12v Winch

[olley]

If you take the slope you speak of being 'gentle' and the surface being grass, then you are looking at 20% of your vehicles weight being added to cover resistence. It is situations such as this that people do not realise as they see it as a gentle slope. If you consider your vehicle being lets say 4000kg what would you consider the weight to be on a gentle slope....not many would guess it as being 4800kg - almost a ton heavier!

If anyone is interested, I can dig out a manual I have somewhere and e-mail them a copy. Rather they are knowledgable than not.

Sorry must be thick as I don't understand this, if a vehicle is on flat tarmac all you have to overcome is rolling resistance, if its hanging of a hook its its total weight, and if its on a 45 degree slope its half its weight plus rolling resistance.

I have been pulled out of the sticky stuff twice without to much trouble and we weigh 9 tons, a much heavier Monaco was pulled out by Jim in his landy at the Newark show a few years back and he was well sunk in, so well sunk in that the bead of the inside tyre was forced off the rim, and the tyre went flat. And they used my 2 ton strops.

I have used winches, and have seen what happens when a steel hawser used to moor a boat lets go, if it had hit anybody it would have cut them in half, so I appreciate the dangers, but the maths don't add up to me.

Ian

 

[pappajohn]

i dont really grasp this off roading thing but why did you drive into that hole in the first place???

i say i dont get this off roading thing but at least its better having a 4x4 and getting bogged every now and again than 80% of 4x4 owners that the biggest bit of off roading it does is mounting the kerb when picking the brats up from school.

as it was a fun day out in the woods, under normal circumstances it would have been intentional but as the day was coming to an end and knowing how deep and muddy it was i tried to go round it....unfortunately i got too close to the edge and slid the front end in.
main problem was lack of tree's/stumps in a suitable position.
that track is 1/2ml long and had to winch out of 3 other mud holes on it that day.

 

[rainbow chasers]

Sorry must be thick as I don't understand this, if a vehicle is on flat tarmac all you have to overcome is rolling resistance, if its hanging of a hook its its total weight, and if its on a 45 degree slope its half its weight plus rolling resistance.

I have been pulled out of the sticky stuff twice without to much trouble and we weigh 9 tons, a much heavier Monaco was pulled out by Jim in his landy at the Newark show a few years back and he was well sunk in, so well sunk in that the bead of the inside tyre was forced off the rim, and the tyre went flat. And they used my 2 ton strops.

I have used winches, and have seen what happens when a steel hawser used to moor a boat lets go, if it had hit anybody it would have cut them in half, so I appreciate the dangers, but the maths don't add up to me.

Ian

Oh No! This is going technical! Right - the physics - there are 3 types of resistence Rolling, damage and gradient. Ignore damage unless you have a flat tyre or wheel locked up.

On a flat tarmac surface, you would divide to weight by 25. This will give the resistence figure that is added to total weight to give toi total resitence or force required from the winch to get it moving.

So to pull you 9000kg rv on a flat level tarmac road would need 9360kg of power to get it moving from a standstill. This is why you can save fuel by not stopping to a standstill, but slowing early and keep rolling at junctions. This rolling resistence.

No lets just say you had a flat - you would take the weight multiplied by the number of damaged wheels (1 for a flat) divided by the number of wheels. to give you damage resistence. One flat on a 9000kg rv would be 10500kg.

A gradient resistence would be the weight divided by 60 multiplied by the slope in degrees. so on a 45 degree angle, 6750kg - so total weight would be 15750kg. Industry standards state thaat any amount over 45 degree would double the weight of the casualty.


Right, I gotta go on appointment! Let me know if that still confuses and I will explain tomorrow!:thumb:

 

[olley]

If what your saying is correct, explain how in strong man competitions they regularly pull hgv tractor units? These must go at least 4 ton.

I have a 300kg dry weight car trailer which i have pulled by hand on many a field, not easy but doable, but put it on tarmac and its a piece of cake, in fact its so easy that i have even moved it with the micra on, very short distances, so as i said before, the maths don't add up.

The rolling resistance is the difference between the force need to compress the front of the tyre and the pressure the tyre exerts uncompressing at the back, plus frictional losses in the drive train. Maybe this is a case of the theory not matching the real world?

