Fuel oil systems consist of storage tanks, pumps, heaters, strainers, and piping. Fuel oil tanks are built into the ship's structure to store fuel oil and include double bottom tanks, wing tanks, and deep tanks. Settling tanks provide gravity head for fuel pumps and allow water and impurities to separate. Fuel is transferred between tanks using transfer pumps and manifolds. At least two fuel service pumps supply fuel under pressure to boilers, and two heaters heat the fuel for efficient combustion. Strainers protect components from impurities, and piping must be schedule 80 steel and pressure tested.

1. Fuel Oil SystemsFuel Oil Systems
►Fuel Oil Systems consist of:Fuel Oil Systems consist of:
 Storage TanksStorage Tanks
 PumpsPumps
 HeatersHeaters
 StrainersStrainers
 Measuring and control devicesMeasuring and control devices
 PipingPiping

4. Fuel Oil TanksFuel Oil Tanks
►Fuel Oil Tanks are special compartmentsFuel Oil Tanks are special compartments
built into the structure of the ship for thebuilt into the structure of the ship for the
express purpose of storing the ship’s fuelexpress purpose of storing the ship’s fuel
oil.oil.
 Double Bottom TanksDouble Bottom Tanks
 Wing Tanks (outboard sections of the hull)Wing Tanks (outboard sections of the hull)
 Deep Tanks (large tanks above the innerDeep Tanks (large tanks above the inner
bottom of the ship)bottom of the ship)
 Settling Tanks (tanks adjacent to the fire room)Settling Tanks (tanks adjacent to the fire room)

5. Fuel Oil TanksFuel Oil Tanks
►All fuel oil tanks must have vents andAll fuel oil tanks must have vents and
overflow connections.overflow connections.
►The vent shall not be less than the area ofThe vent shall not be less than the area of
the filling line.the filling line.
►All fuel oil tanks must be constructed inAll fuel oil tanks must be constructed in
order to facilitate the free passage of air andorder to facilitate the free passage of air and
gases from all parts of the tank to ventgases from all parts of the tank to vent
pipes.pipes.

6. Fuel Oil TanksFuel Oil Tanks
►The vent pipe itself should run vertical, ifThe vent pipe itself should run vertical, if
possible, but if not run vertical, it must bepossible, but if not run vertical, it must be
inclined not less than 30inclined not less than 30° from the° from the
horizontal.horizontal.

7. Fuel Oil TanksFuel Oil Tanks
►Vents from fuel oil and other tanksVents from fuel oil and other tanks
extending above the freeboard orextending above the freeboard or
superstructure deck must be of substantialsuperstructure deck must be of substantial
construction and the height from the deck toconstruction and the height from the deck to
the opening at the inside of the return bendthe opening at the inside of the return bend
shall be at least 36 inches in well onshall be at least 36 inches in well on
freeboard decks, 30 inches on raisedfreeboard decks, 30 inches on raised
quarterdecks and 18 inches on otherquarterdecks and 18 inches on other
superstructure decks.superstructure decks.

8. Fuel Oil TanksFuel Oil Tanks
►Vent outlets must be fitted with a singleVent outlets must be fitted with a single
screen of corrosion resistant wire, of at leastscreen of corrosion resistant wire, of at least
30 x 30 mesh or two screens of at least 20 x30 x 30 mesh or two screens of at least 20 x
20 mesh spaced not less than ½ of an inch20 mesh spaced not less than ½ of an inch
nor more than 1 ½ inches apart.nor more than 1 ½ inches apart.

9. Fuel Oil TanksFuel Oil Tanks
►The vents shall have suitable ball checkThe vents shall have suitable ball check
valve or other suitable approved device tovalve or other suitable approved device to
prevent water from entering the vent duringprevent water from entering the vent during
bad weather.bad weather.
►Fuel oil tanks must provided with soundingFuel oil tanks must provided with sounding
devices for determining liquid level, In lieu ofdevices for determining liquid level, In lieu of
sounding pipes a reliable remote levelsounding pipes a reliable remote level
indicator may be used.indicator may be used.

10. Fuel Oil TanksFuel Oil Tanks
►Provisions (striking plate) must be made toProvisions (striking plate) must be made to
prevent damage to the vessels plating byprevent damage to the vessels plating by
the striking of the sounding rod.the striking of the sounding rod.
►Heating coils are provided to heat the fuelHeating coils are provided to heat the fuel
and lower its viscosity to facilitate pumpingand lower its viscosity to facilitate pumping
operationsoperations

12. Settling TanksSettling Tanks
► Settling Tanks or Service Tanks are installed toSettling Tanks or Service Tanks are installed to
provide a gravity head on the suction side of theprovide a gravity head on the suction side of the
fuel oil service pump.fuel oil service pump.
► To maintain a reasonably large supply of oil forTo maintain a reasonably large supply of oil for
immediate useimmediate use
► To provide a place where water and impuritiesTo provide a place where water and impurities
may settle out of the oil.may settle out of the oil.
► The settling tank are fitted with heating coils toThe settling tank are fitted with heating coils to
preheat the oil and lower its viscosity, and therebypreheat the oil and lower its viscosity, and thereby
accelerate the settling out process.accelerate the settling out process.

13. Settling TanksSettling Tanks
►They generally have an overflow lineThey generally have an overflow line
connecting one settling tank to another orconnecting one settling tank to another or
they can be arranged so that they canthey can be arranged so that they can
overflow to a separated overflow tank.overflow to a separated overflow tank.
►Settlers are usually fitted with two suctionSettlers are usually fitted with two suction
valves a high and low suction valve. Thevalves a high and low suction valve. The
low suction is usually used for normallow suction is usually used for normal
operation. In the event of water in the fuel.operation. In the event of water in the fuel.
Fuel oil service is switched to the highFuel oil service is switched to the high
suctions.suctions.

