Hand vs electric winch: solo travelling

Quote:

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Originally Posted by tact

Fantastic! You try it again. Please.

Throw a rope over a beam. Tie nothing to either end. Pull a meter down on one side. The other side of the rope goes up how far? (1M)

Please physically try this. It's amazing.

Now - tie one end of the rope to yourself. Please. I insist. You must actually do this.

Now pull a meter down on the other end. You go up how far? (1m). Now pass the free end of the rope to your mate and ask him to pull in another meter. How much higher did you go up? (1m)

This is NOT the setup when a vehicle with a front mounted winch spools out wire rope which is run out to a snatch block and hooked back to the vehicle.

Proof : winch in a meter of wire rope. Vehicle moves 1/2 m

Let you figure out why. I have explained already.

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yes and you contradicted yourself...

Ive just gone and done it, because yes, actually my life at this point in time is actually that boring and I have nothing better to do.

with my pully hanging from a tree tied a loop in the rope and lifted the loop about a meter, tied it off and knocked in a star picket as a height gauge. lowered the loop to the ground and knocked the star picket in to near enough 1m from the ground to the top.
went and stood next to the picket with the rope in my hand and using a pair of elastic bands and a meter long piece of string marked a meter on the rope. I pulled the rope down a meter. The chair was at the top of the picket (or near enough) so there we go, someone pulling the end of a rope through a single pully reeved 1:1 to disadvantage moves the other end of the rope 1m. Cool that works...

I stood in the loop.

I moved one of my elastic bands so it was at my eye height. I stepped out of the loop grabbed my bit of string from the first experiment and moved the second elastic band to 1m up the rope

I pulled the loop down and stepped in it again.
I put my belt on around me and the rope to help stop me from falling off.
I checked my first elastic band was at my eye height.
I pulled the rope until the second elastic band was at my eye height.
I noticed 4 things.
1. there was some weight being borne on my foot on the loop but it didnt feel like it was all of my weight
2. there was some weight being taken up by my arms, but it didnt feel nearly as much as if I was doing the flexed arm hang Im required to do for a fitness test at work.
3. It looked as tho the pully was getting closer to me but only at half the rate I was pulling on the rope.
4. The star picket was starting to **** me off because the top of it was banging into the soft part of my leg just under my knee cap.

I can only presume at this point that somehow, even though the pully is stationary it is now no longer rigged 1:1 to disadvantage it is rigged 1:1 to advantage. (ok, Im not presuming I know this for a fact, Im just pretending for the sake of the argument that Im trying to work this out for myself) and I'm thinking this because I only know 2 ways to use a single pully and a rope and thats either to advantage which the pretty picture in my rigging manual looks a bit exactly like the runner rig in this picture
from this website
https://www.aulro.com/afvb/images/im...015/10/794.jpg
or its rigged to disadvantage which looks like the single whip configuration from the same page..

It is however the internet, people have been known in the past to be wrong on the internet and who knows, both my recovery mechanics pam and my rigging pam from the military and my rigging PDF and doggers PDF might also both be wrong so feasibly, this might not be right, I mean its not like its as accurate as say wikipedia or old lady May who lives next door so I thought Id better check it again.

https://www.aulro.com/afvb/images/im...015/10/795.jpg

yep, same same.. so now Ive got 2 actual paper books, 2 pdfs and 2 websites showing me only 2 ways of rigging a single sheeve pully, and since for some reason I didnt go up a meter when I pulled the rope a meter while standing in the bight of the loop of the rope maybe I broke physics because the block didnt move and I didnt move up a meter but I moved a meter of rope past my eyes...

I then derigged all of this...

I took the rope and tied it to the top of the stairs banister rail.
I ran it though the pully and then took the other end up the stairs.
I called myself an idiot because I could have taken both ends of the rope up the stairs at the same time for either of 2 reasons. 1. the ropes long enough, I could have threaded it first and then taken both ends up together 2. its a snatch block I could have taken both ends of the rope up and then just opened the cheek plate to put it on the rope.
I lifted the rope until the pully just touched the ground. I grabbed my elastic band and string, marked the rope, pulled up a meter and tied it off. I swear, it looked like that pully only came up half the distance that I pulled that rope.

I measured the pully height.
40ish cms off the ground.
I turned the pully right side up.
50ish cms off the ground.

Its ok everyone relax, clumsy and oafish as I am, I didnt break physics, it still works exactly like it says in the pictures and in the interent and in the modern rigging manuals... If you rig up a single block from a rope hanging up high and then pull upwards, the pully only comes up half as much as the rope you pull up. Apparently if I wasnt so lazy I could also then use this to lift up either almost twice as much weight as I would normally be able to lift OR I could use a bit more than half as much effort to lift the same amount of weight as I would normally.. Id have to do it for twice the distance of rope tho...

now hang on...

