Information Sheet Number: 2.12
The U. S. Navy's ability to project sea power over long ocean distances depends on the capability to sustain ships at sea for long periods. This is accomplished by being able to replenish ships
underway. Requirements for fuel and food require warships to go alongside the replenishment ships at regular intervals. It requires special shiphandling skills to conn a ship alongside during such evolutions.
(a) NWP 14 (Rev D) Replenishment at Sea
(b) Naval Shiphandling, Crenshaw
(c) Fleet Replenishment Guide
(d) Watch Officer's Guide
(e) SORM (OPNAVINST 3120.32C)
(f) Surface Ship Operations (NAVEDTRA 10776)
A. SETTING UP:
1. ORDERS TO THE HELM/LEE HELM:
a. During connected replenishment (CONREP) evolutions, it is best to control the ship's head by giving the helmsman a course to steer rather than rudder orders.
(1) Giving rudder orders is attempting to do the helmsman's job and could be dangerous at the close ranges used during CONREPS.
b. Speed Changes - State the exact number of revolutions/pitch desired rather than telling the Lee Helm to add or drop revolutions.
c. Both the helmsman and after steering helmsman (after steersman) must be qualified as Master Helmsman in accordance with the applicable Personnel Qualification Standard
2. PRIOR TO TAKING WAITING STATION:
a. Steering control will be checked in all modes of operation both from the pilot house and
after steering. Steering checks are a Planned Maintenance System (PMS) requirement and will
be conducted in accordance with applicable Maintenance Requirement Cards (MRC's).
b. Gyro error will be determined and the operability of the standby gyro and associated alarms will be tested.
c. Personnel assigned to steering control stations will be PQS qualified.
d. Watch station personnel substitutions will be kept to a minimum.
e. Training should be conducted with qualified supervision only.
f. Dedicate a S/P phone circuit to ship control functions. After steering should be kept constantly informed.
g. Rehearse procedures for man overboard.
h. Shift to restricted maneuvering casualty control procedures in Main Control.
i. Verify station data and extract required stadimeter inputs from the Atlantic/Pacific Fleet Replenishment Guide. Ascertain the relationship of your ship's replenishment stations with the other ship's replenishment stations.
B. WAITING STATION/LIFEGUARD STATION:
1. Take Waiting Station (300-500 yards astern of the ship alongside for replenishment) or Lifeguard station (1,000 yards astern of the delivery ship) as ordered in accordance with ATP1(C) Vol II. Waiting station is usually assigned to that ship which is "next in line" for replenishment during extended CONREP operations. Lifeguard Station is the station taken
by the ship which is assigned to recover any person who falls overboard from the ships engaged
in CONREP. This ship will often be the last to conduct replenishment. When in close proximity to a CV/CVN/LHD/LHA, vigilance is the key. Expect the unexpected. The conning officer can
begin to rehearse the approach while in either of these stations.
2. Determine the exact course and speed needed to equal the delivery ship's course and speed.
3. Observe other ships alongside to see how they are riding. Conditions might dictate that a wider approach than normal would be prudent.
4. Attempt to get into a position for a parallel approach.
5. Display appropriate flaghoist.
C. FLAG SIGNALS USED DURING CONREP:
Several flags have special meanings when displayed on the control and approach ship during an
Underway Replenishment (UNREP) or CONREP evolution. It is possible to conduct a complete
replenishment using only flag hoist signals. Ships often practice these "silent UNREPS," and the conning officer must recognize and understand the flag signals associated with them.
1. ROMEO - indicates readiness and is displayed on the side rigged for replenishment operations.
POSITION SHIP DISPLAYED ON MEANING OF FLAGHOIST
At the dip Control Ship - Steady on Romeo course and speed and preparing to receive you on this side.
Approach Ship - Am ready to come alongside you on this side.
Closed up Control Ship - Am ready for your approach.
Approach Ship - Am commencing my approach.
Hauled Down Both Ships - Messenger is in hand (not the shotline).
2. BRAVO - indicates handling of fuel, explosives or inflammable material.
POSITION SHIP DISPLAYED ON MEANING OF FLAGHOIST
At the dip Both Ships - Have temporarily stopped supplying.
