Installation of the upgraded stations will require
some structural and power modifications. The T-AOEs’
three starboard UNREP stations will retain the current
STREAM system. The new capability is estimated to
cost $12.1 million per station.
Kaskin noted that two distinct operations are conducted simultaneously during a normal connected UNREP:
resupply of solid cargo, such as ammunition, provisions
and spare parts, and refueling.
With the current UNREP system, NAVSEA officials
said, the transfer of a typical load of 400 to 500 tons of
ordnance, stores and repair parts could take four to
five hours, about twice as long as is needed to replenish a carrier’s jet fuel supplies. Vertical replenishment
of lighter loads by helicopters usually occurs before or
after the connected UNREP, they said.
One goal of the Heavy UNREP program is to increase
the transfer rate of the solid cargo system to eliminate
that disparity and greatly reduce the time future carriers will be out of combat for resupply.
NAVSEA could not disclose the total time a carrier
is unable to conduct flight operations due to underway
replenishment, calling the information operationally
The other key operational aim of Heavy UNREP is to
increase the system’s load capacity from 5,700 pounds
to 12,000, at Sea State 5 (wind speed at 17-21 knots,
wave height at 6 feet). That will allow the system to
transfer heavier items currently in
inventory, such as aircraft engines
or arresting gear cables weighing
up to 9,000 pounds.
With the STREAM system,
items that heavy must be loaded
while in port or by using a “
work-around” UNREP system that
requires bringing the two vessels
closer together and tensioning the
rigs beyond normal operating limits. The “work-around” method
increases the hazard of the evolution, and restricts the operation to
Sea State 3 and under.
Such transfers were not necessary when STREAM was introduced
to the fleet. But since then, carriers
have continually improved their
ability to sustain ever-increasing flying hours during a deployment, and
those heavier loads now are transferred regularly at sea, Kaskin said.
And the new F- 35, or Joint Strike
Fighter, which will be a major part
of future carrier air wings, will have
engine components heavier and larger than those in
“Heavy UNREP will allow us to safely transfer these
items with no operational restriction on sea state,”
Heavy UNREP is only part of the major improvements in the material-handling process being built
into the CVN 78-class carriers as part of a “
system-of-systems approach” to replenishment. Simply speeding
up the replenishment machinery would have little
effect on the overall evolution and would create a bottleneck of material elsewhere in the process, NAVSEA
The future carriers also will have advanced weapons
and dry cargo elevators, improved material-flow routes,
and better weapons- and package-handling equipment
to help shorten the solid cargo replenishment times.
The ability to replenish quickly is a critical factor in
the carrier’s ability to sustain more flying hours in a
given mission, Kaskin said.
The material-handling equipment aboard the logistics ship is not expected to change. But procedures,
such as pre-staging, will be optimized to support the
faster throughput. The operational manning requirements also will remain the same, but maintenance and
repair requirements will be significantly less.
In addition to the high-line transfer of material, a
carrier UNREP usually includes loads lifted from the
The aircraft carrier USS Ronald Reagan steams alongside the Military Sealift
Command fast combat support ship USNS Bridge during a replenishment at
sea Aug. 15 in the Pacific Ocean.