The thrust shaft is complete to the after section of the crank shaft and has thirteen collars, between which are fitted cast-steel horseshoes lined with white metal, which are hollowed for circulating water. The horseshoes may be adjusted by nuts on the side rods, which are secured to cast-iron pedestals at each end. These pedestals are bolted to the sole plate, and are capable of being moved in a fore-and-aft direction by adjusting wedges. The pedestals with their ends and side walls form a trough for an oil bath which has in it a cooling coil.
The line shaft is forged on the thrust shaft and continues to the stern tube, where it couples to the stern-tube shafting. The latter is supported by two stern tube bearings, which are of brass and fitted with lignum vitae.
The inboard coupling of this shaft is made so as to permit the shaft to be drawn outboard. The outboard body of the propeller shaft is covered with a watertight composition sleeve, shrunk on and then pinned. Each propeller shaft is supported by strut and stem-bracket bearings fitted with lignum vitae bearing surfaces similar to those in the stem tube.
There are two three-bladed propellers, both outboard turning for ahead motion; the blades and hub are of manganese-bronze. The blades are a true screw at 19 feet 9 inches pitch, and the pitch is adjustable by having oval bolt holes in the flange of the blades. The hub is tapered to fit the shaft, and keyed, the nut being securely locked. All underwater fittings are covered by casings and fair-water sleeves filled with rosin and pitch to make them waterproof.
The boilers are of the Babcock & Wilcox type, with super-heaters built and installed by that firm. The battery consists of fourteen boilers in four watertight compartments, two being installed in the after compartment and four in each of the three forward compartments.
The capacity of the boilers is such that all steam machinery can be run at full power with an average air pressure in the ash pits of not more than 2 inches of water. All pressure parts are made of open-hearth steel plate and seamless-steel tubes with no screw joints exposed to the fire. The general design of boilers is the usual type built by this well-known firm and are provided with super-heaters.
Each boiler has the following fittings: One main steam stop valve closing toward the boiler and one dry pipe in the steam drum; one main-feed stop valve and check valve, with internal pipe; one auxiliary-feed stop valve and check valve, with internal pipe; one surface-blow valve, with internal pipe and scum pan, and two bottom-blow valves, with internal pipes; one main safety valve and one steam gauge; three gauge cocks to operate from the fireroom floor; two glass water gauges of the Klinger Reflex type, fitted with quick-closing devices; one salinometer pot, one drain cock and one air cock; one stop valve, three-quarters of an inch in diameter, for cleaning pipe connections; two cleaning hoes and lances; one connection for testing water; necessary pipes and fittings for attaching all the above to boilers. Zinc protectors with baskets for catching pieces of disintegrated zincs. There are air connections for blowing soot off the tubes.
The uptakes have a clear area at all points of one-seventh of the grate, and are provided with dampers and doors for examination of the interior. The space between the inside and middle sheets is open to the air space of the smoke pipe at the top, and is provided with dampers at the bottom for the free circulation of air when forced draft is not used. These two sheets are free, one from the other, to allow for expansion. The space between the middle and outer sheets is filled with magnesia to prevent conduction of heat, and this lagging extends to the protective deck.
There are two smoke pipes, each about 91.5 feet in height above the grates. The forward pipe is 12 feet 4 inches, and the after pipe 10 feet 8 inches, inside diameter. The inner and outer casings extend to the top; and between these two casings is the usual air space. The weight of the smoke pipe is taken by the protective deck. The forward smoke pipe is connected with the uptakes of the eight forward boilers and the after smoke pipe with the uptakes of the six after boilers, as shown in sketch.
There is installed in each fireroom an electrical indicator for regulating the intervals of firing the furnaces. The interval of firing the furnaces is controlled from a transmitter in the starboard engine room. A gong in each fireroom calls attention to the number displayed.
In addition to the usual coal-burning appliances, a complete oil-burning system has been installed, consisting of the necessary pumps, tanks, oil heaters and piping. Each boiler is fitted with three oil burners of the Schutte and Koerting type. The oil is stored in the double bottom of the engine room. In each engine room an oil pump takes the oil from the storage tanks and discharges into an 8,ooo-gallon settling tank, located aft and outboard of the port engine room. An electrical signaling device, operated from a float in the settling tank, is used in connection with regulating the oil pumps to keep the oil supply in the settling tank as near the normal level as possible. The signal consists of three electric lights, located near the pumps, which indicate the normal, low or high oil level. In each fireroom two small oil pumps are installed, which take the oil from an oil-suction main connecting with the bottom of the settling tank. These pumps discharge the oil through oil filters and oil heaters and then to the oil burners.
The main steam pipes are arranged symmetrically in two systems, one on each side of the ship. The valves and connections are such that the steam, after being generated in the boilers, may be sent either through the super-heater or, if desired, direct to the main steam pipe. The branches from the boilers and the super-heaters are 5 ½ inches diameter, and the main steam pipes, which are 8 inches diameter at the forward boilers, are increased from forward aft to 9 ½ inches, 10 inches, 11 inches, 12 inches and 13 ½ inches, respectively, the latter diameter continuing to the engine. Slip joints, bleeder pipes and separators are provided, as well as stop valves, which are suitably located in the lines of piping. There is provision for supplying live steam to the intermediate and the low-pressure receivers.
Forward of the connections from the forward boilers and the main steam pipe there is an auxiliary steam pipe, forming a connecting loop between the forward ends of main steam pipes.
In each engine room there is an auxiliary steam pipe connecting with the separator and passing along the outboard side of the engine rooms, and through the middle-line bulkhead, forming a connecting loop between the two sides of the ship.
The auxiliary steam pipe in the forward boiler room supplies steam to the machinery in the forward part of the vessel and the auxiliary steam pipes in the engine rooms supply steam to the machinery in the after part of the ship. In connection with the auxiliary steam line there are the following systems:
Dynamo steam and exhaust piping;
Evaporator steam and exhaust piping;
Steam heating and pantry system;
Ice-machine steam and exhaust piping;
Anchor-engine steam and exhaust piping;
Steering engine;
Galley steam;
Laundry steam.
Other systems of piping are:
Main-feed suction and discharge;
Auxiliary-feed suction and discharge;
Bilge suction and discharge;
Reserve-feed tank connection;
Distiller and evaporator piping;
Fresh-water piping;
Discharge from pump to fire mains;
Sanitary system;
Water service to main engines;
Drains;
Steam piping to sea valves;
Refrigerator piping;
Ice-machine water piping;
Vapor piping;
Safety-valve escape pipes;
Indicator piping;
Forced-lubrication piping;
Fuel-oil piping.