Better Options
for Rescue PFDs
A post in an SWR group got me thinking about some of my other tools I use from other disciplines of technical rope work. One of the questions asked was about using the ring provided on the Quick Release Harness System (QRHS) or not and how folks are connecting to it if they do. I have thought about this myself, so I took to the “lab” to do some testing…
Now, I am not a certified test facility by any means, but the work I have been doing with Ryan Jenks and HowNOT2 has taught me the value of simple “backyard” testing. Often I come away with more questions, but I always have more knowledge than when I started.
I started my testing by simply pulling on the rope with my hands to see how much force I could generate before my hands gave out. The rope I used was a standard ⅜” polypropylene found in many throw bags and was dry. Even with a little bounce, I was only able to generate about 150 lbs of force (apologies to the metric folks).
For this testing, I decided to double the force to 300 lbs because I knew 150 lbs wasn’t going to tell me much. Now the more questions part; how much force can a tethered swimmer generate? I know from experience it can be more than what a single person can hold, but soon after that, the person on the tether end gets really uncomfortable.
More testing to come…
Issues of Cross Loading
The first test was simple. We all know cross-loading a carabiner is bad. Now, with a tethered swimmer, we know will not generate enough force to break a certified carabiner no matter how it’s loaded, but…
What is best practice?
Why not use a simple fix?
A lot of weird shit can happen when things come in contact with the gate of a carabiner, even well below its breaking strength. And before you say “well, that’s why I use ________ carabiner”, check out this little experiment with HN2 with a quad-locker.
That experiment was not to prove a failure would happen, but about understanding how something would fail. I learned that I should really mind the gate of my carabiners.
The rope access community refers to a connection point as “incompatible” if the carabiner is able to rotate and place the gate against the anchor. This is why they use ANSI carabiners that have a rated strength against the gate, because weird shit happens.
When tied with a figure eight knot and clipped with a carabiner, cross loading is inevitable at ring and the belt of a rescue PFD
This is still an issue when clipped directly to the belt. This is less likely to happen when the belt is tight against the back of the PFD.
New Knot for Connection
To solve this issue I would suggest using a Poacher Knot as the tie to the carabiner. This knot is used in many applications for life support in caving, canyoning, and rope access as a way to build a personal lanyard. Personally, I would choose this knot over the F8 anytime I am connecting to something in the water and the rope will become slack at any point. This knot is chosen for these applications because of its ability to maintain the carabiner orientation. It is easy to tie and inspect. If you are teaching the Double Fishermen to make a prusik loop you have already taught this knot. Once you know it with a single strand of rope you can tie it with two to combine the ropes in a V-lower and prevent tri-loading.
Makes a very secure loop in the end of a piece of rope. The Poacher’s Knot is also known as a Strangle Snare and a Double Overhand Noose – because the knot tied round the standing end is known as a Strangle Knot (ABOK # 1239, p 224.) and as a Double Overhand Knot.
Untying the two knots after loading to 300 lbs
I tied, set and dressed both knots to a carabiner and pulled to 300lbs. The only notable difference between the two was the poacher knot was easier to untie.
I set up and pulled what a typical V-lower would look like to see how the FPB would perform.
The knot performed well without deformation. I did not see any slipping of the tails nor did the knot want to capsize. The angle of the two lines was slightly less then 90°
It was easy to untie after seeing a peak force of 362 lbs
Should I Use The Ring?
If the ring is there, use it. The QRHS was designed to be used with the ring. With the few vests I have it was easy to find ways for a missed connection. I can see how of these would be difficult to spot in the moment of a rescue. Since this is my primary and single connection point it should be clear, simple, and easy to inspect.
Interestingly enough these rings are not rated or marked in any way. This should be a clear indicator that the manufacturer does not expect you to put much force on this point. (the rest of the belt is not rated either).
If the ring is lost I would be very diligent about checking the connection!
Can I Tie Directly to the Ring?
If I did not have, or ran out of carabiners I would tie directly to the ring. However, it comes with a cost. Tying the poachers knot directly to the ring can be a little more difficult to untie. When tied to a carabiner, I remove the carabiner first to provide space in the knot making is easier to untie. I don’t have that option when tied to the ring and I definitely don’t have any options if I do not have a ring.
Why not use the the retrace figure 8 then?
I can tie the poacher faster and in the end they are about the same to untie after loading. So, pick your poison.