In our discussion on a winching scenario last month, we used a direct line recovery rig but in extreme situations such as deep bogs with suction and very steep slopes, it may be necessary to undertake a double line recovery.
A double line recovery uses a snatch pulley block, allowing the winch rope to be doubled back to the vehicle. The rope is free-spooled from the vehicle through the snatch block (attached by a tree protector to an anchor point) back to the vehicle where it is attached to a recovery hook, tow point or loop.
This type of rig doubles the pulling power of the winch and reduces the load on the winch by half. The snatch block acts as a simple pulley system so a 9000lb winch delivers 18000lb of effort or a 9000lb vehicle will require only 4500lbs of effort to achieve it.
This method reduces current draw as well as wear and tear on the winch but it will take about twice as long to do the job because twice as much cable has to be wound in – well, not quite twice as much since the double rig line speed is higher due to the reduction in load.
When the going is particularly tough, a triple line rig may be applied. The double line rig is extended with a snatch block attached to the front of the vehicle and the rope is passed through the block and then attached to a second anchor point.
If you have 50 to 60 metres of Dynamica rope on your winch, this rig can be useful and efficient because it triples the pulling power of the winch and reduces load by a factor of three.
While I have not had to use this approach many times, it was critical on two occasions extracting a vehicle from glue-like mud in Strzelecki Creek. It was a case of maximising winching and pulling power with no alternative.
This type of rig is a bit more complicated. It is used when anchor points are askew of the vehicle and where more than one anchor point is required. It is used when a vehicle needs to be recovered around bends in a track or around obstacles and the accompanying figure depicts a situation where offset anchor points must be used.
The snatch block is attached via a short winch strap or drag chain to a tree protector around the first tree base, allowing the winch cable to be passed through and secured to a second tree protector attached to the second tree.
The use of two further snatch blocks could also allow for double line recovery in this situation – one extra block secured by a winch strap or chain to the first tree and a second attached to the second tree, allowing the winch rope to be passed back on itself to the vehicle.
In the case of a bend in a track, a number of snatch blocks attached to additional anchor points (trees, rocks or vehicles) could be used to avoid having the vehicle pulled across the bend into obstacles. As the vehicle is winched forward, the rigs are progressively released so the vehicle can continue to be winched forward.
All of these situations illustrate the need for extra shackles and snatch blocks in serious recoveries.
In some situations an anchor point may be too far away to be reached by a standard 30m wire rope. Use a webbing winch extension strap, synthetic extension rope or extension cable.
The eye loop of the strap is attached securely to the hook on the winch rope, thus allowing an extended reach – up to 30m with some straps.
Extension synthetic ropes or wire cables are attached to the winch rope hook with shackles.
Obviously, during winching, these straps or ropes will have to be removed at a strategic time to allow the winch rope to be fully spooled. When this operation is undertaken, the vehicle will need to be secured (brakes applied, gears engaged and chocks inserted) while the winch rope tension is released to allow the extensions to be removed safely.
Replacing a traditional wire rope with a synthetic rope such as Dynamica rope would allow over 50m of rope to be installed on the drum of an 8000 to 12,000lb winch, greatly extending its reach. Add all the other benefits we have discussed previously relating to this product, including greater strength, and you can understand why Dynamica has gained such wide acceptance.
Winching using two vehicle winches hook-to-hook can be used in a variety of situations. One can even use a winch strap or extension rope in between the hooks.
Shackles do not need to be used because the clips on the winch hooks ensure that the straps or ropes do not come adrift.
The main advantage of these types of rig is that they potentially doubles (plus extensions) the reach and speed of the winch. It does not, however, double the power or pull because the two units are pulling in opposite directions.
Winches can also be used to remove from a track obstacles such as fallen trees. The log can be trimmed or cut with a chainsaw to allow it to be rotated and dragged from the track. The winch rope is attached by a shackle to a drag chain passed around the log. The chain can be passed through its own eye and attached hook to hook, or the chain secured via its own hook around the log with the eye attached to the winch rope hook.
The rope is attached at the cut end of the log, allowing the winch to pivot the log out of the way. A double line rig can also be used for very large logs or two winches used in unison.
When a vehicle is deeply bogged in mud so fine that it applies suction to the vehicle, it may be necessary to apply lift to the vehicle up out of the mud before pulling it forward.
This can be achieved by using a spare wheel or a sturdy piece of log or timber. We’ll use the example of a wheel, which is placed across the line of the winch rope about a metre from the vehicle. The wheel may be placed on piece of timber but it must not be able to roll.
