Parbuckling on the Costa Concordia: Historical Origins

You've probably seen the term parbuckling in connection with the Concordia work, as on The Parbuckling Project website. The website is partly correct in its description of early parbuckling as a way to roll heavy casks uphill.

That was one meaning in 1800, but “parbuckling” goes back earlier, and concerns artillery instead. Parbuckling was a way to haul heavy cannon from the base of a hill to the top, say when building a new fortification. Relocating heavy wheeled cannons across rough landscape proved such a problem during the Seven Years War in Canada that the Royal Artillery added rough-ground rigging to its curriculum for new cannoneers, and set up obstacle courses to train them.

As an example, a common parbuckling job for artillerymen was to remove the gun tube from its carriage (which can be done without a major effort by tilting the carriage forward until the muzzle is on the ground), then rolling the tube uphill, using ropes, blocks, and wooden runners. The carriage was brought up separately, on its wheels.

  

While it may seem that the gun crew could have saved some trouble and used whatever wheeled carriage the gun came with, when it came to the bigger guns, those carriages were only usable on a level, hard surface. Otherwise the carriages were top-heavy and the wheels dug in. If dragged across rough and steep ground, the carriage and mounted gun would likely mire or tip over on a slope, rolling over and freeing the tube's trunnions from their mounts, at which point the cliche “loose cannon” takes on real meaning.

So it was best to pull the gun tube from the carriage at the start of the operation and roll it along the ground, using parbuckle ropes, then remount it at the destination. For very heavy tubes, the gun crews laid wooden rails along the ground to ease the job.

Parbuckling is one of many ingenious rigging methods worked out by combat engineers through the centuries. Many are still in use, such as the gin pole I saw used by tower workers when I visited a tower-building job for Smithsonian.

Costa Concordia: Ready for the big pull

Readers of Disaster-Wise may know that I'm a fan of heavy rigging and the related work of collapse rescue, because such projects demand ingenuity, practical knowledge, and nerve. Through the years my writing research has taken me to rigging sites including collapse scenes, tunnels, towers, and derailments.

Photo: Parbuckling Project

 

In the heavy-rigging news this week: almost 20 months after Costa Concordia blundered onto the rocks off the island of Giglio, Italy, drowning at least 32 people, Italy's Civil Protection Department has given the Titan-Micoperi joint venture permission to pull the Costa Concordia upright, which (if the ship holds together) will allow a row of steel flotation boxes called sponsons, welded to the sides and bow like water wings, to ease it off the seabed so that tugs can haul it to a breaker's yard.

Weather permitting, the job of setting Concordia upright could start on Monday morning, September 16, local time. It will take the better part of a day to execute. Rest assured that hundreds of media reps will be watching from land, sea and air, so you won't miss anything.

The salvors will use computer-controlled strand jacks, wire rope, and sponsons to roll the ship very slowly from its capsized position. Right now it's laying on the starboard side, 65 degrees off vertical. If the parbuckling works as intended, the ship will come to rest in one piece, grounded but now upright on a temporarily leveled seafloor. (The leveling work was done with big bags of cement grout and giant steel frames, all of which will be pulled out later. Only anchor holes will be left in the reef, we are told.)

The groundwork should help keep the ship from breaking in half, as it would surely do without the leveling job, since the hull came to rest on two underwater promontories.

Here's my summary of the parbuckling plan. It will need three moving forces:  a row of flotation tanks welded to the port side of the ship that will serve as a downward force when flooded, and two sets of tension rigging on opposite sides of the ship. (By "rigging” I mean the full set of blocks, wire ropes, chains, anchors, and computer-controlled strand jacks.)

Here's a strand jack:

Now for the moving machines.

1) Parbuckle rigging: These are visible as a set of cables on the portside, the side facing the open sea. They will haul the ship upright most of the way, until weight from the flotation tanks (aka sponsons) take over. Specifically, strand jacks mounted on the sponsons will slowly take up cables whose other ends are anchored to underwater steel frames that make up the temporary seabed foundation.

2) Holdback rigging. This will keep tension on the bottom of the hull. Strand jacks will be visible on anchor towers on the starboard side. (Starboard is the side facing the seashore.) The main job of the holdback rigging is to keep tension on the hull nice and even, and to keep the ship from sliding across the temporary seabed, destroying the underwater platforms, and then rolling down the slope in reaction to the pull from the parbuckling cables.

