The boilers fitted to these ships varied considerably. The _King Edward_, _Hindustan_, and _Britannia_ were given a mixed installation of Babcocks and cylindricals; the _New Zealand_ Niclausse boilers; the other ships Babcock only. In the _Britannia_, super-heaters were also fitted to six of her boilers. The point differentiating these ships from their predecessors was the mounting of four 9.2 guns in single turrets at the angles of the superstructure. Equally novel was the placing of 6-inch guns in a battery behind the armour on the main deck.[21] Fighting tops, a feature of all previous ships, disappeared, and in place of them fire-control platforms were substituted. When produced, these ships were considered as something like the “last word”; but in service later on it was very soon found that the two calibres of big guns rendered fire-control extremely difficult, and they have been a somewhat costly lesson in that respect. They cost about £1,500,000 each, and were found to be all that could be desired tactically, their turning circles with engines being only about 340yds. at fifteen knots. All of them did not make their speeds on trials, and some have never quite come up to expectations in that respect, but they have all proved remarkably reliable steamers. Six armoured cruisers provided for in the 1901–02 Estimates were the _Devonshires_. These were originally intended to have been enlarged _Counties_, carrying a single 7.5 fore and aft, in place of the twin 6-inch turrets of the prototype ships. The design was, however, modified to the extent of substituting a single 7.5 for each of the forward pairs of 6-inch casemates. Details of these ships are:-- Displacement--10,850 tons. Length (between perpendiculars)--450ft. Beam--68½ft. Draught--(maximum) 25½ft. Armament--Four 7.5, six 6-inch, 45 cal.; two 12-pounders, twenty-two 3-pounders, two 18in. torpedo tubes submerged. Armour Belt--(length 325ft. from the bow, width 10½ft.), 6in. amidships, thinning to 2in. right forward. Barbettes 6in. Turrets 5in. Casemates 6in. Horse-power--21,000==22.5 knots. Coal--(normal) 800; (maximum) 1,800 tons. Other details are:-- ================+============+==================+============== Name. | Laid down. | Built at. | Engined by. ----------------+------------+------------------+-------------- _Devonshire_ | Mar. ’02 | Chatham | Thames I.W. _Antrim_ | Aug. ’02 | Clydebank | Clydebank _Argyll_ | Sept. ’02 | Greenock Foundry | Greenock F.C. _Carnarvon_ | Oct. ’02 | Beardmore | Beardmore _Hampshire_ | Sept. ’02 | Elswick | Elswick _Roxburgh_ | June, ’02 | L. & Glasgow | L. & Glasgow ================+============+==================+==============