# 8 tonne rope failure, shock loading



## TimberMcPherson (Aug 1, 2007)

We have been removing some big montery cypress (macs) and pine on a steep hillside development. Its all been ugly stuff, the whole area is sand with a little topsoil. Trees have been between 50 to 80inch DBH. When you have to be roped just to get to the base of the tree you know its steep. (but some have been on flatter ground). 

Yesterday one of the ugliest of the bunch we had to get down, it was about 120 feet high, probably 70dbh. It was on a STEEP incline (like the lowest part of the back of the tree was about 10 foot higher than the lowest part of the front of the tree. In the attempt by the developer to cut a track below the tree the ground had slumped about 14 feet below the tree, a few roots exposed, we have been getting alot of rain so time was crucial.
We had spent 2 days taking off its lower 70 feet of limbs (some overhanging house but much higher) but been rained off a week prior.
Tree had a strong lean downhill, right at a house at the bottom which was about 50 feet away as the crow flys. Dismantling would have taken time we didnt have with wood to big to rig safely, to close to the house to just block and I really didnt know just how stable it was going to stay in the near future. 
No chance of crane or anything this side of a 4wd getting there. Helicopter would have been an option but this place is right on the coast under a ridge in which we have seen the wind direction change from calm to 3 directions of gusts and then still again in 15 minutes. Really nerve racking with big flops. 

Just to get in the cuts we had scaffolding put around the tree (and we totalled most of it). I put a scarf in that started out really small aimed at the house and its lean which opened up as it moved to about 10 o'clock of its lean direction (which is at 12). At 9.30 oclock we had a tirfor set up. 

About 2/3 up the tree we set up my big line, 4 inches of mooring line set up to a BIG fresh stump at about 8 oclock up on the hill. the line was horizontal and we did all we could to pretension it (but a line that heavy is hard to work with). The idea was that the tree would move slightly towards the house, the line would take the load and help with the tirfor to direct the tree to swing and fall into the bank. A couple of city arborists had been watching the set up, experienced guys. They pretty much said they were very glad they werent doing it and couldnt see a better way of doing it.

Put in the backcut, left alot of holding wood on the LHS. I REALLY didnt want that side to fail and send the tree right at the house and needed it to hold so if the tree did a violent swing the butt wasnt going to end up heading towards the house to fast (although it was butt roped/cabled) , I had alot of trust in that line but wasnt willing to aim at the house when it came down to it. The tree was VERY stubborn, I cut and wedged hell out of it, and then after alot of work and sweat the tirfor pulled it over. When the tree came over it didnt follow the lean at all, so didnt pre tension the big line. About a third of its way the it found tension, of course to late. It gave that gut thumping gunshot sound as the 4 inch line snapped. The tree fell in line with the scarf at 10 o'clock. 

The tree didnt fall exactly where I ideally wanted, but did fall within what I had considered a safety zone. Nothing of value or consequence broken. Developer was stoked. Owner of house was VERY happy (although I did break a few branched of her lemon tree.) She had been living in fear under that tree for years and when the ground slipped a couple of days ago, she stopped sleeping at night.

I have run the whole thing through a hundred times, and aside from coming up with a way of pretensioning a 4 inch line set horizontally 50 feet away or just having a bigger line, I dont think I could have done much different aside from aiming the tree more at the house, but even that make me worry about how things could have been much, much, much worse.

I dont think Im being to pedantic. I take my very clean record for breakage very seriously. Big tree, bad ground, target rich environment with a tight timeframe and limited options. I am confident in my ability and track record but I am simply not happy with how it went, do I just need to harden up?