3) Flotation tanks on the starboard side. These will flood to provide seawater ballast at the time of the parbuckling. (Later, for the tow to salvage, they will be pumped out and provide buoyancy for the flooded hull.) Apparently this ballast is necessary to bring the hull down to the seabed, because the ship's compartments will still have some buoyancy as the parbuckling begins.

There are several risks associated with this work, and I'll go into that in another post.

Visiting the B-2 Bomber Wing: A look at weapons loading

For those curious about the nuts and bolts of weapons that might be employed over Syria if the US intervenes, following is information I gleaned during a recent visit to Whiteman AFB at Knob Noster, MO, for Air&Space/Smithsonian Magazine.

The article as printed in August, "Stealth Bomber Elite," is here; this is bonus material.

(USAF / Senior Airman Nick Wilson )

Having heard of the sophisticated rotary launcher available to B-2 mission planners, I had the mistaken idea that such a high-tech bomber must take on its cargo automatically: perhaps a launcher preloaded with munitions elsewhere in the base, then hustled to the aircraft on a trailer and plugged into a B-2 bomb bay a half-dozen bombs at a time … fast and easy, like ramming a clip into the 9mm pistol issued to pilots before each combat mission.

Time with a bomb-loading crew in Whiteman AFB's Weapons Load Trainer straightened me out: While machines substitute for some of the muscle-power, it's very much a hands-on task, from bomb assembly in the weapons depot to loading the plane behind the closed doors of a dock. That goes for the 30,000-pound Massive Ordnance Penetrator to the smallest, a 500-pounder: all are individually loaded.

Conventional bombs can go on board with no more than tail fins and fuses, or they can be enlightened with JDAM guidance packages. The JDAM unit (short for Joint Direct Attack Munition) relies on satellite signals and inertial navigation to steer the bomb with swiveling tail fins and strakes. Because each JDAM-guided bomb is individually cabled to the plane's targeting computer, the crew can reassign targets over enemy territory. Boeing recently announced manufacture of the 250,000th JDAM kit.

On display when I visited the training facility, which is about the size of a high-school gymnasium, were a full range of conventional bombs. That included green-painted free-fallers, and gray glide bombs with wings that swung out, along with a powered version like a small cruise missile. All were practice models, for loaders to use during initial training and recertification.

The demonstration that morning featured a 5,000-pound bunker buster called the EGBU-28: taking it from its perch on a trailer and loading it into a practice version of the B-2, which featured a rotary launcher in the right bay and Smart Bomb Racks in the left.

According to the pair of sergeants giving me the tour, the combination of GPS and inertial guidance on this bomb's JDAM kit would be accurate enough to put the first bomb in the top of a steel drum, then a second bomb in the hole made by the first.

The loaders had a diesel-powered truck with a hydraulic arm designed for bomb loading, a rugged and bulky remote control, hand tools, and a checklist with grease pencil. And a good deal of elbow grease, as shown by the first job: moving the bomb-bay door from a vertical position and pinning it back so that it's out of the way, against the wing.

The green bomb was long and slim, with a rod-like nose.

(USAF / Airman First Class Shelby Orozco)

The driver edged the loading arm under the bomb's midpoint, then raised and rotate it to line up with the truck's direction of travel. A few turns of the steering wheel and it was lined up under the left-hand bomb bay. Each step was called out and repeated. Watched carefully by an airman on an orange ladder wearing a headlamp, the lift arm edged around obstructions to snug the bomb against an open slot on the rotary launcher, called a station.

For a brief moment, as the loading crew released temporary fastenings in preparation for shifting the deadweight to the aircraft, the 2 ½ ton bomb lay neatly balanced on the tip of the loading arm. Now it was time to make all connections and verify that nothing would come loose: a sway brace to hold it in place, a data cable to provide updates from the aircraft, and an explosive cartridge to separate the mechanical fastenings during the run. Loading the bomb took about five minutes. After each bomb goes aboard, a control panel at the stairway to the cockpit activates hydraulic power that swivels the launcher to take on the next weapon.

While the noncoms had good words for the efficacy of this particular bunker-buster, what I didn't expect was their enthusiasm for a lowly 500-pound non-bunker GBU-38 bomb with a MK-82 warhead ... if JDAM-equipped. The B-2 can haul 80 of these in the Smart Bomb Rack, totaling 20 tons, compared to a maximum of 16 one-ton bombs using both rotary launchers.

