Knot Question

[George Miles]

Use one rope, tie as tight as you can. Then another rope to get it tighter. Then back to the first rope

[Fredxx]

And the webbing is wider than rope and so cut into the tree much less.

I was also thinking spreading out the force with multiple straps rather than through a single contact point. Again causing less damage.

[John_j]

Hopeless compare with a truckers hitch or a ratchet strap.

[Vir Campestris]

But it's probably what he should have asked about.

I'd be concerned about damage to the bark of the trees. Anything that slides over them will cut into the bark.

I'd probably use a bit of old mainsheet and a jammer, with cloth padding under a bowline around each tree. But I doubt he'll have an old mainsheet or a jammer. Ratchet blocks are cheap and easy.

Andy

[AJH]

I agree and a 5tonne rated one only costs about a tenner.

It also has the benefit of spreading the load on the beech (or was it shingle) the disadvantage is the fairly limited movement.

Personally I would protect both trees from the rope with something to spread the load without constricting stems and use two poles to make a simple flipflop winch and tie one pole off to the standing line when tight.

Not knowing the reason for the tree leaning makes me a bit worried anything will accomplish the desired effect.

[T i m]

Why? What if he was (and, as predicted, he is) perfectly aware of 'other solutions' but for reasons *he* (not you or anyone else chooses), wants to use rope and knots, why would he ask about anything else?

The subject was about knots, not pulling equipment and it seems words like "I am trying to encourage an apple tree in a certain direction by gradually pulling it over" don't paint a picture to some?

And this is my point with some here Andy, they are very quick to belittle people because they haven't though of what they did, without knowing (or even reading into) the full story?

Quite and why I, one of the first to reply mentioned cambian savers / strops etc. Even if it doesn't slide over (or round, like a wire saw) there is a chance that with enough tension you will damage the bark and / or the tree will start to grow over the line.

But isn't the problem there that you might get insects and the like under that part and they could do damage?

Ironically, I have a an old / substantial mainsheet in the boot right now and it's come in handy for all sorts of things. ;-)

Yes, as are car engine hoists but the OP has a winch and chooses not to use it. ;-)

Cheers, T i m

[T i m]

He gave us the reason though didn't he (probably after you posted)? The beech canopy was over-shielding the apple and so it grew towards the light and (so) away from the beech.

That's why the reduced canopy beech can now make a suitable anchor point to "encourage" the apple back up again. ;-)

IMO, The best time to do any of this would be starting when the sap is in full flow so when the leaves start to form. Before that the wood wouldn't be as moist, would be more brittle and so may break (depending on the size and age of the tree and the tension applied etc).

So, a widish strop round both trees, wide enough to spread the tension reasonably but not so wide as to make nice habitat for creatures / damp into that area and with just enough tension to 'encourage' (as the OP says) the tree in the desired direction.

A mate did this exact same thing with his (12 year old, 8" diameter trunk, 6' to the first limb) apple (but to a post hammered in as an anchor), some old car seatbelts to form the loop and a Spanish Windlass to provide the tension .... and a couple of years later, the tree was back upright again.

Before that, the end of one of the two opposing lower limbs was nearly touching the ground.

Cheers, T i m

[AJH]

Doomed to failure then without some excavation. It would make more sense to heavily prune the downward side of the apple and let nature take its course, accepting a sloping stem.

BTW carter's hitch is 3:1 because you lie off the tail on the load hook giving 3 tensioned ropes attached to the single. I used it enough before ratchet straps became ubiquitous.

[Roger Mills]

+2

[Jonathan]

The correct solution.

Jonathan

[T i m]

<snip>

Go for it ... ;-)

Ok.

And as I have said before, adding 'more pulley wheels' may not add any MA to a system.

Put 200kg weight on floor and try and lift it, you can't (let's pretend).

You fit a pulley to the ceiling above the weight, tie a rope to the weight, pass it though the pulley and back down into your hand. You try to pull the weight up but find you have to still apply 200kg to get the weight to move. Zero MA.

