- Location
- Longmont, CO
This is a clean set up for a climbing hitch. I don't know why I don't see many people using the Fixe this way.
Petzl Fixe pulley
- Thread starter jerseygirl
- Start date
- Location
- sunny Madison, WI
The fixe isn't rated for life support (22kn). by tying one end of your split tail to the fixe, you're bringing it into play.... at least that's how I see it.
NickfromWI
Participating member
- Location
- Los Angeles, CA
Zac, each end of the hitch tail is only holding 25% of your body weight, FWIW.
But you're right- it doesn't meet the 5000 pound mark.
love
nick
But you're right- it doesn't meet the 5000 pound mark.
love
nick
Post #1
jerseygirl,
If I understand correctly, you’re ascending by footlocking the tail on a Dbrt set-up and using a Blake’s Hitch as your friction hitch. And, what you’re looking for is an efficient and inexpensive way to advance your hitch automatically as you footlock.
If so, I strongly recommend the Fixe pulley used together with a #3 bronze swivel snap and a Prusik loop made from 4 or 5 mm accessory cord. (See the attachment to this post, post #1. It shows these three items. Then, go to post #2.)
jerseygirl,
If I understand correctly, you’re ascending by footlocking the tail on a Dbrt set-up and using a Blake’s Hitch as your friction hitch. And, what you’re looking for is an efficient and inexpensive way to advance your hitch automatically as you footlock.
If so, I strongly recommend the Fixe pulley used together with a #3 bronze swivel snap and a Prusik loop made from 4 or 5 mm accessory cord. (See the attachment to this post, post #1. It shows these three items. Then, go to post #2.)
Attachments
Post #2
The attachment to post #2 shows how these three items are used together.
This arrangement should cost under $30 and will provide the most efficient automatic advancement of your Blake’s Hitch.
Here’s an explanation of what each of these components does and why you would want them:
The Prusik loop: The Prusik loop allows you to fine tune the placement of the slack tending micropulley.--You do not want the micropulley either too close to your Blake’s Hitch or too far away. If the micropulley is too close, the Blake’s Hitch will not be able to open up fully and relax its grip on the climbing line when you try to advance it. (This assumes you’ve positioned your micropulley with at least some of your weight on the climbing line.) Pushing up a still-constricted Blake’s Hitch is a huge waste of effort. If the micropulley is too far away, you will have to pull down several inches of rope before the micropulley starts slack tending, and when you finish each pull or stride and transfer your weight back to your Blake’s Hitch, you will drop down several inches and lose some of the height that you had gained. This is also a big waste of effort. The Prusik loop allows you to move the micropulley up or down quickly and easily and find the sweet spot for the micropulley, the spot that’s as close as possible to the Blake’s Hitch that still allows the Blake’s Hitch to relax its grip fully.
The #3 bronze swivel snap: The snap part provides a quick way to connect and disconnect the micropulley. The swivel part fairleads the micropulley onto the climbing line so that, regardless of the angle of pull on the climbing line below the micropulley, the side plates of the micropulley will not be twisted against the climbing line as you pull the line through the micropulley. A twisted micropulley can introduce a lot of unnecessary friction and effort. (You want the climbing line to run over the sheave of the pulley, not the side plates.) The #3 (or large size) is needed to accommodate the Fixe pulley.
Go to post #3.
The attachment to post #2 shows how these three items are used together.
This arrangement should cost under $30 and will provide the most efficient automatic advancement of your Blake’s Hitch.
Here’s an explanation of what each of these components does and why you would want them:
The Prusik loop: The Prusik loop allows you to fine tune the placement of the slack tending micropulley.--You do not want the micropulley either too close to your Blake’s Hitch or too far away. If the micropulley is too close, the Blake’s Hitch will not be able to open up fully and relax its grip on the climbing line when you try to advance it. (This assumes you’ve positioned your micropulley with at least some of your weight on the climbing line.) Pushing up a still-constricted Blake’s Hitch is a huge waste of effort. If the micropulley is too far away, you will have to pull down several inches of rope before the micropulley starts slack tending, and when you finish each pull or stride and transfer your weight back to your Blake’s Hitch, you will drop down several inches and lose some of the height that you had gained. This is also a big waste of effort. The Prusik loop allows you to move the micropulley up or down quickly and easily and find the sweet spot for the micropulley, the spot that’s as close as possible to the Blake’s Hitch that still allows the Blake’s Hitch to relax its grip fully.
