the displacement of the battle-cruisers will be only 34,800 tons [later increased to 43,500 tons]. This is several thousand tons less than the full-load displacement of the Lusitania and about 20,000 tons less than the full-load displacement of the Imperator. The apparent discrepancy is explained by the relatively modern beam, 91 feet, of the battle-cruisers, and the remarkable fineness of their model. The Imperator had 7 feet more beam and she carried this throughout several hundred feet of her mid-length. The battle-cruisers, on the other hand, fine away rapidly towards bow and stern, the entrance and the run of the vessels being as fine, if not finer, than that of a destroyer. Moreover, the midship section shows a decided dead rise and the round of the bilge is turned in with a large radius, differing in this respect greatly from the cross-section of the typical warship of big, displacement.

The design featured a boiler-and-engine plant of 180,000 horse-power. This was two-and-a-half times larger than the motive power of the Lusitania, which made 25 knots with 70,000 horse-power, and it was over twice the horse-power of the Imperator, which made 23 knots with 80,000 horse-power. The engines and boilers of the Lusitania, for instance, took up approximately three-quarters of her floor space, extending from the stern to the bridge. The solution of the problem is a demonstration of the remarkable advance which had taken place in marine engineering during the past decade. The Lusitania used the bulky Scotch boiler. She demanded a width of 18 feet on each side of the ship for her huge coal bunkers, of 7,000 tons capacity, and her relatively slow-speed compound turbines demanded a large share of the tank top area for their installation. The battle-cruisers substitute the compact watertube boiler for the Scotch boiler; oil fuel, stored in the double bottom, takes the place of coal and the coal bunkers, thus permitting the whole width of the ship to be given up to the boiler plant; high-speed turbines direct-connected to generators will furnish current for driving motors placed directly upon the four propeller shafts, and, lastly, these ships featured the novelty of the boiler-and-engine plant being located upon two decks.

If it were not for the use of oil fuel, watertube boilers, and the turbo-electric drive, it is certain that these wonderful ships could never have been designed, much less, built. The electric drive solved the problem of reconciling the demand for high speed of rotation in the steam turbine with the demand for relatively low speed of rotation of the propellers. To get the full efficiency of the turbine it was necessary that the speed of the blades in the turbine be high, but in large ships such as this, to obtain the best efficiency with the propellers, it was necessary to keep their speed of rotation down within certain limits. In the earlier turbine ships, when turbine and propeller were on the same shaft, the matter was compromised by running the turbine below its best economical speed and the propeller above its best economical speed. The problem had been solved of late years by the introduction of reduction gearing. Westinghouse of this country and Parsons abroad have secured good results with mechanical gearing, and the General Electric Company obtained excellent results with their turbo-electric drive, as installed on the U.S. Collier Jupiter. It is their system which will be used on the new battle-cruisers.

The question of the type of gun (14-inch or 16-inch) to be mounted in the main battery of the new battle-cruisers was initially decided in favor of the new 14-inch, 50-caliber gun, and ten of these were to be mounted in four turrets, two of them carrying three guns and two of them two guns each, the number of guns and their method of emplacement being similar to that of the battleships Nevada and Oklahoma. The total energy, however, was considerably greater, the 50-caliber gun of the battle-cruisers developing 70,000 foot-tons of muzzle energy as against 65,000 foot-tons for the 45-caliber gun as mounted on the Nevada. This meant that a broadside salvo from the battle-cruisers will have a total muzzle energy of 700,000 foot-tons, or sufficient to lift 1000 tons 700 feet into the air.

Defense against torpedoes was to be entrusted to a battery of twenty, 50-caliber, 5-inch guns, sixteen of which were to be mounted amidships on the upper and superstructure decks. In the final design, the secondary battery was altered to sixteen 6"/53 guns in single mountings (eight guns on each side of the ship). No less than eight torpedo tubes for firing the new 21-inch torpedo with a range of 10,000 yards will be emplaced, four of these being above water and four below.

The new ships, because of their great size, would naturally carry a large complement, greater indeed, than that of any ship afloat. The total number, including officers and men, was to be 1274.

So far as appearances go, it must be admitted that these stupendous ships would have been exceedingly handsome in appearance. Although their freeboard was ample for all conditions, except perhaps that of chasing the enemy at full speed in a head sea; they did not tower above the water to anything like the height of transatlantic liners like the Aquitania and Imperator, and hence they look even longer than their great length. Their appearance would seem to justify the enormous speed, for ships of this size, of 35 knots [later only 33.25 knots]. Thirty-five knots is over 40 land miles per hour, and, in view of their great length, fineness of model, and large horse-power, there was every prospect of their making this speed when the Government trials take place.

It will be noted that the upper, or spar deck, extends for fully three-quarters of the length of the ship, its after-end projecting beyond the muzzles of the aftermost 14-inch guns. An excellent improvement is the placing of the forward mast immediately upon the conning tower, thus preventing the possibility of its being brought down by a shell bursting between decks below it - a liability to which the mainmast would seem to be exposed. Another novelty is the provision of a lower, or secondary control station for both fire and ship control, below the fighting top on each mast.

The possession of a division of six of these ships, assisted by the two divisions of 7000 tons 35-knot scouts which are to be built, would render the US fleet supreme in the field of scouting, or information. They would be able to drive in or break through any enemy screen, and because of their great speed they can accept or refuse battle as the conditions demand. The combination of great speed and heavy batteries would make them the terror of destroyer flotillas, and their speed and quick maneuvering power was hoped to render them practically safe against the torpedo.

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Page last modified: 22-07-2011 17:36:40 ZULU