That is exactly what you have with the first stage on a truckers knot.

Then you add the second pulley at the trailer hook, that gains you the

2:1 MA. The only time you *effectively* get more is when you have a trucker *pulling down* on the line over the truck, via the rope though the loop. As soon as he stops pulling (or ties it off), that *additional* (tension on the main line) stops. Just as it describes in the Wiki page.

Really? Ok, the 'Truckers Hitch' is only 'special' in the way the loop is formed (on the bite) and that it gives some advantage when tightening it up. EG, add a loop in the standing part of the rope any way you like, pass the end under something and back though the loop and pull down and it will do the exact same thing. Very much like my bowline on the end of the line and formed between the two trees in a continuous loop in fact. ;-)

I was tired, it was late.

It is, except there are no weights, just resultant tensions.

Only Rod, he's the only other one without a life. ;-(

Well done ... and?

Have *you* actually read that? Do you understand it? Can you apply it to the Wiki diagram and actual knot?

Just read this bit again (and keeping it real world but sill ignoring any frictional losses etc)):

"However in the common use of the trucker's hitch, a static hook, ring, or rail, serves as the lower pulley, and the rope across the top of the load is the portion being tensioned. Thus, the standing part of the rope is represented by the top anchor point in the diagram, and the theoretical ratio is indeed 3:1 WHEN THE WORKING END IS

*TENSIONED*."

The bit you seem to keep missing is what happens when the *working end is NOT tensioned*, eg, when it's tied off to the knot with a half hitch.

Part 1, hand to first pulley, adding tension to the main rope at that time. (say 100kg tension)

Part 2, from loop in standing line down to attachment point on trailer. (also 100kg tension)

Part 3, from attachment point on trailer back up to the loop.

Fact 1. There is only one point providing any actual mechanical advantage, the anchor point on the trailer.

Explanation of that. You pull the rope 1" and it moves one in on part

1. It also moves 1" on part two, however, that part two is part of a pair (part 2+£) so the resultant is the knot is tensioned by the fact that it's trying to move the knot down 1/2", that's your only

*Mechanical* advantage.

Fact 2. The tension only exists in the Part one, when the trucker is providing it. He is effectively hanging on the rope with his own weight, adding his weight to the main line via the loop combination and so is ONLY here when he's doing so.

Fact 3. The first movement of the rope though the loop only provides a change of direction, so has no MA and therefore can be discounted re MA in this machine.

Fact 4. Once the line is tied off, to the knot (not anywhere else), that first pulley vanishes but as it wasn't adding any Mechanical Advantage in the first place, it doesn't matter.

Now, Rod is trying to wriggle out of the whole thing (and you maybe?) by pretending the Truckers Knot was some double / extra complex version where the last part was also tied off within part of the load expanding machine and so yes 'of course', that will retain that component (the truckers tension) in the final calculation.

However, that wasn't what we were discussing, wasn't what was referenced on the Wiki or any other example links.

Cheers, T i m

[T i m]

<snip>

Except not what the OP was asking about. It was a question about knots, not pulling devices (as he already has a winch). ;-)

Cheers, T i m

[Brian Reay]

It is just an adaptation of what is/was traditionally used in fencing- I can't claim to have invented it.

[T i m]

<snip>

I wouldn't say it was necessarily more correct than any other solution that answered the OP's question. ;-)

I have used a 'Spanish Windless' for all sorts of things, the most memorable was a jury-rigged fix to put the trunnion back together on my Morris Minor van to be able to drive home. ;-)

Cheers, T i m.

[T i m]

Depending on the age / size of the tree I agree it could be.

That's one way. ;-)

Understood.

As have I, (and variations thereof) when loading plant on trailers and in van etc.