The #3 bronze swivel snap: The snap part provides a quick way to connect and disconnect the micropulley. The swivel part fairleads the micropulley onto the climbing line so that, regardless of the angle of pull on the climbing line below the micropulley, the side plates of the micropulley will not be twisted against the climbing line as you pull the line through the micropulley. A twisted micropulley can introduce a lot of unnecessary friction and effort. (You want the climbing line to run over the sheave of the pulley, not the side plates.) The #3 (or large size) is needed to accommodate the Fixe pulley.
Go to post #3.
Attachments
- Location
- Seattle WA
paul! you got a computer!
nice to see you here..
did you figure out the ITCC kosher backup for marbars yet?
(sorry for the derail)
k.
did you figure out the ITCC kosher backup for marbars yet?
(sorry for the derail)
k.
Post #3
The Fixe pulley: This is, without question, the best micropulley for your use. I’ll begin the explanation of why by introducing a little terminology:
Top of micropulley: The end to which you normally make attachments. It has two side plates with an attachment hole in each one.
Bottom of micropulley: The end opposite the top.
The choice of micropulley is dictated by the path the climbing line takes through the micropulley. When someone slack tends by grabbing the climbing line below the micropulley by hand and then pulling upwards, the climbing line both enters and exits the bottom of the micropulley during slack tending. (See the attachment to post #3.) For this in-the-bottom/ out-the-bottom style of slack tending, virtually any micropulley will work well. But, this is not the style you’ll be using. During your method of slack tending, the climbing line will enter the top of the micropulley and exit the bottom (as is shown in the attachment to post #2). Here, the choice of micropulley matters a great deal. If the side plates of the micropulley come together, the climbing line can be pinched severely as it enters the top of the micropulley. Whether or not this spot is a major pinch point is determined by several factors including the following ones:
1. How smooth or rounded the edges of the micropulley are.—Smoother or more rounded means less pinching.
2. The angle at which the side plates join.—A more acute angle contributes to worse pinching.
3. Whether or not the attachment point on the micropulley is outside the junction of the side plates.—The further the attachment point is outside this junction, the more the sloping ends of the side plates will lean into the climbing line and the worse the pinching will be. (The further the attachment point is inside this junction, the further the sloping ends of the side plates will be held back away from the climbing line, and the less the pinching will be. In fact, when the attachment point is at or inside this junction, the climbing line will often run against the attaching snap or carabiner and not at all on the micropulley side plates.)
4. The contact angle between the side plates and the climbing line.—If the side plates are running parallel to the climbing line at the point of contact, there will be little pinching or friction.
Go to post #4.
The Fixe pulley: This is, without question, the best micropulley for your use. I’ll begin the explanation of why by introducing a little terminology:
Top of micropulley: The end to which you normally make attachments. It has two side plates with an attachment hole in each one.
Bottom of micropulley: The end opposite the top.
The choice of micropulley is dictated by the path the climbing line takes through the micropulley. When someone slack tends by grabbing the climbing line below the micropulley by hand and then pulling upwards, the climbing line both enters and exits the bottom of the micropulley during slack tending. (See the attachment to post #3.) For this in-the-bottom/ out-the-bottom style of slack tending, virtually any micropulley will work well. But, this is not the style you’ll be using. During your method of slack tending, the climbing line will enter the top of the micropulley and exit the bottom (as is shown in the attachment to post #2). Here, the choice of micropulley matters a great deal. If the side plates of the micropulley come together, the climbing line can be pinched severely as it enters the top of the micropulley. Whether or not this spot is a major pinch point is determined by several factors including the following ones:
1. How smooth or rounded the edges of the micropulley are.—Smoother or more rounded means less pinching.
2. The angle at which the side plates join.—A more acute angle contributes to worse pinching.
3. Whether or not the attachment point on the micropulley is outside the junction of the side plates.—The further the attachment point is outside this junction, the more the sloping ends of the side plates will lean into the climbing line and the worse the pinching will be. (The further the attachment point is inside this junction, the further the sloping ends of the side plates will be held back away from the climbing line, and the less the pinching will be. In fact, when the attachment point is at or inside this junction, the climbing line will often run against the attaching snap or carabiner and not at all on the micropulley side plates.)
4. The contact angle between the side plates and the climbing line.—If the side plates are running parallel to the climbing line at the point of contact, there will be little pinching or friction.
Go to post #4.
