Prusik knot strength

[morgancountry]

I bought a Tethrd teather to use with my Guidos web. This is my first saddle and I’ve been up the tree about 5 times and shot from it twice and I LOVE it. However I just feel like the Prusik knot rope is the week point. It seems thin. I know the Ropeman 1 is the way to go and will eventually get one as funds allow. Would all you guys ease my mind and tell me I’m overthinking it and that the prusik is way more than strong enough? Lol. I know the Tethrd guys are awesome and their stuff is high quality. Just have a hard time with that in the back of my mind.


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[Nutterbuster]

I bought a Tethrd teather to use with my Guidos web. This is my first saddle and I’ve been up the tree about 5 times and shot from it twice and I LOVE it. However I just feel like the Prusik knot rope is the week point. It seems thin. I know the Ropeman 1 is the way to go and will eventually get one as funds allow. Would all you guys ease my mind and tell me I’m overthinking it and that the prusik is way more than strong enough? Lol. I know the Tethrd guys are awesome and their stuff is high quality. Just have a hard time with that in the back of my mind.


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I'd say the prussic is most likely just as strong it stronger than the ropeman.

 

[Dragsmack]

The prussic needs to be a smaller diameter rope than the tether to work correctly. Ropemans are pretty cheap. You are overthinking it.

 

[swamp_possum]

A prussic hitch is probably the most common fall arrest hitch used in climbing. It is designed to stop a fall when under tension. If you are using a quality rope smaller diameter than your tether and appropriately tied/spliced it literally can not fail. I use a ropeman for my lineman out of convienience but I trust a prussic for my tether.

 

[kyler1945]

http://itrsonline.org/wordpress/wp-content/uploads/2015/02/004.Evans_.2014.pdf

 

[kyler1945]

http://www.paci.com.au/downloads_public/knots/14_Report_hitches_PBavaresco.pdf

 

[elk yinzer]

Either are strong enough when there is no slack in the system.

It becomes a concern when there is slack, i.e. fall factor > 0. In saddle video demonstrations I see this often climbing, climbing above the lineman's belt. It also comes into play when tethered to the bridge and climbing up onto a platform.

In the hybrid treestand applications using a platform such as the predator/assassin, slack can also be introduced in varying ways such as standing on the platform, i.e. rotating for a shot to the offhand side.

From the studies I have read, an 8mm prusik cord will be a decent amount stronger than a ropeman 1. As long as we keep our fall factors well below that dangerous 2 threshold, we should be fine. I think eventually more testing to this effect would be awesome to see.

 

[redsquirrel]

I bought a Tethrd teather to use with my Guidos web. This is my first saddle and I’ve been up the tree about 5 times and shot from it twice and I LOVE it. However I just feel like the Prusik knot rope is the week point. It seems thin. I know the Ropeman 1 is the way to go and will eventually get one as funds allow. Would all you guys ease my mind and tell me I’m overthinking it and that the prusik is way more than strong enough? Lol. I know the Tethrd guys are awesome and their stuff is high quality. Just have a hard time with that in the back of my mind.


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Maybe @Erniepower can comment more specifically on the ratings of the prussik material that he chose to ease your mind.

 

[Babshaft]

Elk Yinzer is bang on with what I've been taught in terms of rope rescue. Generally when we see failures in our rope equipment, it's not the rope. It's a carabiner or another piece of hardware. If it is the rope that fails, we left a lot of slack in it and were very inattentive or trying to break it. If I could find a quiet pulley, I'd use it to mind a prussic instead of the ropeman. It wouldn't be as easy to use, but it'd be optimal for safety.

In my limited opinion, almost every system I've seen guys introduce on here is safe. It's just a good, better, best type of scenario.

 

[Mag1]

I can not vouch for the strength of the Prusik rope used by tetherd, but this is what I bought from rwrope, and it looks similar. I went with the 6mm. They didn’t recommend going over 7mm on a 1/2” line do to it needing to grip the main line.

6mm Prusik cord = 1843lb.
7mm Prusik cord = 2788 lbs.

 

[kyler1945]

I can not vouch for the strength of the Prusik rope used by tetherd, but this is what I bought from rwrope, and it looks similar. I went with the 6mm. They didn’t recommend going over 7mm on a 1/2” line do to it needing to grip the main line.

6mm Prusik cord = 1843lb.
7mm Prusik cord = 2788 lbs.

I would imagine those are maximum breaking strength, not working load limit? It probably wouldn't be a bad idea to specify that for the folks cruising the forums who see it and assume the wrong things.

 

[morgancountry]

Thanks everyone for their expertise and input! This is an awesome forum! I think I might go for a Ropeman for my lineman’s belt. It seems like I adjust it more while climbing. When I get to height I set my teather and I’ve really only had to make one adjustment with the prusik. That doesn’t seem to bad. Might stick with it on the teather.


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[BayouBeauxhunter]

Since we are talking Prusik strength what are yalls thoughts about having the carabiner clipped on the knot side of the loop? If rope is most likely to break at the knot, would it be safer to run the Prusik “backward”? Hold the knot at the tether and run the loop through 3 times attaching the carabiner to the loop side rather than knot side.

 

[pesqimon]

Since we are talking Prusik strength what are yalls thoughts about having the carabiner clipped on the knot side of the loop? If rope is most likely to break at the knot, would it be safer to run the Prusik “backward”? Hold the knot at the tether and run the loop through 3 times attaching the carabiner to the loop side rather than knot side.

If you’re referring to the “barrel” that is formed by the double fisherman’s knot you don’t want it wrapping around the rope since then the prusik will not constrict the line.

Generally speaking where a knot is spatially located has little effect on breaking strength.

 

[brydan]

I can not vouch for the strength of the Prusik rope used by tetherd, but this is what I bought from rwrope, and it looks similar. I went with the 6mm. They didn’t recommend going over 7mm on a 1/2” line do to it needing to grip the main line.

6mm Prusik cord = 1843lb.
7mm Prusik cord = 2788 lbs.

It isn't necessary to go that small on 1/2" line and personally I wouldn't want to go that small. 6mm is going to want to bite in to the rope hard and make it difficult to use and 1843# isn't nearly strong enough for life support. 9-10mm is more in the range you're looking for. I don't use 1/2" line but since the primary issue with a friction hitch on a tether is the tendency to want to bind up, I'd be inclined to experiment with 10mm and adjust the number of wraps on the hitch to get the desired friction. .

 

[Mag1]

Just ordered up some 9mm ultra tech. The 6mm was what they recommended.

 

[Buchholz06]

Will amsteel work in a prusik on 11mm? Trying to get rid of knots and could splice a continuous loop in amsteel. Anyone using amsteel this way?

 

[redsquirrel]

Will amsteel work in a prusik on 11mm? Trying to get rid of knots and could splice a continuous loop in amsteel. Anyone using amsteel this way?

No amsteel is not intended to be used as a friction hitch.

 

[Buchholz06]

Thanks Red.
FYI you can pick up sewn loops that are intended for use as prusiks to eliminate knots.

 

[redsquirrel]

Thanks Red.

No prob!