“With these you can destroy all the facilities on an airfield and leave the daycare center standing,” said one of the non-coms. Because a 500-pound bomb can demolish most targets as well as a one-ton bomb can, having such a big swarm of bombs in the belly might allow a single B-2 trip to take the place of three, or even four, B-2 sorties carrying one-ton bombs. Hard or buried targets could be left for a separate mission carrying bunker-busters.

That's if people and computers can rise to the opportunity without errors along the way. The 80-bomb load hasn't yet been tried in wartime, even in the most recent engagement, the 2011 attack on Libyan airfields. There's a risk that, along with the more sophisticated situational-awareness tools now available to the pilots, the extra capability could over-tax pilots and mission planners back at Whiteman.

Thoroughly Modern Fantasy: Europa Report

Have been working on a wide variety of projects over the summer (the history of DEFCON alerts, a kids' book, and an article on helicopters for a luxury magazine called The Private Journey) but now it's time to catch up on the blog.

Some buzz in the last week in reviews about Europa Report, about the movie rising to an accurate depiction of space exploration.

Hmm - certainly compared to Armageddon, which was lucky to get even a 39% rating in Rotten Tomatoes.

Once the premise is accepted -- that a company would send people out to look for life by landing on the surface of the Jovian  moon Europa -- the procedures are  fine enough. But the plot line isn't accurate in the sense that any such human-led plan will be organized and carried out, now that robots and remote sensing are so capable and offer so much value. The JPL advisers were polite about this, referring in interviews to the importance of robots in planetary exploration.

For an article in Air&Space about "Humans or robots -- who's driving the spacecraft?" I asked former astronaut Story Musgrave his thoughts on the issue. He sees it as a partnership, but with robots touching down first.

"There's a robotics program and a human program, and we've kept them separate," he said. "True exploration of space is not happening. We need to integrate humans with robots." He illustrated with a Mars scenario. "The way to do this is to sent robots first – design and operate so that they lead the way for humans. As opposed to just doing the robot thing."

Strand Jacks, Pulling for You

One thing that makes the job of freelance writer interesting is the sheer diversity. In the last year I've written about drones, strategic bombers, astronauts vs. automated spacecraft, and crisis teams. Right now I'm working on war alerts, the validity of computer models, and a children's book.

Which brings me to yet another unconnected topic, the strand jack. Back when I worked in construction with my brothers, one tool that we greatly admired was the railroad jack, a heavy duty (and also very heavy) manually-operated jack sturdy enough to lift a bridge beam.

Railroad jacks push; strand jacks pull (more on that below). Here's a big strand jack, from mammoet.com:

(For those who might wonder what heavy riggers do, Mammoet does stuff like this, delivering coking units:)

Now about strand jacks, which will be critical to the success of salvage work coming up at Costa Concordia. First, the big picture, from Corriere Etrusco:

As animated in the Parbuckling Project, salvors will be pulling the cruise ship upright (that is, rotating the ship so that the superstructure moves to the left, in this photo), refloating the ship, and towing it to a drydock for scrapping.

While that may not sound too difficult, it is, for many reasons. And it's why the insurers' cost estimates are now edging $400 million.

Here's one reason for the high cost: Concordia is huge and its hull came to rest sideways on two subsea promontories, one fore and one aft. So that means the midships is sagging. While a gang of strand jacks can move any artificial object that mankind cares to build, however large, they can also tear it apart. If salvors were to just start using them to drag the ship upright, the tension on that unsupported midsection would break the hull in half.

So they've been laying down 20,000 tons of cement grout in big bags, filling in the valley (temporarily) to give the hull a sturdier foundation before the hydraulics do their stuff.

Recently Salvors have started the next phase, attaching big steel boxes called caissons to the port side. These caissons will be filled with water, and then it's time for the strand jacks. Here are a couple of the big blue machines, hanging from a formidable crane hook (Photo, Parbuckling Project):

Setting aside the caissons, here's a Parbuckling Project illustration showing how the strand jacks will be lined up along the port side, working in unison to drag the ship upright. 

The term strand jack comes from the fact that it exerts force on strands, commonly steel cables. Think of how you'd lift a bucket on a rope, hand over hand: one of your hands pulls on the rope, as the other shifts to get a new grip.

