Underway Replenishment

AUTHOR LtCdr. Donald D. Hill, USN

CSC 1989

SUBJECT AREA - Logistics



Underway replenishment has always been recognized as

important, but took a back seat in development until it was

absolutely required. Research indicates that underway

replenishment dates back to the days of sail. Since then,

there have been four major periods in the development of

underway replenishment. The first was at the turn of the

century when coaling-at-sea was investigated. The second

was refueling-at-sea development. The third was underway

replenishment during World War II and the Korean War. The

final period was the late l95Os when the modern underway

replenishment concept was developed.

From the underway replenishment concept came the modern

underway replenishment ships and equipment. Underway

replenishment by these ships has evolved into a highly

efficient and reliable system that can replenish the naval

fleet day or night in all kinds of weather. This

replenishment is accomplished using single-product

replenishment ships (fleet oilers, combat stores ships, and

ammunition ships) and multi-product ships (fast combat

support ships and replenishment oilers). Each ship's

capabilities are taken into account when deciding what type

of ship is going to be used to handle fleet commitments.

There are not enough replenishment ships to handle all

the replenishment requirements that could occur during a

major crisis when much of the fleet would need support.

The Navy is looking at using various merchant tankers and

containerships to aid the Navy replenishment ships in fleet


Underway replenishment has positive direction and

enjoys higher status than the past. New ships are being

built, new equipment is being developed, and new ship types

are being explored to carry underway replenishment into the




Thesis Statement: The US Navy underway replenishment

program has come through the time of forced development to

an evolving doctrine that will adequately serve the fleet.

I. History of Underway Replenishment

A. Days of Sail

B. Coaling at Sea

C. Eearly Refueling/World War I

1. USS Maumee

2. Close-in fuel rig

D. World War II

E. Korean War

II. Modern Underway Replenishment Concept

A. Designed-For-Purpose UNREP Ships

B. Multi-Product UNREP Ships

III1. Cargo Transfer System

A. Connected Replenishment


2. Rig configuration

B. Vertical Replenishment

IV. Fleet Replenishment

A. Battle Group Replenishment

B. Underway Replenishment Frequency

C. Underway Replenishment Ship Shuttle

D. Ship Requirements

E. Mini-Multi Concept

F. Merchant Augmentation

V. Future of Underway Replenishment

A. New Ships

B. New Equipment


Underway replenishment for the US Navy has become a

routine, common occurrence for ships at sea. Everything

needed at sea can be transferred while underway; fuel,

food, ammunition, parts, personnel, and mail are

transferred. This reliable, fast transfer-at-sea has not

always been a navy luxury.

Underway replenishment has been required by the US

Navy since its earliest days. Underway replenishment has

been piecemeal, improvised, and lacking direction until

recent times. There is hope on the horizon, and the hard

lessons of the past have been learned. The US Navy

underway replenishment program has come through the time of

forced development to an evolving doctrine, that will

adequately serve the fleet.

The US Navy conduct of underway replenishment dates

back to the earliest years of the Navy. During the

Quasi-War with France (1799-1801) the young United States

traded only in the Caribbean. The neutral US shipping was

harassed by French warships and various privateers. The

Navy was sent to the area to defend US interests. (lO:159)

One particular ship squadron whose flag was USS

Constitution was assigned duty off Haiti. The slow down of

local privateering due to the presence of the US ships had

made the US warships not welcome in Haitian ports. These

were the closest ports for replenishment. The USS

Constitution and squadron had to stay on station to carry

out their mission and could not go off station as would be

required by going to other friendly ports to replenish food

and other items. The Navy Department chartered various

merchant vessels to rendezvous with the USS Constitution

squadron for resupply. The merchant would rendezvous with

a warship and be taken under tow. The stores would be

transferred by ship's boats. This setup allowed the

warships to stay on station. (10:161)

The US Navy also used the frigate USS John Adams with

reduced armament to shuttle men and supplies from the

Chesapeake to the Mediterranean during the war with

Tripoli. (6:78)

Sailing ship UNREPs pale in comparison to UNREP

requirements that were coming with the modern, mechanized

fleet. The first and foremost problem was one of fuel.

