OB Approved - Basic Vehicle Recovery | OVERLAND BOUND COMMUNITY

OB Approved Basic Vehicle Recovery

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Dunco

Rank VI
Member

Off-Road Ranger I

3,346
Warwick Queensland Autralia
First Name
Kris
Last Name
Duncan
Member #

0787

Ham Callsign
VK4FABX
From time to time 4WD’s will need to be recovered from various situations where the vehicle’s capabilities have been exceeded. There are several reasons why vehicles may become immobilised:

1.Poor appreciation or investigation of the route involved, due to:-- Lack of knowledge of the area, or Poor appraisal of the terrain.
2.Driving without due care and attention.
3.Stopping or stalling on poor surfaces.
4.Mechanical break-down.
5.Lost traction or momentum

Recovery Points
All vehicles are fitted with towing/tie down points from the factory. They are designed to do what the name suggests – tie the vehicle down during transport or shipping.They must never be used for recovery.
Your point of attachment to the vehicle must be rated for its purpose and inspected prior to using it.
Towing or tie down points Most vehicles are fitted with factory tow points. These are generally made of
a heavier material such as a loop of steel rod and attached to the chassis by bolts or more commonly welded. These are designed to tow the car with however they are not suitable for recovery due to the shock loadings that occur.
This is a typical towing/tie down point that has been used for recovery.
tie down.jpg
You can see in the image that the area that is welded to the chassis has torn and is therefore compromised. This was an accident waiting to happen

Rated recovery points
Many people believe that just because you purchase a rated recovery point and bolt it to your vehicle that it is fine to recover off. This is not always the case. These items are all rated in their own right however consideration needs to be exercised when these are on the vehicle. Some bolt up directly to factory
holes and others require the chassis to be drilled. Where they bolt to factory holes generally these points on the chassis are reinforced and will take the load better than other sections of the chassis.These items should always be installed by either the point of purchase or through your authorised service agent for your vehicles.
All recovery points must be inspected before each use to ensure that they have no visible signs of damage. In the case of recovery hooks, they must also have an intact keeper that prevents your attached recovery system from falling off
rated.jpg

Never use a trailer hitch tow ball as an attachment point during recoveries
A trailer hitch tow ball is not designed or rated to be used during recoveries.However the hitch pin is more than capable for the task by using a sling to secure it to. Alternatively there are a range of products available that can be fitted into the receiver to provide a rated recovery attachment point as in this example
hitch.jpg

Operation of Winch's

Make yourself familiar with the type of winch that you possess. Whenever handling a winch steel wire rope (SWR) gloves must always be worn to avoid injury to hands from damaged or frayed wire. Take the time to un-roll the electric winch SWR and pace out its length. When pacing the length of the winch SWR it also provides the opportunity to inspect it. This should be done before the winch is ever used. Attention to this
can assist you later when trying to find the optimum distance from your anchor point, without falling short. Never use the SWR for towing as it can damage both the winch and the SWR. After using the SWR, feed it back on to the winch drum. It should feed neatly and evenly as it runs along the winch drum and then back the other way. Endeavour to pull it in a straight line. The winch has been designed to cope with a slight angled pull, but its strength is severely reduced when the SWR is deployed around corners on the fairlead, or the hook up eye at the SWR's end.

Safety when winching
Whenever any recovery is made by winching you should adopts the following safety procedure:-
The operator of the winch hand control is to be seated in the driver’s position and able to steer the vehicle as needed. Make sure an inertia dampener like a blanket is laid over the centre of the SWR. This will work as a shock absorber, removing a large percentage of the stored energy in the taut SWR as it breaks; resulting in the broken ends dropping to the ground and ceasing motion in a shorter distance.

Steel wire rope makes a singing sound just before it breaks.‘Sing and run’

When using the electric winch, take up the slack by ‘pulsing’ the power button.This prevents the slack SWR or shear pin from breaking because of a sudden momentary ‘shock load’ which can exceed the rating of either component.
Enough slack is taken up to the point where the SWR is placed under tension from the intended load.
Recheck connections before proceeding.When the hook is about a metre from the fairlead, use the pulsing method again to pull in the remainder of the SWR. Keep fingers and hands well clear.Increase the engine speed on the vehicle whilst its winch is being operated.This enables the vehicle to maintain charge in its electrical system. Only use the winch in short bursts to avoid overheating the winch motor. During any
pauses in the process, carefully monitor the connections. If possible chock the vehicle’s wheels to reduce the strain on the winching system

All bystanders must be a minimum distance of 1.5 times the length of the payed out winch SWR from any point within the danger zone radius.Never step over a connected winch rope. Always go around the vehicle oranchor point to get to the other side.

