Chapter 9-MACHINERY ARRANGEMENT AND PLANT LAYOUT 



condensate system just ahead of the deaerating 

 feed tank. 



A contaminated drainage system is installed 

 in each main and auxiliary machinery space 

 where dry bilges must be maintained. The con- 

 taminated drainage system collects oil and water 

 from machinery and piping which normally has 

 some leakage, and also collects drainage from 

 any other services which may at times be con- 

 taminated. The contaminated drains are collec- 

 ted in a bilge sump tank located in the machinery 

 space from which the drains are being collected. 

 The contents of the bilge sump tank are removed 

 by the bilge drainage system; they do not go to 

 the feed system. 



FUEL OIL SYSTEMS 



Boiler fuel oil systems aboard ship include 

 fuel oil tanks, fuel oil piping, fuel oil pumps, and 

 the equipment used for heating, straining, meas- 

 uring, and burning fuel oil. 



Three main kinds of tanks are used for hold- 

 ing boiler fuel oil: (1) storage tanks, (2) service 

 tanks, and (3) contaminated oil settling tanks. 



The main fuel oil storage tanks are an inte- 

 gral part of the ship's structure. They may be 

 located forward and aft ofthe machinery spaces, 

 abreast of these spaces, and in double-bottom 

 compartments. However, fuel oil storage tanks 

 are never located in double-bottom compart- 

 ments directly under boilers. Some fuel oil stor- 

 age tanks, called fuel oil storage or ballast tanks, 

 have connections that allow them to be filled ei- 

 ther with fuel oil or with sea water from the bal- 

 lasting system. Other fuel oil storage tanks are 

 designated as fuel oil overflow tanks; these tanks 

 receive the overflow from fuel oil storage tanks 

 which are not fitted with independent overboard 

 overflows. Overflow tanks which can also be 

 filled with sea water from the ballasting system 

 are called fuel oil overflow or ballast tanks. 



Fuel oil is taken aboard by means of fueling 

 trunks or special connections and is piped into 

 the storage tanks. From the storage tanks, oil is 

 pumped to the f uel oil service tanks. All fuel oil 

 for immediate use is then drawn from the service 

 tanks. The fuel oil service tanks are considered 

 part of the fuel oil service system. 



Contaminated oil settling tanks are used to 

 hold oil which is contaminatedwithwater or oth- 

 er impurities. After the oil has settled, the un- 

 burnable material such as water and sludge is 

 pumped out through low suction connections. The 



burnable oil remaining in the tanks is then trans- 

 ferred to a storage tank or a service tank. 



The contaminated oil settling tanks also 

 serve to receive and store oil or oily water un- 

 til it can be discharged overboard without viola- 

 tion of the Oil Pollution Acts. 8 These Acts pro- 

 hibit the overboard discharge of oil and of 

 water containing oil in port and in prohibited 

 zones in oceans and seas throughout the world. 

 It is standard practice, therefore, to empty the 

 contaminated oil settling tanks before coming in- 

 to port or into a prohibited zone so that the 

 tanks will be available for storing oil and oily 

 water until such time as it can be discharged 

 overboard or to barges. 



Fuel oil tanks are vented to atmosphere by 

 pipes leading from the top of the tank to a loca- 

 tion above decks. The vent pipes allow the es- 

 cape of vapor when the tank is being filled and 

 allow the entrance of air when the tank is being 

 emptied. Most fuel oil tanks are equipped with 

 manholes, overflow lines, sounding tubes, liquid 

 level indicators, heating coils, and lines for 

 filling, emptying, and cross-connecting. 



The fuel oil piping system includes (1) the 

 fuel oil filling and transfer system, (2) the fuel 

 oil tank stripping system, and (3) the fuel oil 

 service system. The fuel oil systems are ar- 

 ranged in such a way that different fuel oil pumps 

 take suction from the tanks at different levels. 

 Stripping system pumps have low level suction 

 connections. Fuel oil service pumps have high 

 suction connections from the fuel oil service 

 tanks. Fuel oil booster and transfer pumps take 

 suction above the stripping system pumps. 



The fuel oil filling and transfer system is 

 used for receiving fuel oil and filling the fuel oil 

 storage tanks; filling the fuel oil service tanks; 

 changing the list of the ship by transferring oil 

 between port tanks and starboard tanks; changing 

 the trim of the ship by transferring oil between 

 forward tanks and after tanks; discharging oil 

 for fueling other ships; and, in emergencies, 

 transferring fuel oil directly to the suction side 

 of the fuel oil service pumps. 



The filling system on small ships such as 

 destroyers consists of a trunk filling and tank 

 sluicing arrangement. Larger steam-driven 

 ships have pressure filling systems which are 



The Oil Pollution Act of 1924 (as amended) and the 

 Oil Pollution Act of 1961 are both in effect. The 1961 

 Act broadens and extends the 1924 Act. 



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