The early steam powered ships required large amounts of

coal to operate. The problem of ship coal replenishment

first arose during the Civil War. No method of coaling on

the open sea existed. At any one time, one-quarter of

Union ships on blockade duty were required to be off

station in a nearby friendly port filling their coal

bunkers. (16:157) While very inefficient, no alternatives

were offered

During the Spanish-American War large numbers of US

Navy steam-powered ships were required to fight outside the

continental shores. (12:2) To refuel these ships, merchant

colliers were procured. Coaling was done underway by

bringing the collier alongside the customer ship, placing

fenders in between, and lashing the ships together with

mooring line. Booms on the collier would transfer

the coal to the customer. (15:8) If the sea state became

too rough, the replenishment would have to stop until the

weather calmed, or the ships would have to move to a

sheltered anchorage and transfer the coal at anchor. While

on blockade duty off Santiago de Cuba, the weather was so

rough most of the time that ships had to go to Guantanamo

Bay to recoal. Again one-quarter of the fleet was off

station at any one time taking on coal. USA Massachusetts

and two other ships were 45 miles away recoaling in

Guantanamo Bay and completely useless when the Spanish

fleet came but of Santiago. (16:159-160)

The problems with coaling during the Spanish-American

War led to engineering research in coaling-at-sea mainly by

the engineer, Spencer Miller, Esq. He developed an under-

way coaling-at-sea system in 1904, but when tested, it

operated poorly. The next decade was spent redesigning and

refining this system. The revised system showed promise,

but the development was stopped. Coaling-at-sea had re-

ceived a bad name among naval officers from the 1904 expe-

rience, and with the emergence of fuel oil for navy

boilers, coaling-at-sea became a less critical

requirement. (13:76)

With the emergence of fuel oil as the fuel of choice,

the Navy built a diesel powered oiler the USS Maumee (AO 2)

in 1916. The oiler was designed to transfer fuel oil to

warships while at anchor. Small ships came alongside the

oiler, but the oiler went alongside the battleships. (18:10)

The USS Maumee's crew discussed and developed a plan

to refuel ships while underway, but had no opportunity to

test the plan. At the outbreak of World War I, USS Maumee

was sent to the mid-Atlantic 300 miles south of Greenland.

This location was a rendezvous position to refuel US

destroyers enroute to England who could not transit across

the Atlantic unless they refueled. The destroyers would

approach USS Maumee who would pass a 10-inch manila hawser

which was then secured to the destroyer. The destroyer

would slow to maintain good steering control-and a spacing

of about 50 feet would result. A four-inch fueling hose

was then passed to the destroyer and supported by a wooden

saddle suspended from cargo booms on the USS Maumee. The

hose was lead directly to the-destroyer's fueling bunker,

and fuel was pumped by USS Maumee. In addition to fuel,

stores and personnel could be transferred using the cargo

booms. The whole UNREP took about two hours per

destroyer. USS Maumee refueled 34 destroyers enroute to

Europe while on station approximately three months in

1917. (18:10-11)

This same system was used for Navy fuel UNREPs through

World War II. As ship rudder controls were made more

sensitive and reliable the 10-inch hawser was deleted, but

the rest of the procedure was unchanged. (18:12) (It is still

used today and is called the close-in fuel rig.) After

World War I refueling underway at sea was looked upon as an

emergency operation that may have to be resorted to in

wartime. It was a tolerated, annual exercise. (4:3)

World War II produced the great task of supporting the

fleet from the US west coast and Hawaii far out to the

operating areas in the Pacific. Floating logistic support

was the only alternative to this tremendous undertaking.

However, the depression had left the Navy lacking for

support craft of any kind, so they had to be made and

pressed into use after the war started.

Most Pacific World War II naval shipping was supplied

at anchor by small supply craft designed or built for

specific functions. As the fleet fought toward, Japan, the