International Guild of Knot Tyers Forum

General => Practical Knots => Topic started by: Hrungnir on December 07, 2010, 04:25:47 PM

Title: What knots would you use for these common tasks?
Post by: Hrungnir on December 07, 2010, 04:25:47 PM
Eighteen years ago, me and my grandfather was going to chop down a tree. With some wind, the tree would be a real threat to my grandmothers brothers cottage. That's why we had to bring the tree down. My grandfather knew I was in the scouts and that I knew some knots, so he asked me to fasten the rope on another big tree, so the tree wouldn't crush the family cottage. I've learnt that clove hitch was a good knot, so that was the one I used. When my grandfather had chopped halfway through trunk, he became uncertain about my knot and went to inspect it. With one hard pull, my clove hitch came right off!  :o Nice knots we learn in the scouts, eyh? My grandfather made on of his own boating knots, and we brought down that tree with no damages on property or people.

I don't know what knot my grandfather used, but I would like to know your chose for a knot in this very common task. I assume sailor's hitch and timber hitch would be better alternatives than the clove hitch, but they are perhaps not safe enough when the family cottage is at stake? The timber hitch is also a bit awkward to tie when you have a lot of rope and want to keep tension on the line.

I would also like to know what knot you would prefer when towing a car over a greater distance? Old narrow roads on snow and ice, but also for roads which demands more speed. I guess the slipped buntline hitch would withstand all the pulling and jerking, but I'm a bit worried a slipped knot could accidentally come loose in such a situation. A none slipped buntline would probably jam  :'(
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 07, 2010, 08:59:26 PM
For securing the tree, I would make two round turns, followed by a backhanded turn that is secured to the standing part with two half hitches. The two turns are there, so the hitch will not slide upwards along the tree trunk.

For towing, it depends on what you can tie to on the car, but if there is an eye that is intended for towing, I would use a bowline with a round turn in the eye. Also on the towing hook on a car I prefer a bowline with an extra round turn. I have towed many times with bowlines without any problem. The extra round turn is there to avoid chafe.
Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 07, 2010, 10:37:39 PM
There are so many viable knots that may be used.  Ink provided some good ones.  I've always wondered, what benefits does the backhanded turn provide?
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 07, 2010, 10:49:26 PM
The backhanded turn is very simple, and it also adds more than the friction of one more turn around the tree. The securing by two half hitches thus will take negligible load. The backhanded turn will permit releasing the hitch even under extremely high load. The load is taken by the round turns. Of course one could do without the backhanded turn, but it is a very simple way of adding much more friction to the belaying.
Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 07, 2010, 11:21:10 PM
The backhanded turn is very simple, and it also adds more than the friction of one more turn around the tree. The securing by two half hitches thus will take negligible load. The backhanded turn will permit releasing the hitch even under extremely high load. The load is taken by the round turns. Of course one could do without the backhanded turn, but it is a very simple way of adding much more friction to the belaying.

OK, I just don't see how a backhand turn adds more friction than does another round turn.  I'll take your word for it because I haven't tested the difference.
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 07, 2010, 11:44:07 PM
The backhand adds the friction of turning around the standing part plus the friction of one turn more around the tree. It also expends some of the rope, which comes in handy if it has to be released under load. If needed, you can bend another rope to the end before releasing. The holding power of more than one round turn is tremendous. The first turn around a frictive object like a tree will take about 90% of the load, and the next turn takes another 90% of the remainder, leaving us with just a puny percent of the load on the standing part. So that backhand will not take much load. It is only a bit of overkill, typical for the trade of a rigger.
Title: Re: What knots would you use for these common tasks?
Post by: roo on December 08, 2010, 12:08:43 AM
I don't know what knot my grandfather used, but I would like to know your chose for a knot in this very common task. I assume sailor's hitch and timber hitch would be better alternatives than the clove hitch, but they are perhaps not safe enough when the family cottage is at stake? The timber hitch is also a bit awkward to tie when you have a lot of rope and want to keep tension on the line.