Synthetic winch rope
The rope that is fitted to a vehicles winch introduces a number of hazards to the operator and thankfully SWR is not the only choice available. There are a variety of synthetic rope options that can be fitted to most winches now that are lighter, more flexible and have less associated risks.Consult with a reputable dealer if you intend to replace an older damaged SWR on your vehicles winch, as the roller fairlead must also be replaced when this change is made. There is also an issue with heat in some older winches that prevents this replacement from being possible.The same winching process is used no matter which rope type is fitted
 

Dunco

Rank VI
Member

Off-Road Ranger I

3,346
Warwick Queensland Autralia
First Name
Kris
Last Name
Duncan
Member #

0787

Ham Callsign
VK4FABX
winching Resistance
To be able to calculate the winching resistance created in a vehicle recovery, you first need to have some idea of what your vehicle weighs. The following table provides average weights of a variety of 4WD vehicles with a combination of engine sizes. This is a guide only and a more accurate figure can be obtained through the
manufacturer of your particular vehicle directly or online. The figure is given as the ‘Kerb Weight’ which is indicative to the vehicle in its standard and unloaded form

4WD Vehicle Types Vehicle Kerb Weight
Single Cab Utility-1700 – 1800kg (4 cylinder) 2100kg (8 cylinder)

Dual Cab Utility 1900 – 2000kg (4 cylinder) 2100kg (6 cylinder) 2200kg (8 cylinder)
Mid-sized Wagon (5 seater) 2000 – 2100kg
Large Wagon (7 seater) 2300kg (4 cylinder) 2500kg (6 cylinder) 2600kg (8 cylinder)
Troop Carrier 2340kg
Truck 6000kg minimum
Side by Side ATV 500kg

The kerb weight does not include the vehicle occupants, the quantity of fuel in the tanks, anything that you have loaded on board or any accessories such as bull bar, winch, roof racks, towbar etc. These will all have to be included if they are attached or within the vehicle that is to be winched. The following estimates may help you calculate your final weight.
•Bull bar – (60kg) including the fitting kit
•Electric winch – (55kg)

•Tow bar – (25kg)
•Ute canopy – (80kg)
•Fuel – (1 litre = 1kg).
Now that we can more accurately estimate the vehicles loaded weight (LW) we will be able to establish the
rolling resistance that we have to overcome in any recovery situation that we are confronted with.
There are three types of contributing resistance that need to be considered and accounted for to establish what the total rolling resistance is that has to be overcome. These are:
1.Surface resistance

2.Depth resistance
3.Gradient resistance.

Surface resistance
The firmer the surface that your vehicle is sitting on, the less surface resistance exists for it to roll across as you begin the winching process. In simple terms, you may need to winch your freewheeling vehicle along a very solid and/or compacted track and the path of haul is level. In this scenario the required effort needed to overcome the rolling resistance and achieve this would be somewhere close to 4% of the vehicles loaded weight (LW).However, if the vehicle was just off the side of this same track sitting on the loose gravel edge but still having a level path of haul, the rolling resistance will increase significantly. The required effort needed to overcome the rolling resistance and achieve this would now be somewhere closer to 20% of the
vehicles LW. The exact makeup of mud, types of sand etc. all affect the actual level of resistance. The following list will assist you with your calculations as an approximate value

Surface Type Resistance
Hard Surface-4% of vehicle LW
Grass-15% of vehicle LW
Sand (hard wet)-17% of vehicle LW
Gravel / Sand (soft wet)-20% of vehicle LW
Sand (soft dry, loose)-25% of vehicle LW
Shallow mud-33% of vehicle LW
Bog / Marsh / Clay-50% of vehicle LW

Depth resistance
Simply put, the deeper the vehicle is stuck, the greater the amount of pull necessary to overcome the rolling resistance and extract it
Depth Resistance
Sidewall of tyre-100% of vehicle LW
Axle-200% of vehicle LW
Chassis-300% of vehicle LW

Gradient resistance
The last of the variables which increases the winching load on a recovery situation is the gradient of the slope along your chosen path of haul. The steeper this gradient is, the greater the amount that must be added to the rolling resistance total.To calculate this additional resistance, add 10% of the total vehicle LW for every 5° incremental increase of the gradient up to and including 40°. If the
gradient reaches 45° or more, then simply add the total vehicle LW.







