Pre-sewn webbing slings come in a variety of sizes and colors to help you stay organized. The downside? They’re expensive. A cheaper option is to buy a spool or length of tubular webbing and tie your own using a water knot.
To get the right size every time I cut webbing lengths twice the length of the intended sling and add an additional 18 inches (46 cm) to accommodate for a water knot – this will leave you with approximately 4 inches of tail. Cut the webbing with a hot knife or other appropriate method to prevent fraying.
I like to create webbing slings of multiple lengths so I can quickly choose what’s best for any given situation. I find 2.5ft, 4ft, 7.5ft and 10ft webbing slings to cover most urban situations.
Use different colors of webbing or put colored tape on the tails to help you quickly distinguish between sizes.
Get into the habit of marking webbing slings clearly before placing them into general circulation. The tails are best for this since they’re easy to identify and not load bearing. Use a Sharpie to write the length and service date onto the tails for tracking. Check and ask about the history of any unmarked slings and inspect all slings before using.
Warning: Set the knot! Apply weight and secure all DIY webbing slings prior to use for life support (standing and bouncing on a freshly tied sling is a good way to do this). Short tails have the potential to slip under tension and a loose water knot is dangerously susceptible to snagging so be sure to keep water knots clear of any edges or snag points.
The water knot, sometimes referred to as a ring bend, is used to join two pieces of webbing together. Great for making your own webbing slings or tying off wrapped webbing anchors.
1. Start with a neatly tied overhand.
2. Thread the 2nd end in reverse – make sure to take out any twists!
3. Nest the 2nd end along the path of the overhand.
4. Follow it thru until you’re able to pull the tail from the opposite end of the overhand.
5. Keep the knot loose and adjust as needed to for adequate tail length.
6. Snug up neatly and compact. The water knot should have no less than 4 inches of tail remaining once tied and pulled snug. If creating a sling step into it and weight the knot before use. This will set the knot (leaving closer to 3 inches of tail).
Warning: Apply weight and secure all water knots prior to use for life support (standing and bouncing on a freshly tied sling is a good way to do this). Short tails have the potential to slip under tension and a loose water knot is dangerously susceptible to snagging so be sure to keep water knots clear of any edges or snag points – video here.
Tests show the water knot to reduce webbing strength around 30% (the CMC Rescue Field Guide App gives the water knot a 64% efficiency rating). This reduction in strength is a result of the bends in the knot and associated stress-concentration points. Bar tacks (sewn slings) are stronger because, instead of bends, stitching is used to weave and enforce the overlapped ends. The overall breaking strength of bar tacks differ depending on manufacture and I have yet to find a study that directly compares the strength of bar tacks to water knots under similar circumstances – please send one if you got it! Generally speaking neither type is prone to break under normal circumstances so no need to rush out and buy sewn slings to replace tied ones (although the lack of a bulky knot can be nice). Time is better spent understanding how the overall strength of webbing changes based on its configuration, composition, and use.