codz

Good work lads,

If I lived in the UK I would probably get the camera out every time I saw blue sky and sunshine too.

I will try and get her to snatch load it.

Cody I only used that particular knot in the photo so it was easy to see that it was all one line. I'd use a clove in real life, so long as its secure. Way stronger, without the bite. And a 3 strand works similar to rope-on rope anyway, where there's a bite or a bend i.e. 3-strands. Where they run through the shackle also, they'll near always run side by side in the bow, no cross-over.

 

 

Well of course there are, but thats not the point, you only had one line in the video, that's what I'm going one.

 

 

 

Absolutely, and I dont intend to be double-roping a 40mm rope any time soon either. Again, my point was to show an example of how to potentially increase your safety factor with a limited amount of hardware, while offering an alternative to the configuration of that 40mm you had there in the video. Not trying to compete with or undermine you, just sharing something that has worked in the past for me.

I will have to come back to this one later, the Missus just went into labor.

FWIW. A couple of times in the past where there's been doubt, we've double over a line in the middle and worked it as one. We use a third line to join all 3 parts together and thus keep the doubled line equalized; the groundworker obviously controls the doubled line by holding the 3rd line. There must be enough distance between where the 3 parts join together to where the trunk wraps begin to allow the severed log to touch down.....even though the shock load is over by that stage. I still wouldn't mess with a 3t log on a real job, but if I had a wager on it, that's how I'd set up the rigging line.

I think the strength loss would be similar to our set up or worse. that first bight would reduce the strength dramatically, and what is worse is that it is rope on rope. A good option in this situation is to incorporate a shackle to eliminate rope on rope, I will post a pic shortly. There a much stronger ways of attaching the log if you were to use 2 ropes. 2 splices attached to the shackle and sling we used would be a good option.

That 40mm we used was hard enough to handle as it was even with 2 of us in the tree. A 60mm rope would be around double the strength and easier to handle than the doubled 40mm.

Would you agree then that the big hinge contributed to the large momentum of the log?

Next time maybe a tag line behind aswell to hold it in place to allow more cutting and safety for the descending climber.

It's hard to make out,I don't think the rope snapped at the shackle ,

where exactly did the rope snap?

Thanks

 

 

 

Sent using Arbtalk Mobile App

Me giving the Cruiser **** to snap the log probably did increase the loads however I dont think it was the straw that broke the camels back.

The piece of rope remaining in the tree shows us that the rope broke at the shackle, I believe it snapped when we ran out of elasticity.

Hi, thanks for replying.

I have never put the rope far up the stem, i would need to try it to see, not doubting you, I just get it when I do it.

I am not convinced in my head

On the video, it took quite a pull to get it over, I can see that by the stem moving.

I have never worked with big gum so I don't know how it reacts hinge wise, I just feel if it went over slower it wouldn't of built up so much force.

I understand it's not nice having your work criticised, especially by folk who weren't there .

I should of considered this when I made my original comments, I never and unfortunately it has put a sour feel to this thread.

Long story short, you guys tried it and it never worked, what would you do next time with the same rope to give it a better chance of success?

 

Sent using Arbtalk Mobile App

We had to make sure the log was not going to topple prior to the climber exiting the tree, you know, safety and all that crap, this meant a pretty fat hinge. We would normally put a scarf cut about 1/2 - 2/3 the depth of the log to allow the weight of the piece to drag it over. There is still enough log and rope left to try another log of similar weight, I have a few ideas.

Mental Avatar codz!

It was 46 degrees on the first day of that removal!, I might have a bit of footage.

I think it was over complicated, double the rope up, timber hitch, have it a nats whisker above the cut, put some grooves in the wood to hold it in place, big open faced gob, and cut more to the hinge,

Wouldn't bother with shackles, just hung over the big nug and wrapped down round the stem a few times .

Tim and I are just nipping out to show you, I will send him the pics I take as I can't upload from my phone

It is a common misconception that the attachment to the piece being lowered needs to be close to the scarf cut. It only needs to be somwhere below the midpoint of the log to prevent it doing a 360. No matter where the log is tied on below the midpoint it will fall the same distance.

The scarf cut also would have no bearing on the out come, we could have step cut it for the same result. The hinge is only effective for about 30 degress, probably much less with dead timber. The hinge was completley redundant prior to any load reaching the rope.

codz, joe,

 

just out of interest, how is the shackle attached to the timber? can't quite make it out from the vid?

