This related to, but not the same as, the mechanism by which modern torpedoes kill warships.
Historically torpedoes used to hit the sides of ships, punching big holes. The response by ship builders was to build empty “torpedo bulges” on the sides of ships to trigger the torpedo early, preventing structural damage.
Modern torpedoes instead detonate under the ship. The explosion creates a massive bubble (most explosives being nothing more than a solid that’s itching to turn into a hot cloud of nitrogen). This bubble ends up under the ship, resulting in a ship that’s supported at the ends and not the middle. It turns out modern ships aren’t strong enough to support their own weight in this way, and the ship breaks in two.
Obviously this lacks the grinding mechanism described here, but the similarity is in the application of a huge amount of force in the middle of a ship to break it.
This is a great example of a generalization gone well beyond the end of its usefulness.
This has no relation to a torpedo at all except that the localized mechanical force exceeds what the material can handle. But that's how every, cutting bending shearing, swaging, grinding, etc, etc operation works.
I think it's more that "hey you might assume that ships are these big strong things that you can't just cut through but that's a misconception; they're actually weak enough they can't even support their own weight -- a fact that was exploited by torpedo designers."
It's also not true for some ships, depending on exactly what you're talking about.
It isn't just being forced to support its own weight by a bubble that sinks ships... it's the force applied in the direction it's applied by the explosion of the torpedo. Most hulls aren't designed to handle a sudden non uniform upward moving force in their middle accompanied by a shock wave.
I wish the article had more information about the chain itself. I've seen this done with diamond cutters on wire rope (like used for the Kursk) but not with chain. From the look of it, the chain has the outside of the links coated with abrasive?
I assume it's just a big f-ing chain and they hardfaced the crap out of it. This is the salvage industry so they tend to go for low buck solutions like that for a variety of reasons.
From the photos it doesn't look like the chain is abrading the steel of the ship, more tearing it in the way you can tear aluminium foil with your hands.
I thought the comment was interesting. I wouldn't assume that all readers are looking for exact tech info or already knows what was said or thought about it.
Perhaps instead of saying 'This related to, but not the same as' the commenter could have just said 'this reminds me of'.
Very few people need to know this or will use the info and if they do they wouldn't rely on an HN comment just reading out of curiosity.
>> huge amount of force in the middle of a ship to break it.
But that isn't what they are doing. This isn't cracking the ship into halves. This is very slowly grinding a hole through the structure. Look to the edges of the cut line and you will see the failure mode of the metal is very different. No sharp/jagged fractures, more round peeling off of metal. It is the difference between using an axe and using a saw.
I found what you said interesting (my other comment) and noted if you had said 'this reminds me of' probably others would not have jumped on you for the phrasing. (I thought it was fine and I learned something I hadn't known or thought of.)
Unfortunately, that is wrong as well. Ships generally can support their own weight if only supported at the ends. Because waves exist a ship can find itself with the stern on one crest and the bow on the next with little or nothing supporting the middle. The under keel explosion works better because:
(1) The weight of the ship acts against the explosion increasing the initial stress
(2) The gas bubble created can vent straight up on a side explosion. Under the keel means it has to go through/around the ship increasing the stress.
(3) Since the explosion lifts the ship you're going to get significant additional damage when it crashes back down into the water.
(4) Like (2) as the gas bubble disperses water rushes back into the vacuum. All of this water coming back in will collide in the middle resulting in a geyser going straight up into the ship.
I was thinking the support it at the ends and it will break explanation is lacking.
Thinking about it is you detonate an explosive under a boat it's going to create a shock wave that will hit the boat like a hammer and probably do a fair bit of damage to the hull before maybe the support at the ends thing happens.
What astounds me is that the "cutting chain" appears to be just a normal chain, albeit a very large one. I would have thought they would have made something that cuts it more like a giant chainsaw.