I kind of remember that I had some weight on my leg and some on my arms when I was dangling from a tree and that for some reason the weight on my arms was less than when I do my static arm hang test, that missing weight must have been the weight in my leg.. so roughly that would mean that half my weight was on one side of the rope being taken up by my foot in the loop and the other half was in my arms then all of my weight must have been being taken by the pully up the top and the rope was simply balancing the tension out evenly...

I had another look at that picture from the historical navy site plate 32 and we have a look at fig 245 each end of the rope as a 1 on it and the P at the bottom has a 2 the number on one side of the rope added to the number on the other side of the rope is equal to the P number at the bottom of the weight. theres something fishy here... thats not how its written on the more modern page...

lets see here...
slide 32 fig 244 1=1, yeah i can see that whatever I put on one side of the rope happens on the other
slide 32 fig 245 1+1=2, yep got that. cool historic navy mathy type stuff still works.
single whip, P=W what no wait this isnt math any more its algebra... no fair, I have to take of my sarcasm hat a little to make room for some logicy thinky type hattery... ok so P=1 and W=1 so therefore 1=1 cool
runner P=1/2W so P=1/2x1 therefore p=.5 and therfore since P=W co... wait what i think I just broke maths thats not how the old navy did it surey i missed something obvious
Hmm
ahh
silly

in the runner there is 2 parts of rope supporting the pully and both have equal tension so 2x.5=1
ok relax i didnt break maths its just algebra versus simple addition...

so whats happening here? Im really confused (and if you believe that then mate, let me tell you about this bridge I can get you a deal on) when I stood on the ground and pulled the rope through the stationary pully the loop went up a meter. I mean thats simple but when I stood in the loop and pulled the rope it looked like for every meter of rope I pulled up the pully only came half as close to me... but the pully was tied to a tree it didnt move but the only way that works is like how it did when I had the rope in the pully tied off to the balcony and was pulling it up towards me it only looked like it came up half way too...

I mean in both cases the pully only looked to me like it came half a meter towards me for each meter I pulled in but when I had the pully in the tree the pully didnt move it just looked like it did and I had the top of a starpicket banging my knee because my feet were half a meter off of the ground...

OF course, its relative... The pully looked like it was coming closer to me when it was up the tree because I was coming up off of the ground. and I was coming up off of the ground at half the rate I was pulling the rope Exactly the same as when I was pulling the pully up off of the ground, It came up at half the rate I was pulling the rope then too a single sheeve pully rigged to advantage will always relatively approach the pulling cable at one half of the rate that the cable is being heaved in at. The thing I hadnt worked out earlier was so easily explained by remembering one of the most annoying TV characters from my child hood and his pretty offsider before saying "upside down miss Jane, upside down." look at the single whip and look at the runner, now turn the page upside down.. you seeing what Im seeing... no?

ok Cut just the picture of the block and the ropes out of the picture (best print that first taking to your monitor with a knife and sissors wont do you much good) and then flip them around so that the same rigging through the block and the ropes can be switched between single whip and runner (that actually works if you use the simpler diagrams from fig 244 and 245) leaving the anchor, the load and the pulling indicators in their original positions


magic. Bet it looks and works the same as If I go and lay it down on the ground and tie it all off on the poles in the car port... Give me a minute (pause for dramatic effect here so people think Im out side doing something that I actually did about an hour ago while I had all the stuff out having planned this because after the stairs thing I realised Iwas too lazy to pack up unpack and pack up all this stuff again because someone is going to argue it doesnt or does work if you lay it all down have a coffee if you like, youre eyes could use the rest)

ok so.. IT works the same...

first I did the simple thing..

I tied the rope to the pole sat on the trolly and pulled a meter on the rope and the trolly moved a meter (made winching noises and all, old lady may is highly amused and thinks Ive gone nuts even offered me some of her medication)


http://www.trailersrless.com/images/single.jpg
If I tie the pully to the pole and the rope to the trolly and I stand beside it pull the rope a meter the trolly moves a meter ( in that poor little picture Im the winch the trollys the load

lets just use relativity and.. no, lets not.. I knew there was a reason I did this bit with the pully 3 ways...

lets pretend its the exact same situation but for some reason the load wont move and you dont have enough grip to resist the pull of the winch.

so I tied the rope to a pole ran it through the snatch block and pulled a meter and the trolly moved a meter happy with that if you pull 1 m of a rope through a pully and your not attached to both ends of the rope you move yourself or the load that far. makes sense, it looks like simple 1:1 pullys rigged to disadvantage and simple relativity as to which end of what is anchored or pulling.

now I tied the rope to the trolly, sat on it, grabbed the other end of the rope, made like a winch and pulled 1m of rope. only went half a meter...
thusly
https://www.aulro.com/afvb/images/im...015/10/796.jpg
all good so theres 4 ways to winch off the front of your vehicle using a single single sheeve snatch block.