Calculating the total rolling resistance
So now we are able to calculate a value for the surface, depth and gradient resistance in regard to where our vehicle needs to be recovered from. The next step is to use these values to establish a total for the rolling resistance. This total will be the peak load that will be placed on any winching recovery system that is utilised. When calculating the rolling resistance you must include as many of the variables as possible and relevant to your situation. The formula for doing this is as follows:
123.jpg


LW(vehicle kerb weight + combined occupants, accessories and fuel weight)
Surface resistance (surface type percentage x LW)
+
Depth resistance (depth percentage x LW)
+
Gradient resistance (gradient percentage x LW)
=
Rolling resistance
As an example, you need to recover a 4 cylinder dual cab utility from shallow mud that is bogged to the sidewall of the tyres. The direction that you need to haul it is uphill with a 10° gradient. The vehicle is fitted with 320kg of extras that includes fuel and the member who will be the driver during the recovery
weighs 80kg.
Therefore the calculation will be:

LW = 2000 + 320 + 80 = 2400 (kg)


In this recovery situation, the initial load on the winching system will peak at 3680kg to lift the vehicle out of its bogged position. After that the load will reduce significantly. A direct pull with a 4000kg winch will be more than sufficient for the task.If the vehicle was stuck axle deep, the resistance increases significantly.

The depth resistance will double to 4800kg and the total rolling resistance becomes 6080kg. Our 4000kg winch will no longer be capable of achieving this with a direct pull but a double pull will provide the mechanical advantage required.
As you can see the force required to extract a bogged vehicle can be quitesignificant. With the additional weight from equipment and accessories found on most 4WD vehicles, those requirements can increase dramatically
 

Dunco

Rank VI
Member

Off-Road Ranger I

3,346
Warwick Queensland Autralia
First Name
Kris
Last Name
Duncan
Member #

0787

Ham Callsign
VK4FABX
Direct Pull
This method is the most commonly used. When securing the winching rope to your anchor point, never wrap it around the anchor point and then hook it back onto itself. This is a dangerous practice and the pressure placed on the winching rope will ultimately damage it. A sling should always be used to wrap around the anchor and a shackle usedto connect the sling and winching rope. The direct pull method should only be used when the load to be pulled does not exceed the safe rated capacity of the winch and all attached equipment.
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Double Pull

This method is used to gain a mechanical advantage. It is commonly known as a (2:1) two to one pull. The winch rope is paid out towards the anchor, fed through a snatch block and taken back to the vehicle that is to be hauled and attached to a recovery point on this vehicle.
Using a double pull will reduce the amount of force required from the winchto achieve the same pull. This in turn will result in the winch drawing less amperage than a single pull which results in less wear and tear on the winch. The trade off with this method is that it takes twice as long to winch the same distance as a direct pull.For every one metre of winch rope that is wound onto the drum, the vehicle will
only move half a metre towards the anchor point.
llll88888.jpg

Angled Pull
This is when a snatch block is used to change the direction of the pull. This system is used when stable ground for a direct pull is not available in front of, or behind your vehicle.Mechanical advantage can also be obtained, if required, by attaching a second snatch block to the load and running the winch rope back to the anchor point.
llll8888800000.jpg


Winching Hand signals
Warn-winching-hand-signals.jpg

Ensure any hand signals to be used are understood by all involved.
Observe the following:
Do’s
Do select a position where you can see and be seen.
Do give signals with distinct arm movements.
Do ensure that all concerned understand the signals.
Don’ts
Don’t walk backwards while signalling advance.
Don’t get out of the drivers vision.
Don’t forget the driver should only look at you.
Don’t shout instructions.



