Photogenic removal

  • Thread starter Thread starter rbtree
  • Start date Start date
  • Replies Replies 59
  • Views Views 9K
rbtree said:
sure, Pete, maybe 15-25% of the load is lateral....that is, the portion of the load that is actually transferred to the biner, which is very minimal when rigged the way I teach my crew. I didn't see what Mickey was doing or would have insructed him to do it the better way. The way Mickey rigged it, and on smaller diameter wood, the side load would be higher.

I know that a few times, I've rigged stuff a bit too heavy.....but also checked the tension on the biner...and it is minimal compared to the load...even considering what the dynamic loading could have been.

In my non-scientific (or backed up with dynamometer evidence) I'd venture to say that the peak force on a biner of a properly tied setup would never go beyond 1/4 of the total load, as it is spread out, starting at the marl. So, say a 500 pound load is butt hitched, and let run a fair bit, applying 3500 pounds on the rigging point, and 1750 pounds on the load. That is about 450 pounds on the carabiner. Now no more than 1/2 of that would be a side load force, I'd say. Now tell me, do you really think that would break a 50K rated biner?

And that is worst case (well, besides a snafu such as snubbed load which could apply 10x the force on the rigged load), I think. As well, i've never butt hitched a 50 pound load with a biner termination, and won't.

Part of my reasoning is to offer, that hard and fast rules, such as one handed chain saw use, and this new OSHA bs ruling, while they may have merit, aren't necessarily the end all.
Click to expand...

Your maths is better than mine! and methods are well founded. I agree that in that configuration the side-loading forces will be minimal, compared to the peak loads at the marl. The doubling back, clipping onto the line would further reduce the load, and as you pointed out in your later post you were working with a factor of safety in excess of 10 to 1.
With your massive experience, ability and attention to detail, I have little issue with such usage. It is when a less experienced individual mis configures the system, or by mishap the marl or half-hitch drops off the cut piece that I would worry, especially on larger wood, and if the load was not allowed to run to dissipate some of the energy.

I'm still learning- and do every day in this game. I like to understand the limitations of the methods I use, and the implications in the case of mishap. I am a firm believer that if more people understood the benefits of learning and research, there would be a reduction of accidents and the HSE here in the UK and the OSHA for you in the US will leave us the hell alone!

There is some information out there on the side loading of biners, I will attempt to source it but i don't know if it's available yet.
 
Sorry Roger - I wasn't trying to be critical. I was just wondering if anybody else had had biners break in this type of scenario. The experience you've got under your belt is worth more than any rigid rule anybody could come up with and you're right to trust that. I have never had a biner break in this kind of scenario either, but I stopped doing this after the 5th or 6th phone call I got from upset customers. I'm sure you are aware of this, but a carabiner rated at 50 KN does not have a 50 Kn rating when side-loaded. It goes down to about 7 or 9 Kn, which is still probably strong enough for light pieces. I would just emphasize the word "probably."
 
Sean, unless you positioned the carabiner so that it was laying right up against a knot, you'd be hard pressed to get more than 100-150 lbs side load on that carabiner even rigging 1000 lb pieces. And like somebody else mentioned, if they were that fragile then you could bend one sideways with your bare hands. It's still 1/2" steel, and it's not going to bend with a hundred pounds of side load.
 
Yeah, I didn't think it could happen either until I started getting phone calls from people who'd had it happen. When you force the carabiner up against a round object such as a log, you apply force to the side of the carabiner. When this force gets shock loaded, the gate can break off allowing the rope to fall out of the biner. The 1/2" steel doesn't have to break for a carabiner gate to break off.
 
Skwerl said:
Sean, unless you positioned the carabiner so that it was laying right up against a knot, you'd be hard pressed to get more than 100-150 lbs side load on that carabiner even rigging 1000 lb pieces. And like somebody else mentioned, if they were that fragile then you could bend one sideways with your bare hands. It's still 1/2" steel, and it's not going to bend with a hundred pounds of side load.
Click to expand...

If it's timber of any size, why take a chance? Plus knots are cheaper:D
 
When I spoke to the technical advisor at Omega Pacific about this, he said that this constitutes misuse of the product. He equated it to riding the clutch on a new car - in the short run it will continue to work, but in the long run the chances that it will cause a problem are 100%. When it does cause a problem, the problem is not due to a defect in the product but to improper usage.