Ian

 

[Landy lover]

This gets very involved and anyone that is interested would be well advised to look at this web site http://www.wittenburg.co.uk/OffRoading/Reference/WinchTheory.html which does give some good information - you will see that the effort to move a vehicle in good order with no rolling resistance is about 4% of its gross weight however put a flat tyre on it and the effort increases dramatically. If the wheels have been spinning and there is a wedge of mud in front of each wheel the force to overcome the resistance could well be 50% of gross - every situation is different hence the reason why I said get some training understand the issues and be safe and learn the protocols

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[darklord]

To explain what i do on a daily basis, on a forum, is very difficult, some of the physics have been explained, but one thing to remeber, is that its not as important to know what you CAN do with a winch, but what you CANT do with it.
For instance, a 4.5 ton winch, will normally have a 1 ton winch cable on it, it can be used safely, with the use of other equipment...ie snatchblocks, but you have to know how to do the math, what to attach to (will THAT take the weight/) and make sure you have enough room. Ive seen MANY times, where a vehicle is attached to another via a winch.....and the wrong vehicle starts moving!!!!
Sometimes, I,ll attend a job, spend ten minutes or so assessing it, start the recovery.......and things do not look like they will go to plan, so we start all over again. Other tmes (especially with offroading), you'll see some drivers see someone get stuck, and all th equiment starts getting flung around, there are winches /strops/etc all over the place,....when all it needed was a gentle tow out.
I cant give too many details, but on a major job, on a major road, for the police two weeks ago, a VERY expensive truck was being used by three VERY experieneced collueges, and a part of the recovery equipment failed and caused a container to fall back. No injury (H&S distances were in place), and damage only to the part involved which has now been sent for analysis, the whole operation was video,d, and that is being looked at.
£200.000 worth of equipment, 60 yrs worth of experience, and all the time in the world, did,nt stop an accident happening,....this is why extreme care should be used, and any cavalier attitudes dismissed.:thumb:

 

[Jim]

This gets very involved and anyone that is interested would be well advised to look at this web site http://www.wittenburg.co.uk/OffRoading/Reference/WinchTheory.html which does give some good information - you will see that the effort to move a vehicle in good order with no rolling resistance is about 4% of its gross weight however put a flat tyre on it and the effort increases dramatically. If the wheels have been spinning and there is a wedge of mud in front of each wheel the force to overcome the resistance could well be 50% of gross - every situation is different hence the reason why I said get some training understand the issues and be safe and learn the protocols

Thanks Bill a good link. There is no doubt that a winch is a great self recovery tool, and the maths on the site show a light winch might well be worth it's weight in gold to a wildcamper. (once in a blue moon) But does the very little use it will get justify that weight? Depends on where you are travelling of course, but I don't think so.

 

[rainbow chasers]

If what your saying is correct, explain how in strong man competitions they regularly pull hgv tractor units? These must go at least 4 ton.

I have a 300kg dry weight car trailer which i have pulled by hand on many a field, not easy but doable, but put it on tarmac and its a piece of cake, in fact its so easy that i have even moved it with the micra on, very short distances, so as i said before, the maths don't add up.

The rolling resistance is the difference between the force need to compress the front of the tyre and the pressure the tyre exerts uncompressing at the back, plus frictional losses in the drive train. Maybe this is a case of the theory not matching the real world?

Ian

The algo is an industry standard - it is what evey recovery driver uses, every crane driver uses - albeit slightly modified for drum size - and so on. If you have a recovery passport or licence - that is what you use. It is designed for winching and has nothing to do with physical pushing and pulling as it includes the dimensions of the drum as the final drive of an electric motor with only one single amount of power used through planetary gearing.

When you push your trailer, it is heavy at first and them momentum makes the weight lighter as that would reduce weight. The resistence will add only 12kg to the weight, (49kg on grass) which is what you feel. There are different algo for a human pushing, a different set of rules, so you cannot determine weight via that algo for physical pushing of an object. It is designed to determine the power required of a winch to pull a vehicle from standstill. If you have a look around for the human algo, then you may find that with your height, weight and strength you may be clsoer to your own max
imum pull on grass - which is why you would struggle, but find it easier on tarmac as the initial resistence is much less.

