Scheduling combat logistics force replenishments at sea for the US Navy

The article of record as published may be found at http://dx.doi.org/10.1002/nav.21780The Replenishment at Sea Planner (RASP) is saving the U.S. Navy millions of dollars a year by reducing fuel consumption of its Combat Logistics Force (CLF). CLF shuttle supply ships deploy from ports to rendezvous with underway U.S. combatants and those of coalition partners. The overwhelming commodity transferred is fuel, ship-to-ship by hoses, while other important packaged goods and spare parts are high-lined, or helicoptered between ships. The U.S. Navy is organized in large areas of responsibility called numbered fleets, and within each of these a scheduler must promulgate a daily forecast of CLF shuttle operations. The operational planning horizon extends out several weeks, or as far into the future as we can forecast demand. We solve RASP with integer linear optimization and a purpose-built heuristic. RASP plans Replenishment-at-Sea (RAS) events with 4-hour (Navy watch) time fidelity. For five years, RASP has served two purposes: (1) it helps schedulers generate a daily schedule and animates it using Google Earth, and (2) it automates reports command-to-ship messages that are essential to keep this complex logistics system operating.Office of Naval Research; Military Sealift Comman