Bad crane rigging example - video

"Randy333" wrote

Using a protractor, I come up with a boom angle of around 35 degrees. And it looks like the boom is pretty much fully extended. I wonder how experienced the operator and supervisor were. That's a rookie mistake.

Steve

Heart surgery pending?

Heart Surgery Survival Guide

This looks to be in the Grove TMS900E family. Hard to get a number from the youtube, but definitely a Grove. Load charts available for anyone who cares to peruse them. Too fine print for me, and can't find a simple boom angle chart.

steve

url for operating manuals

Upon closer readings, I can't find any load charts for 35 degrees. The lowest is 45 degrees. Around page 21. Loads at 45 degrees and full extension max out in the 1200# range, if I'm reading it right.

Steve

Boomed out too far and gravity didn't like him enough to take the day off.

I just got Broadband2Go wireless Internet to supplement $7/month dialup and now can watch these posted videos. So far its speed averages 37 KBPS from my house with 1-2 bars, with bursts possibly over 100 KBPS.

If you buy the modem from Walmart their prepaid $20 top-ups get you 1 GB of data and a month to use it, from Virgin Mobile it's 500MB. I think I could skip a month or two and effectively have fast service for large software updates for $7-$10 a month.

Has anyone else tried it?

jsw

The Virgin Mobile Broadband2Go works quite well. I have it on their unlimited plan and I've been on VPN on my work laptop while riding in a van at 75mph from Dallas to Houston with only two brief connection drops along the way and very good performance. I've also used it at home on one of the rare times my cable modem was out for an hour or so.

"Steve B" on Fri, 17 Jun 2011 02:08:53

-0700 typed in rec.crafts.metalworking the following:

OTOH, the owners is not livid, the damage is "minimal", and he seems to be accepting that it was an electrical glitch which over extended it. That said, I'm sure the company's insurance agent is not going to be happy writing the check.

There was a distinct SNAP! sound, followed hy the Holy Shit! What was the snap sound?

Joe Gwinn

These are much more fun than cranes:

-- Happiness is when what you think, what you say, and what you do are in harmony. -- Mahatma Gandhi

No. Any GOOD crane operator can defeat any built-in safety system. Just look at the Saudi pilots who cut loose the Airbus with zero flight miles into the blast deflectors by defeating the safety system.

Grove Cranes are great cranes. I have operated up to the 12.5 ton models. They give you guidelines and parameters, but there is no manual shut down when those are reached or exceeded.

I have seen more than one boom, crane, or combination thereof go into the Gulf of Mexico simply because the crane operator either didn't know the physics, or ignored them.

Reality is nature's way of keeping things straight.

Steve

Heart surgery pending?

Heart Surgery Survival Guide

"Larry Jaques" wrote

Centrifugal force is underestimated.

Eh?

Steve

Well that's what it looked like to me but I've never operated a crane. Knowing you from this newsgroup I believe you over what they told the owner. Aren't these things investigated to see who screwed up? Found it: "The crane company, Truck Crane Service, told the homeowner, who did not want to be interviewed, that a computer error is to blame for the mishap." Here's the link:

Well that's what it looked like to me but I've never operated a crane. Knowing you from this newsgroup I believe you over what they told the owner. Aren't these things investigated to see who screwed up? Found it: "The crane company, Truck Crane Service, told the homeowner, who did not want to be interviewed, that a computer error is to blame for the mishap." Here's the link:

Yeah, and almost every fire is attributed to a weldor.

I ran cranes for quite a while. I have run a crane very similar to this one, a Grove 12.5 ton. From what I know, what I can see, what I measured, and my real life experiences, the crane was boomed down too far, and the boom was extended too far, and the load was too heavy. If those things had been correct, we wouldn't be talking about it right now. The boom could have been raised, or the boom extended in, and it wouldn't have happened. But they wouldn't have been able to place the load where necessary.

