Recovery and Towing

[gritineye]

Back to their normal relaxed retardation mode, or am I just too gentle?

[rbrtcrowther]

Can't really compare as i've only driven mine a shot distance. I have got loads of slop in the cables at the moment so the pedel travels about 4 inches and most of the air disapears but i did stomp on them before i arived home and was really quite chuffed.

Best find a quiet road and go for it.

[croc]

Just found this on Marlow KERR whilst looking for something else. There are several videos on the link, KERR is second from last.

http://www.marlowropes.com/index.php?option=com_content&view=article&id=51&Itemid=2

KERR specs.

http://www.marlowropes.com/index.php?option=com_content&view=article&id=154&Itemid=164

Edited August 16, 2010 by croc

[GlosterMB]

Enjoy!

 

 

 

This would have been really funny if he'd attached the cable to the next pylon and pulled that over!

[nptimber]

check out ENLROC TANK RECOVERY TEAM PART 2 on youtube

The landrover club is no way associated with the recovery team

[cosrec]

A few tips on winch ropes. The biggest cause of wear (and eventual breakage on winch ropes)

are abrasion, point loading, and sudden shock

Abrasion causes premature wear on the rope and can be caused by something as simple winching at an angle with front mounted winches on the US militry trucks on which there are no winch rollers.

Cure line the truck up or use a snatch block to give a chance of direction.

Even on vehicles fitted with fairlead rollors winching to one side for any distance will cause great wear to rope.

Cure winch so far then stop pay rope out again and relay evenly across drum before starting to winch again or better still realign truck or use snatch block

 

Point loading

earlier in post somebody put pictures of a fibre rope hooked back on to its self and the damage it did exactly the same happens with wire ropes going around an axle say and hooking back to its self is a definite no. this is easy to spot and easy to cure

less easy to spot is say winching up an embankment and the rope is cutting through the earth you dont know what you are pulling against. Buried just below the surface could be a rock or an old piece of metal. This will kink or break you rope as sure as doubling back on its self.

Cure back up with recovery vehicle so rope is clear of earth or throw a sleeper or wooden rollor for rope to pull over

A point loading that caught me out and put me in hospital. A heavy winching job on a mixer i rigged up and all was within SWL limits. When the lads reconstructed what had happened as the tension was applied the rope had come up from the axle and was resting on a pinch bolt on front hanger this created a point loading in wire snapping it.

Cure this applies to all recovery jobs dont rig up and then go for it apply some moderate load then stop have a walk round check the run of ropes take loops out of cables put packings in to save chaffing suprising how many times you will save some damage to a radiator or brake line say not mention that expensive rope you have just paid for.

Shock loading How can that happen My winch only comes in very steady. Easy your mate is stuck down a 45 degree slope you work out you can pull him up embankment with a pull of 8 tons 2 tons less than the winch capacity. You go for it and up it comes nice and steady mate thinks i will give a hand and starts to drive vehicle lurches forward then drops back Suddenly you are imposing a moving load against your equipment maybe 20 tons not good

Cure get mate out of vehicle and stand along side you if you cant winch it with out his assistance driving then you have not got right kit or your not rigged right.

 

Hope you find these tips useful

[nptimber]

A few tips on winch ropes. The biggest cause of wear (and eventual breakage on winch ropes)

are abrasion, point loading, and sudden shock

Abrasion causes premature wear on the rope and can be caused by something as simple winching at an angle with front mounted winches on the US militry trucks on which there are no winch rollers.

Cure line the truck up or use a snatch block to give a chance of direction.

Even on vehicles fitted with fairlead rollors winching to one side for any distance will cause great wear to rope.

Cure winch so far then stop pay rope out again and relay evenly across drum before starting to winch again or better still realign truck or use snatch block

 

Point loading

earlier in post somebody put pictures of a fibre rope hooked back on to its self and the damage it did exactly the same happens with wire ropes going around an axle say and hooking back to its self is a definite no. this is easy to spot and easy to cure

less easy to spot is say winching up an embankment and the rope is cutting through the earth you dont know what you are pulling against. Buried just below the surface could be a rock or an old piece of metal. This will kink or break you rope as sure as doubling back on its self.

