I’ll be adding the Versabar 10000 to my Christmas wishlist
A chain cuts through a capsized cargo ship filled with cars
111–120 of 136 posts
Re: A chain cuts through a capsized cargo ship filled with cars
#112This 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 explosive…
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 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.
Re: A chain cuts through a capsized cargo ship filled with cars
#113Earlier quoted context omitted.
>> 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.
It’s almost as if I put a disclaimer at the top of my post about how these two concepts were related, but not the same....
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.)
Re: A chain cuts through a capsized cargo ship filled with cars
#114This 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 explosive…
Other people here are shitting on your comment, but I appreciate your random torpedo facts!
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.
Re: A chain cuts through a capsized cargo ship filled with cars
#115Earlier quoted context omitted.
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.
This salvage operation is far more expensive than the scrap value of the ship and cargo.
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.
Re: A chain cuts through a capsized cargo ship filled with cars
#116Earlier quoted context omitted.
>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…
Until the intern decides that running a nut up 30 feet of threaded rod is silly, uses two rods, and you have the Hyatt-Regency. :-)
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 and everyone else has to try and hold their tongue.
Re: A chain cuts through a capsized cargo ship filled with cars
#117Earlier quoted context omitted.
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.
Well put. 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.
Re: A chain cuts through a capsized cargo ship filled with cars
#118How do they put the chain under the ship for the cutting? The ship is on the ground, and the article doesn't provide any details on that part.
Re: A chain cuts through a capsized cargo ship filled with cars
#119Earlier quoted context omitted.
"Insurance losses on the ship are estimated at $70 - 80 million, and $80 million in its contents."
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...
Merchant ships are actually pretty cheap. If you think about it, it's mostly steel supporting empty space and a really big engine.
It's not at all unusual for the cargo to cost far more than the ship that's carrying it.
Re: A chain cuts through a capsized cargo ship filled with cars
#120Earlier quoted context omitted.
Presumably a lower margin activity though.
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.
Only the ones that get marooned have the really high costs.