1. direct pull without using the block. 1:1 (did I really need to put this here? maybe you keep the snatch block on the cable for some reason and its just dangling there incase you need it)
2. Direct pull using the block to redirect the rope to move a load. 1:1 rigged to disadvantage
3. direct pull using the block to redirect the rope to an anchor point and winch the vehicle 1:1 rigged to disadvantage (this actually gives your winch a break as you have more cable run out so its working on a lower layer)
4. Compound pull running the rope from the winch to the snatch block and back to another anchor point on the same vehicle. 1:1 rigged to advantage giving an MA of 2:1

so heres the simple bit..

if you can work out that going out to a snatch block and back to your vehicle gives you a 2:1 advantage and that for every meter you winch in your going to move forwards half a meter heres a simple idea to prove how hanging a pully from a tree (or a rafter) and sitting in a chair with a rope tied to it, going through it or standing in a loop of rope then pulling on the other while you're standing in the loop or sitting in the chair will only ever pull you up at half the speed that you take the line in at.

mark your winch cable every meter.
get a very tall very strong tree
get a very very tall ladder
have a tape measure handy
pay out all of your winch cable anchor one side to your recovery points and snap on your snatch block
put the snatch block way up in the tree and secure it tightly
power up the winch and let it winch in
as it winches itself up the tree antichrist style measure the movement relative to the ladder using your tape measure measure its progress for every meter of cable it winches in.
when its all done climb off the ladder, put everyting away, grab some old blue overalls, grow a beard (if you dont have one already) and say
aye i ia ia ia...

simple huh...

Quote:

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Originally Posted by Tank

To each his own, at least I understand what I'm doing is not 100% correct, BTW it is only 90 degrees not 180 degrees, this method has worked many times for me and have not had a problem, I'm aware of what is happening to the cable, but sometimes you need to compromise. What's the alternative, have 2 winches.

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https://www.aulro.com/afvb/images/im...016/02/886.jpg
nope, 3 snatch blocks

and a winch extension cable. and enough chain to let you position your blocks relative to your anchor points

and before you ask yes I do and yes, I have (Mostly just to prove you can safely and legitimetly winch backwards from the front) and a standard 30m usable winch cable using the above example rig with ideal anchoring points will permit about 5m of effective winching before the angles on the snatch blocks reduce the effective pull at he back to below .5MA go much futher and the MA drops off exponentially and you wind up with the winch stalling when the back angles hit around about 120-130 included angle on the rear recovery point. and thats just on grass using ground anchors.

Dave running a wire cable over 3 pulleys, all in different directions is the quickest way to destroy a wire cable you would cause more damage to a cable using those 3 pulleys than you would doing the "evil" thing of running the cable back under the car.
Would work of course, but you would need a lot of cable,
As the vehicle moves back you are creating a dangerous angle between anchor point 2 & 3, check out "Span Rope" tensions, can be lethal, using a single anchor point and pulley behind the vehicle would be safer and less damaging to the cable Regards Frank.










=Blknight.aus;2432659]https://www.aulro.com/afvb/images/im...016/02/886.jpg
nope, 3 snatch blocks

and a winch extension cable. and enough chain to let you position your blocks relative to your anchor points

and before you ask yes I do and yes, I have (Mostly just to prove you can safely and legitimetly winch backwards from the front) and a standard 30m usable winch cable using the above example rig with ideal anchoring points will permit about 5m of effective winching before the angles on the snatch blocks reduce the effective pull at he back to below .5MA go much futher and the MA drops off exponentially and you wind up with the winch stalling when the back angles hit around about 120-130 included angle on the rear recovery point. and thats just on grass using ground anchors.[/QUOTE]

Quote:

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Originally Posted by Tank

Dave running a wire cable over 3 pulleys, all in different directions is the quickest way to destroy a wire cable you would cause more damage to a cable using those 3 pulleys than you would doing the "evil" thing of running the cable back under the car.
Would work of course, but you would need a lot of cable,
As the vehicle moves back you are creating a dangerous angle between anchor point 2 & 3, check out "Span Rope" tensions, can be lethal, using a single anchor point and pulley behind the vehicle would be safer and less damaging to the cable Regards Frank.