The rope is passed over the top of the tyre with a piece of wood or sturdy cloth separating the two to avoid damage to the tyre. As winching commences, the cables passing over the wheel/tyre lift the vehicle upwards and forwards and the wheel rotates forwards, falling on its face. Reapply the method if necessary.
This method also allows traction materials to be inserted under the wheels – with great care. Obviously this type of rig requires strict attention to safety and is undertaken slowly. It is however, very effective.
Imagine a steep, slippery slope where you could slide out of control or a steep, rocky, stepped slope where your vehicle could nose dive and up-end itself.
In such situations it is far wiser to lower your vehicle down the slope under control securely attached to a winch rope. Alternatively, you can use a second vehicle and a number of winch extension straps or ropes. In this case the vehicle undertaking the lowering moves well back from the lip of the slope and with appropriate commands and communications moves towards the lip, lowering the other vehicle down the slope.
If you intend to use the winch, turn your vehicle around safely – do not do it on a steep cross slope – and reverse it towards the lip of the slope under supervision. Apply brakes, engage gears and insert chocks.
Locate an appropriate anchor point. Make sure it is strong and well-grounded and secured. Set up your straight-line rig as discussed earlier, except in this case you will be operating the winch engaged in ‘out’ position.
Take up the slack and only then release the brakes, take the vehicle out of gear and remove the chocks. Commence reverse (‘out’) winching, making steering corrections as you go.
Well before you run out of cable reach, locate a flatter section of track to re-secure your vehicle, find a new anchor point and complete the exercise.
Warning: Always leave at least five turns of rope on the winch drum because it these turns that keep the rope attached to the drum. The small positioning screw at the end of the rope only positions the end of the rope and is not load rated and will not hold the rope on the drum! This may sound obvious but I have encountered people who were amazed that it did not do so.
I have already said that there can only be one person in charge of the operation. Any winching requires effective and efficient communication so we can choose the right equipment and procedures and then apply them in the right way.
This applies even to situations where you are alone. Communicate with yourself. Agree on what has to be done, how and when. Establish a mental checklist if necessary but communicate.
Get the whole operation clear in your mind. Practise it mentally before you start if necessary.
In a group, more than one person may be involved but only one is in charge. Agree on hand signals or radio commands and stick to them.
In slippery situations, especially on steep slopes, it may be wise to deflate tyres to increase the tyre footprint and hence traction and slip-resistance. This will greatly assist winching.
Tyre deflators help, along with a good pump to reinflate tyres. In very slippery situations on steep slopes we have also used mud chains with a diamond pattern (is there any other?) to minimise slippage down slope and to the side.
All electric winches currently come with wire rope, normally 8mm diameter and 30m long, secured to the drum by a positioning screw and a loop swaged to the rope at the other end. The winch hook is attached to this eye or loop.
During manufacture, the cable is wound evenly onto the drum but is not spooled under load. It is important that when you purchase a winch that you re-spool or bed the cable onto the drum under load. This stretches the rope, avoiding pinching and kinking during use.
This same procedure should be repeated after using the winch – the rope needs to be re-spooled under load. In this way you will get many years of service out of your winch.
Why re-spool? Simply because if the rope on the drum is not tight and bedded securely, the part of the cable under load will force itself down into the lower layers, causing it to seize or get wedged and making it very difficult to spool out.
In the worst-case scenario, the rope may become kinked, bent or even frayed. If frayed, it will need to be replaced; if kinked, it can be straightened by passing it under load through a pulley block. If the rope is frayed near the eye, it can be cut and re-swaged. If frayed in the middle, the rope becomes dangerous and should be discarded.
Where and how do you re-spool? If possible, get your 4WD store to do it when you take delivery of your mounted winch. Certainly we do it at our stores.
Two other options are available.
Set up a straight-line rig leaving at least five coils on the drum. Winch the cable in under load, feathering the brakes to create resistance or load. Bed the cable neatly by guiding it by hand – remember, use leather gloves and stand one metre away from the fairlead.
Or you can choose an isolated location with a low, even slope and undertake the same procedure. Have someone assist to ensure that the cable bedding is even and that no passer-by trips over the cable – choose your location wisely. And if you have used your winch in a wet environment, this operation has the bonus of drying out your winch, which is not waterproof. We generally recommend that this procedure be undertaken every three to four months.Reads: 1388