----------



## clearance (Aug 1, 2007)

Glad it all worked out. Last month we cut down a dead, heavy leaner Doug fir, about 4' dbh and about 100' to where the top had broken off at about 6". It leaned heavily downhill, directly towards the three phase powerline across the road and the guywire pole that supported the guywire that ran above the road across to the power pole. I climbed it and took off lots of branches, then tied on two bull ropes at about 60'. We made a clearing for it to go into and set two medium sized Tirfors uphill and out of the bight. We had radios and flaggers, shut the road down, had a faller at the tree, two guys on the Tirfors, me standing on the road, running the show. The tree was guyed directly in the path we wanted it to go, everything worked out just fine and she thumped down nice. But still, you are always thinking, what if? I like the direct pull, maybe you could try that, I have hung blocks on the end of a choker to put them in the right spot.


----------



## Magnum783 (Aug 1, 2007)

clearance said:


> Glad it all worked out. Last month we cut down a dead, heavy leaner Doug fir, about 4' dbh and about 100' to where the top had broken off at about 6". It leaned heavily downhill, directly towards the three phase powerline across the road and the guywire pole that supported the guywire that ran above the road across to the power pole. I climbed it and took off lots of branches, then tied on two bull ropes at about 60'. We made a clearing for it to go into and set two medium sized Tirfors uphill and out of the bight. We had radios and flaggers, shut the road down, had a faller at the tree, two guys on the Tirfors, me standing on the road, running the show. The tree was guyed directly in the path we wanted it to go, everything worked out just fine and she thumped down nice. But still, you are always thinking, what if? I like the direct pull, maybe you could try that, I have hung blocks on the end of a choker to put them in the right spot.



What are Tirfors?
Jared


----------



## clearance (Aug 1, 2007)

A line pulling machine that unlike a come-a-long does not wind the cable around a drum. It pulls it sort of like you pull a rope hand over hand. They pull or back off under load in a very controlled manner. Pretty expensive, made by differnt manufactures, varying quality as well. 3/8" to 5/8" line is common.


----------



## TaoTreeClimber (Aug 1, 2007)

That sounded like some sketchy stuff. Glad everything worked out for you and no one got injured or property damaged. I would have loved to see some pics or video of that big Muldoon. 

Kenn


----------



## TimberMcPherson (Aug 2, 2007)

I did get some pic on my phone, I have to get a cable to download stuff of it onto the comp. 

I just put a file on youtube. A large pine done a few years back that wanted to go all by itself, thankfully the lean was right. Bet you havent seen many go over like this one! No backcut. I just ran for the camera when the ground started shaking.

http://www.youtube.com/watch?v=1XozZhBeCnU


----------



## Ekka (Aug 2, 2007)

Fundamental errors made.

*The "big line" was not pretensioned and not set at 90 degrees to the scarf (notch).
*
Trees follow scarfs, leans give weight, providing hinge wood never breaks then trees are delivered on scarf.

*However gunning adjustments need to be made for lean.
*
All of this explained and showed in real life on this video. By the way, this is the most heavily viewed video in my collection, I suppose that is because fallers/forestry and arborists watch it.

http://www.arboristsite.com/showthread.php?t=34252

Diagram attached showing angles pertaining to your words.







Also, in support of my video I made these diagrams so people get a better understanding.


----------



## TimberMcPherson (Aug 2, 2007)

Great diagrams Ekka, although I cant get the video to work.

Your right Ekka, and your ideas are bang on. I did consider sloping the scarf, seriously considered it. I understand the benefits of them and used them on smaller trees, but I have also had trouble getting them right in larger diameter trees. Especially with macs being so knotty and unpredicatble. Even with a horizontal setting the scarf was at least 50 inches (about 1.3m) across. 

I wish I could have pretensioned the line, but it was just to heavy and reaching to far and I was stuck with the anchors i had to get a better angle. And I wasnt keen to direct the tree closer to the house! If the same situation comes up again, I will come up with a system to pretension using a tirfor (without the tirfor staying in the system of course). I thought the tree would lean enough towards the house to tension the line early on and was wrong, I also didnt think it would go so far over before loading. 

