Deck Officer




Information Sheet 1.14


Underway Replenishment (UNREP) is a complicated evolution involving two or more ships. Proper planning is necessary for the safe and efficient accomplishment of an UNREP, particularly when both fuel and supplies are to be transferred or when a single Combat Logistics Force (CLF) ship is serving several customer ships.


(a) NWP 4-01.4

(b) ATP 16

(c) NWP 3-04.1

(d) APP 4



1. NWP 4-01.4 (Replenishment At Sea)

a. Provides information necessary to prepare both the customer and the delivery ship for a replenishment evolution

b. Contains information about the types of rigs available, necessary equipment, required reports and safety precautions

2. ATP 16 (Replenishment At Sea)

a. Establishes common doctrine for Refueling Alongside (RAS) for NATO and allied ships

3. NWP 3-04.1 (Standard Helicopter Operating Procedures)

a. Outlines the operational procedures and training requirements for the shipboard employment of helicopters

4. APP 4 (Allied Maritime Message Formats)

a. Two volume document that provides user with a ready reference for structured and formatted messages relating to tactical command, control, and coordination of ships at sea


NOTE: The logistics staff for the battle group or the amphibious task force will use a combination of these methods to ensure that fuel and stores are delivered to the customer ships. The CLF ship may be in Service Station for several days, then after reloading in port, it may come back out and perform Shuttle URG the following week.

1. The UNREP Coordinator (URC) will coordinate replenishment needs and rendezvous details.

a. URC will issue standing RAS guidance.

b. Screen commander will designate order alongside.

c. CO of the UNREP ship (senior CO if more than one ship is involved multiship) will be OTC for all UNREP operations.

d. URC

(1) Consolidation

(2) Recommended ROMEO corpen/speed

(3) Movement of URG (Underway Replenishment Group) to rendezvous

e. Pass through rendezvous point on time

2. Delivery Boy method

a. This method is used when the customer ships are grouped together for tactical operations or when customer ships cannot be relieved on station for some reason.

b. The battle group will maintain a constant position of intended movement (PIM), that enables the CLF ship to rendezvous with the battle group after loading stores in port.

c. The top speed of the CLF ship must be taken into account when deciding on the battle group Speed Of Advance.

d. The CLF ship will make the rounds of the customer ships, replenishing each in turn.

e. Because the CLF ship is relatively defenseless, this method is used in low-threat environments and for traditional blue-water operations.

3. Service Station method

a. This method is used in high threat environments, or when the customer ships can be relieved on station.


b. The CLF ship will be stationed within the protective screen of the battle group and will maintain PIM.

c. The customer ships will pull in to the UNREP station for gas and groceries.

4. Gasoline Alley method

a. This method is frequently used today. The battle group will stay on station. Off the coast of the hostile country, a CLF ship will be positioned 30 to 40 miles away in a 4-Whiskey Grid, or a "box." There is no PIM, as the ships are not in transit.

b. Combatants will break away from the battle group and rendezvous with the CLF ship for replenishment.

5. Shuttle URG (Underway Replenishment Group) method

a. This method is used when the battle group is operating together in a traditional blue-water scenario.

b. The single-product CLF ship (AFS, T-AFS, AO or AE) will rendezvous with the multi-product ship (AOE/AOR) and conduct "consol ops". During consolidation operations, two CLF ships exchange goods to ensure that each has the required stores (including mail) for the customer ships they are scheduled to serve. The AOR/AOE will then rendezvous with the battle group and pass along the stores.

6. Considerations

a. Task group commitments:

(1) Time constraints

(2) Romeo corpen/speed

(3) Sea conditions

b. Own ship capabilities/limitations:

(1) CONREP vs VERTREP balance

(2) Internal cargo movement

(a) Break-out/staging

(b) Traffic flow

(c) Safety/shelf-life

(3) Comms

C. Within-the-lifelines UNREP planning.

1. UNREP considerations: Task Groups'/Own ships' limitations.

2. How long will it take? Use standard tables for transfer rates, approach times, and rig/unrig times.

3. Rig selection based on cargo characteristics and rig capacities, as well as weather conditions.

4. STREAM vs. non-tensioned methods. Prefer STREAM, recognize limitations on using non-tensioned.

5. How is cargo going to be moved off the station and using what route?


7. Personnel/Watchstanders

a. Who are the key players? Where do you want your most senior and experienced people? Who is required at each watch station?

b. Minimum briefings are held in the Wardroom and on station. Where else do you want briefs conducted? Who presents which parts of the brief? Who must attend?

c. Who observes steering checks prior to UNREP, and when do you do them?

d. If you overlap meal hours, do you have a plan for rotation or relief of teams?

D. Replenishment Seamanship

1. Maneuvering

2. Romeo Corpen/Speed

3. Distance between ships

4. Maintaining station

5. Breakaway

6. Emergency breakaway




  1. Ship "player" designations

1. Control Ship

a. Maintain course and speed

b. Coordinate base course/speed changes to avoid hazards or as ops require

(1) Limit to 5 degree course/1 kt speed changes

(2) Use rudder to produce 3 KYD tactical diameter turn

c. Advise when:

(1) Rudder is put over

(2) Each degree of heading is passed

(3) Rudder is shifted to steady up

d. Do not change course and speed simultaneously

2. Approach Ship

a. Makes approach

b. Maintains station

c. Considers: winds, seas, water depth, pressure, and suction effects

d. Displays appropriate signals/shapes

e. Provides phone and distance line

f. Check gyro against Romeo Corpen prior to approach

3. Delivery Ship

a. Normally the control ship

b. Furnishes rigs, including:

(1) Bolo/gun line

(2) Messengers


    1. Station to station phone line

(4) Always furnishes shot line (Except CV's, LPH's and LHA's)

c. Assumes control during emergency breakaway

4. Receiving Ship

a. Ordinarily approach ship

b. Receives rigs

c. Handles all phone lines

F. Shiphandling Considerations

1. Course selection based on the following:

a. Sea State

(1) Swells are principle concern

(2) Sea state 5 is limit for UNREP

(3) Course into seas moderates effect

b. Sheer currents

(1) Wall of water (edge of Gulf Stream)

(2) May effect heading by 10 degrees

c. Wind

(1) 30 knots of wind = 1 knot current

(2) High relative winds affect lift capabilities

(3) Lee for customer?

