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A bad day for Liebherr in Rostock

Posted: Mon May 04, 2020 11:18 pm
by JayinKitsap
So on Saturday was the load test for a 5,000 ton capacity crane, lifting 5,500 lb in the test. Before the barge that was the test weight was lifted out of the water, it appears the massive 4 way hook fractured, causing slack in the line and a whiplash. The crane went over backwards in a total failure. This is the largest Marine Crane ever and this is like the first flight of the A380 crashing on takeoff. Over $ 100 million in damages, wonder if the massive swing bearing was affected, that would not be good.

https://gcaptain.com/demes-game-changin ... ent-video/

https://vertikal.net/en/news/story/3531 ... tCookies=1


Older reference posts.
https://vertikal.net/en/news/story/3515 ... completion

https://www.swp.de/panorama/liebherr-kr ... 37877.html

https://www.swp.de/suedwesten/staedte/e ... 17317.html

Re: A bad day for Liebherr in Rostock

Posted: Mon May 04, 2020 11:35 pm
by LabQuest
A 5000 ton capacity crane collapsed lifting 5,500 pounds?

I could lift that much with a couple pickup trucks. What on earth?

Re: A bad day for Liebherr in Rostock

Posted: Tue May 05, 2020 12:17 am
by Okie
JayinKitsap wrote:
So on Saturday was the load test for a 5,000 ton capacity crane, lifting 5,500 lb in the test. Before the barge that was the test weight was lifted out of the water, it appears the massive 4 way hook fractured, causing slack in the line and a whiplash. The crane went over backwards in a total failure.


The video does not start until long after the failure of the hook mechanism/swivel.
The entire barge in the foreground was the test weight and I did not see any waves from when the test barge would have settled after the hook failure which indicates to me that it failed long before it reached its 5,500 ton test.

Argh matety someone will have to walk the plank. :shock:

Okie

Re: A bad day for Liebherr in Rostock

Posted: Tue May 05, 2020 12:28 am
by rfields5421
At least there appear to be no fatalities. When something that big lets go, a lot of energy is release suddenly and anyone can be hurt/ killed even if they are not close.

Re: A bad day for Liebherr in Rostock

Posted: Tue May 05, 2020 1:48 am
by JayinKitsap
Okie wrote:
JayinKitsap wrote:
So on Saturday was the load test for a 5,000 ton capacity crane, lifting 5,500 lb in the test. Before the barge that was the test weight was lifted out of the water, it appears the massive 4 way hook fractured, causing slack in the line and a whiplash. The crane went over backwards in a total failure.


The video does not start until long after the failure of the hook mechanism/swivel.
The entire barge in the foreground was the test weight and I did not see any waves from when the test barge would have settled after the hook failure which indicates to me that it failed long before it reached its 5,500 ton test.

Argh matety someone will have to walk the plank. :shock:

Okie


I saw in one of the stories in German a photo from a distance in front of the ship showing the rigged block with 8 cable parts snugged tight from the barge eyes (the barge is visible at the end of the video) to the 4 way hook. If the barge is 90'x200', each foot of draft in seawater is 576 Tons, so loaded for a 9.54' draft. In the video there are some waves that would be like the barge settling back into the water 3 to 4' or so, if so the hook broke well below full load which would be with the barge out of the water. Possibly as low as half load. Strange how no rigging is seen on the barge, I would have thought to see a nest of cables, shackles, and the like everywhere, but not visible.

What is really strange is in January, Liebherr in Rostock was loading two portal cranes onto a ship, one of the ships crane booms struck the portal crane, it tipped, causing the ship to list, tipping the 2nd crane into the water. A huge crane was needed to lift each of these cranes out of the water. Their insurance company must now be going quite nuts.

Saving that $ 5,000 of extra UT on the hook doesn't look as good today. <Sarcastic, but somewhere either Design, QC, or QA really botched this one>.

Imagine if it passed here and then broke setting turbines out in the North Sea. Not good - not good at all.

Re: A bad day for Liebherr in Rostock

Posted: Fri May 08, 2020 10:56 am
by Sokes
It seems the hook was bought from an outside supplier:
https://vertikal.net/en/news/story/3534 ... e-incident

I wonder if the hook manufacturer didn't make an overload test? Bad calculation or casting mistake?

Anyway offshore is a new technology. Such accidents can be expected. At half load is a bit strange though.

Re: A bad day for Liebherr in Rostock

Posted: Fri May 08, 2020 2:05 pm
by Okie
Sokes wrote:
I wonder if the hook manufacturer didn't make an overload test? Bad calculation or casting mistake?


It would be interesting to know but my best keyboard material engineering "guess" from the pictures available is that the nut or whatever mechanism that retained the swivel failed.
The shaft that is visible in pictures appears to have threads to retain the quad hook and most likely a thrust bearing to provide swivel since there is a two cable connection to the lifting carriage that would transfer those loads to the hoist lines and twist them together without swivel.

Only having a wild guess there was a bad calculation since the failure was apparently less the 50% of the rated load.


Sokes wrote:
Anyway offshore is a new technology. Such accidents can be expected. At half load is a bit strange though.


Building cranes is not new technology no matter their use. The technology has been around since Egyptian times.

Hopefully there will be a report on the cause before it finds its way to back page news. It would be interesting to know.

Okie

Re: A bad day for Liebherr in Rostock

Posted: Fri May 08, 2020 6:05 pm
by Sokes
Okie wrote:
Only having a wild guess there was a bad calculation since the failure was apparently less the 50% of the rated load.

One should assume that each casting of such a size is checked with ultrasound. What you write sounds most likely. It's hard to imagine that they used the wrong alloy.

Okie wrote:
Building cranes is not new technology no matter their use. The technology has been around since Egyptian times.

Gear boxes have been around a while. But in the beginning of wind turbines gear boxes couln't handle the load of sudden gusts of wind.
Solar cells were around many decades before serious money was thrown at the technology.
Artillery is around for some time, planes,...
Managing the details as opposed to knowing the concept, so to say.