Report on Evergiven at the Suez Canal 4

[spsalso]

Here's a new post by Sal Mercogliano discussing the analysis of the grounding of this ship in the Suez Canal:

https://www.youtube.com/watch?v=UfchAELXsVI

spsalso

 

[IRstuff]

https://interestingengineering.com/transportation/ultra-large-container-msc-tessa-delivered

says 240,000 ton capacity with volumetric capacity of 24,000 TEU, so the math is clear.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[3DDave]

How is that math?

A 1 TEU container can be designed to carry 24 metric tons, so 24,000 TEU could weigh as much as 24*24,000 metric tons.

It just isn't economically worthwhile to build a ship to that displacement; instead they are expecting a worst case average of 10 metric tons per TEU, less than half the structural capacity of the typical container.

Which makes a great deal of sense as no one can pack even 10 metric tons of toasters or TVs or laundry equipment into 1 TEU.

 

[dik]

I suspect that depending on the cargo, it may be difficult to load them all to their maximum weight.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[IRstuff]

That was my point; an AVERAGE of 10 tons per TEU, which works out to ~1/4 the density of water, seems plausible for manufactured items with packaging, etc.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[TugboatEng]

Take a look at the MOL Comfort sinking. I think it was the most expensive insurance claim ever and that was some 12-14k TEU. The ship was a total loss in the very deep Indian ocean so there has been no examination of the hull. The sisters were inspected and buckling of the bottom plating was found which indicates structural deficiencies. However, the pictures of the ship after failure show an obvious hogging condition. Mis-reporting of container weights is a known problem in the industry.

 

[MintJulep]

About nuclear powered merchant ships.

https://www.wired.co.uk/article/nuclear-cargo-ships

 

[TugboatEng]

The US built commercial nuclear ships were a failure because they were built as break bulk ships with passenger accomodations at the onset of containerization. Passenger accomodations were already s liability and the cargo handling abilities made the ships obsolete at completion.

I sailed on a 1975 build ship in 2005 that had an "owner's stateroom". It had some VERY contemporary furniture. It was like a time capsule to walk in there but it STUNK because it was never used and the P traps in the drains would dry out.

 

[davidbeach]

What I’ve seen suggests that the 20’ boxes may gross out, but that the 40’ boxes almost always cube out. Observations suggest that most boxes on the ships are 40s rather than 20s. That suggests that overall the capacity is limited by volume and not by weight.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[TugboatEng]

It's rare to see a 20ft unit on a ship. For international trade I "feel" that 40 and 53 foot containers make up 99% of trade.

 

[spsalso]

I think davidbeach has nicely summed up the capacity "equation".

53' containers are very rare in ocean use. They are commonly "land use" only. That's especially true because the below decks storage has guides that are based on the 20/40 spacing. You CANNOT put anything bigger than 40' below decks. Then ask yourself how many times you see a ship with 53' boxes on top. I believe there may be some to Alaska and/or Hawaii, though. And maybe some other very special (and unusual) routes.

There ARE longer boxes in ocean service. They are 45'. They only go up top. The 2 1/2' overhang on each end isn't a problem, EXCEPT for those pesky diagonal tie-downs--the ones that keep the boxes from falling off in rough weather.

I see quite a few 20' boxes on the road and on trains. So they are certainly used. I will guess there's an average of 3-5% of them on a ship.


spsalso

 

[1503-44]

I asked Bard to do the displacement tonnages based on ship classification dimensions and to estimate the max number of containers. Not sure if it deducted ship weight.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[TugboatEng]

Funny, Bard gave a very large crude carrier a container capacity...

Anyways, this chart shows the most current containership classifications

 

[ALK2415]

@ TugboatEng if you could recommend ship building textbook for structural engineers ?

 

[TugboatEng]

Despite attending a maritime school, there were no naval architecture courses available. However, these people would know:

https://www.sname.org/sname-text-reference-books

 

[dik]

Thanks for the book list, Tug... If I weren't so old and wobbly, there are a couple of titles that I'd look into. It looks like a pretty good selection.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[TugboatEng]

I should probably read this one:

https://www.sname.org/naval-architecture-non-naval-architects

 

[MintJulep]

The US Naval Academy makes some naval architecture texts available here:

https://libguides.usna.edu/c.php?g=410506&p=2795318

 

[TugboatEng]

We had some class-wide machinery failures recently. I had my suspicions on cause and found this document while researching.

https://apps.dtic.mil/sti/pdfs/ADA117056.pdf

 

[ALK2415]

@ TugboatEng where could i find textbook on floating structures (housing, airports, transport-submerged-tunnel, offshore drilling) these are complex structures that related to navel engineering or different branches ?

 

[1503-44]

Try a search of "offshore wind turbine dynamic analysis". Seems to be a lot of recent works listed that include their hydrodynamic analysis considerations. I guess that's what you are interested in.

What was funnier still was that Bard at first got the wrong answers simply multiplying L x W x D
Even simple math can be a problem for LLMs, so I just left its VLCC container calc alone. Engineering jobs are still not threatened by AI. AI still can't hold a candle to REI, real engineering intelligence. At this point, only software engineering jobs appear to be threatened, whatever software engineering is. But I am biased, since I also hate that they and the drug companies have stolen the word "pipeline".

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."