Closed up Both Ships - Fuel, explosive or inflammable materials are being transferred.
Hauled Down Both Ships - Delivery is complete.
3. PREPARATIVE PENNANT (PREP) - displayed only on the receiving ship in order to inform the delivery ship and ships in waiting station as to the status of the CONREP.
POSITION MEANING OF FLAGHOIST
At the dip Expect to disengage the final station in 15 minutes
Closed up Transfer complete - am disengaging final station
Hauled down All lines are clear.
D. COMMENCING THE APPROACH:
1. Objective - arrive abreast of the supply ship on a parallel course and speed at a convenient but safe distance.
2. The most practical approach is parallel to the other ship's wake at the desired distance. This approach is also safest as it allows the Conning Officer the opportunity to continually check the accuracy of the approach.
3. The Radian Rule:
a. By applying the mathematical definition of radian measure to shiphandling problems, the conning officer may make effective use of the gyro repeater and bearing circle for calculating both distances to objects at sea and courses to steer to pass clear of a navigational hazard. When used in conjunction with the three minute rule, the radian rule gives a sound basis for station keeping in formation "by seaman's eye."
b. The Rule:
(1) The Radian Rule is defined as follows:
D / 60 = S / A where D = DISTANCE IN YARDS
S = LATERAL SEPARATION IN YARDS
A = ANGULAR DIFFERENCE IN DEGREES
In the following paragraphs we will look at the actual use of the radian rule in making a CONREP approach using the "Coast-in Method." Additional uses of the Radian Rule will be discussed at the end of this lesson. Remember the rule and look at the applications so that you can use it to help you maneuver the ship safely and smartly.
c. Coast-in Method of Underway Replenishment Approach.
(1) You are conning officer on an FFG taking part in NATO exercises in the Mediterranean Sea. Today you are scheduled to refuel from the USS RANIER (AOE-7) in the Ionian Sea south of Malta. In planning your approach you have decided to maintain a distance of 90 feet from RANIER'S side in order to facilitate the hookup of rigs. At the present time, you are steady on replenishment course and speed, deep on the port quarter of RANIER. Flag "ROMEO" is closed up on both vessels. Assuming that you are able to maintain a 90 foot separation from RANIER during the maneuver and using a gyro repeater and bearing circle, you can calculate your distance from being alongside if the bearing to the oiler's stern is 2 degrees off the replenishment course. Figure 2.11-1 shows this situation graphically. If the replenishment course is 000 T and the oiler's side bears 358 T, the angular difference is 2 degrees. After rearranging the terms of the equation, we can write the Radian Rule as:
D = 60 x S / A and in this case: S = 90 ft = 30 yds and A = 2 degrees
So, D = 60 x 30 / 2 = 1800 / 2 = 900 yds
Furthermore, you may continue to check your range during the approach as the angle of he bearing tangent to the oiler's side changes. As this angle changes to other values that divide easily into 1800, you can quickly calculate the distance (e.g., when the angle reaches 6 degrees, distance equals 1800 / 6 = 300 yds).
4. When ready, the Conning Officer, on the engaged wing of the bridge, increases speed and begins the approach.
a. Using the "coast in method" the approach ship will be moving into station at least five knots faster than the speed of the control ship.
b. Keep about 5 yards of open water between wakes to ensure a parallel approach.
c. The conning officer may now use the radian rule to check the approach.
(1) At 900 yards the supply ship's side should bear 2 degrees from "R" course.
(2) At 600 yards the supply ship's side should bear 3 degrees from "R"course.
(3) At 300 yards the supply ship's side should bear 6 degrees from "R" course.
d. Drop speed to match the replenishment speed at a distance which will have you coast alongside into station.
(1) Watch the ship's speed indicator carefully as the speed drops.
(2) Practice will determine when to drop to replenishment speed.
5. Be aware of the Venturi effect.
a. When underway, there are areas of decreased water pressure (suction) amidships and increased water pressure at the bow and stern as the result of the differences in velocity of the flow of water around the hull.
b. When ships are alongside each other underway, this Venturi effect is increased and becomes further complicated because of intermingling of the pressure areas.
c. The Venturi effect is increased as the ship's speed increases, as the distance between ships decreases, and as the depth of the water decreases.
d. Avoid pointing your bow in toward the supply ship at the point of overlap or your bow will be sucked in by the Venturi effect.
