Combat Logistics Force  

Overview

CONREP
VERTREP
Capacities of Selected CFL Ships
Average Daily Fuel and Ordnance Consumption Rates
Sources and Resources

The idea of taking supplies to ships at sea and handling them across the water was new to the Navy at the turn of the century. Sailing ships had been able to stay where the action was for weeks or months; sea breezes provided the power, Sailor's diets were less complex, and round shot was more easily stocked than bombs and missiles.

Then came the day of the steamship with its huge appetite for coal. The large men-of-war burned 50 tons of coal a day, and to keep their bunkers full, had to return to port every 10 days or so to re-coal. The Navy learned a lesson in 1898 during the Spanish-American War. The Spanish Fleet was blockaded in the Harbor of Santiago, Cuba. When the Spanish made a run for the open sea, three of our ships (including the old battleship MASSACHUSETTS) were 45 miles away being re-coaled at Guantanamo. The need for on-station at-sea refueling was obvious. Early efforts to solve the problem led to the development of a high-line for carrying bags of coal from a coaler to a warship, one in the wake of the other.

World War One saw the beginning of the Navy's conversion to oil- burning ships, and soon the coalers were out of business."

It took the pressure of the Second World War in the Pacific, which reached into the far corners of that ocean, to make Underway Replenishment (UNREP) a regular feature of Naval Operations. The war in the Pacific made new demands on the Navy -- supply lines had to be extended, quickly, in order to project power across the oceans and keep it there.

Underway Replenishment is the method by which provisions, ammunition and fuel are transferred from one ship to another at sea. The technique of replenishment at sea enables a fleet or naval formation to remain at sea for prolonged periods of time. There are two methods by which UNREP is accomplished:
 
(CONREP) - Connected Replenishment is a way for Ships to replenish other Ships at sea of needed Supplies. This involves rigging a cable to the ship they are supplying and sending supplies over a ram-tensioned Wire system known as (STREAM) using a system of pulleys to travel the Wire. In this method, the ship maintains a steady course and speed, while the receiving ship comes alongside at 80 -200 feet. The replenishment ship can service two ships at a time, one on either side. Depending on the material to be transferred, the ships are connected together with wires which run through UNREP rigs where fuel hoses or trolley devices are passed. When fueling, the hoses are hooked up and fuel is pumped to the receiving ship. When transferring supplies, they are palletized and sent over to the receiving ship. The trolley is then returned to the replenishment ship for another load.  Return to Top
 
(VERTREP) - Vertical Replenishment is another way for ships to replenish Ships at sea of needed supplies often Replenishment ships will use this and (CONREP) at the same time to speed up the process. This method utilizes helicopters to transfer prepositioned palletized supplies from the flight deck of the replenishment ship to the flight deck of the receiving ship. The helicopter then hoists up the pallet (which has been placed in a cargo net), and flies it over to the receiving ship where it is lowered onto their flight deck.  Return to Top
 

The Navy operates a Combat Logistics Force fleet of about 40 ships that resupply combatant ships at sea with several commodities. The ships carry significant amounts of these commodities, for example, ship and aviation fuel (DFM and JP-5, respectively), ordnance, and other supplies such as ship and aircraft fuel, ordnance, and food, which enables combatant ships to operate at sea almost indefinitely, if required, without ever needing to go into ports to replenish their stocks. The force represents additional days of sustainability for the naval force by serving as an extension of the combatant ships' bunkers, magazine and store rooms.

Capacities of Selected Combat Logistics Force (CLF) Ships  Return to Top

Class Speed
 Fuel
 Ordnance
 Other Supplies
  (knots)
 (barrels)
 (tons) (tons)
(T-) AE-26 20
 \b
 6,000
 \b
(T-) AFS-1 20
 18,000
 \c
 7,000
AO-177
 20
 150,000
 625
 420
(T-) AO-187 20
 180,000
 \c
 \d
AOE-1 30
 177,000
 2,500
 750
AOE-6 30
 156,000
 1,800 650

Note: T-class Combat Logistics Force ships are operated by the Navy's Military Sealift Command.  These ships use civilian, instead of military, crews but may have a small military detachment aboard. A majority of the non-AOE class ships are now operated by the Military Sealift Command.

\a Reflects a combined total for DFM and JP-5.
\b Primary mission is ordnance replenishment.  Limited quantities of fuel and other supplies are also available.
\c No ordnance carried.
\d Primary mission is fuel replenishment.  Limited capacity to carry other supplies.

Average Daily Fuel and Ordnance Consumption Rates for Selected Ship Classes    Return to Top

Ship Class

DFM

JP-5

Ordnance

(barrels)
 (barrels)
 (tons)
Carrier (CV)
 2,700
 6,500
 70-150
Carrier (CVN)
 \a
 6,500
 70-150
CG-47
 725
 \a
 \a
DD-963
 710
 \a
 \a
DDG-51 710
 \a
 \a

Note: \a = No quantities shown.


Evaluated force levels for various scenarios show that station ships are required to maintain battle group endurance. The ability of the AOE's to provide all replenishment services simultaneously minimizes the non-operational time of the battle group. Alternatives which use multiple shuttle ships in combination to perform the station ship functions (such as AORs combined with AEs) require multiple replenishment which, coupled with their slower speed, reduces the on-station time of the battle group. These combinations are more expensive to operate and exacerbate the shortfall of AE ships.

The conventionally powered cruisers and destroyers that are a part of carrier battle groups are dependent on underway replenishment support by Combat Logistics Force. Compared to a conventional carrier, they have smaller fuel storage capacities and relatively high fuel consumption rates at higher speeds. Station ships travel with carrier battle groups. They carry petroleum products, ordnance, and other supplies and are generally replenished by shuttle ships operating from land-based facilities worldwide. The presence of a station ship in the battle group extends the group's range considerably.

There are several UNREP areas that are candidates for improvement. Selected areas for improvement, consideration and industry involvement are listed below:

  • Reduction in manning
  • Inventory management and planning aids
  • Computerized inventory tracking of cargo
  • Software planning aids for cargo stowage handling and transfer
  • Incorporation of commercial practices and new technology
  • Cargo handling systems
  • Commercial packaging systems
  • Means of stowing and handling solid waste
  • Flexibility to adapt to any cargo load
  • Flexibility to stow and handle various type of ammunition and ordnance
  • Improved operations in high sea conditions
  • Improved cargo strike up and strike down rates
  • Fiber optics for lighting and communications systems
The actual transfer of material from ship to ship is not the weak link in the replenishment chain. During actual UNREP operations, the ability of the receiving ship to strike down palletized material usually dictates the pace of the evolution. For the delivering ship improvements in strike up, pre-staging management of materials and inventory management are all needed.

Sources and Resources  Return to Top