The limits of the Timber Hitch

NickfromWI

Well-Known Member
Location
Los Angeles, CA
Today we were removing a Norway Maple. It was 80 feet tall, yet did not have branches unit 50 feet up (it was fun foot locking up there!) Well, I got all the branches down easy, then was working on the body wood. Something happened that had never happened before. I was using one of those red blocks/pulleys (the big $140 dollar ones that sherrill sells) anchored to the tree with a 3/4" piece of Yalex. I usually do a Timber Hitch. For this particular piece, I had five wraps on the hitch. The tree was about 8' from the house. I made my notch, made by back cut and the piece started to go. The rope ran from the piece, throught the pulley, down to the portawrap, where it took 3 wraps and was being held on by Veton, the ground guy for the day. Well, when the piece dropped, and the rope had it, it pulled the wraps right out of the Timber hitch and the wood, rope, pulley, and the sling holding the pulley all went to the ground. Right when it hit, the clients (husband and wife) applauded and cheered. It was a big piece of wood and they seemed to be enjoying "the show." However, me and Veton looked at eachother in amazement. Clients cheered because the piece came down clean, the top hit first, then, for what ever reason, it fell to the side, and not forward in the direction it was traveling. It landed about 4 feet from the base of the tree. Had it toppled over, it would have surely put a big hole. I sent Veton to the truck for a measuring tape. It was almost exatly 9' long, and 20" on the small side. So my question for you guys....what did I do wrong. I've dropped bigger pieces on Timber Hitches and never had this happen before. The sling got melted a bit from the tail getting pulled trough itself.

Lucky day. That's all I have to say.

love
nick

ps- as soon as I get home tonight, I am going to look on the chart to see what the aprox. weight of this piece was.
 

John_Paul_Sanborn

New Member
Location
MKE, WI
Did you snug up the hitch to set it?

Were the wraps close together or far appart?

I do a 10 second timber hitch regularly; estimate the length needed by matching the splice with a bight in the other end of the rope. Twist the bight so that you get 5-7 wraps going back on the working end, then pass the splice through the bight an snug down.
 

Tom Dunlap

Here from the beginning
Administrator
I have to ask...

Did you make a bight back onto itself before doing the wraps? Too often in timber hitch failures the TH is tied by just wrapping the long end around the spliced end.

Another possibility is that there was slack in the bight. If so, the TH isn't snugged up to the tree and it can slip. This is a case where the TH was Tied, half dressed and not set.

Pilot error but you came in on a wing and a prayer.

Impressed the clients too, not bad for a days work :)

Tom
 

Mike_Maas

New Member
Location
S.E. Wisconsin
The timber hitch is not a knot. It is a mess that some fool came up with because he couldn't remember how to tie a real knot.
This will not be your last disappointment, if you continue to use this knot, it is very undependable, especially in dynamic situations. I defy you to name one other rope discipline, besides "old school" arborists, that would use the timber hitch in a critical application.
You might be better served if you had three or four different length and size slings made up and hung your pulley in a basket configuration. It's stronger and all you need is an eye spliced on each end. I know a guy that could splice them up for you.
Another choice would be to tie a real knot, like the clock hitch or stiltson hitch. If you choose one of these, make sure you terminate them in a clove hitch, not a half hitch like you always see in the pictures of these knots, or they could pull out too.
 
The only limits I see that the timber hitch has are the strength of the rope it is tied with and the ability of the user to tie it.

John Paul’s questions are good ones. If the wraps are not spread out they will slip when a load is applied. If the hitch is not tight it will slip when a load is applied.

Twist the hitch around so that the pull is off center to the bight around the working end. This will cause the hitch to cinch down tight and not slip. Watch the direction you make your wraps. If you make them in the wrong way there is the potential for them to be rolled out if the hitch is pulled up the spar.

Mike. The timber hitch is a very safe and secure hitch if it is tied properly. Do not blame the hitch. I can adjust the timber hitch a lot faster when working down the spar than I can one of the other hitches you suggest. Just my preference.
 

TheTreeSpyder

Well-Known Member
Location
Florida>>> USA
Very nice example. i've always thought of a timber hitch as a loose eyesplice, so might even find some irony here........

Even though it is the same knot, i always look at these things as individual items and lace to fit. If using the timber hitch (most lilkely from lack of line/sling to make stilson etc.) i would lace as any other chosen hitching to task.

If there is any OffSide weight, pull, or even me leaving more hinge on one side just to pull away from me.......that side becomes the block side; while the 'eye'/half hitch restriction goes on the opposite side, so that when the off balance pull tries to favour it's side; the restriction of the eye immediately pulls closed and not open, just like rigging to sweep side ways, the restriction would always go on the opposite side of the sweep, to immediately pull closed IMLHO.

Then as i lace to make that eye, the pull will be down, so i come under to over and back, to immediately pinch off force positively again. For going over first wouldn't pull close/pinch self off as quick and positively against the downward force methinx, again possibly providing initial slip/play in lacing system. i always imagine this as anything else, if their is enough play it not only doesn't start out locked closed for a drop in 'security'; but also presents more potential force to test lacing by impacting it. Also making it harder to untie! i think of so much force as foot pounds, just ddial it down to inches pounds, centimeter pounds etc., and tweak all play out to limit potential impacting on any scale to the max.

