The other two types of the 1909–10 Estimates are the ships generally known as “super-Dreadnoughts.” _SUPER-DREADNOUGHTS._ The most obvious feature of the so-called “super-Dreadnoughts” is the introduction of the 13.5-inch gun, particulars of which will be found at the end of this chapter. This gun was experimented with with a certain amount of secrecy, and was for a long time officially designated as the 12-inch “A,” although practically everybody knew that it was really a 13.5. It was only rendered possible by recent improvements in gun-mountings and gun-construction. It is not very appreciably heavier than the latest type of 12-inch, as mounted in the _Colossus_, and its adoption was not so much a matter of obtaining an increased range and penetration, as of securing the tremendously increased smashing power of the heavier projectile. Somewhat less obvious to the general public, but really of a great deal more far-reaching importance, is the “Americanising” of British naval design exhibited in all the “super-Dreadnoughts.” Though differing in detail, the arrangement of the armament in all the “super-Dreadnoughts” followed the American centre-line system, an interesting indication of the progress of the United States Navy from the days, not so very long ago, when American warship design was more or less a _pour faire rire_! It is none the less interesting from the fact that in the earliest designs, in all ships carrying more than two turrets, the centre line was the only arrangement ever built or even considered. Yet when an increased number of turrets came into being, the American Navy was the only one which followed the original practice. In all other Navies ideas of the period 1870–1880, when strong end-on fire was considered an all-important essential, influenced design. America alone appreciated the prophecy long ago made by Admiral Colomb to the effect that whatever else might temporarily obtain, broadside to broadside would always be reverted to for battle, on the grounds that thus, and thus only, could the maximum number of guns be utilised. It is proper here to remark that though the Americans adopted the centre line from the outset for practical reasons, this disposition became more or less a necessity when 13.5’s came in, owing to the infinitely greater strain on the structure. This has been occasionally used as an argument against American influence having made itself felt, but the balance of evidence shows that even had the 13.5-inch not appeared, the centre line system would have figured in the Navy. The original centre-line idea disappeared because the échelon system looked so superior. The échelon system of the 1875–85 era, however, died out in its turn on account of certain practical disadvantages. It was resurrected when these had been forgotten in the lapse of years; but the disadvantages entailed in firing across a deck soon made themselves felt again once the system was reverted to. [Illustration: