Crane recovery fail - GIF

Crane recovery fail in the British Overseas Territory of Gibraltar.

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Previously:

https://www.homemadetools.net/forum/...104#post195360
https://www.homemadetools.net/forum/...480#post196963
https://www.homemadetools.net/forum/...371#post192609
https://www.homemadetools.net/forum/...753#post190383
https://www.homemadetools.net/forum/...699#post186319
https://www.homemadetools.net/forum/...951#post187196

THATS NOT HOW IT WAS SUPPOSED TO WORK!

Wonder just how deep the water is there? Also, how much other stuff is sitting there under it?

Quote:

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Originally Posted by WmRMeyers

THATS NOT HOW IT WAS SUPPOSED TO WORK!

Wonder just how deep the water is there? Also, how much other stuff is sitting there under it?

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Yes, I'm wondering if the crane or its rope was hooked on something.

My opinion is the straps were probably inadequate, old, worn AND they were improperly secured to the crane. You cannot use straps where they are subjected to abrasion or damage from objects that impose any kind of concentrated force. The head of a bolt, of the rough edge of a casting, or the corner of a beam, etc. will create a very concentrated point load causing the strap to fail at that point.

The straps were probably attached by a diver with poor visibility and perhaps improper knowledge of rigging for a lift like that.

Below are 4 frames showing that the straps we improperly attached to the load.

Notice the first strap broke where it was in contact with the structure of the truck.
Should have used a proper chain attached to the truck then a proper shackle to the straps.
Attachment 42091 Attachment 42092

After the first strap book, there is no way the second would hold the load by itself.
But you can see that even this one failed where it was in contact with the structure of the truck.

Attachment 42093 Attachment 42094

Quote:

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Originally Posted by hemmjo

My opinion is the straps were probably inadequate, old, worn AND they were improperly secured to the crane. You cannot use straps where they are subjected to abrasion or damage from objects that impose any kind of concentrated force. The head of a bolt, of the rough edge of a casting, or the corner of a beam, etc. will create a very concentrated point load causing the strap to fail at that point.

The straps were probably attached by a diver with poor visibility and perhaps improper knowledge of rigging for a lift like that.

Below are 4 frames showing that the straps we improperly attached to the load.

Notice the first strap broke where it was in contact with the structure of the truck.
Should have used a proper chain attached to the truck then a proper shackle to the straps.
Attachment 42091 Attachment 42092

After the first strap book, there is no way the second would hold the load by itself.
But you can see that even this one failed where it was in contact with the structure of the truck.

Attachment 42093 Attachment 42094

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I think you just about summed it up with the comment about poor visibility. and straps Recovery divers in general have a fair amount of rigging knowledge. since we don't have any footage of the dives showing them in the rigging process, I personally wouldn't be too quick on condemning either the diver or the straps. I would be more inclined to fault the breaking surface inspection if there even was one. It would be very dangerous to even consider re rigging at the surface even with a second crane on location. However being able to point out better or more rigging points while the crane was still mostly submerged allowing the density to the water to support part of the weight. then lowering it back to the bottom and either re rigging or adding more lifting straps slings cables ETC. 4 points are better than 3, 5 or 6 are even better.
Plus, for all we know the first strap to fail may have been attached to a tie down eye, and that may have been what failed first creating the domino effect. Tie down eyes are not strong enough to support the full weight of a crane.
Or between the time the underwater rigging was done and the actual lift being preformed currents could have shifted the slack straps to cause them to be hung up where they were not intended

This is a Royal Navy Dockyard so it is very unlikely that the lifting straps were in poor condition. They are subjected to regular inspections as well as visual inspections before use. It is unlikely that the crane had lifting points underneath, but it may have had towing eyes, not rated for such a lift. Whatever happened, nobody got hurt so it wasn’t all bad.