 

Dunco

Rank VI
Member

Off-Road Ranger I

3,346
Warwick Queensland Autralia
First Name
Kris
Last Name
Duncan
Member #

0787

Ham Callsign
VK4FABX
Two Vechicle Recovery

Occasionally a vehicle will become immobilised with no available or suitable anchor points. Hopefully there will be more than one vehicle in your area of operation which can provide assistance. In this scenario a two vehicle recovery can be adopted. Before attempting the recovery there are several important considerations:
1. The recovering vehicle must be placed on secure ground and, ideally, directly in front of the immobilised vehicle.
2. All persons not involved in the action phase of the recovery attempt should be well away from the immediate area.
3. A driver must be present in the immobilised vehicle so that they canassist the recovery by steering the vehicle from the stationary position. If a power winch is unavailable, a hand winch or tirfor can be used, although it will take considerably more physical effort and time to complete.
4. A hand winch is also useful in situations where the retrieval of a vehicle from a bogged or steep area has caused the vehicle to lean severely to one side. The hand winch can be used in conjunction with the power winch to keep the vehicle more stable and level.
Placing a hessian bag or blanket over the winch rope at the half way mark, should minimise the potential damage and momentum of a snapped rope.There is sufficient weight to cause the rope to double up on itself and fall short of the operators. As the operator of the recovery vehicle takes up the slack in the winch, the driver of the immobilised vehicle should assist the recovery by steering the vehicle out of the situation. With the two working at the same time, this should assist the recovery by reducing the load and resistance. They should always operate the winch controller away from the line of haulage. If the lead for the controller is too short to facilitate this then an option is to sit low, inside the winching vehicle. If using a manually operated tirfor winch, remember not to stand over the SWR while under any load.

Snatch/kenitic Straps
It is attached between the bogged vehicle and the recovery vehicle with approximately 2 metres laid out in an ‘S’ shape near the middle of the strap.A damper should be draped over the strap at this point to dampen any recoil of the strap.The recovery vehicle drives away from the bogged vehicle at low speed. As the strap pulls tight it stretches and then contracts quickly to snatch the bogged vehicle free. If the first attempt fails, try a second attempt with slightly more speed.

It is a preferable piece of equipment, particularly if you often travel with other four wheel drives as the snatch strap is by far the quickest and most effective recovery means available when lightly bogged. Two or more snatch straps may be joined as per the image if firm recovery ground is some distance from the bogged vehicle. To safely join two straps, take the loop of the 1st strap and pass it through
the loop of the 2nd strap. Then take the same loop of the 1st strap and place it over the 2nd loop at the other end of the 2nd strap. When you pull the straps tight they will be joined by the 2 loops in a ‘reef knot’. Insert a rolled up magazine or similar into the middle of the joint. This will prevent the knot from over tightening and enable the straps to be undone easily when finished.
llll8888800000kkkkk.jpg
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The strap is not to be used as a general purpose tow rope as this action can damage the strap and make towing between two vehicles unpredictable.


Safety

1. After discussion is completed and recovery begins, ‘….One Person - OneBoss….’.
2. Always wear gloves when performing recoveries.
3. Couple up - Not hook up (use shackles and not hooks).
4. Ensure all connections are safe before commencement and continually monitor during recovery. When connecting to a vehicle and no recovery points are available, use something that is directly connected to the vehicle chassis, i.e. spring mounts.
5. Ensure equipment used is adequate and safe.
6. Always look before starting recovery.
7. Ensure all persons are at a safe distance in case of equipment failure.
8. Never stand in the path of a vehicle under load.
9. Always check that inertia reducers are in place.
10. Never step over a winching rope when under load or connected at both ends.
11. Everyone to be at a safe distance during winching operations, one and a half times the PAYED OUT distance of the winch rope.
12. Never leave a vehicle unattended, unless in emergency cases.
13. Do not continue with an anchor hold once its grip is being lost.
14. Develop and make sure all persons understand signals and communications.
15. Make sure all equipment is collected after a recovery.
16. Maintain all recovery equipment by washing and drying.
17. Inspect all recovery equipment. This gear does not require authorised inspecting as it is not used in a vertical environment. Check straps for tears and abrasions.
 

LocoCoyote

Rank 0

Contributor I

60
Well written....only thing I would comment on is that you missed tackle resistance in your section on resistance....granted it only really applies when using more complex rigging. Otherwise it is negligible.

As far a estimating weight, I recommend using the GVW instead of Kerb. Overestimating the recovery load never killed anyone...the reverse is not true.

Also, you did well on the kinetic straps, but truthfully these things are commonly misused and very dangerous because of that misuse. Properly used they are a great asset.