E. MAINTAINING STATION ALONGSIDE:
1. Final Positioning:
a. Sufficient distance between ships must be maintained to ensure the replenishment can be accomplished with safety and efficiency. The proper distance depends on:
(1) Wind and sea conditions.
(2) Size and type of ships.
(3) Ability of ships to maneuver alongside.
(4) Type of transfer rig.
(5) Depth of water.
(6) Replenishment speed.
(7) Sheer Currents.
b. Normal distance for most ships using a fuel STREAM Rig is 80 to 180 ft., and for a cargo STEAM Rig 80 to 200 ft.
c. Some possible hazards of not maintaining proper distance include:
(1) Ships steaming too close:
(a) Restricts maneuverability.
(b) Increases the probability of collision.
(c) Increases the turbulence between ships.
(2) Ships steaming too far apart:
(a) Puts undue strain on rigs.
(b) Causes decrease in transfer rates.
d. The conning officer should use the phone/distance line to measure the lateral separation between the ships. This line has colored markers every 20 feet and is hand tended to ensure proper tension is maintained.
e. There are two effective methods for the conning officer to use in maintaining the proper fore/aft positioning of the ships. The first of these is to line up two uprights or other objects on the supply ship (such as antennas, stanchions, or UNREP station kingposts) and watch their relative movement. The second is to use the station keeping device (consisting of a white triangle on a black background which will be fully visible when the ship's position is correct).
(1) The conning officer must be alert for trends in ship's movement which indicate that fore/aft positioning is incorrect, but should not constantly change course or speed for minor variations in position. Slight variation is to be expected and attempting to correct it will result in overcompensating.
f. The conning officer is continually monitoring the phone/distance line, fore/aft positioning, the gyro repeater, and the rudder angle indicator repeater.
g. The conning officer should never watch the ship on the opposite side of the delivery ship as vertigo and disorientation may develop.
F. OTHER KEY BRIDGE PERSONNEL:
1. The Ship Control Safety Officer (Helm Safety Officer) - ensures the helmsman and lee helmsman acknowledge and comply with all orders from the conning officer.
2. The Course/Speed Status Board Keeper - maintains a status board as an aid for the conning officer in recalling the last order to the helm or lee helm.
3. Phone talkers - maintain communications between the bridge and UNREP stations and the bridge and the delivery ship's bridge.
4. Relay Officer - stationed between the wing of bridge and helm/lee helm to ensure proper relay of commands when amplified communication between the conning officer and the helm console is not possible.
a. Not necessary if a sound powered headset/handset is set up on bridge wing.
G. INFORMATION RECEIVED/ISSUED BY THE OOD DURING UNREP:
1. Status of the Rigs:
a. The OOD is informed when they are hooked up and when they are broken.
(1) Stations will request permission from the OOD to tension or detension the replenishment rigs.
b. After giving permission, the OOD is informed when the rigs are tensioned/detensioned - In no case should the ships be closer than 140 feet when rigs are tensioned. (IAW NWP-14)
(1) The conning officer should alert the helmsman prior to tensioning/detensioning rigs, because the tensioning/detensioning can cause the ship to yaw, and is important that the helmsman anticipate this effect in order to maintain the ordered course.
c. The OOD is kept informed as to the status of the replenishment, including such items of information as:
(1) How many loads have been received at each station.
(2) How much fuel has been received at each station.
(a) Fueling stations will request permission to commence pumping and take a blowdown/backsuction.
H. BREAKING AWAY:
1. Display appropriate flaghoist - the receiving ship will display the PREPARATIVE pennant (Prep) as previously discussed.
2. Changing course and speed - the receiving ship will normally change course and speed to clear the delivery ship.
a. Upon hearing the report "all lines are clear," the conning officer should:
(1) Check that all lines are in fact clear.
(2) Increase speed moderately (3-5 kts) and clear ahead.
(3) Direct course outboard in small increments of two to four degrees.
(4) Ensure that all wires are clear of the water before altering course so as to avoid fouling the screws.