The chain is made of harder (by a substantial enough margin to not wear through too quickly) metal than the ship. Also, the cross section of any given link is much thicker than any one piece of steel in the ship so it doesn't really need to cut efficiently, it just kind of crunches and tears the ship out of the way using the ship's own weight.
It's a wear part. Yes, it will wear, but that's logical, just like a knife will get dull when cutting cheese. The impressive bit to me is that it lasted 25 hours. They then fixed that one link and went on cutting. Keep in mind that it still is a chain and that all it took was for one link to break under a load that was not exactly typical for a chain and after some abrasion of the link itself.
At these scales, and being able to use the hull's weight against itself, that chain is plenty "sharp" just by itself, I guess (sharpness being the ability to concentrate force on a comparatively small surface area). Adding teeth to the chain would probably not be worth it and/or they would just dull or break soon anyway.
Also using an alternative line an abrasive cable would not make sense either. If friction causes it to tear it would need complete replacing, which would be plenty $$$.
Instead, with a chain they just replace a couple of broken links and back on track. Which is apparently what they've done:
> Unfortunately, the chain actually broke during the cutting operation. “Approximately 25 hours into the cut, the cutting chain broke,” St. Simons Incident Response writes on its website. Luckily, there were no injuries and there was no damage to the equipment. The team simply fixed the chain’s broken link, inspected the other links for signs of fatigue, and continued on.
>>> Adding teeth to the chain would probably not be worth it
When the Kursk was raised they first cut it in half using an abrasive chain/cable. In that instance it was pressed down from above the structure.
"A cutting chain made of abrasive covered bushes on a thick steel wire was pulled back and forth across the hull by the cylinders. Vertical forces were supplied by the controllable vertical position of the suction piles."
Yes, I think this is the right intuition. Given the size and weight of the hull, physics is operating at a different scale and “sharp” looks quite different from our daily experiences.
It reminds me of a Fermi estimate that my physics professor presented of how tall the tallest mountain on Earth or a generic planet of mass M could be. He started with the intuition that when the weight of a mountain overcomes the typical strength of chemical bonds, what we typically experience as “solid” rock will behave like a liquid and collapse.
It is. Between being harder than the iron of the hull, and the links, it acts like a chainsaw. The teeth are not as ideally formed, but it doesn't really matter as ideally formed teeth are not really practical anyway because of size (they need to be huge so as to not load up with chips).
Various other stories refer to the chain as a "diamond-encrusted cutting chain" so perhaps there's more to the chain than what you can see in the pictures.
I'm guessing similar to the diamond blades and pads used to cut granite. The edges usually aren't sharp, the blades are usually pretty wide, 1/8" kerf, but they're encrusted with diamonds. The blades don't usually get dull, they just wear down until the diamonds are gone. The diamonds not the blade itself does the cutting. Once the diamonds are gone, the blade will actually start melting and stuff.
I'm thinking it's got abrasive material embedded in the outside of the chain links. I kind of doubt it's diamonds, because that wouldn't work too well for steel and other ferrous metals, but it might be CBN or similar.
It surprises me that the chain cuts so neatly - if you look at the images the cuts look rather clean and surgical. I would have expected it to be more of a crushing and jagged cut.
The gear used in these large scale engineering ops is absolutely remarkable, it makes me wish I had a better understanding of our physical world.
Hope this interests someone else, the size of the engineering seems impressive.
I've had to cut down the title slightly to make it fit the HN character limit; hopefully it's still readable.
This is great, thanks for sharing.
It makes me think that as engineers eager to fix problems or building stuff we sometimes go for the solution we are most used to from past experiences (eg. use a huge saw to cut through) instead of thinking of the simplest & most cost-effective (eg. use a chain instead).
I was in St. Simons a few months ago, and was able to see this ship first hand. It’s enormous, sitting on its side in what looks like just a few feet of water. It’s close to the shore, maybe a thousand or 1500 feet out. A temporary information placard had been put on the fishing pier explaining what it was.
At the time it was all in one piece, but you could see them attaching the lifting equipment along the length, and it was clear it was going to be cut into pieces.
