I don’t think it needs to be robotic. They’re in cherry pickers with what looks like a cutter device on a pole. They could use a longer pole in case the structure shifts. They can’t know for sure how the weight of the bridge will shift as it is cut up. A small movement in relation to the size of the structure translates into a lot of movement near the workers.
Yup. Easier said than done though. It is dangerous work. Also consider that the lift is on a platform in moving water. That cutting torch will need fine adjustment.
I’m wondering if they have considered wrapping prima cord around the structures that need to be cut, backing off and whammo. Don’t know if it would do the trick.
You answered your own question. A long cherry picker arm on a moving surface (barge in waves) would mean lots of movement for the workers.
There are also lots of videos on youtube of cranes & other construx equipment toppling over when they get too much weight too far from the center of gravity. The longer the boom arm the more it’s not ideally placed, & while that may be okay on stable ground it wouldn’t be on a bobbing barge.
It’s very dangerous work for the divers.
Nerd alert. How to start the ship’s main engine. I thought this was interesting background information with no specific commentary regarding the accident.
Some takeaway from it:
- The stored air pressure is sufficient for 18 starts.
- They rotate the engine before starting to ensure everything is properly lubricated and cylinders are cleared out.
- The engine has a vibration speed that they have to power through to avoid damage. this is reminiscent of WW-1 aircraft engines. Apparently it can’t be balanced throughout the operating range due to it’s size and the fact that it’s direct drive to the propeller.
- Once the engine is brought up to operational speed the turbocharger becomes functional for efficiency.
It’s definitely not a turn-key operation. Lots of manual input from the crew. Very time consuming. Not an easy thing to deal with if the engine quits.
Great cite. Thank you.
Also, diesel engines do not simply “quit” while running. If they stop, there was a reason. And until the reason is corrected, you’re not getting it started again. E.g. No fuel, no oil pressure, water in the fuel, sludge in the fuel, failed fuel pump, failed camshaft drive, holed cylinder, fire in the electronic controls, etc., etc., etc.
What will not be the case is “It was running fine, it quit, we pushed the restart button / did the restart procedure, and it restarted in the normal timeframe and operated normally thereafter. Weird glitch.”
Very true but since the prop shaft is directly attached to the engine they have to stop the engine to reverse it. Something I’d expect after the engine was fully brought up to operating RPM. If for whatever reason they tried to reverse the prop that could have been the beginning of a bad restart.
As of 11-Apr they’ve removed 69 containers from the ship. X-Twitter
I would have thought more at this point but that’s where we’re at.
It wouldn’t surprise me if the collision knocked enough of the containers askew and at least partially free of their tethers that taking them off is like a multi-ton game of Jenga.
Very possible. Particularly if they have to rig straps by hand to each of the containers.
The usual way to lift containers for loading / unloading requires the grapple unit to sit flat on the container roof. Which works fine if the container is level fore/aft and left/right. But not at all if it’s not.
So the quick automated way is out. Multi-ton Jenga indeed.
Anyone know why they aren’t using a larger crane? As best I can tell, the largest (floating) crane they’re using is the Chesapeake, with 1000 t capacity. Sounds like a lot, but it’s modest compared to other floating cranes. Some of those have a rather large draft–but the Hyundai-10000 has a 10,000 t capacity and an 11 m draft.
The BBC article mentions that the ship has a ~4000 t section of bridge on it, so it’ll have to be cut up to be within the capacity of the Chesapeake. But that’s easily within the limits of the Hyundai-10000.
There’s some question of having the right points to grab on to… but that seems like an easier problem (and safer for the humans) to solve than cutting it into pieces.
There appear to be only a few stacks in the first few rows on the port side that have collapsed. The vast bulk of the stacks look fine to me.
I haven’t kept up with the news and don’t know the salvage plan - but my expectation would be that they will only remove containers that need to be removed to get at the collapsed bridge section and free the vessel. They may possibly need to remove some containers to lighten the vessel forward but I doubt it - unless she’s hard aground and well out of draft forward.
They will try to remove as few as possible because it’s far easier to refloat the vessel as is, then take the containers off alongside.
Jenga isn’t really apt because they will start with the top containers. They will hook onto the twistlocks in the top corners of a container, take the weight, then remove any lashings, then either unlock or if jammed (quite likely) gas axe the twistlocks from the lower corners to free the container from the one below. Dangerous work.
Many of the containers are likely to be empties or well under max weight. That can allow them to simply lift a whole stack (or most of one) all at once by the same procedure.
I don’t know if this is covered in the video but during manouvres in/out of berth the bridge team may call for numerous stops/re-starts to go forward and reverse. You mention capacity for 18 starts - that is no doubt true of that youtuber’s vessel, but it isn’t a universal figure and there are vessels which have capacity for fewer.
What happens is that compressors are running full blast compressing more air for more starts, but if there are multiple stop/starts in a short period, compressed air is used faster than the compressors can replace it. I’m given to understand that things get fairly tense on the bridge when the pilot has been calling for numerous engine re-starts and the Chief Engineer phones the bridge and says somewhat tersely “You have two more starts, Captain!”.
In this case, there was no reverse as far as I can see. The Dali left her berth forward and then did a 180 to head down river.
Yes this is a complete sidebar. It has nothing to do with this incident.
Hopefully in a Scottish accent!
There is now a criminal investigation - The FBI and the US Coast Guard are leading the criminal investigation into the disaster and whether the crew failed to report an earlier issue with the vessel that delayed its departure, the official said.
I wonder if it’s SOP or they really have something.
I remember hearing about they were doing some repairs. I’m sure repairs in port aren’t all that uncommon; however, if the repairs weren’t done right or the captain decided to leave before they were completed because they were fully loaded & he wanted to keep to the schedule & those repairs were tied to what failed then there could be something there.
Ongoing discussion at this forum. The report of engine failure during on/off loading is from one person not considered knowledgeable in the area she was speculating about - hearsay.
We’ll just have to wait until the investigation is complete (and also about those three bodies in Kansas City 
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