Im going to do more work with sloping scarfs, but I have to say I very very very rarely get trees with enough safety margins to experiment with! I wonder how hard it would be to make a tree cutting simulator? Or a computer program where you put in the landing zone, danger zone, height, species, DBH, wind, lean, anchor points, available winches, bar length, canopy bias etc etc and it would tell you just were to scarf, at what angle etc etc.

Ah what where would be the fun in that?


----------



## Ekka (Aug 2, 2007)

Finding a suitable anchor for a side rope with nothing in the way is always a challenge.

Rather than a sloping scarf use the horizontal scarf with adjusted gun. You'll have more hinge wood across it.


----------



## masiman (Aug 2, 2007)

TimberMcPherson said:


> Great diagrams Ekka, although I cant get the video to work.



Timber,

If I remember, I could not get the videos to play in Windows media player either. Technically, I almost certain it was a coded problem.

Try downloading and installing VLC player. I prefer it to not be my default player, but I have found it to be able to play alot videos that other players have problems with.


----------



## Ekka (Aug 2, 2007)

Timber, what sort of knots did you have in the rope too?


----------



## TimberMcPherson (Aug 3, 2007)

No knots. the line had big splices in both ends. I had two 5 tonne strops around the tree that were shackled to the line, and the other end (anchor) was wrapped 4 times around a 40 inch stump and locked off. I learned some time ago not to put knots in lines that size as they can be near impossible to undo.


----------



## Ekka (Aug 3, 2007)

That's good, no knots.

I was thinking today about it, the angled scarf, that'd suck lining it up right ... I'll stick with the horizontal and adjusted gun.


----------



## John Ellison (Aug 3, 2007)

I bet that four inch line is a bear to wrestle around. Did the line recoil much when it broke?
I know its not the only way, but,
Got to say that I am for keeping the felling cuts at right angles to the stem. Its the way I was taught, and how the fallers that I respected in Alaska and talked to about it would do it. Depending.... you can gun it dead on, just have to sight in the same plane as the leaning tree.
Horizontal cuts on a leaning tree get more screwy the farther it leans.


----------



## TimberMcPherson (Aug 4, 2007)

It is a pain to work with, you have to work with it feeding it in and out of a large sack the whole time, I found it was the best way to handle it especially where its sandy or muddy.
It weighs less than 40kgs dry though and would have been about 100 foot long I guess (never measured it). Yeah it did recoil, ended up draped over the house! My next line will be bigger and stronger! (and always pre tensioned.) 

its been gold over the years, we do alot of steep work ugly work and it was good insurance,m although I was always careful not to shock load it (much). Will be suprised if its less than a grand to replace it. At least I know have a couple of good butt ropes!


----------



## John Paul Sanborn (Aug 4, 2007)

Instead of a huge standard fiber like look into the exotic fiber, super low stretch, high tensile stuff..

You will have a smaller diameter line for the SWL and less stretch to take up on pretensioning. 

This is out of the the SeaMar catalog
Spectron 12™ Single Braid



> A unique combination of 100% SPECTRA®12 strand braided Parallay® construction with a proprietary Samthane™ coating. This rope yields the highest strength to weight ratio available, fast/easy splicing of a single braid and low elongation with a firm/durable Urethane standard gray coating. Also available in standard commercial and bulk put-ups in a variety of solid colors. Uncoated product available for low snag applications. Specific gravity: .98.


