UNDERWAY REPLENISHMENT NWP 4-01.4 - Historic Naval Ships ...

NWP 4-01.4SHACKLE END OFMESSENGER 350'(106.6 m)MESSENGER1' 0"(30.4 cm)(DOUBLE PROBE RECEIVER)5' 0"(152.4 cm)TWO STOPS ATTACHED 350' (106.6 m) FROMINBOARD (SHACKLED) END OF MESSENGERSQUAREKNOTSPANWIRE(SINGLE PROBE RECEIVER)2' 0"(60.9 cm)MINIMUM OFTHREE TWISTS9/12- THREADSTOP12- THREAD OREQUIVALENT SIZENYLON BECKETSPLICED INTOMESSENGERCUT HERECLOVE HITCH WITH ONEADDITIONAL INSIDE TURNON EACH STRANDSPANWIREEND FITTINGFigure 3-21. Method of Stopping the Span Wire to the Messenger3.9.1.6.2 Back Suction. The term, “back suction,”for FAS purposes, means gravity drain combined with aslight venturi effect at the fuel manifold.NoteThe delivery ship cannot reverse its fuelsystem’s centrifugal pumps and take suctionon the fuel in the hose (and by extension thereceiving ship’s fuel tanks). Back suctionwill not remove fuel from the receivingship’s tanks.To create a “back suction,” the delivery ship cyclesfuel through a line to a cargo fuel tank, bypassing thepiping manifold. This flow to the tank causes a slightsuction (venturi effect) at the piping manifold, whichassists the natural flow of gravity in drawing fuel fromthe fuel delivery hose. Back suction takes much moretime than blowdown to clear fuel from the delivery hose.CAUTION• The receiving ship must not disconnect theFAS coupling until the back suction is completed.Attempting to disconnect the FAScoupling may cause fuel spills.• The receiving ship must leave valves andtank vents open during the back suction sothat fuel may move through the hose. Failureto do so may cause fuel spills.3-26 ORIGINAL