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Gunboat1

Sea Stories: UNREP and Breakaway Songs

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Sea Stories: #45 – UNREP and Breakaway Songs

One of the greatest strengths of the US Navy is its ability to replenish its ships while underway, in the battle area, rather than having to return to a port facility. This process allows refueling, restocking with needed stores, supplies and ammunition, and replacement of personnel, all while remaining at sea and on the move. When necessary, it can be done in conditions of complete radio silence, at night and in bad weather. These skills are not common to every navy in the world, and have been developed to their highest degree of expertise by our fleet.

So how do ships conduct Underway Replenishment, also known as UNREP? It is a complex dance of equipment and personnel, requiring tremendous expertise. Enormous forces are at play, and it is inherently risky in several ways. But the USN does it routinely, maintaining this vital capability to an extremely high degree of combat readiness.

Let's assume that you are the Officer of the Deck of a destroyer. It has been about a week since your last replenishment, and you have been operating continuously all that time. Your Supply Officer drew up a list of needed support items and transmitted it via an encrypted radio message to the supply ship supporting your battle group a couple of days ago. This list included several thousand gallons of your main propulsion fuel, 100 gallons of diesel fuel, and about five hundred gallons of aviation fuel for your embarked helicopter. Additionally, you need to replenish the dry, fresh and frozen foodstuffs being consumed by your crew, and bring aboard some needed spare parts, consumable supplies and of course, a major morale item: postal mail! (Think of your weekly grocery run, but for a crew of about 330, living and working aboard a technologically-complex ship.) If your ship has been engaged in combat, you might also need to replenish the missiles and gun ammunition which you have fired. All of this has been requested and the support ship has pulled your order, prepared it for transfer and made ready to pass it to you this morning.

Your ship proceeded to an agreed-upon rendezvous position in the middle of the ocean. There you met up with the replenishment ship. They have set a course and speed which serve both the tactical situation and the weather conditions, so that the roll and pitch of the ship is minimized. You line your ship up behind them at about 600 yards and slightly to one side of their wake, while final preparations are made, matching their course and speed and holding station. They signal that they are preparing to receive you along their starboard side; they are already replenishing another ship of your battle group from their port side! Soon it will be your turn to commence. They hoist signal flag ”Romeo” (the letter R) from a starboard halyard, but only about halfway up, or “at the dip.” You answer by hoisting Romeo at the dip on your port side, indicating that you are preparing to come alongside. When she is ready for you, she will “close up” Romeo, or haul it all the way up. And when you commence your approach alongside her, your ship will also close up Romeo to full hoist.

You then ring up more speed, so that you accelerate your 9000-ton ship to overtake the supply ship, advancing alongside her, and fighting the venturi suction created by the water passing through the gap between your hulls. When the timing is just right, you reduce your ordered speed to match the support's ship's (probably about 12-14 knots.) If you do this just perfectly, you glide into an exact position beside her, so that your replenishment stations align. Your two ships are now about 160 FEET apart. If you get too close, you collide. If you get too far apart, you can break the replenishment rig. You need to stay in this position, as closely as you can. This is akin to precision flying, but in ships weighing many thousands of tons. It requires skill to do this, and you have to maintain this position for an hour or two, in all weather up to Sea State 5 (8-12 foot seas, characterized as “very rough.”) And oh, yes, you sometimes have to do this in the dark.

Unrep is pretty much an “all-hands-on-deck” evolution, with everyone topside dressed in life preservers, protective clothing and colored safety helmets denoting each man's job for easy identification. Everyone needed is stationed and standing by. The announcement is made over the loudspeaker: “Standby for shotlines, fore and aft.” And at each end of the ship, a crewman fires a rifle loaded with a blank cartridge which launches a rubber plug attached to a very light nylon line across to the other ship. The line is taken in hand, and used to pull over a heavier messenger line, and then a “phone and distance line” which is passed to the bridge wing. This line is marked with numbered and colored flags and chemlights every twenty feet, so it becomes easy to monitor how far apart the ships are at any moment. It also provides sound-powered telephone voice contact between the two ships' bridges.