(4) Wind for helos

2. Speed selection based on rudder control, adequate separation for increased speeds, and customer speed requirements.

a. Optimum UNREP speed 12-16 kts

b. Less than 8 kts - lose some rudder control

c. Speeds greater than 16 kts require more lateral separation

d. DD/FFG critical speed = 12 kts, do not UNREP them at that speed, normally 13 kts.

e. Lateral separation increases as speed increases and depth decreases.

3. Consider Venturi effects at various points in approach and breakaway.

4. Steering control

a. Prior to going alongside, check steering control in all modes of operation from aftersteering and bridge (PMS checks).

b. Determine gyro error and operability of standby gyro and alarms.

c. Ship Control Safety Officer, After steering Ship Control Safety Officer are required during evolution.

d. PQS qualified personnel, Interim PQS substitutions with a PQS qualified watchstander must be present with no other duties.

e. Keep substitutions to a minimum.

5. Tension/detension effects.

6. Review of approach types.

7. Stationing aid usage.

a. Phone and Distance line

b. Station keeping device

8. Pressure effects

a. A ship underway creates a hull wash and area of increased water pressure at the bow and stern with decreased pressure (suction) amidships.

b. The Venturi effect is a result of the differences in velocity in the water flow around the hull.

c. When alongside, the Venturi effect is increased and is further complicated by the intermingling of pressure areas.

d. Pressure effects vary with distance between ships, size and configuration of ships, replenishment speed and depth of water.

e. Replenishment operations in shallow water increases the pressure effects - 100 fathoms is the limit.

G. UNREP Duration

1. Approach time, 5-11 minutes

2. Rig/Unrig times

a. 9-12 minutes for fuel

b. 12 minutes for cargo

3. Transfer rates vary with pumping pressure for FAS, and type of cargo rig for RAS

H. Course and speed changes, the conning officer shall:

1. Observe gyro heading

2. Observe rate of turn

3. Observe distance to control ship

4. Observe parallel relationship of ships

5. Observe the fore and aft position relative to control ship

I. Cargo rig selection, dependent upon:

1. Type and quantity of cargo

2. Capacity of rig and associated fittings

3. Weight of heaviest load and size of largest load

4. Weather and sea conditions

5. Type and location of receiving station

6. Size and draft of customer ship

  1. Transfer at sea rigs




c. STREAM with hand tended outhaul

2. Conventional

a. Synthetic Highline

b. Coaling bag

K. Lateral Separation:

1. Adequate lateral separation is necessary especially when bow passes the control ship's stern.

2. Wider approach for magnetic compass approaches

3. Conning Officer, Ship Control Safety Officer, and helmsman must be alert for swing of compass towards other ship (magnetic compass).

4. Distance between ships dependent upon:

a. Wind and sea conditions

b. Sizes and types of ships

c. Ship's ability to maneuver

d. Types of rigs:

(1) Missile/cargo STREAM

(a) For all ships except carriers - normal 80 - 200 ft, out to max of 300 ft.

(b) For carriers - normal 150 - 240 ft, out to max of 300 ft.

(2) Synthetic

(a) For FFG and smaller - normal 80 - 100 ft, out to max of 180 ft.

(b) For larger ships - normal 80 - 120 ft, out to max of 200 ft.

(c) For carriers - normal 100 - 140 ft, out to max of 200 ft.

(3) Fuel STREAM

(a) For FFG and smaller - normal 80-180 ft, out to max of 200 ft

(b) For larger ships - normal 80-180 ft, out to max of 200 ft

(c) For carriers - normal 100-180 ft, out to max 200 ft

(d) 300 ft heavy weather rig

(4) Close-In rig

(a) For FFG and smaller - 60-80 ft

(b) For larger ships - 60-100 ft

e. Depth of the water

(1) As depth decreases, increase lateral separation

f. Replenishment speed

(1) As speed increases, increase lateral separation



2. Using the RAS message/information received:

a. Prepare a wardroom brief on the UNREP.

    1. Include all information discussed in this lesson (personnel, rigs, time, order alongside, etc.).

2. Using the ship diagrams, be prepared to demonstrate how stations will line up.

3. Coordinate with the other ships in your CVBG/ARG for times and order.

b. A typewritten draft will be turned in to the Unit Lead by the time assigned for review and comment. Final drafts will be due the morning of the brief.

c. Present the brief (and the STT brief assigned in Lesson 1.2).

d. Be prepared to answer questions on the UNREP brief and STT drill plan.


3. Briefing Points

a. These briefs will be given to the Director or Executive Director of DOC. Ensure you address them and answer any questions using the appropriate respect (i.e., answers to any questions should either begin or end with Captain/XO or sir/ma’am).

b. Speak clearly and succinctly. While you will primarily be speaking to the CO/XO, the personnel throughout the room must be able to hear you (hint: have a friend stand in the back for volume checks).

c. Practice your ENTIRE brief in advance, to a mirror, a friend, or the family pet.

d. Keep your head up, do not speak to the paper. Highlight key points for quick reference on your copy of the brief, so you are not constantly seeking your place in the brief.

e. RELAX! The first one is always the most difficult. Briefing gets easier with practice!