The following were also connected to the emergency circuit by means of change-over switches: Five arc lamps, seven cargo and gangway lanterns, Marconi apparatus, mast, side, and stern lights, and all lights on bridge, including those for captain's, navigating, and chart rooms, wheelhouse, telegraphs and Morse signaling lanterns, and four electrically-driven boat winches. These latter, situated on the boat deck, were each capable of lifting a load of 15 hundredweight at a speed of 100 feet per minute.
Ventilating.—There were 12 electrically-driven fans for supplying air to the stokeholds, 6 electrically-driven fans for engine and turbine room ventilation. There were fans for engine and boiler rooms.
MACHINERY.
Description.—The propelling machinery was of the combination type, having two sets of reciprocating engines driving the wing propellers and a low-pressure turbine working the center propeller. Steam was supplied by 24 double-ended boilers and 5 single-ended boilers, arranged for a working pressure of 215 pounds per square inch. The turbine was placed in a separate compartment aft of the reciprocating-engine room and divided from it by a water-tight bulkhead. The main condensers, with their circulating pumps and air pumps, were placed in the turbine room. The boilers were arranged in six water-tight compartments, the single-ended boilers being placed in the one nearest the main engines, the whole being built under board of trade survey for passenger certificate.
Reciprocating engines.—The reciprocating engines were of the four-crank triple-expansion type. Each set had four inverted, direct-acting cylinders, the high-pressure having a diameter of 54 inches, the intermediate pressure of 84 inches, and each of the two low-pressure cylinders of 97 inches, all with a stroke of 6 feet 3 inches. The valves of the high-pressure and intermediate cylinders were of the piston type, and the low-pressure cylinder had double-ported slide valves, fitted with Stephenson link motion. Each engine was reversed by a Brown type of direct-acting steam and hydraulic engine. There was also a separate steam-driven high-pressure pump fitted for operating either or both of the reversing engines. This alternative arrangement was a stand-by in case of breakdown of the steam pipes to these engines.
Turbine.—The low-pressure turbine was of the Parsons reaction type, direct coupled to the center line of shafting and arranged for driving in the ahead direction only. It exhausted to the two condensers, placed one on each side of it. A shut-off valve was fitted in each of the eduction pipes leading to the condensers. An emergency governor was fitted and arranged to shut off steam to the turbine and simultaneously change over the exhaust from the reciprocating engines to the condensers, should the speed of the turbine become excessive through the breaking of a shaft or other accident.
Boilers.—All the boilers were 15 feet 9 inches in diameter, the 24 double-ended boilers being 20 feet long, and the single-ended 11 feet 9 inches long. Each double-ended boiler had six and each single-ended boiler three furnaces, with a total heating surface of 144,142 square feet and a grate surface of 3,466 square feet. The boilers were constructed in accordance with the rules of the board of trade for a working pressure of 215 pounds per square inch. They were arranged for working under natural draft, assisted by fans, which blew air into the open stokehold.
Auxiliary steam pipes.—The five single-ended boilers and those in boiler rooms Nos. 2 and 4 had separate steam connections to the pipe supplying steam for working the auxiliary machinery, and the five single-ended boilers and the two port boilers in boiler room No. 2 had separate steam connections to the pipe supplying steam for working the electric-light engines. A cross connection was also made between the main and auxiliary pipes in the reciprocating-engine room, so that the auxiliaries could be worked from any boiler in the ship. Steam pipes also were led separately from three of the boiler rooms (Nos. 2, 3, 5) above the water-tight bulkheads and along the working passage to the emergency electric-light engines placed above the load line in the turbine room. Pipes were also led from this steam supply to the pumps in the engine room, which were connected to the bilges throughout the ship.
Main steam pipes.—There were two main lines of steam pipes led to the engine room, with shut-off valves at three of the bulkheads. Besides the shut-off valves at the engine-room bulkhead, a quick-acting emergency valve was fitted on each main steam pipe, so that the steam could at once be shut off in case of rupture of the main pipe.
Condensing plant and pumps.—There were two main condensers, having a combined cooling surface of 50,550 square feet, designed to work under a vacuum of 28 inches with cooling water at 60° F. The condensers were pear shaped in section, and built of mild steel plates.