Attachments
Post #4
The CMI pulley you’re considering, the RP 142 would be a bad choice for your intended use. The attachment point is outside the junction of the side plates, it has sharp edges, the side plates meet at a fairly sharp angle, and the contact angle between the side plates and the climbing line varies; sometimes it’s o.k., and sometimes it’s poor. Given these undesirable characteristics, you’d expect the sloping ends of the side plates to be a major pinch point. And, in fact, they can be. (The attachment to post #4 shows the RP 142 in your intended use. In the picture, the climbing line is badly wedged between the side plates.—Note how the tops of the side plates are being forced apart by the climbing line.—This jam was created with only a light downwards pull on the climbing line below the micropulley.) The performance of the RP 142 is inconsistent. Sometimes it will jam terribly. Sometimes it will move but with a lot of friction. And, sometimes, if it hangs just right and catches on the Blake’s Hitch just right, it will work fine.
Go to post #5.
The CMI pulley you’re considering, the RP 142 would be a bad choice for your intended use. The attachment point is outside the junction of the side plates, it has sharp edges, the side plates meet at a fairly sharp angle, and the contact angle between the side plates and the climbing line varies; sometimes it’s o.k., and sometimes it’s poor. Given these undesirable characteristics, you’d expect the sloping ends of the side plates to be a major pinch point. And, in fact, they can be. (The attachment to post #4 shows the RP 142 in your intended use. In the picture, the climbing line is badly wedged between the side plates.—Note how the tops of the side plates are being forced apart by the climbing line.—This jam was created with only a light downwards pull on the climbing line below the micropulley.) The performance of the RP 142 is inconsistent. Sometimes it will jam terribly. Sometimes it will move but with a lot of friction. And, sometimes, if it hangs just right and catches on the Blake’s Hitch just right, it will work fine.
Go to post #5.
Attachments
Post #5
In the CMI line, the RP 110 would be a pretty good choice. (The attachment to post #5 shows the RP 110 in your intended use.) While the RP 110 has sharp edges and its side plates come together at a fairly sharp angle, the attachment hole is inside the junction of the side plates on the RP110, and it has a good contact angle. The RP 110 consistently works well in your application.
Go to post #6.
In the CMI line, the RP 110 would be a pretty good choice. (The attachment to post #5 shows the RP 110 in your intended use.) While the RP 110 has sharp edges and its side plates come together at a fairly sharp angle, the attachment hole is inside the junction of the side plates on the RP110, and it has a good contact angle. The RP 110 consistently works well in your application.
Go to post #6.
Attachments
Post #6
The Hitchclimber also consistently works well in your application. (The attachment to post #6 shows the Hitchclimber in your intended use.) While the attachment point is outside the junction of the side plates on the Hitchclimber, it has <u>very</u> smooth edges, the side plates come together at a very wide angle, and it has a very good contact angle. But, at $60, it’s about three times the cost of the alternatives.
Go to post #7.
The Hitchclimber also consistently works well in your application. (The attachment to post #6 shows the Hitchclimber in your intended use.) While the attachment point is outside the junction of the side plates on the Hitchclimber, it has <u>very</u> smooth edges, the side plates come together at a very wide angle, and it has a very good contact angle. But, at $60, it’s about three times the cost of the alternatives.
Go to post #7.
Attachments
Post #7
This brings me back to the Fixe. Since the side plates don’t come together in the Fixe, there is no pinch point whatsoever when used for in-the-top/ out-the-bottom slack tending. (The attachment to post #7 shows the Fixe in your intended use. Note the space between the side plate and the climbing line.)
Go to post #8.
This brings me back to the Fixe. Since the side plates don’t come together in the Fixe, there is no pinch point whatsoever when used for in-the-top/ out-the-bottom slack tending. (The attachment to post #7 shows the Fixe in your intended use. Note the space between the side plate and the climbing line.)
Go to post #8.
Attachments
Post #8
(The attachment to post #8 shows another view of the Fixe in your intended use, this time from the bottom. Again, note the space between the climbing line and the side plates.)
While the CMI RP 110 and Hitchclimber usually don’t introduce much side plate friction, the Fixe introduces none. While the RP 110 and Hitchclimber consistently work well in your application, the Fixe consistently works extremely well. Where you’ll start to really notice the difference in friction between these micropulleys during in-the-top/ out-the-bottom slack tending is when you start placing the micropulleys really close to the Blake’s Hitch as you try to reduce sit-back to a minimum. For a given amount of overall drag from both the Blake’s Hitch and the micropulley, you will be able to get the Fixe closer to the Blake’s Hitch and have less sit-back than with the other micropulleys. (With the Fixe, the drag will come from the Blake’s Hitch, not the micropulley.)
Another desirable feature of the Fixe is that it has smooth edges everywhere both inside and outside. The Fixe won’t pull strands or yarns, nor will it abrade your lines.
Lastly, at about $20, it is competitively priced with every other micropulley you would want to consider.