As a vehicle is moved on a winch, momentum also makes it lighter, however the winch loses power dramatically for each layer of rope that goes back on the drum. It's rated weight is the maximum pull - which is only available when the drum has three rows on the 1st layer.

 

[olley]

You said:

On a flat tarmac surface, you would divide to weight by 25. This will give the resistence figure that is added to total weight to give toi total resitence or force required from the winch to get it moving.

So to pull you 9000kg rv on a flat level tarmac road would need 9360kg of power to get it moving from a standstill. This is why you can save fuel by not stopping to a standstill, but slowing early and keep rolling at junctions. This rolling resistence.

Because you have no idea of the winch I will be using you must be referring to the force needed to move the RV. The link that landy gave says different:

This is the largest variable when winching. A vehicle in good running condition on a hard, level tarmac surface will only require a force of about 4% of its total weight to induce motion. A vehicle to be recovered from a bog will, however, require a pull equivalent to about 50% of the total weight of the vehicle. The table in the sidebar shows that different kinds of surfaces require proportionate efforts to induce vehicle motion.

A simple formula can be used to show that approximate rolling resistance of a vehicle in good condition on a flat surface can be predicted.

Pulling Effort required (in lbs) = Weight of Vehicle
nnnnnnnnnnnnnnnnnnnnnnnnResistance Co-efficient
Using this formula in the example that follows, we calculate the effort required to move a vehicle weighing about 4500lbs along a flat beach of hard, wet sand (which has a resistance factor of 1/6):

4500 lbs = 750lbs

From that formula I can see a force of around 793lbs or 360kg (4% 0f 9000kg) would be needed to move my RV on tarmac. Which is less than I thought.

This nothing to do with Algo's, or drum sizes, you made a statement which to me just didn't seem to add up, not from any theoretical knowledge, just from my years in the past in heavy engineering. Do you think you might now be mistaken?

Ian

 

[Wildman]

If anyone is interested, I can dig out a manual I have somewhere and e-mail them a copy. Rather they are knowledgable than not.

I have not got involved in this discussion though I have used winches and hoists all my life, however I have never had any training and always welcome the chance to learn something new so would love a copy of the above manual, maybe you could scan it into a downloadable file, and send it via skype or dropbox, just a thought to save on postage, printing etc.
PS My tifor winch was used to pull trains at one time in its working life, I bought it when it was retired, hee hee. With a cable as thick round as my thumb I suspect it is capable of pulling a tree down

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[pappajohn]

.

Pulling Effort required (in lbs) = Weight of Vehicle
nnnnnnnnnnnnnnnnnnnnnnnnResistance Co-efficient
Using this formula in the example that follows, we calculate the effort required to move a vehicle weighing about 4500lbs along a flat beach of hard, wet sand (which has a resistance factor of 1/6):

4500 lbs = 750lbs[/I]

From that formula I can see a force of around 793lbs or 360kg (4% 0f 9000kg) would be needed to move my RV on tarmac. Which is less than I thought.



Ian

thats 360kg over and above the static weight of your RV Ian....9000kg plus 360kg to start movement.

if your calculation was correct you would only need a couple of strong blokes to start it moving.

 

[Landy lover]

thats 360kg over and above the static weight of your RV Ian....9000kg plus 360kg to start movement.

if your calculation was correct you would only need a couple of strong blokes to start it moving.

The only time you would be winching the gross weight of the vehicle would on a full vertical lift - the weight of the vehicle is that vertically imposed on the ground surface - to winch a vehicle from a standing start you are looking at overcoming the rolling resisitance.

I do believe that there is a lot of confusion on this thread between the acts of winching and its rules and protocols and the very different rules and protocols involved with Lifting as with a crane where you are actually taking the total load of the vehicle..

 

[aba]

so basically an agricultural quad bike with 2 hefty blokes sat on it should be able to pull around 90% of euro motorhomes up an incline off a wet field provided they are not bogged more than an inch or so.

 

[pappajohn]

The only time you would be winching the gross weight of the vehicle would on a full vertical lift - the weight of the vehicle is that vertically imposed on the ground surface - to winch a vehicle from a standing start you are looking at overcoming the rolling resisitance.

I do believe that there is a lot of confusion on this thread between the acts of winching and its rules and protocols and the very different rules and protocols involved with Lifting as with a crane where you are actually taking the total load of the vehicle..