I would also like to know what knot you would prefer when towing a car over a greater distance? Old narrow roads on snow and ice, but also for roads which demands more speed. I guess the slipped buntline hitch would withstand all the pulling and jerking, but I'm a bit worried a slipped knot could accidentally come loose in such a situation. A none slipped buntline would probably jam  :'(

Without endorsing your usage, I'll just say that if you want tension on a line, use a tensioning mechanism:

http://notableknotindex.webs.com/Versatackle.html

Deal with the excess rope on the non-tensioning side with a termination that can be performed on the bight before tensioning (like a Timber Hitch on the bight or a Midspan Sheet bend):

http://notableknotindex.webs.com/midspan.html

Towing isn't nearly as big a test of knot security as you might imagine.  There is little slack shaking or flogging.  If you don't want to use a slipped knot form, there are many alternatives.  To name a few:

http://notableknotindex.webs.com/sailorhitches.html
http://notableknotindex.webs.com/timberhitch.html
http://notableknotindex.webs.com/zeppelinloop.html
http://notableknotindex.webs.com/waterbowline.html

Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 08, 2010, 12:12:17 AM
The backhand adds the friction of turning around the standing part plus the friction of one turn more around the tree. It also expends some of the rope, which comes in handy if it has to be released under load. If needed, you can bend another rope to the end before releasing. The holding power of more than one round turn is tremendous. The first turn around a frictive object like a tree will take about 90% of the load, and the next turn takes another 90% of the remainder, leaving us with just a puny percent of the load on the standing part. So that backhand will not take much load. It is only a bit of overkill, typical for the trade of a rigger.

The backhanded turn, do you keep it touching the two half hitches?  Or do you work the backhand turn around so that it ends up pressing against the object (e.g., tree)?  Or does it not matter?
Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 08, 2010, 12:16:51 AM
...Deal with the excess rope on the non-tensioning side with a termination that can be performed on the bight before tensioning (like a Timber Hitch on the bight or a Midspan Sheet bend)...

I don't follow exactly what you're saying.
Title: Re: What knots would you use for these common tasks?
Post by: roo on December 08, 2010, 12:18:31 AM
...Deal with the excess rope on the non-tensioning side with a termination that can be performed on the bight before tensioning (like a Timber Hitch on the bight or a Midspan Sheet bend)...

I don't follow exactly what you're saying.

Which part don't you follow?  How to make a Timber Hitch on the bight (http://notableknotindex.webs.com/timberhitch.html)?
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 08, 2010, 12:25:02 AM
The backhand is akin to #1797, only that I make two round turns first, then go around the standing part and back around the tree, upon which I put two half hitches to secure.

That is just a belaying, anchoring the end of the rope. If you need to haul on the rope, it calls for other solutions.
Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 08, 2010, 12:30:21 AM
...Deal with the excess rope on the non-tensioning side with a termination that can be performed on the bight before tensioning (like a Timber Hitch on the bight or a Midspan Sheet bend)...

I don't follow exactly what you're saying.

Which part don't you follow?  How to make a Timber Hitch on the bight?

I don't follow how the Midspan Sheet Bend conveniently handles excess rope if I'm doing a Versatackle.  Or maybe I'm thinking about it wrong.  There would still be rope excess at the working end of the Midspan.  Is that right?
Title: Re: What knots would you use for these common tasks?
Post by: roo on December 08, 2010, 12:50:33 AM
I don't follow how the Midspan Sheet Bend conveniently handles excess rope if I'm doing a Versatackle.  Or maybe I'm thinking about it wrong.  There would still be rope excess at the working end of the Midspan.  Is that right?

The Versatackle would be on one end of the rope.  This end would have no more rope than what is needed.