It must take an enormous amount of work to build an internal framework that can support the cut section being lifted from the side. I’m not surprised it’s taking so long so salvage.
>It must take an enormous amount of work to build an internal framework that can support the cut section being lifted from the side. I’m not surprised it’s taking so long so salvage.
Ships have to be able to withstand substantial side forces (in both tension and compression) as part of torsional loading in normal operation. There's no internal framework needed. Even if there was that would require a stupid amount of effort compared to just adding more lifting points.
It's stupid easy to figure out lifting solution in this case because this is a new enough ship that CAD models exist. If the owner doesn't have the CAD files you pay whoever you need to to get them (you just need a low detail model of the hull and bulkheads, not the high detail models that include plumbing and whatnot, those would be needlessly expensive), then import the models and then run numbers until you get numbers you like (e.g. section sizes the crane guys won't complain about and a safety factor corporate won't complain about). Then you tell the intern to use the CAD models to whip up a set of matching plates for lifting. If they have extra time on their hands maybe they'll make some random feature dong-shaped. Then you forward that attachment to the sales guy at the steel supplier you usually use.
All this stuff is routine business for the parties involved.
Havens Steel Company had manufactured the rods, and they objected that the whole rod below the fourth floor would have to be threaded in order to screw on the nuts to hold the fourth-floor walkway in place. These threads would be subject to damage as the fourth-floor structure was hoisted into place. Havens Steel, therefore, proposed that two separate and offset sets of rods be used: the first set suspending the fourth-floor walkway from the ceiling, and the second set suspending the second-floor walkway from the fourth-floor walkway.
Investigators concluded that the underlying problem was a lack of proper communication between Jack D. Gillum and Associates and Havens Steel. In particular, the drawings prepared by Gillum and Associates were only preliminary sketches, but Havens Steel interpreted them as finalized drawings. Gillum and Associates failed to review the initial design thoroughly and engineer Daniel M. Duncan accepted Havens Steel's proposed plan via a phone call without performing necessary calculations or viewing sketches that would have revealed its serious intrinsic flaws—in particular, doubling the load on the fourth-floor beams.
Years ago, I was a computer science major at Tulane University. At the time, Tulane put CS in the school of engineering, so every first year had to take a mandatory engineering safety class. The first day of class, they turned off the lights and played a home movie that was recorded during the dance at the Hyatt-Regecy. The video cuts out right before the disaster, but there is audio from one of the musicians, and they played that.
Sitting in a dark room listening to a huge crash followed by screams of pain and terror fully instilled the importance of engineering safety in me. This was 20 years ago and I still remember it clearly.
Often I wish everyone had some mandatory class like that to teach them the seriousness of the consequences of our actions.
When someone tries to tell my hypothetical intern about the Hyatt Regency I'm gonna use that to teach them a lesson about bike shedding. The gist of the lesson will be that "had the person who brought it up actually meant to be helpful instead of just showing off about how much they care about Safety(TM) they would have brought up that jet liner that kept falling apart because of the square corners in the hatch or some other more relevant failure story even if it is a less flashy one. We've all seen this kind of ass-kissing behavior. Some jerk does a reply-all to something with a low effort (and usually obvious) comment about how approach X would be better for <insert corporate initiative or buzzword of the month here> and everyone else has to try and hold their tongue.
Destruction as part of the salvage process to avoid just this situation has been done, though I'm not certain this is standard practice.
Mazda in 2008:
It all started about two years ago, when a ship carrying 4,703 shiny new Mazdas nearly sank in the Pacific.... The mishap created a dilemma: What to do with the cars? They had remained safely strapped down throughout the ordeal -- but no one knew for sure what damage, if any, might be caused by dangling cars at such a steep angle for so long.... The Japanese car maker, controlled by Ford Motor Corp. , easily could have found takers for the vehicles ... [but] Mazda turned everyone away. It worried about getting sued someday if, say, an air-bag failed to fire properly due to overexposure to salty sea air.... So it decided to destroy approximately $100 million worth of factory-new automobiles.