Fair enough :thumb:

personally i used the 'farmers' method of rules and protocols......

if the winch will move it, all well and good

if it wont, then get help from another off roader with a bigger winch.

 

[olley]

thats 360kg over and above the static weight of your RV Ian....9000kg plus 360kg to start movement.

if your calculation was correct you would only need a couple of strong blokes to start it moving.

Papa give another guy, a strong wall to push against and we would move it.

Think about the logic of what you are saying, it takes more power to pull my rv than it weighs, so if i put it on a 45 degree slope it wouldn't move? Bet you life on that would you?

Ian

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[Landy lover]

so basically an agricultural quad bike with 2 hefty blokes sat on it should be able to pull around 90% of euro motorhomes up an incline off a wet field provided they are not bogged more than an inch or so.

Feasably yes - the major problem would be the lack of traction for the quad bike - on most CC or C&CC sites they use the grass cutting tractor to assist any stuck motorhomes

 

[darklord]

As usual, things are getting a tad confusing. The calculations being used, I do not dissagree with and they have been used n the past on jobs I have been on,...one of them in probably the most televised and watched recovery operation ever,.....BUT, nobody is going to sit down with a pen and paper and a calculator if their MH get stuck, so you need a simple effective methos to use.
Your MH may weigh 3500kgs, and lets say it does. But, because some enterprising chap invented the wheel, we can move it. The force needed to move it, will depend on a lot of things, but lets keep safety in mind and say that because it has wheels, and we are on a flat tarmac surface and the tyres are inflated and the brakes are not binding, we only need to exert a proportion of that weight. Keeping safety in mind, I'll say 25% of that weight, so we are looking at less than a ton.
(yes a man, or two could move it, but for how far and how long has too many imponderables, rugby team or a darts team etc tec)

Once we increase the rolling resistance, say by giving the MH a puncture,.. you need to adjust the calculation, the easy way is to add 25%, if it has two punctures (or wheels stuck in mud) ad 50% and so on.
Then we add if there is a gradient, you have to use a bit of common sense here, and think whether the gradient is safe to attempt anyway, a muddy slippery gradient could have your MH turning over!
As a quick one, I,d add 50% for anything up to 20deg, and get plenty of help for anything over.
Lets assume, that you have calculated back up to your MH's weight of 3500.
So, now we need a winch with a pulling power in excess of that, lets say a mate has one rated to 4500kg (average). So now, we need to attach it to our MH, personally, I would not atach to any body parts or supplied tow hitches (towballs are normally 3500 rated), I would use "J-hooks" and attach to wishbones /front axle etc.
We now need to make sure, that the vehicle we are using the winch off, weighs more than the one we are attempting to pull, if it is,nt, we can link two vehciles together, tie to a tree, chock wheels etc.
We now, need to make sure the winch cable can do the job. If it is only 1 ton rated, then we need to "double, or treble " it up using a snatchblock (pulley) rated at over 3500kgs and attached to vehicle parts that will take the strain.
Once set up, this will provide a slow pull (which goves you plenty of time to spot something wrong happening), but a safe one.

If you use the "25%" rule, you are factoring a big margin for error, which will keep you safe and your MH in one piece. At that stage, you may wish to phone your breakdown providor, who will send a pro to assist you, many of them will charge you for this, as you are offroad probably and outide of your contract, but that is surely better than taking a chance of damaging your MH and having a fight with your Insurance company over repairs.

 

[rangi]

You want a bloody winch?????? A Bull Bar?? On a Motor Home?

You going to go Outback, Roo shooting?

Going to go the whole Hog and plaster a line of Spots on yer roof?

Mate this is the UK:thumb: Get Flamin' real

 

[JockandRita]

clipped...... on most CC or C&CC sites they use the grass cutting tractor to assist any stuck motorhomes

Apparently no longer, according to one CC official I spoke to. It's all to do with H & S and CC liability for the potential damage to a member's outfit, etc, etc. :Sad:
I don't know the current situation with regards to the C&CC.

Regards,

Jock.

 

[JJ]

An interesting thread...

I have no real views on winching or winches and have learnt that study of this business would make my head hurt...