A good crane operator knows the weight of the object he is lifting, and the furthest he can boom down and safely pick up that object. Most cranes do not have any electronics to tell the operator that. Just a plate that's usually not there, dirty, or abraded to the point it can't be read. In this case, that didn't happen, or they would have known they were operating out of parameters. When they say a "computer error", they may have been talking about a faulty weight reading when test lifting the object. Other than that, computers have little to do with the actual controlling of the crane, except sensing for out of parameter input and coordinating movements produced by using more than one control at a time.

The comment of "some sound" has not been expounded upon a lot. Perhaps there was a jolt in the cable, even where it rolls over other coils on the drum that gave the load enough moment to tip the balance for the slightest time. The crane DID tip over slowly, indicating it was a very small error on the side of the load, enough to tip the machine. Perhaps it hit something enough to swing the load. I do not think all the evidence is in yet, or hasn't been published.

You must also remember that these are reports by layman. Some sound. Computer error. A loose frammit. That damned weldor.

I'd like to hear from a qualified person for the final evaluation. What we have is the crane owner explaining to the homeowner that it was because of a computer error. Too bad there wasn't a weldor there to blame it on. Do you think they are going to say, "I'm sorry. We screwed up. We were not set up correctly, were boomed down too far, and had the boom extended too far for the weight of the load." Or, "We didn't get the weight of the load, and didn't read the operating manual for load limits or look at the boom chart."

Can you say lawsuit?

What do you think the crane company is going to tell the homeowner? I believe the insurance company will have some far more probing and exact questions, and are not just going to sign off and pay off with a two word explanation from the crane's owner.

Three measurements are needed, which can then be sent to the manufacturers of the crane for evaluation. Weight of load (known), angle of boom relative to level (known from the picture), and extension of boom (easily attainable by simple tape measure). The math would be undeniable.

I believe that's what the insurance company is going to go by. A car crash can be witnessed by four people on four different corners. Each will tell a slightly different story due to their different angles of observation. And some will include details that are not relevent to calculating the answer. All we have here is witnesses who were so frightened, they were "shaking in his boots", and were actually in an altered state of consciousness. And some, obviously, were not even qualified enough to correctly evaluate the accident, yet the press jumps on their testimony.

Steve

Heart surgery pending?

Heart Surgery Survival Guide

Exactly. Hold your phone calls folks. We have a winner!

Steve

TY. I have seen a lot of heavy stuff go into the Gulf of Mexico to at least be a qualified witness. I once saw an operator lose a Hydril, and 40' of boom off the crane from picking up the Hydril off a boat, and not being boomed up enough. He picked up the load, the boat got the hell out of the way, he was coming up on it, the crane's diesel engine coughed at the load, and gravity prevailed. The Hydril, the boom, and all the line went in the drink. Lucky the cab was not torn loose.

If you want to define forlorn, just see a crane operator sitting in his cab with no boom on his crane................... priceless.

This is a Hydril:

The picture tells the story. Compare this weight to that of a fiberglass swimming pool................ Ten feet in diameter of solid steel. And there's some you can't see. But even a lowly fiberglass swimming pool prevailed when the laws of physics and leverage were applied.

Steve

Thanks for the post. Karl

I would bet that the support for the outriggers was defective but I cannot see the condition of them in the video. It is not uncommon for the outriggers to sink when they are not on solid firm ground. If that happens the crane is going over if the load is not near the ground. The operator should have had a measurement of how far he was going out with that load because that is the most important dimension. The crane should have been placed closer to the garage to decrease the distance where they were installing the pool. He should have also made a test pick at a distance from the center of rotation to where the pool was going plus another 5 feet to make sure he was not exceeding the limits of the crane. HIgh loads are a bitch if they are swung too fast. Centrpedal force will add to the moment on the boom and can topple the crane. Once it starts to go with a high load, hang on cause you're going over. At least they were smart enough to use two other cranes to remove the crane from the house, one just to keep it from slamming down after the other crane picked up on the boom. Weight times distance, very simple highschool physics, and then check the charts that are supposed to be inside the cab of the crane.

John