Cure back up with recovery vehicle so rope is clear of earth or throw a sleeper or wooden rollor for rope to pull over

A point loading that caught me out and put me in hospital. A heavy winching job on a mixer i rigged up and all was within SWL limits. When the lads reconstructed what had happened as the tension was applied the rope had come up from the axle and was resting on a pinch bolt on front hanger this created a point loading in wire snapping it.

Cure this applies to all recovery jobs dont rig up and then go for it apply some moderate load then stop have a walk round check the run of ropes take loops out of cables put packings in to save chaffing suprising how many times you will save some damage to a radiator or brake line say not mention that expensive rope you have just paid for.

Shock loading How can that happen My winch only comes in very steady. Easy your mate is stuck down a 45 degree slope you work out you can pull him up embankment with a pull of 8 tons 2 tons less than the winch capacity. You go for it and up it comes nice and steady mate thinks i will give a hand and starts to drive vehicle lurches forward then drops back Suddenly you are imposing a moving load against your equipment maybe 20 tons not good

Cure get mate out of vehicle and stand along side you if you cant winch it with out his assistance driving then you have not got right kit or your not rigged right.

 

Hope you find these tips useful

 

no not really

[Amazon Joe]

Have been recovering various wheeled and tracked casualities using many types of vehicles over last 40 years starting with Marshall 12/20, Unipower Hanibal,, Fordson Majors, Militant MK 1 and 3,Foden EKA, Scammell EKA, Pioneer, Highwayman,and even the chaindrive and never had any problems.

We have been taught from an early age how to recover many types of vehicle,and tree removal which can cause major stresses on the winch tractor and rope. If in doubt add a snatch block or three.

 

Experience and family knowledge.

 

The Freer Family.

[croc]

When it comes down to it using a winch is simple. The important (and interesting) bit is the rigging, getting that right is the real skill in winch work.

[cosrec]

in reply to last three posters am i wasting my time adding these tips or am i talking sense. Little question for two of posters how does adding snatch blocks make vehicle winch more if you have hit limit on holding power. reason i ask is most ex mod vehicles have winch thats matched to its wieght or are we talking deadmen ground anchors etc

[cosrec]

Care of winch ropes

there are two trains of thought on this one is winch ropes are indestructable (talking wire here) they thrive on hard work and neglect

the other is advise issued by the manufacters of these ropes they should be lubricated with this or that spec oil and inspected daily used or not.

people who rely on these ropes for a living on winches that are worked hard eg mariners crane operaters miners tend to follow the advise of the rope manfacturers.

Every body else leans one way between these two tains of thought.

The actual rope is made up of many actual mini ropes which each time are wound in or out roll and flex over one another causing friction or wear. The very least you can do for winch rope is at least when you change an oil filter pore it over the drum. Even if you never use the winch it will stop it going rusty.

[croc]

in reply to last three posters am i wasting my time adding these tips or am i talking sense. Little question for two of posters how does adding snatch blocks make vehicle winch more if you have hit limit on holding power. reason i ask is most ex mod vehicles have winch thats matched to its wieght or are we talking deadmen ground anchors etc

I think that you are talking sense, the purpose of this thread was to discuss recovery techniques and equipment.

To some of us it is a bit like being told how to suck eggs, but, there are plenty of people with no idea how to use recovery kit.

Hopefully they will find it usefull, and nobody knows everything anyway.

The point I was making is that it is very easy to jump into a 4x4 get it stuck and stick the winch onto the closest tree to attempt self recovery. You might be lucky and get out or it might all go horribly wrong. It takes experience to look at a job and know the best way to set it up, there is no substitute for experience but a bit of explanation and education can help you along the way.

Edited August 20, 2010 by croc

[antarmike]

in reply to last three posters am i wasting my time adding these tips or am i talking sense. Little question for two of posters how does adding snatch blocks make vehicle winch more if you have hit limit on holding power. reason i ask is most ex mod vehicles have winch thats matched to its wieght or are we talking deadmen ground anchors etc

 

Adding snatch blocks increases the chances of a successful recovery, because the force required to pull something depends on how fast you are pulling it. Adding snatch blocks slows down how quickly the stuck vehicle is pulled out the mud. the slower the casualty can move forward, the less force is required to pull it.