Really fascinating! And I can only imagine the infernal noise this process produces, with a gigantic "chainsaw" and a whole ship as a resonance chamber...
Talking "feeds and speeds", 7 feet per minute (1.4"/s) as a feed rate would obviously be crazy fast, so I presume this is the "speed", the linear reciprocating speed of the chain.
It's less "cutting" and more "crunching" its way through. Sheer brute force plastic deformation.
Does anyone know who pays for this process? I would imagine the owner of the ship, but I imagine there's a non-zero likelihood that something like this could bankrupt them. In that case... is there mandatory insurance or similar?
Depends on the jurisdiction. In many countries, yes there are insurance requirements. Even in ones where there aren't, most vessels owned by larger companies carry insurance for the same reason anyone else does.
On the other hand, since oceangoing ships are (mostly) regulated by the countries they're registered in, which is frequently a regulation-light jurisdiction like Panama, Liberia, or the Marshall Islands - there are a surprising number of situations where the owner of the ship just completely disappears and the ship is left to rot.
One of the most famous recent examples of this was the ship involved in the Beirut port explosion this year. After being impounded for being unseaworthy, it rotted at its moorings and eventually capsized in the Beirut harbor.
A quick trip through developing-country ports on Google Earth will have quite a few ships like this.
Curiously, this vessel appears to have been registered in the Marshal Islands, which is an independent nation with a rather unusual relationship [0] to the US that I hadn't heard of before. Presumably the law that requires US registration has a special provision allowing this? I wonder if the crew requirements are more relaxed with a Marshal Islands registration?
The difference is that the law only applies to ships that carry goods or passengers from one US port to another. Ships are allowed to (and often do) call at multiple US ports on a voyage, they just can't unload goods in one US port that were loaded in another.
For instance, the ship could have carried cars made at the Kia and Hyundai plants in Mexico to the US, and also loaded cars made at the plants in Georgia and Alabama for delivery to the Middle East.
That's substantially less than I would have expected. It means each car was valued at ~$20,000. I would have expected the ship itself to cost ~$250,000,000, but the HMM Algeciras, the biggest container ship in the world, only cost $140,000,000 to build. https://www.shippingandfreightresource.com/hmm-algeciras-lar...
The insurers of the ship and/or cargo would be paying to salvage whatever value they can extract from the wreck, to reduce their losses. You’re right about the non-zero chance of insurmountable loss, which is why the owner of the ship and the owner of the cargo would both have a shitload of insurance. Read about Lloyd’s and the shipping insurance business. People have been doing this for hundreds of years.
There are also fines for polluting the water. It wouldn't surprise me if the harbor authority was also levying a daily fine for blocking access to the port.
Definitely, but it’s the difference between losing $100 million or $99 million. They’ve already sustained the loss, the only thing to do now is try and offset it.
Scrap steel is worth $0.20 per kg. There is 28 million kg there, so the whole ship is worth $5.6 million in scrap value alone. That probably pays for the operation.
That gantry alone costs more than that. All of the salaries and fuel costs and everything are way more expensive. However, the ship is a navigation and ecological hazard so it has to go. I have no doubt my tax dollars are helping.
I find it pretty fascinating that even though the scale is absolutely enormous, the whole thing can be described in only one or two sentences. "Build a very large crane on a barge, then slice the ship into pieces and transport each section somewhere else".
Kinda like S3 is "a very large static file host", it is technically true but the scale involved makes everything a lot more involved.
If you ever thought tech people got paid obscene sums compared to the rest of society, just look into marine salvage, marine welding, etc. and the cost of those ships per day...
I would guess the opposite actually. There must be such a small number of companies that can handle these scales but a disproportionately large number of ships that we’ve produced of this size. I would bet there’s real good money to be made.
