New Heavy UNREP system aims to reduce carrier’s time away from mission
By OTTO KREISHER, Special Correspondent
Building on Experience
One of the major restrictions on the ability of the
Navy’s nuclear-powered aircraft carriers to
conduct truly sustained combat operations is
the time-consuming process of underway replenishment
of jet fuel, ordnance and spare parts for the air wings, and
food and other supplies for 5,500 personnel.
But Naval Sea Systems Command (NAVSEA) is developing a system that should substantially reduce the time
the carrier must suspend flight operations to replenish.
The new system, called Heavy Underway Replenishment
(Heavy UNREP), is expected to handle loads more than
twice as heavy and operate much faster than the current
system, according to Jon Kaskin, the chief of naval operations’ director for Strategic Mobility and Global Logistics.
“Reducing the time out of combat, or away from a
primary mission, is always a principal objective of any
of our efforts to improve underway replenishment,” he
said. “This is true of Heavy UNREP. Reduced time to
replenish is one of the primary operational advantages
of the system.”
Effective transfer of solid cargo at sea was developed
late in World War II to sustain the fast-moving battle
groups fighting their way through the Pacific. The sys-
tem used at that time was a Burton
rig, which required a winch on
each participating ship, Navy officials said.
That system was replaced more
than 40 years ago by the Standard
Tension Replenishment Alongside
Method (STREAM), which located
nearly all required machinery on the
underway replenishment ship and
increased the capacity, throughput
and range of sea conditions.
The original STREAM system
was designed to transfer missile
components, up to a maximum
weight of 5,700 pounds. That system was adapted for its current primary use — the transfer of ordnance and stores.
The Heavy UNREP development began in 2001
under the Office of Naval Research’s (ONR’s) Future
Naval Capabilities program. It sought to address specific “operational deficiencies” of the STREAM system,
including the excessive time required to replenish a
carrier’s ordnance and the 5,700-pound weight limitation, said Tim Barnard, of NAVSEA’s Naval Advanced
Concepts and Technologies program office.
The new system, with UNREP machinery that will
operate at higher tensions and speeds, will be built into
three starboard-side receiving stations on the first of
the next-generation nuclear carriers, CVN 78, or
Gerald R. Ford, which is under construction.
Northrop Grumman Shipbuilding Newport News,
Va., is responsible for completing the design of the
CVN 78 UNREP receiving station.
The system also will be installed on the three port-side
send stations on two of the Navy’s four T-AOE Supply-class fast combat support ships prior to CVN 78’s initial
operational capability, now expected to be after 2015.
The remaining two T-AOEs are expected to be upgraded
later, as required, to meet the fleet’s needs.
The Heavy Underway Replenishment (UNREP) system addresses specific deficiencies of the 40-year-old Standard Tension
Replenishment Alongside Method, or STREAM.
■ STREAM requires excessive time to replenish a carrier’s ordnance and has a 5,700-pound weight limitation.
■ Heavier cargo must be loaded while in port or by using a work-around UNREP system that restricts the operation to Sea State
3 and under.
■ One key operational aim of Heavy UNREP is to increase load
capacity to 12,000 pounds at Sea State 5.