Unrepping means underway replentishing.
In essence, taking on fuel and other items while at sea under power.
Reminds me of a story I heard many years ago from the late Grace Hopper, one of the pioneers of Navy computing. (All computing, actually.)
As I recall it, as part of some officer training class, she'd been assigned the problem of refueling a defined flotilla in the shortest possible amount of time - the ships in this theoretical exercise all had defined fuel capacities, state of fill, and defined pumping capability.
In response to her question, the instructor told her there were NO constraints other than refueling in the shortest possible time.
She programmed the problem into her computer, and came up with the SHORTEST time the instructors had ever seen.
All the ships were lined up at once, and all the pumps were going full blast. Some fuel went from the oiler(s) into the battleships, only to be pumped out at the same time into a cruiser . . . which in turn was simultaneously being pumped out by a destroyer. You get the picture - in order to move the maximum amount of fuel in the shortest possible time, all pumping capability of the entire flotilla was used.
"A very interesting solution" was the (unhappy) instructor's response.
