THE QUEEN MARY

Evening Post, Volume CXXIII, Issue 55, 6 March 1937, Page 24

THE QUEEN MARY

GREAT STEAMING POWER

Additional facts about the steaming power of the Cunard-White Star liner Queen Mary have now been disclosed. Among them is the power which her turbines, fed by 24 great Yarrow boilers, were built to develop.

The nominal designed output is 158,000 h.p., transmitted through the four shafts. With this power the ship maintains a speed of 28^ knots.

But the Queen Mary's full engine power is much greater than these official figures indicate. Her designers built her to run 145,000 nautical-miles a year, at a steaming time of 112 hours, from Cherbourg to New York and vice versa. To maintain this schedule it was necessary to install not only machinery of the strongest and most reliable type, but boilers which would remain in efficient operation throughout the full travel season without cleaning.

Further, a large margin of power had to be provided to permit of driving the ship at speeds in excess of the normal 28£ knots, to make up time which might be lost through fog or bad weather. '

To meet these requirements extra boilers were installed. As a result, it would be possible, if the necessity arose, to shut down a number of boilers and clean them at sea, without any reduction in the designed output of 158,000 h.p., says a London writer.

While the exact ' figure of horsepower generated when all boilers are in use and working at full pressure is still a secret, it cannot be less than 190,000 and is probably over 200,000. On her record-breaking sixth round voyage the ship averaged 30.01 knots on the the outward and 30.57 knots on the homeward run. At times she was moving at more than 32 knots, a speed' which could hardly be attained with less than 200,000 h.p.

Before being withdrawn recently for overhaul, the ship had completed 14 round voyages, equivalent to about 94,000 nautical miles. Much of this distance was covered in exceptionally bad weather.

Experience gained with the Queen Mary has been embodied in the design of her sister ship, No. 552. As the gross tonnage of this vessel will exceed that of her consort, and a slight increase in speed is understood to be aimed at, the nominal horse-power is likely to be about 170,000, and the maximum output well over 200,000.

The French liner, Normandie, has a designed horse-power of 160,000.

The highest power, ever developed at sea, according to official records, was that of the United States aircraft carrier Lexington. This ship, of 39,000 tons displacement, is nominally of 180,000 h.p., with a speed of 33J knots. On a run from San Francisco to Honolulu she developed for one hour 210,000 h.p., attaining a speed of 34J knots.