(5) Refrain from major course changes and rudder orders until well clear of delivery ship so as to avoid swinging the stern into the other ship.
I. EMERGENCY BREAKAWAY:
1. An Emergency Breakaway is conducted as an accelerated normal breakaway (the procedure is explained in detail in Unit 5). The object is to disengage quickly without damaging the rigs, the ship, or personnel. Five short blasts of the ship's whistle are sounded and word is passed on the 1MC (eg. "Emergency breakaway, Emergency Breakaway, port side").
2. The conning officer must attempt to maintain station until all lines are clear. In no case should the receiving ship disconnect a tensioned spanwire. The delivery ship will detension all rigs as quickly as possible, and if necessary will allow hoses and wires to run into the water in order to clear all lines (this is avoided if possible since wires may foul the screws, but may be preferable to parting a tensioned spanwire). No attempt is made to clear fluid from the hoses in an emergency breakaway.
3. If a collision is unavoidable, an attempt should be made to reduce the fore/aft relative movement between ships when they hit and to hit at as wide an angle as possible (ie. the ships as near to parallel as possible) in order to reduce damage.
a. A glancing blow is better than one which scrapes along the ship's side.
J. ADDITIONAL USES OF THE RADIAN RULE:
1. The Radian Rule, which was previously discussed as a tool for making CONREP approaches, has other applications as well. The following paragraphs contain several examples of the use of the Radian Rule.
a. Station Keeping:
(1) You are the conning officer, steaming at night with Task Group 60.2 in the Atlantic and bound for Gibraltar and a Mediterranean Deployment. The Task Group Commander has ordered all ships to maintain strict EMCON silence on all radars. Ships are, however, allowed to make a few sweeps with the SPS-55 surface search radar at random intervals (no more often than every 30 minutes).
Your assigned station is on the starboard beam of the guide at 2000 yards. During your last few sweeps of the 55 Radar, you were able to determine that the range to the guide closed to 1800 yards over the last 30 minutes. Using the radian rule and the three minute rule, you can determine the course change required to regain station within three minutes. Formation speed is 20 knots.
The first step in this problem is to rearrange the Radian Rule such that
A = 60 S / D
D = THE DISTANCE THAT THE GUIDE WILL TRAVEL IN THREE MINUTES
S = THE DISTANCE THAT WE WISH TO MOVE OUT FROM THE GUIDE IN THAT SAME THREE MINUTES
A = THE ANGLE THAT WE MUST STEER OFF THE GUIDE'S COURSE TO END UP ON STATION AFTER THREE MINUTES.
NOTE: The time period may be any multiple of three minutes that is convenient to the conning officer. Putting in the values in this case we have:
A = 60 (200) / 2000 = 6 degrees
In other words, if we steer 6 degrees to the right of the guide's course, and hold that 6 degrees for three minutes before returning to the formation course, we will be on station (or slightly aft in bearing). The bearing may be easily corrected by a slight increase in speed once you return to formation course.
b. Range to a Contact at Sea:
(1) You are the conning officer on a DDG conducting peacetime exercises in the Persian Gulf. As part of your assigned duties, your ship is to shadow the CIS Udaloy class guided missile destroyer, Admiral Kharlamov, which is conducting ops in the area. You are not radiating any radars. The U.S. Navy cruiser in whose company you are operating has ordered you to maintain station on the Admiral Kharlamov's port beam. From the INTEL brief you received, you recall the Admiral Kharlamov's length is about 180 yards (177 yds). Observing a beam aspect, using the Radian Rule, your knowledge of the contact's length, the gyro repeater on the starboard wing, and a bearing circle, you make the following calculation to determine the present range to the Admiral Kharlamov.
D / 60 = S / A where D = RANGE TO CONTACT
S = APPROXIMATE LENGTH OF THE CONTACT
A = DIFFERENCE IN BEARING BETWEEN THE BOW AND STERN OF THE CONTACT
And D = 60 x S / A
In this case D = 60 x (180) / 25 = 432 yards.
Remember that the Radian Rule is an approximation and that its application is limited to small angles (where a straight line is a good approximation of a segment of the circle). Knowing the limitations, the utility of the radian rule is a function of the conning officer's mathematical ability and imagination.