Stock # - Dia. - App. Tensile - Apx. Wt/CFT 
SAM81501100 - 1" 80,000 23.43


These are used for tug and mooring applications, Roger in Seattle uses these types of rope for speedlines and I know people who use it for specialty slings. One thing I've heard that they are higher wear then poly or nylon


----------



## joesawer (Aug 4, 2007)

To the best of my understanding, you faced the tree somewhat in the direction of the lean and then opened the face/scarf in the direction of the fall and intended to swing the tree into the intended lay/dropzone.
I have never cut this species, but have cut a lot of big trees in North America. Swinging big trees is a lot different than smaller younger trees. The younger trees have much more resilient fiber, the older trees are usually much more brittle. The large diameter and hight equals huge weight that really compresses the opening cut and puts a lot of lift on the holding wood.
Wedges don't work well on large hinges, for them to really shine you need just enough hinge. Really hard to do around high value hazards. Pulling will work much better on a thick hinge. I think this is why pulling is so much more common in the arbor world.
You might consider using smaller rigging and a false anchor to properly position and tension your side rope. If you can stop it from moving in the wrong direction, it is much better than trying to catch it and change its direction.
Without seeing your tree, it is hard to say what I would have done differently. From your description, I would normally face the tree in the desired direction with a very straight and clean hinge, probably with a small gap in the back to give the fiber a little radius as it bends. The hinge would go all the way across the stump, tapered, smaller on the compression side, but thick enough to hold the weight up. I would not want it to lean any more than it already does. Then I would pull and wedge it into the direction off the lay.
As others said, allow for the lean while gunning the face. Remember that the tree can drift to the lean when the hinge breaks.
Don't feel to bad about not hitting a bullseye with this tree. You didn't hurt anyone or tear anything up. You are doing the right thing, learning from it.


----------



## woodchux (Aug 4, 2007)

Glad to hear no damage was done. 
IMO i would get rid of that big unmanageable rope and get something more user friendly. 
My 5/8 double braid is rated at 18,000 lbs. and you can carry it with one hand.


----------



## John Paul Sanborn (Aug 4, 2007)

woodchux said:


> My 5/8 double braid is rated at 18,000 lbs. and you can carry it with one hand.



It is nice for rigging, but with WL ratio of 5 you have a SWL of 3600 LBS. Also it is rather dynamic so you need to work the streach out of it for heavy pulls, the stretch is a factor in the tensile, so you reduce your SWL by preloading it.

A short ton is 2000# which is what we use as a standard, he is talking metric tonne which is almost 205# more.

With a 4 inch mooring line I figured he was either using his SWL or dropped a decimal point in the thread title, 8 tonne is only 17640#


----------



## lees trees (Aug 4, 2007)

turfor? is that wire or sinthetic line? thanks


----------



## TimberMcPherson (Aug 5, 2007)

It did have some stretch as it was mooring type rope. 8 tonne was the SWL (if memory serves), so it was truly a friend that will be sadly missed.

Tirfers use wire rope.cable. A beautiful bit of kit that pulls harder than a schoolboy.


----------



## fast*st (Aug 5, 2007)

Any pictures of the broken line? I'd guess the remaining 
rope is only safe for a driveway barrier or maybe a tire swing? 
In other words, out of service, cut into short pieces for xmas
gifts. 
-Jason


----------



## TimberMcPherson (Jun 28, 2008)

Managed to get one image off my phone, by transfering to my wifes and sending it on.

You can see the two lines on the rhs, one is the 8 tonne line going to the tree stump above, the other line is the tirfor line. Im up on scaffolding preparing the base (well a few metres above the base) before the cut.Truck to right is mine and is where the tree ends up thankfully

Heres the set up of the job


----------



## TimberMcPherson (Jun 28, 2008)

Another pic, taken from near the tree stump where the big line was fastened, thats me in the tree.

You notice how pics look less dramtic?


----------



## ray benson (Jun 28, 2008)

TM is this a pic of the line?
http://www.arboristsite.com/attachment.php?attachmentid=64397&d=1202287697


----------



## TimberMcPherson (Jun 28, 2008)

ray benson said:


> TM is this a pic of the line?
> http://www.arboristsite.com/attachment.php?attachmentid=64397&d=1202287697



Yeah the line on top with the splice is the 8 tonner


----------



## ropensaddle (Jun 28, 2008)

Ekka said:


> Fundamental errors made.
> 
> *The "big line" was not pretensioned and not set at 90 degrees to the scarf (notch).
> *
> ...



