Due to the difference in the types of valves, pumps, filters, and other equipment installed on vari- ous ships, this section will use general descriptions. While your ship may have a gate valve in a specific location, another ship may use a buttefly or limitor- que valve in the same location. Therefore, we will use the terms cutout valve, discharge valve, filter, etc. Specific components will be discussed in the next section. FILLING AND TRANSFER SYSTEM The filling and transfer system (fig. 4-1), and its interconnecting piping and valves, serves many func- tions in the operation of the JP-5 fueling system. It is used primarily for receiving JP-5 aboard to fill the storage tanks; transferring JP-5 from storage to ser- vice tanks; transferring JP-5 internally from forward to aft or port to starboard (or vice versa); and filling the amidship emergency tanks (on ships so equipped) when JP-5 is required for boiler fuel. It is also used to receive and direct JP-5 from the independent defuel main to a preselected storage tank, and to receive JP-5 from the stripping pump discharge header and direct it to any storage tank for consolidation. Off-loading of JP-5 is accomplished by the service pumps through cross-connection piping to the filling and transfer sys- tem. Filling System The filling system includes all piping, valves, and related equipment from the filling connections on the main deck to the fill and suction tailpipe in the storage tanks. The main-deck filling connections provide a means of attaching the refueling hose to the ship and controlling the quality and quantity of JP-5 being received. They are located on the starboard side of the main deck, outboard of the hangar deck, on fueling sponsons, or in elevator ramp recesses. The number of filling connections varies, depending on the type and class carrier. Most carriers have additional filling con- nections on the port side to enable refueling from a barge when moored to a pier. The probe fueling rig is the standard fitting used at the starboard-side filling connections for underway replenish merits. It consists of a fueling probe and a probe receiver. The receiver is supported by a swivel fitting mounted on the receiving ship. A 7-inch-di- ameter, wire-reinforced rubber hose connects the re- ceiver to the filling connection. The port-side filling connections use flanges to bolt the refueling hose to the connection. Filling connections begin with a 90° elbow and a stop valve. A flushing line is installed outboard of the fill connection stop valve on some carrier and am- phibious aviation-type ships. It is used for hose flush- ing and to receive the initial flow during refueling. The flushing line directs fuel flow to the reclamation system and into contaminated storage tanks through the defueling main. All filling connections should be equipped with the following: 1. A sampling connection, to determine the quality of fuel being received. 2. A pressure gage, to determine the discharge pressure from the refueling source. 3. A low-pressure air connection, for blowing JP-5 in the hose back to the refueling source (if necessary). The downcomer is that section of piping that con- nects the filling connection on the main deck with the transfer main on the seventh deck. There is normally one downcomer for each filling connection installed. The transfer main runs fore and aft through the bilge just below the seventh deck. New CV/CVNs have a dual transfer main that runs forward and aft on both the port and starboard sides, creating a “closed loop” transfer main. The transfer main interconnects the forward and aft group of storage tanks, and the amidship emergency tanks (on ships so equipped). In addition to being con- nected to the downcomers, it is also connected to the independent defuel main and the discharge headers of the transfer and stripping pumps. Cutout valves are installed at strategic points throughout the transfer main, mostly at fore and aft bulkheads. These valves are used to isolate the system during the secured condition and to control the flow of JP-5 during various transfer and filling operations. Each valve is unclassfifed or Damage Control marked @-ray. The extreme forward and aft ends of the transfer main are connected to the transfer-main branch headers. The transfer-main branch headers extend outboard from the transfer main and interconnect the storage tank manifolds with the transfer main. Normally there are only two branch headers for each of the forward and aft groups of tanks: one port and one starboard. But on ships with double bottom and peak tanks for JP-5 stor- age. additional branches are required. Located between the transfer-main branch head- ers and the storage tank fill and suction tailpipes are valve manifolds. All manifold valves are Damage Control marked @-ray and MUST be closed when not actually in use. 4-2