Why not just refloat the ship? Floats and weights in the right places, together with the tide going up and down ought to be able to turn it over. It wouldn't be too expensive either because all work could be done above the waterline at low tide.
When it's the right way up, industrial diesel powered pumps could pump it out enough to float and reuse.
Perhaps there were political reasons? (ie. if the ship is refloated, the original owner would own it, whereas if its scrapped the port authority can take the collected 'litter' as payment for the work)
Refloating was already tried a few times and failed
>PCTC Golden Ray was partially capsized in St. Simons Sound, Georgia, when the pilot deliberately grounded the 20,000-dwt ship in response to a fire on board on 8 September. It was sailing out with 4,200 vehicles on board and was grounded on a soft seabed.
>Attempts to refloat the vessel have so far failed and the US Unified Command handling the salvage has decided to disassemble the ship in situ. It believes attempting to right and refloat this ship would not be technically feasible.
The key to the salvage effort not involving refloating is probably related to the loose tangled masses of vehicles it's carrying; the ones that already caused the ship to fall over.
I don't think the original owner would own it outright, at the very least there is the Law of Salvage (https://en.wikipedia.org/wiki/Law_of_salvage) where the port authority (or whoever else refloated it) would be entitled to "a reward commensurate with the value of the property salved."
Also, from the first image in the picture you can see that the cargo has shifted and is now all on the side of the ship . Modern cargo vessels don't have that much excess stability, so chances are that it would not stay upright even if it were completely pumped full of air.
Interesting to see whether this will work for the "last" part. I can understand why it works while cutting off smaller parts of a longer ship, but at some point I would expect the ship not to be heavy enough. At that point I would expect it to be lifted and turned by the chain instead.
But they probably already thought about that and I just missed it in my rapid skimming of the article.
A salvage operation with some similarities was that of the MV Tricolor, a car carrier ship with a bumpy history sunk in December 2002 and salvaged 2003--2004.
Sure, somewhere around 1/1000000 of a contribution. One ship grounded out of how many successful trips? One car out of how many shipped per trip?
Plus, the cost for cleanup for this kind of disaster is built into the price of each car/phone in the form of shipping costs, which include insurance costs. So while they contributed to the damage, they also contributed to the cleanup.
I'm not going to lose sleep over it. It's just a trained response to how sensitive we are about it in the local area. Motor oil spills are a big deal because they are more than just a fraction of the crude oil - they contain various toxic additives including heavy metals and can affect the local watershed.
I realize it's still likely a drop in the proverbial bucket. :(
Does nobody else have a problem with these "lazy loading" webpages?
Each image takes a few seconds to load, and if I scroll too far then the images no longer load. It seems that no image will load until the previous image has loaded, and only images currently at the scroll position will load, so I cannot just scroll to the bottom of the page and let it all load. This is on Firefox 83 / Ubuntu.
This looked really cool, but I kept getting distracted by the sheer amount of blank ad spots (tysm UBO!), they were constant.
Literally every picture in the 'article' was paired with an ad. How tf is anyone supposed to concentrate on what they are reading with constant interruptions?
Even with the ads just being blank spots it drove me so nuts I added jalopnik.com to my blacklist.
The new owners of the media company have been...liberal with their sale of advertising space. Jalopnik has long been an interesting site, but the ownership is making it very difficult to continue as a reader.
Historically torpedoes used to hit the sides of ships, punching big holes. The response by ship builders was to build empty “torpedo bulges” on the sides of ships to trigger the torpedo early, preventing structural damage.
Modern torpedoes instead detonate under the ship. The explosion creates a massive bubble (most explosives being nothing more than a solid that’s itching to turn into a hot cloud of nitrogen). This bubble ends up under the ship, resulting in a ship that’s supported at the ends and not the middle. It turns out modern ships aren’t strong enough to support their own weight in this way, and the ship breaks in two.
Obviously this lacks the grinding mechanism described here, but the similarity is in the application of a huge amount of force in the middle of a ship to break it.