... but I was disappointed with the use of the word "retard" when referring to someone who was doing something that someone else thought was stupid.

Of course I am just a namby pamby, pc, health and safety, left wing Funster and my views on this can be easily dismissed but imo it is such a horrid word to use in this context.. :Sad:

JJ :Cool:

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[olley]

Just seen an old picture (1905) of a horse being used in Ipswich shunting yard, so 1 horse power is enough to move a railway waggon.

Ian

 

[ChocNessie]

An interesting thread...

I have no real views on winching or winches and have learnt that study of this business would make my head hurt...

... but I was disappointed with the use of the word "retard" when referring to someone who was doing something that someone else thought was stupid.

Of course I am just a namby pamby, pc, health and safety, left wing Funster and my views on this can be easily dismissed but imo it is such a horrid word to use in this context.. :Sad:

JJ :Cool:

I must agree whatever' the thread and whatever your thoughts about other people's ability or their capability to comprehend the dangers or complexity of situations we must all be mindful of our language.

Thanks to all who replied.

 

[ChocNessie]

not necessary to be nasty.....

You want a bloody winch?????? A Bull Bar?? On a Motor Home?

You going to go Outback, Roo shooting?

Going to go the whole Hog and plaster a line of Spots on yer roof?

Mate this is the UK:thumb: Get Flamin' real

This IS the UK. But I don't just drive the uk and we as a family do like to explore a bit more than most.


All that besides even if it was just the UK, too many site owners put MHs on grass pitches in the wet and not on level ground. It rains a lot and I have seen people get stuck on practically level pitches after a torrential thunder storm.

In case you had not noticed most MH are not 4 x 4 s and have terrible axle load balancing. Plus standard MH tyres are like driving with slicks on an ice rink.

I am careful where I stop, I have invested in some chunky tyres on the driving axle, but I can guarantee that some places I have been lesser experienced MH drivers would have been challenged.

I was not asking about winches to extract a 4 x 4 from a mud pit half way up a mountain.

I was looking more for some gentle assistance out of slippery conditions in the same way snow chains are used in certain conditions.

Many thanks again for your informative response.

 

[ChocNessie]

horse power that is the answer......

Just seen an old picture (1905) of a horse being used in Ipswich shunting yard, so 1 horse power is enough to move a railway waggon.

Ian

I could tow a horse box complete with Shire Horse and shackles

If I get stuck I can get the horse out, as you say about rolling stock plus they used to tow barges etc......

Much nicer solution than an electric winch

Thanks for a nice light hearted moment

 

[ChocNessie]

Thanks fo all the advice - in summary.....

Thanks to all that got involved, it is great to see such wide ideas.

Basically I was only looking for assisted traction, assuming the engine was still able to turn the wheels, so as some suggested a dead lift is not necessary.

My main concern was about the current drain, but thanks to all of you that is probably a red herring for MHers.

I always walk and survey before I pitch and have found some chunky M&S tyres that meet the requirements of my front axle weight.

I try not to get stuck if I can help it, so I already do all the common sense approaches suggested.

In summary I think:
1 a fixed winch is a bit OTT
2 a portable winch if I can find a suitable one with a snatch without breaking the bank may be an answer
3 a couple of decent sand ladders may be better suited to getting off a grassy pitch if I can find some that a're not too heavy to carry
4 some snow chains for the alps - any experienced suggestions
5 from experience a bag of 25mm gravel hammered into the wet grass in front of the tyres helps (if you can pinch it of the site road or somewhere close by)

Finally be gentle with the clutch and accelerator because once you bury the driving wheels it becomes a whole lot harder to get moving.

Thanks again all

Richard

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[Landy lover]

A simple and effective mud track could be these http://www.ebay.co.uk/itm/360467009249?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648 they are a lightweight version and with a suitable length of rope attached to pull out after use should be more than sufficient in most situations - they also pack down quite small

 

[Snowbird]

You could of course change your MH for this one. Link Removed

 

[ROB1CHELSEA1]

Old one but a very informative thread and a good read

Thanks
Rob

 

[tonyidle]

.

 

[Tea Bag]

Hi.
Caution. Knocking a metal bar/pole into the ground? If on a site,beware of Electic cables going to EHU points.
Tea Bag

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