CHAPTER 9 



MACHINERY ARRANGEMENT AND PLANT LAYOUT 



To understand a shipboard propulsion plant, 

 it is necessary to visualize the general con- 

 figuration of the plant as a whole and to 

 understand the physical relationships among the 

 various units. This chapter provides general 

 information on the distribution and arrangement 

 of propulsion machinery in conventional steam 

 turbine propulsion plants and on the arrange- 

 ment of the major engineering piping systems 

 that connect and serve the various units of 

 machinery. 



It is important to note that the information 

 given in this chapter is general rather than 

 specific. No two ships— not even sister ships- 

 are exactly alike in their arrangement of ma- 

 chinery and piping. The examples given in this 

 chapter are based on the arrangements used 

 in various kinds of ships, large and small, old 

 and new. The examples give some idea of the 

 variety of arrangements that may be found on 

 steam-driven surface ships, and they indicate 

 the basic functions of the machinery and piping; 

 but the examples cannot provide an exact 

 picture of the machinery and piping on any one 

 ship. For detailed information concerning the 

 arrangements on any particular ship, it is 

 necessary to consult the ship's blueprints, 

 various ship's manuals, and the manufacturers' 

 technical manuals that cover the engineering 

 equipment and piping systems installed in the 

 ship. 



ARRANGEMENT OF PROPULSION 

 MACHINERY 



The propulsion machinery on conventional 

 steam-driven surface ships includes (1) the 

 propulsion boilers, (2) the propulsion turbines, 

 (3) the condensers, (4) the reduction gears, and 

 (5) the pumps, forced draft blowers, deaerating 

 feed tanks, and other auxiliary machinery units 

 which directly serve the major propulsion units. 



On most steam-driven surface ships other 

 than oilers, tankers, and certain auxiliaries, 

 the propulsion machinery is located amidships. 

 Turbogenerators and their auxiliary condensers 

 are usually located in the propulsion machinery 

 spaces; other engineering equipment that is not 

 directly associated with the operation of the 

 major propulsion units may be located in or 

 near the propulsion machinery spaces or in 

 other parts of the ship, as space permits. 



A word about terminology may be helpful 

 at this point. The boilers in a propulsion plant 

 may be identified as propulsion boilers (or 

 occasionally as main boilers) when it is neces- 

 sary to distinguish between propulsion boilers 

 and the auxiliary boilers that are installed on 

 some ships. The turbines are identified as 

 propulsion turbines when it is necessary to 

 distinguish between them and the many auxiliary 

 turbines that are used on all steam-driven ships 

 to drive pumps, forced draft blowers, and other 

 auxiliary units. The propulsion turbines are 

 also sometimes referred to as the main engines, 

 although this usage is not considered parti- 

 cularly desirable. The term propulsion unit 

 is correctly used to identify the combination 

 of propulsion turbines, main reduction gears, 

 and main condenser in any one propulsion plant; 

 however, the term propulsion unit may also 

 be used in a more general sense to indicate 

 any major unit in the propulsion plant. 



Each propulsion shaft has an identifying 

 number which is based on the location of the 

 shaft, working from starboard to port. The 

 shaft nearest the starboard side is the No. 1 

 shaft, the one next inboard is the No. 2 shaft, 

 and so forth. On recent ships, the propulsion 

 machinery that serves each shaft is given the 

 same number as that shaft. For example, the 

 No. 2 shaft is served by the No. 2 propulsion 

 unit and the No. 2 boiler. Where two similar 

 units serve one shaft, the identifying number 



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