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Sorry tank but maybe back in your day when cable was in its infancy and steel wire rope had only marginally more flex than a bar of steel anyway.

but I guess that given my statch blocks are all sized to suit my winch cable and all my snatch blocks are around the D20 mark in size and since the maximum permissable loading angle is 120 degrees and as I fairly clearly stated it pretty much self stops there from the winch stalling due to the increased loads and as my cables SWL is roughly 30% higher than my winches bottom row pull. And that I identified that you can winch back but only about 5m with a stock 30m winch cable that it cant be done without breaking my cable as compared to say running the cable over a dead flat roller, reversing the direction of the rope as soon as its coming off of the drum (assuming your winch like most is underwound). I think that given the option of setting that up, or doing what you'd do

I'll run three snatch blocks and not crush my cable into the bottom fairlead roller and having it do an immediate direction change off the fairlead roller or run the risk of rubbing the cable through things like diff housings

the other thing that I really like a lot more about using the multiple snatch blocks is this....

when the vehicle is bogged in water up to the door sills and mudded up to the chassis rails... I dont have to get anything more than my boots muddy to setup my method of recovery to make it winch backwards. But I digress

Its also not a span rope... they are static, and the setup and calculation of them require you to pretension the line and then increase it as you add load points to the rope. This is Dynamic and the maths is the other way around. You pull in on what you would call your "span rope" and you use it to move a load you do all of the math based on the maximum amount of pull the winch can provide, and then calculate out if you ever exceed the SWL of the rope (and unless mines damaged, I cant) on any of your pullys and anchor points and then you calculate how much pull you're going to generate to move your load.



Please go and get a more up to date set of documents.

and if you still want to insist that reversing a cables direction through a set of pullies is a problem you need to explain how anti twist rigging a 4:1 pully set works and why if it cant be done because it kills cables. and while your at it also explain why its an acceptable rigging method for fig 253. 254 traverse carriage dolly cranes, or using a leader pully to turn a disadvantage rig to advantage.

I will accept that there are specifications that identify what the minimum distance between changing the direction of the rope should be to prevent binding the cable. and that going inside these is not recomended because cable damage may result.

can you tell us what those specs are in a simple easy to express manner that a novice trying to rig something complicated can understand?

There's no reason to suppose the wire will be damaged by the snatch block provided the groove is a suitable profile for the wire, and the correct diameter relative to the wire diameter say, greater than 10:1, 15 or 16 to 1 is better.
A snatch block is kinder to our wires than the winch drum because the wire is usually better supported.

That sounds about right, my snatch block is about 150 mm, and the wire is about 9 mm. Given our winches don't do much work compared to industrial winches or cranes, (some working about 20 hours or more a day), the likely effect on their life or strength is not significant. But the down side is our wires don't have the big safety factor of industrial equipment. I think my 9000 lb winch wire has a breaking strain of about 15,000 lbs. some reading attached from the internet. cheers simmo

Dave, from the "Riggers Guide";
Reverse bends


Avoid reverse bends because they cause much greater fatigue than if all bends were made in the


one direction.


A rope running in one direction over one sheave and then in a reverse direction (ie ?S? fashion) over


another sheave will suffer early fatigue and deterioration. As the rope passes over a sheave it is bent, and


as it leaves the sheave it is straightened, two distinct actions causing fatigue. This is made worse if the


rope after being bent in one direction is then straightened, and again bent in an entirely opposite direction


over another sheave after which it is again straightened.

Quote:

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Originally Posted by Blknight.aus

Sorry tank but maybe back in your day when cable was in its infancy and steel wire rope had only marginally more flex than a bar of steel anyway.

but I guess that given my statch blocks are all sized to suit my winch cable and all my snatch blocks are around the D20 mark in size and since the maximum permissable loading angle is 120 degrees and as I fairly clearly stated it pretty much self stops there from the winch stalling due to the increased loads and as my cables SWL is roughly 30% higher than my winches bottom row pull. And that I identified that you can winch back but only about 5m with a stock 30m winch cable that it cant be done without breaking my cable as compared to say running the cable over a dead flat roller, reversing the direction of the rope as soon as its coming off of the drum (assuming your winch like most is underwound). I think that given the option of setting that up, or doing what you'd do

I'll run three snatch blocks and not crush my cable into the bottom fairlead roller and having it do an immediate direction change off the fairlead roller or run the risk of rubbing the cable through things like diff housings

the other thing that I really like a lot more about using the multiple snatch blocks is this....

