Underway Replenishment (UNREP)

To commence the approach and begin closing the guide, all that is required of the approach ship is to increase engine speed by 4-5 knots. While closing the distance to the guide ship, the lateral separation between ships deserves some attention; however, if the approach ship has established good waiting station, it is likely that nothing more than minor course corrections will be required until alongside.

When about one ship length astern of the guide, the approach ship reduces speed to 1-2 knots above base speed. From this point until alongside and settled in position, matching speed will be the conning officer's primary concern.

As the approach ship's bow crosses the guide ship's stern, the approach ship rings up an engine order to match base speed. Before reducing to base speed the conning officer should ensure that there is enough momentum to pass through the pressure wave generated by the guide ship and carry the approach into station. From this point forward, engine orders to bring the ship into position and match speed are made almost entirely by eye, keeping in mind the base speed determined while in waiting station.

As soon as the approach ship reaches adequate position, a shot line is sent for the phone and distance (P&D) line, which is marked every 20 feet by a flag. Once the P&D line is across, the job of maintaining separation becomes much easier, since constant "eyeballing" is no longer required. The P&D line also provides for bridge-to-bridge communications via the sound powered phone line. Once alongside, the shot lines for the replenishment stations can be sent over, the messenger hauled across, with span wire and hoses following. The team on deck and in the pump room are then ready to commence cargo transfer.