If you’ve ever been part of a rescue you’ve undoubtedly encountered a Z-drag. But, this begs the obvious question of what is a Z-drag and how does it work?
Firefighters get a lot of calls for rescue situations, often for victims that are trapped in confined spaces, fall from cliffs and drive vehicles into ditches.
In these situations, firefighters need to efficiently follow their rescue plan to get the victim(s) to safety in an efficient manner.
When it comes to some of the more basic victim retrievals, high-angle and low-angle rope rescue teams can use a simple pulley system to haul the individual out.
But, this isn’t always going to be safe or practical for situations with heavier objects or multiple victims. This is where the Z-drag system comes into play.
What is a Z-Drag and how does it work?
A Z-drag is a system of ropes and pulleys that create a 3 to 1 mechanical advantage. This typically is used in rescue situations where a simple pulley system wouldn’t be adequate to haul the weight.
In this guide, I will provide a brief run-through of what it takes to set up one of these systems in a rescue attempt. I also want to talk about some of the applications and safety considerations involved for a broader sense of the importance of this system.
So, what situations are these Z-drag systems appropriate for?
While this may look like a very complicated system, it is worthwhile taking the time to plan it all out and get it up correctly.
A Z-Drag can have a massive impact on the amount of weight that you can handle as a rescuer. If you have a heavy object that you need to move, tying a rope to one end and pulling isn’t going to work unless you happen to have the world’s strongest man on your team.
It can be ineffective and potentially dangerous for all those straining to move the weight.
Instead, this series of pulleys and the use of anchors and carabiners will support the rope, take the strain and allow teams to pull as much as three times the weight they normally would.
Thus, creating a 3 to 1 mechanical advantage.
The biggest consideration here is the weight of the object. This system is generally used where there is a large vehicle or other heavy items that you need to pull out of the way or retrieve.
This could be a car or other vehicle that has crashed down a ravine or another tight space.
You can also set these systems up on riverbanks to pull out boats that have crashed or come free from their mooring and become stuck.
With the right application of the Z-drag in the right place, firefighters can lift or drag pretty much anything from anywhere. It is all about adapting the process to the situation.
There may also be cases where these systems prove helpful for rescuing patients. If rescuers know that they might struggle with the retrieval and hoisting of larger victims that are packaged on boards, a Z-drag pulley system could make things easier.
This is why firefighters that specialize in all different types of rescue attempts must be aware of how to set up this sort of Z-drag system.
Anyone that works in high angle rope access situation or similar rope rescues – such as confined space rescue – may find that this approach is helpful in their attempts. Marine fire services that work around the coasts and docks will also find this system helpful in their work.
So how do you set up a Z-drag system?
- Make sure that you have the right gear together for the job
- Figure out where your anchor point is going to be
- Connect your prusik knots for a strong, reliable pulley system
- Make sure that you attach the rope to the right place on the object you’re moving
- Double-check everyone is in position and start pulling
Selecting the right equipment
Familiarity with your ropes and cords are important here to create an effective system. You need a strong line of haul rope that is long enough for the job.
You then need two pieces of quality rope that can be used to make the Prusik knots that create the pulley system. You also need you webbing sling for your anchor point to hold everything in place.
We have created a guide on 7 knots all firefighters must master. Click the link to read that article as well.
Creating that anchor point
Your Z-drag system needs a strong anchor point that can take the strain from the weight of the object and create that first angle in your z-shaped system.
The anchor should be a stable point where you can attach your sling and create the first pulley.
The best options are trees with a clear path in front of them down to the object being retrieved. Large stones, pillars and if all else fails use your truck as an anchor point; just be sure that the attachment is secure, and the anchor won’t shift its position in any way.
Create your pulley system with prusik knots
A prusik knot isn’t necessarily going to be in your initial training while in the fire academy, but you do need to be confident in creating these knots when designing a Z-drag system.
You need to place them along the length of your haul line to create those bend and pulley in your Z-shaped system.
There is a brake prusik at the first bend at the anchor point with the tree.
This creates that first pulley system to drag the object/victim towards the anchor.
Then there is a secondary traveling prusik between the object and the brake. This then connects to the haul line on the other side to create a second pulley and that second angle in the Z-shape.
Make sure the attachment point is secure
Crews have to choose precisely the right point on the object they are moving for the best result. The connection of the rope has to be secure so that it won’t slip off or come untied.
At the same time, that attachment point has to be structurally sound on the object.
For example, you might decide to attach the system to the fender on the back of a car that has traveled down a ravine. It might seem like a logical place but what if the fender is damaged. A sharp pull on the rope could break it off and the car could fall further, placing people at risk.
Always double check your work
Double check all the connections, knots and that everyone is on the same page.
Everyone must be in precisely the right position to begin the hauling process safely. You need the right number of people working on the haul line at a 45-degree angle on the pulley.
It’s important to have team members keeping an eye on the progress of the rescue and any potential threats.
I appreciate that this can all sound quite complicated on paper. The structure and the different components can be difficult to visualize when you haven’t experienced this sort of rescue attempt.
Here is a great video demonstrating the process from beginning to end.
Even if there is no victim to transport or anyone within the vehicles or boats being moved, you need to ensure that you work safely at all time to protect your team and anyone in the area.
A failure with the connection point could send the boat/car crashing back down to where it started. Breaks in the pulley system or anchor point could alter the force and position of the rope, potentially harming all those working on the ropes at the time.
That is why there must always be someone on the scene watching the prusiks and the integrity of the system (this is usually an officer on the scene).
They can tell the rest of the team to stop pulling if they notice a weakness or flaw. It is also important here to make sure to wear all appropriate safety gear, just in case.
All firefighters that work in rope rescue need Z-drag hauling training.
This technique is one that can save a lot of time and help to protect crew members during dangerous rescue operations. I know I’ve been involved in several rescues including hauling everything from cars out of water to victims from off cliffs.
It is, therefore, completely essential that all those that work with ropes and rescue situations understand how to set this up.
This should be a key part of any training courses for fire rescue and firefighters need to have that practical experience and practice before they handle the real thing.
There are lots of smaller details that make up this complex hauling system. A clear understanding of the different types of ropes, creating the prusik knots and the anchoring systems is essential.
If you are a probationary firefighter and are interested in learning about rope skills for these sorts of rescue attempts, make sure that this Z-drag system is part of your training.
You may find that you don’t have to use it that often. But, it is vital that you can use it effectively and correctly when needed.
The truth is, you never know what you will be faced with when you respond to a call. This is one more tool in your arsenal that can make rescue attempts much easier.