 

Addind snatch blocks also give time for the suction of the mud to break, allowing the casualty to move forward.

 

Force = Mass multiplied by Acceleration. reduce the acceleration and you reduce the force required to achieve it.

[Tony B]

Mike surley if Force is measured by the Mass of the object multiplied by the aceleration applied to it. The faster the force applied to the mass better? Aceleration being the change of speed of an object over a unit time. i.e. 1 meter per second per second.

Newton's 3 laws.

An object will remain at rest or continue in a straight line at constant velocity, until acted upon by a resultant force.

 

Force is equal to the mass of an object multiplied by it's aceleration

 

To every action there is an opposite and equal reaction.

 

The last one can be identified as snatching a object too fast, so a lot of force is applied. If the force applied does not over come the inertia ( the property of an object to resist a resultant force) but does exceed the breacking strain of the attachements, DUCK! A NATO hitch flying of the front is lethal.

[gritineye]

I think that you are talking sense, the purpose of this thread was to discuss recovery techniques and equipment.

To some of us it is a bit like being told how to suck eggs, but, there are plenty of people with no idea how to use recovery kit.

Hopefully they will find it usefull, and nobody knows everything anyway.

The point I was making is that it is very easy to jump into a 4x4 get it stuck and stick the winch onto the closest tree to attempt self recovery. You might be lucky and get out or it might all go horribly wrong. It takes experience to look at a job and know the best way to set it up, there is no substitute for experience but a bit of explanation and education can help you along the way.

 

Well put croc...just keep posting cossyrec.

[Tony B]

Three pices of advice given to me as a young sprog 1. Don't go in where you think you might not get out. 2. You got it stuck , you dig it out. 3. Four wheel drive can get into twice the trouble of two wheel drive.

[ruxy]

Mike surley if Force is measured by the Mass of the object multiplied by the aceleration applied to it. The faster the force applied to the mass better? Aceleration being the change of speed of an object over a unit time. i.e. 1 meter per second per second.

Newton's 3 laws.

An object will remain at rest or continue in a straight line at constant velocity, until acted upon by a resultant force.

 

Force is equal to the mass of an object multiplied by it's aceleration

 

To every action there is an opposite and equal reaction.

 

The last one can be identified as snatching a object too fast, so a lot of force is applied. If the force applied does not over come the inertia ( the property of an object to resist a resultant force) but does exceed the breacking strain of the attachements, DUCK! A NATO hitch flying of the front is lethal.

 

============

 

And in physics I suppose the word energy has to come in - amount of work that can be performed by a force (and I suppose the control of the energy during the application - thinking of KERR snatch recovery). All gets a bit complex - so many factors.

[cosrec]

Adding snatch blocks increases the chances of a successful recovery, because the force required to pull something depends on how fast you are pulling it. Adding snatch blocks slows down how quickly the stuck vehicle is pulled out the mud. the slower the casualty can move forward, the less force is required to pull it.

 

Addind snatch blocks also give time for the suction of the mud to break, allowing the casualty to move forward.

 

Force = Mass multiplied by Acceleration. reduce the acceleration and you reduce the force required to achieve it.

 

I supose you could add in wind resistance as well the slower you go the less of it.

 

being practical people i think both can be ignored for the differance it makes in a recovery situation unless you are using a glider launching winch.

 

the question i asked was if a vehicle has hit its limit on holding force how would adding a snatch block (with out using deadman etc) alter anything.

I agree suction can be a problem but this can be overcome by applying force then walking away and having a cup of tea

[antarmike]

Mike surley if Force is measured by the Mass of the object multiplied by the aceleration applied to it. The faster the force applied to the mass better? Aceleration being the change of speed of an object over a unit time. i.e. 1 meter per second per second.

Newton's 3 laws.

An object will remain at rest or continue in a straight line at constant velocity, until acted upon by a resultant force.

 

Force is equal to the mass of an object multiplied by it's aceleration

 

To every action there is an opposite and equal reaction.