On the end of the rope with too much length, a Midspan Sheet Bend would pinch off a loop around the object without the need to have access to the end of the rope.  See the center diagram here:

http://notableknotindex.webs.com/midspan.html

Title: Re: What knots would you use for these common tasks?
Post by: SS369 on December 08, 2010, 12:51:56 AM
Normally when I have to fell a tree and need to add some directional assistance, what I do if there is a suitable anchoring structure to use is:
Tie off on the tree with one end of the rope using multiple wraps of the cord and fasten the cord to itself with a bowline hitch, generally slipped. This really depends on so much,i.e., there is only straight trunk, a branch crotch available, able to get to the tie off location, etc.
Then I will find the mid-point of the cord between the tree and the anchoring structure (can certainly be another tree) and tie a mid-line loop. I tie a Butterfly loop and I leave it loose. Then I will take the free end and go around the anchor and thread the rope into the loop and take up the slack, pulling approx. 90 degrees to the tensioned line.
This affair gives you a slight mechanical advantage but more importantly, to me, it lets me or the help pull the rope in a safer direction than the the tree will lean and fall towards. It has always worked, except when the wind and tree weight are too much.
But then some more common sense is needed for such tasks.

As for a tow rope. I opt for a sling out of overly suitable material. Webbing is wonderful and strong stuff, but rope works as well, sized accordingly.
Me, I use a Zeppelin bend for a rope sling that I re-tuck the working ends back into the center of.
For the tape sling I have only used the "Beer knot" because the tape was tubular in design. < This is still tied, guess why.

If the towing is going to be lengthy and jerky and you have accessibility to suitable anchor points I would opt for a simple cow hitch (using the sling) if possible. Just depends on where you will tie in.

Title: Re: What knots would you use for these common tasks?
Post by: Dan_Lehman on December 09, 2010, 08:10:47 AM
As Knot4U noted, there are many ways to solve this problem.
And the particular circumstances can influence what one might
do (e.g., tying to a big tree one might do so with just a couple
wraps and then tie off to a small nearby tree.  The so-called
"Tensionless Hitch" --implying that the final, knotted termination
sees little if any force-- can be approximated by the wraps and
tying off to the SPart with a Rolling Hitch (or a couple turns
on the SPart and then the hitch beyond them.

I would use a bowline with a round turn in the eye.  ... The extra round turn is there to avoid chafe.

Where is the chafe point?
How does the Dbl. Bowline (aka "Round-turn Bowline") help?

--dl*
====
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 09, 2010, 10:51:29 AM

I would use a bowline with a round turn in the eye.  ... The extra round turn is there to avoid chafe.

Where is the chafe point?
How does the Dbl. Bowline (aka "Round-turn Bowline") help?

--dl*
====

Sometimes an image says more than a thousand words. An extra round turn where chafe might be expected at a belaying point will keep the rope fixed so that it will not rub against edges or a rough surface of the object where you attach it.
Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 09, 2010, 03:31:23 PM
Ink, how would that Round Turn Bowline compare to a Cow Bowline (i.e., replace that Round Turn with a Cow)?
Title: Re: What knots would you use for these common tasks?
Post by: Dan_Lehman on December 09, 2010, 06:16:50 PM
Sometimes an image says more than a thousand words. An extra round turn where chafe might be expected at a belaying point will keep the rope fixed so that it will not rub against edges or a rough surface of the object where you attach it.

!!! Whoa, especially if those words are not carefully chosen!
"Round turn bowline" has meaning (as indicated) as "DOUBLE Bowline",
where one is addressing the knot, not the attachment point.

Okay, hmm, I see.  (But I'm not sure I understand why,
as one should expect MORE movement & hence rubbing,
with a span of material between where each eye leg comes
to the ring!?

To answer Knot4U, one might expect either the Cow or more
commonly the Clove hitch here.  The former would have the
benefit of some jamming to the ring; the latter is common
among commercial-fishing knotting.

