In the arsenal of every driver, be it an avid off-roader or a lover of long journeys, a sling strap is a must. This is a versatile tool that can solve many problems: from securely securing luggage on the roof to organizing emergency towing or creating a temporary winch. However, the tape itself is useless if you don’t know how to properly form a working loop out of it.
The ability to quickly and firmly tie a sling into a loop is a skill that can save a situation far from civilization. An incorrectly assembled knot can come undone at the most inopportune moment or, conversely, become so tight that it cannot be untangled without a knife. In this article we will look at time-tested methods for forming hinges that will withstand serious loads.
First you need to decide on the type of sling you have. Modern ribbons are made from synthetic fibers such as polyester or nylon, which have high tensile strength but have a smooth, slippery surface. Sliding is the main enemy of reliability. Therefore, the choice of node depends not only on the desired shape of the loop, but also on the material, as well as on whether the node will carry a static load (for example, securing a load) or a dynamic one (towing).
Selection of material and sling preparation
Before you start tying knots, it is necessary to inspect the existing equipment. Old, frayed ribbons with protruding threads may not withstand even minimal tension. If you plan to use a sling to tow a vehicle weighing more than 1.5 tons, make sure that its rated load significantly exceeds the weight of the vehicle. For such purposes, tapes made of polyester, since they stretch less under load compared to nylon.
The ends of the sling also require attention. If the tape does not have stitched edges, the synthetic fibers may begin to fray, weakening the structure of the knot. In the field, melting the ends with fire is not always safe or effective, so it is better to pre-treat the edges or use factory-made products with reinforced edges. A smooth surface is an advantage when pulling, but a disadvantage when fixing a knot.
It is important to understand the difference between static and dynamic load. Static loading occurs when you simply tie a load to the rack. Dynamic is a jerk when towing a stuck car. Dynamic loads require nodes that do not “creep” or slip when the force vector changes abruptly.
- 🔍 Carefully inspect the tape for microcracks and rubbing before use.
- 📏 For towing, use slings with a width of at least 50 mm and a load of 4 tons.
- 🧵 Avoid knots on wet or icy lines without additional fixation.
⚠️ Warning: Never use static load securing units for jerk towing of a vehicle. The energy stored in a stretched synthetic belt when it breaks can cause serious injury.
Worksite preparation also plays a role. If you are tying a knot in the cold or in the mud, try to clean the surface of the ribbon as much as possible. Dirt acts as an abrasive, grinding the fibers from the inside under strong tension. A clean sling is the key to predictable behavior of the unit under load.
Knot "Bowlin" (Gazebo knot) - a classic of reliability
One of the most famous and reliable ways to tie a sling into a loop is bowline, or gazebo knot. Its main advantage is that it does not tighten tightly under load and is easy to untie even after the tape has been tightly stretched. This makes it ideal for situations where multiple uses or quick release are required.
The technique of tying a bowline on a flat sling is slightly different from tying on a round rope. Since the tape is flat, it is important to ensure that it does not twist while forming the loop. The knot consists of the main loop (root end) and the running end, which is passed through the loop, goes around the main end and returns back to the loop. The resulting non-tightening loop is ideal for creating an attachment point.
However, the classic bowline has a drawback: on a slippery synthetic ribbon, it can spontaneously unravel under variable loads if the running end is too short. To avoid this, experienced motorists always leave “mustaches” - free ends at least 10-15 centimeters long. In addition, the node requires control, since if there is no load it can begin to “crawl”.
To increase the reliability of the bowline on slippery slings, its modification is often used - double bowline. In this case, the running end is passed through the loop twice, which significantly increases friction and fixes the knot. This is especially true when using belts made from low friction materials.
- ⛓️ The bowline forms a reliable, non-tightening loop, convenient for hooking.
- 🔄 The knot can be easily untied after removing the load, which saves time in an emergency.
- ⚠️ Requires mandatory control of the length of the free end to avoid untying.
When tying a bowline on a wide sling (50-75 mm), it may be difficult to form a neat loop due to the rigidity of the material. In this case, it is recommended to first crumple the tape at the site of the future knot to give it softness, or use a thinner cord as an auxiliary loop for threading the main end.
Figure Eight knot - maximum fixation
If you need a loop that is guaranteed not to come undone and will withstand extreme loads, then eight (or Flemish loop) is the best choice. This knot is often used in mountaineering and speleology, which indicates its highest reliability. Unlike the bowline, the figure eight tightens under load and holds “dead.”
There are two ways to tie a figure eight on a sling. The first is the classic one, by forming a loop, twisting it into a figure eight and threading the end through. The second, more convenient for wide ribbons, is to tie a knot in the middle of the doubled sling. This method allows you to obtain a double loop of increased strength, which is important for organizing attachment points on the car body.
The main disadvantage of the figure eight is that it is extremely difficult to untie after a strong pull. If you were using this assembly to tow a heavy SUV, be prepared to have a long time disassembling it, possibly using a screwdriver or pliers to loosen the coils. Therefore, use it where reliability is more important than dismantling speed.
To make it easier to untie a Figure 8 knot after a heavy load, insert a small, smooth object, such as a nut or piece of plastic, into the loop before tightening to create a gap.
There is also double eight, which is used to create two parallel loops or to thicken a knot. On a flat sling, the double figure eight looks more massive, but distributes the load over a larger area of the material, reducing the risk of local fraying of the fibers at the bend point.
| Parameter | Bowline (Gazebo) | Eight (Flemish) | Straight knot |
|---|---|---|---|
| Reliability | High | Very high | Average |
| Detachability | Easy | Difficult | Average |
| Risk of crawling | Yes (on slippery) | Missing | High |
| Application | Securing, towing | Statics, anchoring | Tying up ends |
When using figure eight on synthetic ribbons, it is important to ensure that the turns lie evenly, without overlapping. An incorrectly laid figure eight can act as a “cutter,” locally overheating and grinding the material under jerky load.