when the vehicle is bogged in water up to the door sills and mudded up to the chassis rails... I dont have to get anything more than my boots muddy to setup my method of recovery to make it winch backwards. But I digress

Its also not a span rope... they are static, and the setup and calculation of them require you to pretension the line and then increase it as you add load points to the rope. This is Dynamic and the maths is the other way around. You pull in on what you would call your "span rope" and you use it to move a load you do all of the math based on the maximum amount of pull the winch can provide, and then calculate out if you ever exceed the SWL of the rope (and unless mines damaged, I cant) on any of your pullys and anchor points and then you calculate how much pull you're going to generate to move your load.



Please go and get a more up to date set of documents.

and if you still want to insist that reversing a cables direction through a set of pullies is a problem you need to explain how anti twist rigging a 4:1 pully set works and why if it cant be done because it kills cables. and while your at it also explain why its an acceptable rigging method for fig 253. 254 traverse carriage dolly cranes, or using a leader pully to turn a disadvantage rig to advantage.

I will accept that there are specifications that identify what the minimum distance between changing the direction of the rope should be to prevent binding the cable. and that going inside these is not recomended because cable damage may result.

can you tell us what those specs are in a simple easy to express manner that a novice trying to rig something complicated can understand?

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[QUOTE=Tank;2433156]Dave, from the "Riggers Guide";
Reverse bends


Avoid reverse bends because they cause much greater fatigue than if all bends were made in the


one direction.


A rope running in one direction over one sheave and then in a reverse direction (ie ?S? fashion) over


another sheave will suffer early fatigue and deterioration. As the rope passes over a sheave it is bent, and


as it leaves the sheave it is straightened, two distinct actions causing fatigue. This is made worse if the


rope after being bent in one direction is then straightened, and again bent in an entirely opposite direction


over another sheave after which it is again straightened.

I read this entire post very thoroughly up to about page #7.
Something more interesting may have happened in the last 3 of 4 pages, but it doesn't look like it at first glance.
Here's my summary, for what it's worth:

• Dave is correct in every detail.
• Everyone else except Frank understands pretty much what Dave is saying.

Frank's not exactly wrong, he's just been confused by what may have been a too literal, and perhaps a too rigid, understanding of the education he was offered 50 years ago.
To be fair, I got my education not long after he got his, and rigid and literal was pretty much how it was served up to me too.

Quote:

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Originally Posted by Fast Freddie

I read this entire post very thoroughly up to about page #7.
Something more interesting may have happened in the last 3 of 4 pages, but it doesn't look like it at first glance.
Here's my summary, for what it's worth:

• Dave is correct in every detail.
• Everyone else except Frank understands pretty much what Dave is saying.

Frank's not exactly wrong, he's just been confused by what may have been a too literal, and perhaps a too rigid, understanding of the education he was offered 50 years ago.
To be fair, I got my education not long after he got his, and rigid and literal was pretty much how it was served up to me too.

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So in the above post #94 Dave is CORRECT and the RIGGERS GUIDE is WRONG, guess everything I learned is all wrong, I should have consulted all the EXPERTS on this FORUM, Regards Frank.
Quote: Riggers Guide, "Avoid reverse bends because they cause much greater fatigue than if all bends were made in the one direction.
A rope running in one direction over one sheave and then in a reverse direction (ie ?S? fashion) over another sheave will suffer early fatigue and deterioration. As the rope passes over a sheave it is bent, and as it leaves the sheave it is straightened, two distinct actions causing fatigue. This is made worse if the rope after being bent in one direction is then straightened, and again bent in an entirely opposite direction over another sheave after which it is again straightened."

Quote:

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Originally Posted by simmo

There's no reason to suppose the wire will be damaged by the snatch block provided the groove is a suitable profile for the wire, and the correct diameter relative to the wire diameter say, greater than 10:1, 15 or 16 to 1 is better.
A snatch block is kinder to our wires than the winch drum because the wire is usually better supported.

That sounds about right, my snatch block is about 150 mm, and the wire is about 9 mm. Given our winches don't do much work compared to industrial winches or cranes, (some working about 20 hours or more a day), the likely effect on their life or strength is not significant. But the down side is our wires don't have the big safety factor of industrial equipment. I think my 9000 lb winch wire has a breaking strain of about 15,000 lbs. some reading attached from the internet. cheers simmo

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Did you read that pdf file esp. p.30 to p.34, maybe Dave and fast freddie should read it before putting their feet in their mouths, Regards Frank.