 

The last one can be identified as snatching a object too fast, so a lot of force is applied. If the force applied does not over come the inertia ( the property of an object to resist a resultant force) but does exceed the breacking strain of the attachements, DUCK! A NATO hitch flying of the front is lethal.

 

The obvious way to increase the pull of a winch vehicle that is slipping backwards towards the casualty is to put in snatch blocks to a sepaerate ground anchors such as miliatary pattern holdfasts, but if these are not available, attemting to recover the stuck vehicle at the slowest possible forward speed is the best hope, because it takes less force to drag it out very slowly, than it does to try and yank it out fast. If you have tried bottom gear, at tickover on the winch, and still you get dragged backwards, putting in snatch blocks to slow the recovery even further might just lower the required force to a point at which the winch vehicles anchoring system will hold. It will not half the force for every snatch block, as is the case with bringing back the tail to a seperate Holdfast, but it will make some difference, maybe just enough.

 

For recovery, the slower the better.

 

As for Kerr, you are storing up potential energy in the rope that is released as the casualty comes unstuck. The stored energy is directly proportional to how far the rope is stretched before the casulaty unsticks. You can only store so much energy by driving forward using the grip of the tyres on the tow vehicle provide and the stored energy in the rope can never exceed what could be achieved by using a normal Hawser or chain if used just as a rope ( ie trying to tow the casualty out).

 

The principle in KERR is to drive the recovery vehicle fast forwarde at a slack KERR rope, so that the Kinetic energy of the vehicle is changed into potential energy in the rope, and the stored potential energy is then released as kinetic energy in the casualty. Obvoiusly Kinetic energy is half the mass of the vehicle multiplied by the Velocity Squared, so yes in Kerr, the faster the better, but in winched recovery, with a static anchored winch vehicle, the slower the better for the reasons I stated earlier. With Kerr if you can double the speed you hit the rope at you quadruple the stored energy and quadruple your chances of popping the cork out of the bottle.

 

As for glider winches I thought that is what Scammell had fitted to the Explorer, since to my mind it is not matched to the vehicle( or why else was it steadily uprated by playing with the cut out, one model of Exlorer must have been built with a winch that was underrated or one that was overrated since depending on Contract there are vastly different winch ratings. ), it is far to fast to be useable.

 

Think about a super bike put on to much power and you pull a wheelie, drive slower and you don't. putting in snatch blocks has a similar effect to driving a super bike sensibly.

Edited August 20, 2010 by antarmike

[Chrisg]

in reply to last three posters am i wasting my time adding these tips or am i talking sense. Little question for two of posters how does adding snatch blocks make vehicle winch more if you have hit limit on holding power. reason i ask is most ex mod vehicles have winch thats matched to its wieght or are we talking deadmen ground anchors etc

 

Keep posting cosrec some of us are learning something

[cosrec]

For recovery, the slower the better I will second that Mike

if for no other reason than it gives more time to stop if things arnt going right

 

A little more on winch ropes. The end of the winch rope is terminated with a machine or hand splice a lead collar (think its called a Tulurit unless thats a trade name) bulldog clips or i have actually seen knots. How ever its done as long as its done correctly it is of secondary importance to the little steel piece thats fitted inside the loop called the thimble. Why is it so important. Down to point loadings again if you look at the cross section of the mounting piont on a hook say its only very small it creates high point loads on the wire. if its missing completely the wires working load is reduced to 1/4 of what it should be. So if your thimble is missing damaged are stretched my advice would be dont use it.

The guy who comes to do our Lolar examinations carries a 4 inch cordless grinder in his van and cuts the ends of any wires he finds damaged to stop there use.

The cure is not a bad as you think our local ships riggers charge £5 for swagging a new end on cheap for peace of mind.

 

When you have used a winch and are stowing it away allways hook it on to something and stow with a little weight on it. This stops it unwinding and saves the risk of using it next time with lose coils some of which you may not see causing damage to the rope or trapping of coils.

We hear more heated words between drivers over this when one has had to strip the whole line of and rewind at the side of a busy motorway than anything else.