Connecting ends: straight and weaving knots
Often a situation arises when you need not just to make a loop, but to connect two slings into one long one or close one sling into a ring. Traditionally used for this straight knot. It is simple to perform: the two ends are folded and tied like a regular knot on shoelaces, but with a cross in the other direction in the second step. However, on smooth synthetic slings the straight knot is extremely unstable.
A more reliable alternative for joining the ends is weaving knot or variations thereof. It allows you to connect two tapes of different thicknesses and textures. The principle of its operation is based on mutual girth: each line wraps around the other, creating a reliable grip. When tensioned, such a knot tends to tighten, but does not “creep” as aggressively as a straight one.
If you are using slings with carabiners, the ends can be connected through the carabiner, but this creates a weak point. A metal carabiner can burst when jerked, while a correctly tied synthetic knot will only redistribute the load. Always make sure that the load is on the back of the carabiner and not on the latch.
☑️ Node security check
For a temporary connection that is planned to be unfastened frequently, you can use clew knot. It is similar to a straight one, but one end is passed into the loop of the other, which prevents it from slipping out. This is especially useful if one line is significantly thinner than the other.
- 🔗 The straight knot is categorically not recommended for critical connections on slippery slings.
- 🛡️ The weaving knot provides better fixation of dissimilar materials.
- 🚫 Avoid using knots that can pinch and damage the structure of the tape.
When tying two ends into a ring (to create a sling-loop), make sure that the knots at the ends are located symmetrically or, conversely, spaced apart so as not to create a bulge at one point. This is especially important when passing such a loop through narrow eyes or around trees.
Load fixation and control
Once the knot is tied, it must be tightened correctly. Many beginners simply pull the ends with their hands, believing that this is enough. This is a mistake. In order for the unit to “sit down” and all its elements to start working, it is necessary to apply a force close to the working one. In auto-expedition conditions, they often use their own body weight or even a lever for this.
Load control is a critical step. After the initial tension (for example, when you have already tied the load or started to pull the car), be sure to stop and tighten the knot. Synthetic tapes tend to stretch slightly and tighten at the knot during the first pull. If the assembly is not tightened immediately, it will create slack, which can lead to slipping or shock due to vibration.
Particular attention should be paid to the “whiskers” - the free ends of the sling after the knot. They should not dangle, clinging to moving parts of the car or wheels. It is best to wrap the long ends around the main tape and tuck them under the coils or secure them with electrical tape/tie, but do not cut them! The cut end may begin to unravel at the most inopportune moment.
⚠️ Warning: Never leave long loose ends of a sling dangling near the wheels or driveshaft. Once in the mechanism, the tape will wind up in a split second and can damage the car.
For long-term parking with tensioned slings (for example, drying clothes or a temporary awning), it is recommended to use additional locking units on top of the main ones. A simple half-bayonet placed on the running end will prevent it from being pulled out of the main assembly.
Common errors and safety
The most common mistake is using knots that are not designed for synthetics. For example, grasping knots, which work great on hemp rope, may not hold on to a flat tape or, conversely, may damage the fibers. It is also dangerous to use knots that are tied “by eye” without understanding the principle of their operation.
Another mistake is ignoring the state of nodes after use. If the sling has been exposed to mud, sand or water, the knot inside may have accumulated abrasive. With the next strong pull, these particles can cut the internal threads. After severe operating conditions, it is better to tie the knots, moving the inflection point.
Safety when working with tensioned slings is priority number one. The energy stored in a stretched synthetic line is comparable to the energy of a bullet. When broken, the ends of the line fly apart at great speed. So when you check tension or adjust a knot, never be on the tension line.
- 🚫 Do not stand in the line of the tensioned sling when checking the knots.
- 🧤 Always use gloves when working with loaded synthetics to avoid friction burns.
- 👁️ Regularly check the condition of the nodes along the way, especially after overcoming difficult sections.
Remember that any knot reduces the strength of the sling. Even the most perfect bowline or eight weaken the tape at the inflection point by 30-50%. Consider this safety margin when planning towing operations. If the rated load of the sling is 2 tons, then taking into account the knot, the real safe load will be about 1-1.2 tons.
Can regular rope knots be used on flat slings?
Not all knots work equally well on flat belts. Knots that rely on the friction of a round surface (like many grippers) can slip on a flat belt. It is better to use units specially adapted for belts, or increase the number of turns to compensate for slipping.
How to unravel a very tight Figure Eight knot?
Use the “fluffing” principle: take the ribbon on both sides of the knot and twist it forcefully in opposite directions, trying to turn the turns. It also helps to use a blunt object (the handle of a screwdriver, the edge of a shoe), which can be used to push the coils apart, relieving the pressure.
What is the minimum free end length allowed?
For synthetic slings, the minimum length of the free end after the knot should be at least 10 tape diameters (usually 5-10 cm). Short ends may slip out of the assembly under dynamic load or vibration.
Does frost affect the reliability of a tied knot?
Yes, in severe cold, synthetic fibers become stiffer and less elastic. A knot tied in heat may loosen when cooled due to changes in the geometry of the ribbon. In cold weather, it is recommended to use knots with a large number of turns and more carefully control their tightening.
Is it worth melting the ends of the sling after cutting?
It is possible and necessary to melt the ends to prevent unraveling, but this should be done carefully, forming a slight thickening (“fungus”). However, too large a melted head may interfere with the passage of the tape through the knot or carabiner, so be careful.