--dl*
====
Title: Re: What knots would you use for these common tasks?
Post by: SS369 on December 10, 2010, 12:07:09 AM
But back to the original post. I do think that the use of a timber hitch would be a suitable knot and I use it as well when it is the best for the application. Tying it, the Timber hitch is easy and I don't think you would/should try to tie it with the rope tensioned at all!
I have been able to throw the rope over a large branch and retrieve the end, tie the hitch and actually draw it up and snug it from the ground. Chancy, yes.
Tie the Timber hitch as elevated in the tree that you can safely and then apply the tension using the technique mentioned before or another.
Title: Re: What knots would you use for these common tasks?
Post by: knot4u on December 10, 2010, 12:12:18 AM
I see the purpose of the Round Turn in Ink's photo.  It doubles the surface area where the rope contacts the ring.  So, the pressure (force/area) on the rope is cut in half.  Yes, there's more abrasion to more of the rope, but again the pressure is cut in half.  So, if the ring is capable of wearing through the rope via abrasion, then the round turn helps to slow down such a process.  Having said all that, a Cow instead of one Round Turn may be preferable.  A Cow doubles the surface area too, but it also provides jamming properties (when there is a load), as Dan noted.
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 10, 2010, 12:23:11 AM
What happens in reality is that the friction is so much higher, that there is virtually no abrasion against the attachment point. All movement is contained in elasticity in the two legs of the loop, that distorts a bit when the pull changes direction slightly. There is less abrasion, because there is less movement over the surface.
Title: Re: What knots would you use for these common tasks?
Post by: Dan_Lehman on December 10, 2010, 07:37:31 AM
> it doubles the surface area of the rope contacting the ring,
> therefore it halves the pressure.

No & yes : it doesn't halve because of doubling surface area,
but because of taking the two eye legs around the ring at two
points.  (Make that round turn a triple round turn, and you'll
see that you cannot reduce pressure by this increased surface
contact!)  Or, a better way this, it is the area directly opposed
to the force against the ring being doubled that matters; the
other area doubled (in the structure) doesn't matter.

> the friction is so much higher that there is virtually no abrasion ...

No, this can't be : the friction is less or irrelevant --there will be MORE
movement, from availability of material between the eye legs for them
to draw out (when they are not immediately connected to each other
as in the simple case).  But as noted above, the pressure will
be less in now two points of opposition vs. the one.

--dl*
====
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 10, 2010, 01:41:32 PM
As this is the Practical Knots section, I shouldn't theorise too much. It works, you may try it for yourself and make up just any theory of why it works, but it works. Boats that are moored for months on end chafe their attachment points of the rope without that extra round turn, but with a round turn, there is virtually no chafe.

I made a videoclip to show how it behaves: http://www.youtube.com/watch?v=mEFvEiD8ANA
Title: Re: What knots would you use for these common tasks?
Post by: alpineer on December 10, 2010, 04:19:31 PM
I made a videoclip to show how it behaves: http://www.youtube.com/watch?v=mEFvEiD8ANA


Great video to demonstrate your assertion Inkanyezi.

alpineer
Title: Re: What knots would you use for these common tasks?
Post by: DerekSmith on December 10, 2010, 04:23:19 PM
As this is the Practical Knots section, I shouldn't theorise too much. It works, you may try it for yourself and make up just any theory of why it works, but it works. Boats that are moored for months on end chafe their attachment points of the rope without that extra round turn, but with a round turn, there is virtually no chafe.

I made a videoclip to show how it behaves: http://www.youtube.com/watch?v=mEFvEiD8ANA

While I accept the principle that less chafing will happen if the tree is given a round turn, the duration of the felling event is not likely to reflect the sort of chafing exposure seen by a boat moored for several months.

The realities of felling however might lead us in a particular direction when selecting bindings for this job.

Lumber is HEAVY, particularly when it has gained inertial from gravity and especially when this is further enhanced by wind in the branches.  The purpose of the guide ropes then is to ensure that these potentially massive forces are met and overcome in order to ensure the tree falls where it is safe.

With this in mind, every knot weakens your rope, so don't knot the loaded part of the rope.  Add to this the possibility/probability that you will not be able to climb the tree to make a tree fixing and you have the basis of an idealised system.

First up, pass a guide cord over some bough high in the tree and use it to haul the working rope up and over the bough and against the trunk.
Bring both ends down to the anchor point - we now have a double line to the tree, potentially halving the load in each line.
Make four or five turns of each rope around the anchor and tie them off to their SP or to a handy bough.  If you make the turns of each rope in opposite directions, then the ends can be tied one to the other with a simple square knot.  Given enough turns, virtually none of the force from the falling tree will reach the knots in the rope's ends, so untying will be straight forward, and the risk of overloading the rope and snapping it at an inline knot is eliminated.

