Page:The Development of Navies During the Last Half-Century.djvu/286

, and so the account, taken from The Times, of the 'Blake's' machinery may answer for both vessels, which are, from many points of view, the most important that have been ordered for the Admiralty for many years. The 'Blake' "will be propelled by twin screws, driven by four sets of triple-expansion engines of the inverted vertical cylinder type. Messrs Maudslay, Sons & Field are the makers of these engines and boilers. The collective power they guarantee is 13,000 horse power for twelve hours' steaming at natural draught, and 20,000 horse power for four hours with forced draught; the corresponding maximum speeds are estimated at 20 knots for natural draught and 22 knots for forced draught, when the vessel is run in smooth water with everything at its best. On actual service, judging from past experience, with ordinary conditions of coal and stoking, the engines may be expected to develop about 9000 to 10,000 horse power for long periods of continuous steaming, which would probably give the vessel a continuous speed of 18 to 18½ knots in smooth water Everyone knows, what recent manœuvres have illustrated afresh, that in cruisers of moderate dimensions, capable of attaining high speed in smooth-water trials, the working speeds at sea are limited by other considerations than the power available for propulsion Sailors generally will be sure to welcome the greater length and size of the 'Blake' and 'Blenheim,' because of their capability of maintaining speed in rough water; and their enormous engine power and very high trial speeds give