ANSI just updated the fall protection standards recently and it requires a gate face strength for all rope snaps of 3600 +or- lbs. It used to be around 350 lbs. This means that until this year, rope snaps that have a breaking strength of 5000 lbs could have the gate snap off if a side pressure of 350 lbs was exerted. Carabiners have NO gate face strength requirement.
 
Well, if you don't face the carabiner so that the load is on the spine then you can have those problems. As I posted before, it's not a good technique for someone who has to be told which way to turn the carabiner so that the load is on the spine instead of the gate. If it's turned the wrong way then it would be very easy to put a side load on the gate, causing failure.

I use this method because it's faster than tying knots and waiting for the groundman to untie knots. I'm a subcontractor and as such, I do not work with the same groundman every day. Most of the guys I work with are simply brush draggers and few of them are capable of untying a knot without wasting lots of time trying to figure it out. I'm not there to educate every new brush dragger on his knot skills.
 
I think using a shackle or clevis instead of a biner might solve the problem since they can't be sideloaded and have much higher load ratings anyway.
 
Actually that's a good idea, Sean. Once in a while I have to re-rig and mess with a setup when I can't get it to lay right so that the carabiner isn't side loaded. A clevis would eliminate that concern.
:thumbup:
 
  • Thread Starter Thread Starter
  • #37
Sure, I'm now having eye splices put in my rigging lines.....for heavy loads, I'd use a shackle, for sure.

I agree to not use a biner on heavy loads, especially butt hitching which results in shock loading. But I stand by my use of them for up to 1000 pound loads if there's no shock loading. I've never had a gate fail, and, if I did, if the biner were properly set, it owuld still be nearly impossible for the line to come out.

By the way, I talked to Ben today. He's getting in 600 feet of coated 1/2" PS Ropes double braid for me...and will sell me what I want, prolly 250 feet..... The leftover is up for grabs. Lemme know if anyone wants some...about .60 a foot plus shipping, and maybe sales tax....
 
  • Thread Starter Thread Starter
  • #39
Wet, I'm sure, dark....similar to Samson's Samthane...maybe not as stiff or long lasting. Works fine, helps keep the rope from picking
 
Its good rope hey ?
We used to do good old biner testing all the time .
Place bolt in concrete driveway.
Attache biner to bolt and attach your cord of choice to your car of choice.
Now either floor it say in a VW bug or just let it roll say in a giant hummer.
Always fun to see what breaks first.
 
darkstar said:
...Always fun to see what breaks first.
Click to expand...

You mean like this?
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/ec8BDnhy1-0&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/ec8BDnhy1-0&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>

Sorry for the derail, but that video is just too funny to pass up.
 
  • Thread Starter Thread Starter
  • #42
Ha..saw that one some time ago.....
 
I do alot of rigging with a carabiner.
It works pretty well for multiple limbs at once like a Redwood or Fir.

Though false crotching any wood I'd use a knot.
 
Skwerl said:
Side loading isn't nearly the issue that some make it out to be, especially if you're aware of it and place the carabiner accordingly. And ALWAYS make sure the load is along the spine of the carabiner, not the gate side.
Click to expand...

I agree. I use steel all the time. And, adding a half hitch (or marl) will help reduce the load to the biner as well.

Biners are much faster for production.

Sweet pics BTW! ;)
 
sure its true, most ropes break at the marl, it takes the load, the rest would have to travel around the wood to get to the biner
 
Hahaha that bumber blew out like fiberglass.
FUNNY
Why did they just keep pulling it futher in the snow ...
 
You must log in or register to reply here.

Similar threads

MatthewMMeckley
Helicopter tree removal
2
Replies
28
Views
336
flushcut
flushcut
Mick!
Branch walking, how do you do it?
Replies
21
Views
1K
Bodean
Bodean
J
Filling Hollow in Tree?
Replies
13
Views
834
Jager
J
Altissimus
GRCS , tips and technique for greatness
2
Replies
26
Views
1K
friedrich
friedrich
Altissimus
"Reverse Stump Shot"
Replies
19
Views
1K
SeanKroll
SeanKroll
Back
Top