Then, for the same reasons i like bringing the tail behind and down and start the turns that way.

i always look a the direction of most pull, and set eye/half hitch etc. to pull immediately/ positvely pinching off closed with force from the predicted direction in any knot lacing.

Then, of course, all slack and play out of the lacing system, so that the tightness forms the self lock and any pull only sets it tighter.

i go with long wraps too. For one thing i think that going under line for coils presents more surface contact area if slanted rather than straight, as well as turns not facing the stiff ness of the line trying to 'spring' open, as line becomes stiffer as it loads, longer turns deform the line less etc.. If using a spanset sling or eye to eye etc. will even extend with loop runner etc. (at tail/ point of lowest pull) to achieve this. When i used Timber hitch i would always put a stopper in tail then bring it up through a couple of wraps earlier. For security is it's weak point to watch.

if making a quick timber hitch in a longer line, i would make a bowline for the block and make turns with a bight, till the bight was short enough to slip over block 2x, for positive lock.

i imagine that a bus pulling a line as a lot of power; though with enough turns on a tree a baby could hold it. A baby holding a bus on leash! So if you take the point where a baby could hold a bus, and pinch it under the busses pull; the bus couldn't move. So just add security from slip and you are there.
So, to give this security; start with everything tight, self pinching, and set so that at the predicted pull, it will pull tighter and closed. Use stopper knots, as a positive mechanical stop; whereas the knot can't squeeze through only way out.

Part of the reason i've looked at Timber Hitch as a loose eye splice is it's strength and not resembling much else to categorize. i've found with these images guiding decisions, that all kinds of things of baby holding a bus, starting with everything tightt so it is self pinching and potential force into lacing is reduced, by reducing the amount of impact into system and any loading immiediately pulls closed and tighter immediately will work. They are my common elements.


Or something like that!
 

Joey_P

New Member
Location
Nova Scotia
The only thing I could add to all that when spreading the 5 or more wraps out, I try to make it 2/3 around the trunk or branch. I don't no where I heard this rule of thumb, but thankfully I've never had a problem with this hitch.
 

NickfromWI

Well-Known Member
Location
Los Angeles, CA
Well, let me see if I can provide some more info.

Starting with Tom...Yes, I wrapped the rope around the eye, then headed back and started my wraps. I did not wrap around the splice.

JPS- After I make each wrap, I pull the tail away from the eye. This sort of "elongates" the wrap.

Mike Mass- can you get me the email address of the splicer you know!!! I need to get some stuff made up!

I don't know. I wish I could take a look at the instant replay! I am going to stick with this knot for now. I will make sure to snug it up tight, and I might start using 6 or 7 wraps.

Climb safe, guys!

love
nick
 

Kevin

Well-Known Member
Location
Ontario, Canada
This is the stuff you don't expect to happen and when nothing drastic comes from it a good lesson is learned and good tree men become better for it.
It's the shared knowledge good and bad that help prevent future accidents.
Good work!
 

Mike_Maas

New Member
Location
S.E. Wisconsin
Tim wrote:
"The timber hitch is a very safe and secure hitch if it is tied properly. Do not blame the hitch. I can adjust the timber hitch a lot faster when working down the spar than I can one of the other hitches you suggest. Just my preference. "


This is perhaps a good application for the timber hitch, because you are right there and able to inspect it before each cut.
When I read that Nick was using the timber hitch to hang a pulley, I had visions of the hitch being up overhead and being used multiple times without the advantage of being able to see it closely. In this application, where the lowering line flips around both loaded and unloaded and wiggles the pulley, I would worry that the hitch could loosen up and come untied more easily that a real knot.

I recall being on a job and watching a climber lower a hunk of wood secured with a timber hitch. It took a bounce and held, but when it bounced up, it loosened then on the return down it came out, sending the hunk through a shed.
We concidered what happened and did mock ups on the ground. It was easy to duplicate the untieing of the hitch by whipping the tail around a little.
Only the most carefully tied hitches held up to scrutiny. It behaves like a chinese finger trap, as long as there is pressure it holds, loosen the load and it can loosen.
 

NickfromWI

Well-Known Member
Location
Los Angeles, CA
"This is the stuff you don't expect to happen and when nothing drastic comes from it a good lesson is learned and good tree men become better for it.
It's the shared knowledge good and bad that help prevent future accidents."

Exactly! That's why I posted this here.

love
nick
 

didjon

Member
Location
Hole,Norge
I have seen timber hitches slip before when subjected to shock loading or in this case slam dunking.I think its because the hitch is subjected to a sudden jerk.Progressive force put on the hitch makes it grip tighter but when its a sudden and violent jerk the tail can be pulled through before the force can make it grip tighter especially if it hasn't been pulled really tight before if you know what I mean.I generally only use the hobbs for snatching out but three wraps on the portawrap sounds like it could have been enough to stop the piece running and cause a very violent shock load pulling the tail through and causing the failure. For this reason I always use an adjustable woopee sling on my block and I have never seen one of those fail..
 

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