Just out of curiosity have a look at any 4x4 slide bed recovery or plant truck you come across you will be amazed how many have winches that look as though they have spagetti taffled round them and damaged thimbles. Dont look good and potentialy dangerous

Edited August 21, 2010 by cosrec

[abn deuce]

In the CCKW manual they suggest using a fixed object to winch the vehicle too so as to place some load on the cable as its being wound back on the winch drum , there is also a split block that can be fabed that would mount on a vertical 2x4 which has a single bolt through a second 2x4 which runs upward at an angle from ground across the bumper to provide a drag load and guide that a person moves to feed the cable back on to the winch drum in even layers , these methods require two people to do as the WWII American winches did not incorperate a cable laying on system , I think those came along on the Vietnam era and newer vehicles.

[N.O.S.]

Very useful information, Cosrec :thumbsup:

 

What's your take on snatch block pulley diameters? Some recovery type blocks look way too small for my liking.

 

It should be noted that some recovery block pulleys look as if they will accept a larger diameter rope than their design size, due to the wider mouth of the rope groove - which are intended to reduce damage if the rope pulls sideways. It is the radius of the bottom of the groove which is critical for safe operstion, and which determines diameter of rope to be used.

[antarmike]

For recovery, the slower the better I will second that Mike

if for no other reason than it gives more time to stop if things arnt going right

 

A little more on winch ropes. The end of the winch rope is terminated with a machine or hand splice a lead collar (think its called a Tulurit unless thats a trade name) bulldog clips or i have actually seen knots. How ever its done as long as its done correctly it is of secondary importance to the little steel piece thats fitted inside the loop called the thimble. Why is it so important. Down to point loadings again if you look at the cross section of the mounting piont on a hook say its only very small it creates high point loads on the wire. if its missing completely the wires working load is reduced to 1/4 of what it should be. So if your thimble is missing damaged are stretched my advice would be dont use it.

The guy who comes to do our Lolar examinations carries a 4 inch cordless grinder in his van and cuts the ends of any wires he finds damaged to stop there use.

The cure is not a bad as you think our local ships riggers charge £5 for swagging a new end on cheap for peace of mind.

 

When you have used a winch and are stowing it away allways hook it on to something and stow with a little weight on it. This stops it unwinding and saves the risk of using it next time with lose coils some of which you may not see causing damage to the rope or trapping of coils.

We hear more heated words between drivers over this when one has had to strip the whole line of and rewind at the side of a busy motorway than anything else.

Just out of curiosity have a look at any 4x4 slide bed recovery or plant truck you come across you will be amazed how many have winches that look as though they have spagetti taffled round them and damaged thimbles. Dont look good and potentialy dangerous

 

The pressed on ferrule to secure a thimble and form a termination is actually Aluminium.

 

Regarding Bulldog grips (clips) it is surprising how many are put on the wrong way round.

 

The saddle formed with two holes through which the threaded U bolt fits, should be against the rope coming from the winch. Taking the free end of the cable back round a thimble, the U bolt is inserted so that the U is against the unstressed free end of the cable. At least three grips should be fitted and each one should be three rope diamters away from the next one.

 

Using Bulldog grips lowers the strength of the cable by about 25%.

 

Using double Bulldog grips, where two identical halves are put together, each taking its own U bolt (one facing each way) is stronger but still not as strong as a pressed on type termination.

 

remember U bolt against "U"nstressed cable.

[ruxy]

Regarding rope grips - there are big differences in performance of the BS "Bulldog" grip and the continental DIN rope grip.

Following slip through on lift ropes this was investigated over 25 years ago IIRC by the HSE Sheffield Labs / British Ropes test facilities @ Sheffield.

 

The point coming to mind is that the BS grips in 100% black finish were far more efficient than the ones with a hot dipped galvanized finish to the saddle - the galv. acts as a advanced lubricant for ever.

Torque is all important - you will note that the DIN grip hex. nuts incorporate a serrated flange washer.

 

On lift ropes - you could correctly torque the plain hex. nuts but had no assurance that they would not slack off soon after. Obviously the type of rope construction makes a big difference. Following research - more frequent checks were made to terminations , subsequent rope renewals - changes to DIN grips were made and industry has tables available for quantities according to rope dia. / construction.

 

Obviously the above not so important when dragging with temp. rigging - ..