A handy trick I have used is to make a Prusik with a short loop of cord and slide this up the guy ropes to roughly the mid point, with a hauling line attached to the Prussic loop.  This will allow you to add some serious leverage force to the guy ropes by hauling on them at right angles to the guy lines, and because the guy lines are not knotted to the prusik, the guys are not weakened by any unnecessary inline knots.

One final note is - make sure the anchor is man enough to take what the falling tree throws at it...  You do not want the anchor ripping out and following an errant tree on a mission of destruction.

Derek
Title: Re: What knots would you use for these common tasks?
Post by: SS369 on December 10, 2010, 04:51:49 PM
Hi Derek,
the Prusik at mid-line is a good idea, but so far one that I have not found necessary. If I run short of bull-rope I may try an approach to that need that is at least similar. Perhaps a hitch of some sort that is good for perpendicular pull, for affixing the mid-span attachment of additional line.

But since we've delved deeper into the felling subject, I feel compelled to mention that whoever does this task, they should be competent.
The bull-rope should be there to coax the load in the direction of chosen fall. Most ropes or at least the ones around the most homes are nowhere near rated for limiting the falling weight of a sizable tree. Even with going around and around both tree and anchor point(s).

Notching the tree properly is key and most felling is accomplished without rope use.

And yes the mid-line knot will be the location of the most chaffing (as I described in my previous post), but that is why a suitable rope is used. And when that rope is abraded to the suggested (common or uncommon sense inserted here) limit you turn it into something else less demanding.

All that said, I would not use a rope to arrest the leaning/falling of a tree at all if possible.

Scott
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 10, 2010, 06:03:55 PM
Oh Derek, the round turn mentioned was for the towing. Tree felling is a completely different animal that shouldn't be undertaken without some knowledge of how to fell a tree in the direction you want it to fall. I was fourteen years when I learned to handle a chainsaw and fell trees, and so far, all of them fell exactly where I wanted. You certainly know why.

Usually, when there's no wind and the tree is straight, it is easy. By removing a wedge-shaped piece (notching) in the direction you want it to fall, and then sawing almost through from the other side, it is usually easy to make it fall where you want it. The difficulty is when the tree is leaning some other way or the wind wants to push it the wrong way; there's where we need guide ropes and perhaps also have to haul on the tree to make it lean over to the side where you want it to fall. And then of course, if you have a line attached to haul, it makes sense to pull with another rope at right angles to that rope somewhere in the middle, to make the tree fall, so you're out of harm's way. I have done that too, and in similar situations, although it wasn't a house, but electric cables that were endangered.
Title: Re: What knots would you use for these common tasks?
Post by: Dan_Lehman on December 10, 2010, 07:53:03 PM
I made a videoclip to show how it behaves: http://www.youtube.com/watch?v=mEFvEiD8ANA
Great video to demonstrate your assertion Inkanyezi.

Okay, this isn't quite the circumstance I had in mind
--this, to a *spar*/*pile*, and I was thinking of an *ring*,
such as on an anchor; and I was only considering the effects
of tensioning, not shifting angle of incidence.

The behavior shown in the video (where it kinda seems like
the upper rope is given more wiggle, hmmmm!   ;)  )
is something I've wondered about affecting knot behavior,
with the cyclical slackening on one leg (maybe only one,
maybe both alternately).

AND, we might conjecture that the movement-from-length
which I pointed to is relatively minor in effect to that of
the shifting of the eye from changes in angle.  But do
realize that the video shows angle shift (laterally and also
perhaps vertically --around & along the cylindrical object),
and not pure tension variation.

Around a RING, I don't see same behavior occurring.  And
we do have, in the unwrapped eye, the concentration of
pressure to aggravate if not be the primary cause of rope
deterioration.

Thanks,
--dl*
====
Title: Re: What knots would you use for these common tasks?
Post by: [Inkanyezi] gone on December 11, 2010, 11:10:07 AM
If it's a ring it's the same thing. On cars, this "ring" is often cut out of a plate, leaving edges in the hole. Those edges can cut a rope that is not wrapped with an extra turn, but when the turn is there, there is less movement, and the chafe is less. It works on rings as well as poles, and the difference is greater when the surface is rough.