It's the same with strand jacks, which use hydraulic grips to pull cables a few inches at a time. Commonly the jacks work in groups under computer control.

Strand jacks are slow but very powerful. In 2004, strand jacks raised a 2,000-ton section of roof at the Wembley Soccer Stadium (Photo, Engineering News-Record):

 

Fertilizer-Plant Explosion in West, Texas

A little about the explosion at West, Texas. A Chemical Safety Board go-team is at the site, along with investigators from the Texas State Chemist . This news report says experts have identified the epicenter of the explosion, but aren't releasing that info yet. Later, we'll get the official word about exactly what exploded and why.

But the center is pretty clear from this photo in the Fort-Worth Star-Telegram, given streaks and the location of debris (Tony Gutierrez, Associated Press):

Note, for example, where the company's big ammonia tank sat (the round yellow foundation at upper right) and where the walls of that tank ended up. A line connecting those two locations leads to the center point of the explosion. While I haven't seen an official diagram of the plant, the epicenter looks like the north end of the dry barn mentioned in some news reports.

Here's a labeled photogram of the blast site, along with an aerial posted on Bing.com from last year. (Kudos to Bing and Pictometry for having recent aerial photographs on line):

We're told that West stored a large quantity of dry ammonium nitrate fertilizer in the dry barn, perhaps 270 tons at times. From a good piece in Chemistry World about ammonium nitrate, here's a snip:

"It is an intriguing feature of ammonium nitrate is that it should not, according to thermodynamics, even exist. It is a compound that contains nitrogen in two forms - surrounded by oxygen in one and by hydrogen in the other. In chemical parlance the nitrogen is, side-by-side, in oxidised and reduced forms. Normally one would expect them to react together, combining to form the more stable dinitrogen, dioxygen and water in a complicated partner swapping process called comproportionation. But in ammonium nitrate, this process does not happen at room temperature, making it a metastable compound, like a lake of water trapped behind a dam. Even if you are careful, ammonium nitrate is an accident waiting to happen."

When heated in a fire, ammonium nitrate doesn't always blow up but it might. If the smoke changes color to some shade of orange, that may mean the material is in a runaway reaction generating oxides of nitrogen. I interviewed a worker at a dynamite plant who once saw fumes from an overheating vat of metriol trinitrate change color in such a fashion, and he ran fast enough and far enough to survive the blast.

And one witness in West mentioned that the smoke from the fire at West Fertilizer changed color shortly before the blast.

Nightmare Range, South Korea

I'm a fan of H.P. Lovecraft. In our POW (plain old world) one doesn't often come across geographical names that measure up to Lovecraftian standards, along the lines of his Mountains of Madness. 

But here's a real one that comes close: Nightmare Range, a target-practice area in far north South Korea. It's just a hop-skip-and-a-ricochet from the DMZ, certainly reachable by shell from the DPRK's dug-in heavy artillery just north of the border.

Here's a map, from a recent naval survey of training sites, with the label for Nightmare Range highlighted at upper left, with its location to the side:

 

 

The border with North Korea is the gray line on the map just above Nightmare Range. On an island in the Yellow Sea south-southwest of Nightmare is Chik Do Range -- see the other label. Chik Do is where US bombers did practice runs last month. So we haven't been as provocative as some commentators are saying; practice bombing runs at Nightmare Range would have pushed tensions up a lot more.

Here's an aerial photo of Nightmare, from the Wikimapia site:  

This obscure location came up briefly during an August 18, 1976, meeting of the Washington Special Action Group (WASAG), a small but very influential foreign-policy advisory group in the Ford Administration and, previously, the Nixon White House.

The subject that day was what to do about a murderous attack in which a squad of North Korean soldiers jumped a small American-ROK team that was attempting to trim a poplar tree for better sightlines between observation posts in the DMZ.

Among the many response concepts bounced around by WASAG (not all of which have been declassified) was having American aircraft do practice bombing runs all the way up to Nightmare Range. That was scrubbed as too provocative, and more modest measures were taken when finishing the tree-trimming two days later ... but with a great deal of firepower waiting just over the nearest hill. Call it armed arboreal diplomacy.

For those interested in knowing more about what North Korea itself called an "ultra-tense" situation, I'm researching it as part of an article on military alerts to be published in Air&Space.