Been utilizing those techniques for years but could never draw it like
you


----------



## Mikecutstrees (Jun 28, 2008)

*Great thread!*

Thanks everyone for an informative and interesting thread without any of the usual BS. I learn alot from threads like this, it's what arboristsite is all about. Impressive work!


----------



## jomoco (Jun 29, 2008)

I had an interesting learning experience on an extremely steep slope about 3 years ago in the moutains of Julian east of here on a county removal contract.

It was one of those contracts that involved shutting down traffic both ways on a major HWY called Banner Grade. Because of this the work had to be done at night in the wee hours of the morning. It was one of those contracts that had to be completed by a certain date or else get fined heavily for each day over it went.

It was winter and the rains would not let up as the completion date loomed closer and closer, so the owner of the company sat down with me to explain the pickle he was in if the job wasn't completed regardless of the weather. He threw some serious money on the table and let me have my picks of his best men and equipment in his 70+ man company.

So essentially I took on this nasty complicated night time job in the middle of a winter storm. I had two crews, a total of 10 veteran treeworkers, a bucket crew for road clearance, and I ran the removal crew complete with crane and whole tree chippers, the county guys shut down traffic and patrolled the 7 mile stretch we were working.

The problems started as the rain picked up and began washing boulders on the steep mountainside above us down onto the HWY on which we were working. My men started getting real nervous despite being paid triple their normal pay, and looked to me expecting me to shutdown the operation before something bad happened. They were disappointed when I merely assigned 2 men as spotters, one for each crew and kept on going as the rain kept falling in sheets.

The job progressed slowly but surely as we worked into the early morning hours driving around the many boulders and rocks now littering the rain soaked HWY. Only one removal was left to do, a big cedar on a steep down slope in such close proximity to high power lines that the crane could not be used on it. So I put on my gear, had my men tie a rope to me and lower me off the hwy and down to the big cedar, I clipped into the tree and untied the belaying rope, then I limbed the cedar out and dropped the top downhill away from the power lines up hill on the HWY, leaving a nice fat 80 foot pole.

The scary thing about this tree's location was that about 100 feet down the incredibly steep mountainside directly below it was a vertical drop off of many hundreds of feet with a raging river at the bottom that I could hear from the tree but could not see. We short sticked the crane below the power lines and yanked the top of the cedar and brush up onto the HWY and chipped it up.

All that was left now was the 80 foot pole and the job would be finished. I couldn't drop it up hill because of the power lines, and I couldn't piece it down without the logs tumbling down the slope and over the cliff into the river, which any licensed timber operator knows is a big no no. That left me with two choices, rigging and catching the wood in the storm, or dropping the stick downhill and trying to catch it with 3/4 inch steel chokers clevised together, one around the stump, the other about 15 feet up on the stick.

The men were already a little ticked off with me for insisting we finish the job in such foul dangerous conditions and weather, they wanted to get the heck out of there pronto and I didn't blame them for feeling that way.

I decided to drop the stick down hill and try and catch it with the steel chokers, I figured that if I minimized any slack in the chokers, the stick would not build up any momentum capable of snapping 3/4 inch steel chokers, but I was dead wrong, and it was an amazing sight to behold when those chokers failed. Of course I was tied off to the belaying rope when I dropped it downhill with my MS440 Magnum, and that big stick snapped those steel chokers like a piece of thread, but the amazing thing to see was the 3 foot flames lighting up the night at the exact point where the chokers separated. All that was left was a shredded section of steel choker around the stump.
That stick never slowed down even a little bit as it slid down that slope and over the cliff and finally splashed into the river and downstream, I presume.

None of the county guys were around to see my very convenient mistake, the guys were thrilled to see the job over(the cliff), only the crane operator was a little upset with me for destroying two of his long chokers and one of his big clevis'.

