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 | Six Yarrow watertube boilers were installed in each of four main boiler rooms on board the Queen Mary. They looked like the model (at left) but were as tall as a 4-story building!
These 24 main boilers generated steam at a working pressure of 400 lbs. per square inch at a temperature of 700 degrees fahrenheit. This steam was delivered to the four sets of quadruple-expansion turbines.
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| Each of the four quadruple expansion steam turbine sets had a 50,000 horse power capacity. With the combined 200,000 HP, the 81,000-ton vessel was propelled at 28.5 to 31 knots with a fuel consumption rate of 1,020 tons per day! The boilers in rooms 2 and 3 were designed to be slightly smaller than those in boiler rooms 4 and 5 because the ship is narrower towards the bow. You can see the arrangement of machinery spaces by clicking on the riveted "ship's plans" panel. The four main boiler rooms operated under the closed stokehold system of forced draught. Boiler rooms 2 and 4 worked in conjunction with the forward engineroom and boiler rooms 3 and 5—the after engineroom. |
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The "powertrain" and boiler installation of the vessel was arranged in 10 watertight compartments. Starting at the bow and working aft, these are: The watersoftening plant, No. 1 Boiler room, No. 2 Boiler room, Forward turbogenerator room, No. 3 Boiler room, No. 4 Boiler room, After turbogenerator room, No. 5 Boiler room, Forward engineroom and After engineroom. |
Cross Section Five drums were incorporated in each watertube boiler. These consisted of one steam drum, three water drums and one superheater drum. The furnaces were arranged for side firing. The boilers in each room were situated in three rows with two boilers in each row so that the firing or working spaces ran fore and aft. Air preheaters of the three-flow tubular type were arranged one on each side of the steam drum, close to the top of the boiler casings. Dampers were provided in the smoke passages and at the combustion air inlets whereby the degree of superheat and air supply were regulated. |  |