The principal item of the Estimates of 1910–11 was five armoured ships. Of these, four, the _King George V_ class, are slightly improved replicas of the _Orion_, while the remaining vessel, the _Queen Mary_, is a battle-cruiser of the _Lion_ type. Ships of the _George V_ class are as follows:-- ================+===============+============== Name. | Built at. | Machinery by. ----------------+---------------+-------------- _King George V_ | Portsmouth Y. | Hawthorn _Centurion_ | Devonport Y. | Hawthorn _Ajax Scotts_ | Scotts | Scotts _Audacious_ | Cammell-Laird | Cammell-Laird ================+===============+============== The over-all length is increased to 596ft., and the horse-power to 31,000. All were laid down during 1911, with a view to launching during 1912 and completion in 1913. The displacement of these ships is 23,000 tons odd. The _Queen Mary_, laid down at Palmers’ early in 1911, and engined by Clydebank, is virtually a sister to the _Lion_, differing from her merely in a slight variation of the lines, and some increase in length. Save for these items, and a small difference in the arrangement of the anti-torpedo armament, the ship belongs to the same class and type. The 1911–12 Estimates provided for five further large armoured ships, which represent an increase in dimensions over their predecessors. Of these the first four are battleships varying from their predecessors in the inevitable increase in size to allow of somewhat superior protection and an improved secondary battery--twelve 6-inch being substituted for the sixteen 4-inch of the _King George_ class. The selection of the 6-inch gun as the anti-torpedo craft weapon was due partly to the way in which Germany had persisted in her rigid adherence to that calibre for her minor armament, and partly to the rapidly increasing size of destroyers. It was held as questionable, even by the most ardent believers in the ability of the big ship to defend herself against destroyer attack, whether the 4-inch was sufficient to disable large destroyers. Hence the adoption of the 6-inch--the largest gun that can be man-handled. The nominal displacement of these battleships, the _Iron Duke_ class, rises to 25,000 tons as against 23,000 of the previous class. The length is increased to 620ft. and the beam to 89½ (instead of 89ft.). Owing to improved lines, the horse-power is reduced to 30,000 without any very material loss of speed. In all these super-Dreadnoughts, as in the Dreadnoughts themselves, 21 knots has always been the selected speed, though in units there have been slight variations. Ships of the _Iron Duke_ class are as follows:--