system is connected at the next lower level, and the tank stripping system is connected at the lowest level. We’ll explain  the  function  of  each  in  the  following paragraphs. Fuel Oil Filling and Transfer System The fuel oil filling and transfer system receives fuel oil aboard and (1) fills the fuel oil storage tanks, (2) fills the fuel oil service tanks, (3) changes the list of the ship by transferring oil between port tanks and starboard tanks, (4) changes the trim of the ship by transferring oil between forward and after tanks, (5) discharges oil for fueling other ships, and (6) in emergencies, transfers fuel oil directly to the suction side of the fuel oil service pumps. The fuel oil filling system of some ships consists of a tank-filling and tank-sluicing arrangement. Other ships have pressure filling systems that are connected to the  transfer  mains  so  the  filling  lines  and  deck connections  can  be  used  both  to  receive  and  discharge fuel oil. The pressure filling systems operate with a minimum pressure of approximately 40 psi at the deck connections. In general, the filling and transfer system consists of large mains running fore and aft. These are transfer mains, cross-connections, mains to fuel oil booster and transfer pumps, and risers to take on or discharge fuel oil. Other lines and manifolds are arranged so the fuel oil booster and transfer pumps can transfer oil from one tank to another and, when necessary, deliver fuel oil to the suction side of the fuel oil service pumps. Fuel Oil Tank Stripping System The fuel oil tank stripping system can clear the tanks of sludge and water before oil is pumped from these tanks by the fuel oil booster and transfer pumps or by  the  fuel  oil  service  pumps.  The  stripping  system  is connected through manifolds to the bilge pump or, in some ships, to special stripping system pumps. The stripping  system  discharges  the  contaminated  oil, sludge, and water overboard or to the contaminated oil settling  tanks. Fuel Oil Service System The fuel oil service system used aboard any ship depends partly on the type of fuel oil burners installed on the boilers. The fuel oil service system includes the fuel  oil  service  tanks,  a  service  main,  manifolds,  piping, and fuel oil service pumps. Fuel oil service pumps take suction from the service tanks  through  independent  tailpipes,  cutout  valves  or manifolds,  suction  mains,  and  pump  connections.  The suction  arrangements  for  fuel  oil  service  pumps  allow rapid changes in pump suction from one service tank to another. The pump suction piping is arranged to keep to a minimum any contamination that might result if one service pump takes suction from a service tank that is contaminated with water. The tank stripping system is connected  through  stop-check  valves  to  the  service suction mains so these mains can be cleared of oil that is contaminated with water. The service suction main is common to all pumps in one particular space. It has connections  to  the  fuel  oil  transfer  main  through stop-check valves that are normally locked in the closed position. Aboard some ships, JP-5 can be used as boiler fuel in emergencies. The JP-5 systems are arranged so they can discharge to the fuel oil service system. Two  classes  of  fuel  oil  service  pumps  are commonly used: (1) main fuel oil service pumps, and (2) port and cruising fuel oil service pumps. Both are usually screw-type rotary pumps that may be either motor- or turbine-driven, the difference is in size and in gallons  delivered. The  fuel  oil  service  system  also  needs  fuel  oil strainers, burner lines, and other such items to deliver fuel oil to the boiler fronts at the required pressures. PRECAUTIONS IN HANDLING FUEL OIL All  petroleum  products,  including  fuel  oil,  are potentially dangerous. Heated fuel oil may generate vapors that are flammable, explosive, and dangerous if you  inhale  them.  The  oil  king  must  have  thorough knowledge of these hazards. The oil king also must make certain that all personnel in fuel oil details take the necessary precautions. The following list covers the most  important  precautions: 1. Do  NOT  allow  anyone  to  smoke  or  to  carry matches or lighters while handling fuel oil. 2.  Use  only  approved  types  of  protected  lights when working near fuel oil. 3. Do  NOT  allow  oil  to  accumulate  in  bilges, voids, and so forth. The vapor from even a small pool of heated fuel oil can cause an explosion. 4. NEVER raise the temperature of fuel oil above 120°F  in  fuel  oil  tanks.  If  the  tanks  are  next  to  a magazine, NEVER allow the oil to become hot enough 6-7