14. Settling TanksSettling Tanks
►Valves for the high and low suctions shallValves for the high and low suctions shall
be arranged for local control at the valvebe arranged for local control at the valve
and remote control at a readily accessibleand remote control at a readily accessible
and safe location.and safe location.

15. Filling SystemFilling System
►Filling lines are provided to permit theFilling lines are provided to permit the
transfer of oil to the storage tanks from atransfer of oil to the storage tanks from a
port facilities.port facilities.
► The filling system generally has a deckThe filling system generally has a deck
connection on each side of the vessel pipedconnection on each side of the vessel piped
to the filling and transfer manifold.to the filling and transfer manifold.
►From this manifold oil delivery to individualFrom this manifold oil delivery to individual
storage tanks is controlled.storage tanks is controlled.

16. Transfer SystemTransfer System
►The fuel oil transfer system is the means byThe fuel oil transfer system is the means by
which oil is moved from one storage tank towhich oil is moved from one storage tank to
another and from the storage tanks to theanother and from the storage tanks to the
settling tanks.settling tanks.
► The transfer system consists of a pipe fromThe transfer system consists of a pipe from
each tank that connects to the suction andeach tank that connects to the suction and
discharge (filling) manifolds of the transferdischarge (filling) manifolds of the transfer
pump.pump.

17. Transfer SystemTransfer System
►Suction piping in the engine room runs fromSuction piping in the engine room runs from
the suction manifold to the transfer pumpthe suction manifold to the transfer pump
and discharge piping connects the pump toand discharge piping connects the pump to
the discharge manifold.the discharge manifold.
►The transfer pump is fitted with a suctionThe transfer pump is fitted with a suction
strainer and a relief valve for protection ofstrainer and a relief valve for protection of
the piping and pump.the piping and pump.

21. Fuel Oil PumpsFuel Oil Pumps
► Fuel oil service pumps take suction from theFuel oil service pumps take suction from the
settling tanks and supply oil at high pressure to thesettling tanks and supply oil at high pressure to the
boiler fronts.boiler fronts.
► They are positive displacement rotary type whichThey are positive displacement rotary type which
are designed to handle small volumes at highare designed to handle small volumes at high
pressures.pressures.
► The pumps are fitted with a relief valve on theThe pumps are fitted with a relief valve on the
discharge side of the pump which is piped back todischarge side of the pump which is piped back to
the suction side of the pump or to the settlers.the suction side of the pump or to the settlers.

22. Fuel Oil PumpsFuel Oil Pumps
►Each vessel must have at least two fuel oilEach vessel must have at least two fuel oil
service pumps, each of sufficient capacity toservice pumps, each of sufficient capacity to
supply all the boilers at full power. Theysupply all the boilers at full power. They
shall be arranged so that one may beshall be arranged so that one may be
overhauled while the other is in service.overhauled while the other is in service.
►Service pumps must be equipped with aService pumps must be equipped with a
means to secure the pump from a readilymeans to secure the pump from a readily
accessible position outside of the boileraccessible position outside of the boiler
room.room.

23. Fuel Oil HeatersFuel Oil Heaters
►At least two fuel oil heaters of approximatelyAt least two fuel oil heaters of approximately
equal capacities are provided to heat theequal capacities are provided to heat the
fuel oil to the proper temperature for mostfuel oil to the proper temperature for most
efficient combustion at the burners. Theyefficient combustion at the burners. They
are arranged so that one may beare arranged so that one may be
overhauled while other is in operation.overhauled while other is in operation.

24. ►Relief valves are fitted on the heaters toRelief valves are fitted on the heaters to
relieve excessive oil pressure to the settlingrelieve excessive oil pressure to the settling
tanks or the suction side of the pump.tanks or the suction side of the pump.

25. Fuel Oil StrainersFuel Oil Strainers
►Fuel oil strainers are installed in the systemFuel oil strainers are installed in the system
to protect the pumps. valves, and atomizersto protect the pumps. valves, and atomizers
from becoming damaged or clogged byfrom becoming damaged or clogged by
mechanical impurities in the fuel oil.mechanical impurities in the fuel oil.
►The strainers must be of the duplex typeThe strainers must be of the duplex type
and are designed so that the oil flow is notand are designed so that the oil flow is not
disturbed when shifting from one strainer todisturbed when shifting from one strainer to
the other for cleaning purposes.the other for cleaning purposes.

26. Fuel Oil StrainersFuel Oil Strainers
►A coarse strainer is installed before the fuelA coarse strainer is installed before the fuel
oil pumps and a fine mesh strainer isoil pumps and a fine mesh strainer is
installed after the fuel oil heaters since theinstalled after the fuel oil heaters since the
oil is less viscous after heating.oil is less viscous after heating.

27. Fuel Oil PipingFuel Oil Piping
►All fuel oil discharge piping shall beAll fuel oil discharge piping shall be
schedule 80 seamless steel and must beschedule 80 seamless steel and must be
readily observablereadily observable
►Discharge piping from the fuel oil pump toDischarge piping from the fuel oil pump to
the boiler installation shall be hydrostaticallythe boiler installation shall be hydrostatically
tested to a test pressure of 1 ½ times thetested to a test pressure of 1 ½ times the
maximum allowable working pressure ormaximum allowable working pressure or
500 psi which is ever greater.500 psi which is ever greater.