We loaded up and headed home and kept our mouths shut about my big rigging mistake in the middle of a storm that day, but I learned a valuable lesson about what a big green cedar stick can do to 3/4 inch steel chokers.

If you've ever seen a high caliber rifle's muzzle flash at night, that's exactly what that choker looked like when it separated that night, and all my worries went over a cliff and floated downstream.

jomoco


----------



## ray benson (Jun 29, 2008)

TimberMcPherson said:


> Another pic, taken from near the tree stump where the big line was fastened, thats me in the tree.
> 
> You notice how pics look less dramtic?



Rotated and lightened up the pic. Hella of a job, not one for me.


----------



## NickfromWI (Jun 29, 2008)

TM- I think JPS gave some great advice. It is time to step up your line choice. Not in size, but in materials. It may cost you more, but you could get a line maybe 1 or 1.5 inches in diameter that can handle double what you got out of that 4" line. 4 inch rope is a waste of space and a waste of energy to carry around.

Is this sort of stuff available in Oz? Anything made of dyneema/spectra, technora, vectran...

Glad this all worked out alright.

love
nick


----------



## TimberMcPherson (Jun 30, 2008)

The line was fine but I shock loaded it with a LARGE falling tree, it was at least 2/3 of its way over before the tension came on. I should have figured a way of pre tensioning the line by sending the tree towards the house at the start of the cut. If I had done this, it woud have not been a problem.

I think if the line was twice or 3 times its strength there was still a chance of breaking it due to the size of tree, position of rope, direction of fall and the all destroying shock loading. I have snapped 18mm line and it sounds like a rifleshot, this was like a cannon a moment before the ground shook when the tree hit the floor.

The rope had done alot of work, but not shock loaded until then. It had been used as a far reaching anchor line and was my "go to" line for jobs like this. I miss it. 

I do understand and agree with what you say nick but I will buy a simular line if I can, I have alot of other ropes (spectra, stable braid etc) and they get alot of use. I called this an 8 tonne line but since then I have rechecked with a provodor and its closer to 25 tonne. Big lines are a real PITA but they are very rugged and when working around machines etc its good to have a line thats easily visable and have there place in the right situation. Its been great.


----------



## The Lorax (Jun 30, 2008)

Where is that photo taken? Kilbirnie or Island bay direction?


----------



## rbtree (Jun 30, 2008)

Ekka said:


> Finding a suitable anchor for a side rope with nothing in the way is always a challenge.
> 
> Rather than a sloping scarf use the horizontal scarf with adjusted gun. You'll have more hinge wood across it.



Correct!


----------



## rbtree (Jun 30, 2008)

Hi Timber. Mighty difficult and technically challenging job! That is one huge line! I was thinking spectra would be good for this application....maybe, but do you want some dynamic properties in this application, i.e., a bit of give? I'd think a little would be good to minimize shock loading? If not, you'd only need 5/8 Plasma or Amsteel Blue, rated at ~55,000 pounds. Pricey but a lot easier to handle. And 1 inch Plasma is 110000 pounds rated, lists for ~$11 a foot. I could probably get it for you for $6-7 from my supplier. don't know how much it would cost to ship it to ya though!

To preload, you could have installed a prussic on the line, and then pretensioned it with a tirfor or any mechanical advantage method.


----------



## CJ-7 (Jun 30, 2008)

That was a 4" diameter line? Larger marine lines are measured in circumference (4" circum = 1 1/4" dia). That's a mighty big line to be toting around if its 4" in diameter.


----------



## TimberMcPherson (Sep 5, 2008)

CJ-7 said:


> That was a 4" diameter line? Larger marine lines are measured in circumference (4" circum = 1 1/4" dia). That's a mighty big line to be toting around if its 4" in diameter.