 

Also if you look beneath the side stub on the left, what's happening here?

 

cheers

The shackle is attached to the log vis an eye to eye sling double wraped, just loke you would if you were setting a cambium saver on a straight stem. This method maintains the integrity of the 2 parts of rope with minimal strangth loss through bend ratios. It also meant the sling did not have to be choked.

The dead end of the rope is wrapped around the stub and then wrapped around the log beneath. We were not confident in the structural integrity of the stub so we did this to back it up in case it failed. It was difficult to set the ropes to avopid rope on rope and also not have the ropes lock up.

What would have been cool is to have a dynometer (?) or what ever its called to measure the peak loading. At the workshops I've been to, being able to know the peak load on the riggin system teaches us something, far more than a big snatch breaks a rope, makes you realise the forces involved and the importance of using correctly rated kit-knowing, not guessing the forces is an eye opener for those attending the workshop.

Tbh I'd be a bit disappointed going to a workshop, seeing a demo with an obvious outcome and not being able to learn anything-just how much did the rigging system exceed the mbs? That was a 5ton log, but what force did it peak at when it snatched? How far would you have to let a log like that run/be slowed down before it was safe to stop it before it hit the deck?

Again hindsight reveals the "obvious outcome" it would have been great to incorporate a load cell in place of the large shackle and if anyone is willing to loan us one we will repeat the test. As for how far you would need to let it run? More than we did!

it was a good advert for their slogan though. I dont see wht the deal was with all the wraps round the seperate trees? Surely they would have all locked up over them selves and the timber would have been suspended? Theres no way that would have gone smoothly is there? Can someone explain?

When done correctly the wraps will not lock up and can be released gradually.

Everyone apart from Joe, myself and the crew that attended the workshop has had the privledge of hindsight from which to draw thier conclusions. It is easy to watch the rope snap then say yeah I knew that was going to happen. As Joe has stated, prior to breaking the piece off the majority off those onsite were confident we had a reasonable chance of success. The scale of the rope compared to the log looked reasonable, taking into consideration we had at least 2 parts of rope supporting the load at all points. The rope was re-directed through a 40 tonne bow shacke attached to the base of an adjacent tree via a cow hitch using 25mm double braid polyester line. The cow hitch became fused together despite the reduction and friction before it in the system when it was loaded. This gives us an indication as to how much force was being dissapated through the system, although that is hard to pick up in the video.

It would have been nice to be able to let the log run as we would normaly do in a working situation. The forces involved meant we could not accuratley predict the number of wraps needed which is why we were reliant on the dynamic charateristics of the rope to do the work for us.

Thanks for all of the positive feedback that we are recieving both from here and outside.

RC0, I dont doubt that there are plenty of guys on this forum with heaps of experience. That said I will not hold back for a second if I feel it is warranted.

.

Yeah its tough when you cant get a crane big enough to get over them.

As always Joe you are the voice of diplomacy and reason, but where is the fun in that.

With regards to your comments above, if someone has developed the ability to think critically they're free to express their opinions, regardless of their relative experience in treework. Put it this way Cody, Stevie Wonder could've seen that rope was gonna snap.

 

I'm not a desktop arborist, and neither is anyone who has posted critical comments in this thread (apart from Stevie Blair but he's a very wealthy man and can afford to be one, kidding Stevie )

 

Australians/Kiwis and Australian/Kiwi based climbers, you dont have a monopoly on big tree work. This is a Redwood we worked on recently about 30 mins drive from Glasgow. A lot of people on this forum dont post pics and vids of their work because they've nothing to prove, especially not to thin skinned Aussies/Aussie based climbers who can't take a few words of criticism.

You need to post a pic of the Redwood from a different angle, I can only see the little one next to the house, the big one is behind it I guess.

I got a heads up from Joe about the banter on this site regarding the video of our snatch, I did not realise that there was such a thing as irresponsible rigging and that people may be offended because we did not use shiny pulleys and double braid rope.

I have enjoyed reading through peoples differernt takes on the set up and reasons for it, I have also had a good laugh at the pissing in the wind from the desktop experts who probably have spent most of thier career pollarding plane trees.

Big thanks to Mog and Ewan for coming to the rescue of our tattered credibilty. I think Joe has covered why we we did what we did in enough detail. The video does not really do the size of the piece justice so I will attach i pic of it with somthing for scale.

Here is another video to show that we dont always break our ropes.

Split Eucalypt removal on Vimeo