Roll-On/Roll-Off Discharge Facility (RRDF)
The Roll-On/Roll-Off Discharge Facility (RRDF) is a Floating Platform moored to a ship that consists of 7 Causeway Sections. This system provides a roadway between Ship's Ramp and Lighterage. The system requires 6 to 8 hours to assemble. Its use is limited to Sea State 2, with a maximum current of 4 Kts
Arguably one of the most important items of lighterage used in LOTS operations is the roll-on-roll-off discharge facility (RRDF). The RRDF is a floating platform constructed by connecting causeway sections together. The RRDF can be moored (with both anchors down or tied to a pier, an anchor buoy, or a mooring buoy) to a non-self-sustaining ship in sea states 0 and 1 or to a self-sustaining ship in sea states 0 to 2. The RRDF can be operated safely through sea state 2. Joint Publication 4_01.6, Joint Tactics, Techniques, and Procedures for Joint Logistics Over the Shore (JLOTS), identifies the principal elements of the RRDF as the roll-on-roll-off platform, the ship's fendering system, and a calm water ramp. The ramps of ships are opened onto the RRDF to allow roll-on-roll-off cargo to be driven from the vessel onto the RRDF and then ferried to shore.
The RRDF has several limitations. The ramp of a ship to be unloaded opens onto the deck of the RRDF, which is connected to the ship by the ship's hardware and an end adapter. Because the ship and the RRDF move constantly with the motion of the water, heavy dunnage (packing material) must be placed between the two to prevent wear and chafing.
Another difficulty encountered when using the RRDF is the various ramp configurations on vessels owned or contracted by the Military Sealift Command (MSC). An after-action report from a 7th Transportation Group exercise called Resolute Phoenix recommended a standard ramp configuration for ships that must hook up with Army lighterage, especially the RRDF. Each vessel has a different type of ramp, which increases the time needed to moor the RRDF to it. Also, the lack of standardization requires more test runs and coordination to ensure that each platform meets all requirements for a successful hookup.
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