As mentioned elsewhere, a mate has used the OP's idea to straighten a smallish 12 yr old apple tree. It took a couple of years but it's back upright now. ;-)

He's also got some pear trees that now look like willow because the fruit has pulled most the branches down (and broken many off). ;-(

Cheers, T i m

[Robin]

Let's try to deal with one point at a time - what happens when the rope is tied off.

Imagine the rope is stretching a spring. The way the rope passes round the hook on the truck bed and round the loop gives a theoretical MA of

3:1. So pulling, say, 50 kgf puts 150 kgf on the spring. If you tie off the rope *without letting the spring contract* then it must still be under 150 kgf.

That may be counter-intuitive. But the spring neither knows nor cares how and where the rope's tied off, or how many lengths of rope are under what tension.

[T i m]

Ok, if you think it will help you .... ;-)

Whilst it generally is, in a frictionless theoretical model it wouldn't be, but carry on ...

Ok ... a theoretical and temporary 3:2, defaulting to 2:1 when you stop pulling and tie off.

Agreed (with above proviso).

Except, you have 'let go' and you were 1/3rd of that initial tension.

Your version of it is, yes.

Of course it does. If there are 3 parts, all applying 50kg each and you remove one (that is acting directly against the tension on the spring), you only have two?

Ok, lets say it's tied off leaving just two parts carrying 50kg each and so 100kg in the main line.

You come along, grab hold of the loop and pull down with a load of

50kg. How much load is the main rope *now* carrying?

You let go the loop, how much in the main rope now?

Please don't confuse what happens when you tie the free end down to the trailer, not to the hitch as that does maintain the load in that part and so retains the (theoretical) 3:1.

Cheers, T i m

[Brian Reay]

Interesting, I didn't know it had a name.

It is just something I saw somewhere, probably decades ago, possibly in the Scouts.

[T i m]

<snip>

Just something I learned from my Dad when I was a kid and helping him on various woodwork projects. ;-)

Whilst he had some pretty long sash cramps, there were times when they weren't long enough and I clearly remember helping him rig and use 'Spanish Windlass's' to hold / pull stuff together whilst gluing etc. I also remember they could be pretty powerful and I have used them several times since on all sorts of things.

Yeah, possibly ... they used to do useful things in those days (and you could carry a large knife). ;-)

The other handy trick (back to the Truckers / Dolly hitch) is pulling on the standing parts to get some tension in the system whilst taking up any slack on the loop.

Dad used to be in the 'Lifting gear' game and used to get webbing products made for all sorts of tasks (suspending dinghy's from the roof of the garage, holding loads on roof-racks and in trailers etc).

He had some long seat belt type straps with self locking friction buckles that were both soft and flexible yet very strong and held very well.

One day a mate and I were going RC power boating and had a small flatbed type truck on the roof of his Dolomite Sprint, to help us get all our gear to the side of the lake.

We were stopped by a random Police check and after looking round the car in general he said 'I'm just going to check the security of the load on your roof rack. I can remember to this day feeling the car rocking from side to side till he eventually stopped and obviously out of breath, told us to be on our way. ;-)

I think those straps could hold a tonne each and I'd nipped them up properly. ;-)

Cheers, T i m

[Robin]

I'll pass on what forbids springs in frictionless theoretical models.

I am assuming 3:2 was a typo.

The spring knows?

I stated "*without letting the spring contract*" to try to get away from that stuff to focus on the question: "is it *possible* to tie off the rope without letting the spring contract?" But since you insist on moving to that before clearing the ground...

You refer to the working end being without tension when it is tied off while there is still the full tension in the rope round the cleat/ring. I am not clear how you expect the trucker to maintain that tension.

The truckers I rode with relied on friction. That was a lot of friction with traditional rope - very much in line with Wikipedia's "well less than 2 to 1 in many cases". And the friction could be increased when tying off by e.g. pulling the rope passing through the loop tighter round the rope that forms the loop.

The same point is made in Wikipedia: "One advantage of the friction within the trucker's hitch, compared to a hypothetical pulley-based system, is that it allows the hitch to be held taut with less force while the working end is secured."