The messenger line is then used by the deck crewmen to pull over heavy steel cables which are attached to your ship above each replenishment station, and then tensioned using enormous hydraulic rams with cable pulleys which try to maintain a constant tension. One of these is rigged at each end of your ship. You are now tethered together with your support ship, fore and aft, by tensioned steel cables. And you maintain your position alongside, using constant rudder and speed corrections to do so. (Yes, this is as much art as science. Some officers drive better than others. It is a mark of seamanship. )

Perhaps your forward station is rigged to receive fuel. A large hose is sent over from the supply ship, with a special nozzle attached which fits into a matching receiver on your ship. Your crew pulls it across using its messenger line and latches it into place in the receiver. That receiver is ported through piping and valves, and aligned with the specific empty fuel tanks aboard your ship where you need THAT KIND of fuel to go. A separate hose brings a different kind of fuel to another fitting and alignment. And when all is ready, the support ship starts pumping fuel, at high rates of transfer.

Meanwhile, your after station is set up to receive dry cargo, which is contained in large cardboard containers called Tri-walls, suspended from heavy nylon cargo nets. Over the huge and heavy Tri-walls come; they are pulled across the intervening seas, are suspended over your deck and then lowered to it. As quickly as possible, the contents are manhandled into the ship for stowage in whatever place is appropriate. Here comes another Tri-wall. Repeat. And another. Repeat. All the while, both ships are underway, at night in 12-foot seas and howling winds. Can you see how this might be a bit dangerous?

If passengers need to be exchanged, they climb into a special chair and are passed along the wire between the ships, hopefully without suffering a dunking in the high seas as they transit the gap.

Oh, I forgot to mention. Supply helicopters are also passing ammunition to you, by suspending it in nets beneath them, and easing it down onto your flight deck all the way aft, while the rest of the operation continues. It likewise must be safely handled and stowed in the proper magazines aboard the ship. Can you say “ballet, conducted by a cast of hundreds, on a hazardous, moving stage?”

When all is completed, the cargo nets and empty tri-walls retrograded back, and you have taken aboard another week's worth of the sinews of war, preparations are made to retrieve all the lines, wires and hoses, finally leaving only one wire attached. Upon signal, the final connection is severed by a quick release, and the wire is quickly spooled back aboard the replenishment ship. Your ship rings up power to accelerate away, and gently diverges in course so that you don't collide.

Here is where panache takes over. An old tradition among USN ships is that you want to look sporty as you part company. You drive smartly, speed away and play a unique tune called your “Breakaway Song” over your topside loudspeakers so that it is audible to the supply ships crew. Your song reflects your ship's unique personality (and perhaps your Captain's musical tastes.) In my ships, our breakaway songs at one time or another included “On The Road Again” by Willie Nelson, “Long Train Runnin' “ by the Doobie Brothers, “Home Sweet Home” by Motley Crue, “Break On Through To The Other Side” by The Doors and Enter Sandman by Metallica. We actually once paraded a live band playing instruments on a high deck topside for extra style points! (They weren't that good, but made up in enthusiasm what they lacked in musical skill.)

Meanwhile, another ship is lined up aft, awaiting its turn to come alongside. Just another day at sea.

All hail the US Navy. This evolution is the pinnacle of the seaman's art, in my opinion. The next time you meet a qualified Surface Warfare Officer, spare a thought to his professional abilities, unsung though they usually are.

 

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Edited by Gunboat1
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As railfan stated in another of these stories, they are appreciated. Thanks for sharing an insight into Navy life that those outside the ranks would never get to know about. Great stories!

Edited by tadbart
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25 minutes ago, tadbart said:

As railfan stated in another of these stories, they are appreciated. Thanks for sharing an insight into Navy life that those outside the ranks would never get to know about. Great stories!

Thanks for the kind words .  Glad you are enjoying the stories.  GB1

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