THE PROPELLING MACHINERY OF THE U. S. S. LEVIATHAN. 217 



slialts, each unit of which drives a separate shaft. In other words, each shaft with 

 its propeller wheel is driven, respectively, by one go-ahead turbine and one go-astern 

 turbine. 



The machinery installation contains many clever features, the chief being that 

 under any extraordinary conditions which may arise at sea it is possible to operate 

 the two turbines of any one shaft entirely independent of the other units. This 

 means that it is hardly possible for any contingency to arise whereby the turbine 

 installation can be entirely disabled. 



Further, all the interconnecting valves and pipes between the turbines are lo- 

 cated on the lower half of the casings. The design of these valves, together with 

 the hydraulic operation of the valve pistons, is such that any change can be carried 

 out at sea without having to shut down or stop the vessel for any appreciable length 

 of time. 



The turbines are arranged in three separate engine-room compartments, as 

 shovi^n on Fig. 2, Plate 96. On referring to this diagram, it will be seen that the 

 four units of the two inboard shafts are in the main or forward engine-room, whilst 

 the two turbines of each outboard shaft are in the two aft engine-rooms, these com- 

 partments being separated by the fore-and-aft bulkhead down the center line of the 

 vessel. 



The high-pressure ahead turbine drives the port inboard shaft, and coupled 

 directly to the aft end of this is a high-pressure astern turbine. 



The mid-pressure ahead turbine drives the starboard inboard shaft, and coupled 

 directly to the forward end of this unit is the other high-pressure astern turbine. 



The two low-pressure ahead and two low-pressure astern turbines drive the 

 outboard shafts, each pair being arranged in one of the separate aft engine-rooms. 



The forward or main engine-room is about 66 feet long by about 60 feet wide. 



The turbine compartment, however, is only 42 feet wide, whilst the feed pumps, 

 feed heaters and other auxiliary machinery are arranged in two side compartments 

 adjoining the turbines, each about 9 feet in width. 



The maneuvering valves and gauge board are located at the forward end of this 

 engine-room, the working platform and main floor is directly over the turbines, and 

 nothing is visible of the turbines from this working platform. 



The floor does not extend over the two side compartments, and this auxiliary 

 machinery is exposed and can be seen always by the engineers in charge. On this 

 platform or floor, and extending down the center line of the vessel, are located the 

 forced lubrication pumps, oil coolers and oil strainers. 



The turbine steam to gland connections, oil supply pipes and valves to the tur- 

 bine bearings, and turbine drain valves are all operated from manifolds arranged 

 on this platform, and at the aft end the engine-room elevator also opens on to this 

 floor. Directly under this platform gratings are arranged so that access to the 

 rotor bearings and thrusts, and dummy micrometer of high-pressure ahead tur- 

 bine can be reached quickly. 



Floor plates are also provided above the double bottom, over the engine-room 