It was a bear of a line. Huge. I had a few other tree companies comment on it including some guys that turned on up on the job and said "thats the kind of rope I would want doing this." It was kinda hollow, or should that be not tightly bound and if you squeezed it the diameter lessened a little.


The tree can be seen on google earth at 41 19'52.42S 174 47'21.15E
The image on earth is at least 5 years old from what I can tell. The tree was leaning towards the east.

I am going to invest in some amsteel or plasma or spectra or something simular.

Nice jeep cj, have the seen the mitsubishi 2.7 turbo jeeps? I want one!


----------



## moray (Sep 5, 2008)

CJ-7 said:


> That was a 4" diameter line? Larger marine lines are measured in circumference (4" circum = 1 1/4" dia). That's a mighty big line to be toting around if its 4" in diameter.



Good catch, it must be circular measure. 100 feet of 1/2 in line would weigh about 8 or 9 lbs. TM's rope weighs about 10 times that much. The diameter of the rope would then be a little over 3 times as much, or roughly 1 1/2 inches.


----------



## rbtree (Sep 5, 2008)

TimberMcPherson said:


> It was a bear of a line. Huge. I had a few other tree companies comment on it including some guys that turned on up on the job and said "thats the kind of rope I would want doing this." It was kinda hollow, or should that be not tightly bound and if you squeezed it the diameter lessened a little.
> 
> 
> The tree can be seen on google earth at 41 19'52.42S 174 47'21.15E
> ...




Timber, would you be interested in 300 feet of 1/2 inch spectra? 24,000 lb tensile....As light as it is, the shipping prolly wouldn't be bad....and I'll sell it for 1.50 US per foot...it is almost brand new. Retail is probably 2.50 a foot.....


----------



## TimberMcPherson (Sep 5, 2008)

moray said:


> Good catch, it must be circular measure. 100 feet of 1/2 in line would weigh about 8 or 9 lbs. TM's rope weighs about 10 times that much. The diameter of the rope would then be a little over 3 times as much, or roughly 1 1/2 inches.



You couldnt get your hand around the line, only about half way. I did get a knot in it that required careful use of a sledgehammer and wedges and running it over with a truck to get undone.

I would be interested in that line RB, It does depend on the shipping though as that can have a huge effect on price, I just ended up paying some rip off artist $89 to ship a $13 part the size and weight of a couple silver dollars from the US. Dont ask, long story!


----------



## randyg (Sep 9, 2008)

TimberMcPherson said:


> I have run the whole thing through a hundred times, and aside from coming up with a way of pretensioning a 4 inch line set horizontally 50 feet away or just having a bigger line, I dont think I could have done much different aside from aiming the tree more at the house, but even that make me worry about how things could have been much, much, much worse.
> 
> I dont think Im being to pedantic. I take my very clean record for breakage very seriously. Big tree, bad ground, target rich environment with a tight timeframe and limited options. I am confident in my ability and track record but I am simply not happy with how it went, do I just need to harden up?



Had you pretensioned that line, the tree would have started over and shortly after the line would have halted the felling process completely. Been there, done that, not a good feeling having that tiger by the tail. Fortunately for me, I was tied off to truck and able to release the brake and follow down, with 26,000 lbs plus of truck skidding near the end, but nobody got hurt. Pucker factor was at an all time high. I since learned how to "predict" that scenario and adjust/eliminate altogether.

For me, I try and picture a door with two hinges. One is the hinge on the tree being felled, and the other the anchor point of the side loaded line (the stump in your case). One principal to keep in mind is the "hinge pins" must be in line. If you hung a door and the hinge pins were not in line, as you closed the door they would bind and something would have to break to get the door shut. 

SIDEBAR: If you had a 20" diameter at the stump tree and after making the face cut and kicking out the "pie" you rolled a 20" long piece of 1" pipe all the way in to the apex of the face cut, and got down on one knee and eyeballed through that pipe, you SHOULD see the anchor point. If you can not, that line will either go slack or go tight as the tree starts over. No, I don't carry around a pipe, but you bet your boots I get down and eyeball along the apex to look for proximity of the anchor point. Start with a very shallow notch and adjust till it is sighted in, then make it deep as you want and re-check alignment. 

Timber, using that stump like you did, and adjusting the hinge accordingly, I think the tree would have fallen way to close to the house. I'm not trying to explain how you should have done it differently, but hoping to explain WHY the rope broke. The desire to be more accrurate predictors sets us apart from those "cut and see" types. 

What I WOULD have done differently if time allowed would take more limbs off the downhill side and leave them all on the uphill to counter the lean.


----------



## TimberMcPherson (Sep 10, 2008)

Trucks always make me nervous as anchors but we dont always have much choice. Your right about lining up the hinges between scarf and arc of travel, the direction was fine as you can tell by where the tree ended up landing, I just didnt send the tree towards the house which would have got the line tight. Line got shock loaded instead of loaded by tree heading towards house gently, it snatched when the tree was about 45 degrees over, thats what broke it

If it was tensioned it wouldnt have stopped the process, and if I was able to pretension the big line I would have scarfed the tree differently, the idea of doing a collapsing scarf towards the house was to tension the line so it could swing the tree sideways along with winch help.
the tirfir had plenty of pull and the way the big line would have just guided it sideways, restricting its felling path in an arc.

A great plan if only I had the faith to aim the tree at the house! (well the best plan 4 arbs could come up with at the time)


----------



## knudeNoggin (Sep 21, 2008)

> Instead of a huge standard fiber like look into the exotic fiber, super low stretch, high tensile stuff..
> You will have a smaller diameter line for the SWL and less stretch to take up on pretensioning.


And much less tolerance for dynamic/shock loading. (The rapid loading that
I've seen stated for tug lines of HMPE is a far cry from "shock" as seen here.)



> Yeah, the line on top with the splice is [it]


Oh, hmmm, not the more monstrous lines around the saw, also with splices,
but 8-strand not 12/24?!
We haven't heard what the composition of the monster line was, but from
the photo & color, I'm guessing it's the increasingly popular CoExtruded PP/PE
material (often erroneously called "copolymer" (Technora is a copolymer,
in a technical sense, but not the coextruded stuff)). That's not so good for
absorbing shocks, in material or structure. (A light blue hue is common,
though there are some other colors.)

Btw, where did the break occur in the line--at a splice, or elsewhere
(since you said it kinda caressed the house, I guess it broke towards
the anchor end and was flung over ... )?

The bigger lines of your picture might be "polyDac" combo-fibre lines
(where polyester is combined w/PP or increasing CoEx, to bring surface
qualities vs. UV & abrasion of PES with lightness of olefins). And the
8-strand I think has more inherent load absorption.

Could a good big laid nylon bridle have given you the cushion necessary,
I wonder? --it's the sort of thing done in some heavy towing, at least.

-------


> I did get a knot in it that required careful use of a sledgehammer ...


Which knot?
(In mooring lines of trawlers I've seen lots of bowlines that have capsized
into Pile Hitches on a dog-legged standing part! But a simple extended
tucking of the end could prevent this.)

*kN*


----------



## knudeNoggin (Oct 4, 2008)

Hmmm, still curious, about which rope & knot.

*kN*


----------



## TimberMcPherson (Oct 4, 2008)

Sorry missed your post!

Breakage occured about 15mm from the end splice which was attached to the falling tree, I regularly check my ropes and although this rope was far from being perfect, there were no obvious areas of weakness. 

The knot was a simple marlin spike. My climber had tied it to secure the line a hitching pin we put on the end of a diggers arm to pull over some pines, pin came out easy, knot required some work. Really hard to put knots in such a long and heavy line. We kept it in a wool sack and used it from there.

Im not sure what you mean by a nylon bridle, is it like the rubber suspension you find on mooring lines?


----------