I encourage you try out these and other micropulleys so you can compare them for yourself. There is no substitute for direct trials. I’ve mentioned some characteristics that are usually undesirable that you should watch out for. If you find a micropulley that seems to work, but it has one or more of these undesirable characteristics, really test it a lot. It might perform inconsistently like the RP 142 and just be behaving temporarily. I’ve had that very experience.
If any of these posts is unclear, please let me know, and I’ll try to clarify it.
Good Luck.
Paul
(The attachment to post #8 shows another view of the Fixe in your intended use, this time from the bottom. Again, note the space between the climbing line and the side plates.)
While the CMI RP 110 and Hitchclimber usually don’t introduce much side plate friction, the Fixe introduces none. While the RP 110 and Hitchclimber consistently work well in your application, the Fixe consistently works extremely well. Where you’ll start to really notice the difference in friction between these micropulleys during in-the-top/ out-the-bottom slack tending is when you start placing the micropulleys really close to the Blake’s Hitch as you try to reduce sit-back to a minimum. For a given amount of overall drag from both the Blake’s Hitch and the micropulley, you will be able to get the Fixe closer to the Blake’s Hitch and have less sit-back than with the other micropulleys. (With the Fixe, the drag will come from the Blake’s Hitch, not the micropulley.)
Another desirable feature of the Fixe is that it has smooth edges everywhere both inside and outside. The Fixe won’t pull strands or yarns, nor will it abrade your lines.
Lastly, at about $20, it is competitively priced with every other micropulley you would want to consider.
I encourage you try out these and other micropulleys so you can compare them for yourself. There is no substitute for direct trials. I’ve mentioned some characteristics that are usually undesirable that you should watch out for. If you find a micropulley that seems to work, but it has one or more of these undesirable characteristics, really test it a lot. It might perform inconsistently like the RP 142 and just be behaving temporarily. I’ve had that very experience.
If any of these posts is unclear, please let me know, and I’ll try to clarify it.
Good Luck.
Paul
Attachments
- Location
- balancing on the edge . . . .
WHAT CAN I SAY
Thank you for this - it is wonderful
and understood the pictures do help with your explainations.
I will get on this asap and see how it works
JZ
Thank you for this - it is wonderful
and understood the pictures do help with your explainations.
I will get on this asap and see how it works
JZ
- Location
- Bloomington, Indiana
Nice photos Paul. Good to see you here.
[ QUOTE ]
did you figure out the ITCC kosher backup for marbars yet?
(sorry for the derail)
k.
[/ QUOTE ]
Yeh, I'd be interested to see that too.
[ QUOTE ]
did you figure out the ITCC kosher backup for marbars yet?
(sorry for the derail)
k.
[/ QUOTE ]
Yeh, I'd be interested to see that too.
Kathy,
There are a number of ways to back-up Mar-Bars that would probably be ITCC compliant. But, I still have to talk with the officials.
My personal opinion, based on lab tests, field trials, and use in actual tree work, is that just using an upper unit alone provides a very high level of safety, and if you use an upper unit together with a lower unit you <u>are</u> using a backed-up system. (I need to do an article, a video, or at least a detailed post about all this.)
I would like this discussion of MB back-up to take place in the context of a very vigorous and open-minded discussion of safety and the need for back-ups in general. It seems to me that we are developing a double standard with respect to the requirements for back-ups, at least at the competitions. Why should an ascender require a back-up but a climbing hitch not. The arguments I’ve been hearing aren’t very good:
• If the cam in an ascender failed, the climber could have a serious fall.—Well, if the eye splice or termination knot on a Prusik cord or the cord itself failed, you could have the same result. Why require a back-up for one system and not the other? Nobody seems to be looking at actual equipment failure rates. Just how “unsafe” are ascenders anyway?—I’ve used ascenders in tree climbing for about 25 years and never had a failure. I’ve certainly had friction hitches slip, run, or jam during that time.--Why should we expect an ascender to be more subject to failure than a friction hitch? Where’s the case for this?
• Ascenders are only for going up. Ascenders need to be backed up because if you encounter an angry bees’ nest, you’ll then have a means of quickly descending and getting out of harm’s way.—Well, what if you’re using a secured footlock entry. Where’s your instant means of descent. A footlock Prusik isn’t supposed to be used for descending. And, if taking a footlock or wrap on your boot to do an emergency descent using the Prusik only as a back-up is acceptable, why wouldn’t doing the same thing with an ascender as the back-up be o.k.? Also, the bees argument really doesn’t make a case for why ascenders need to be backed up. It makes a case for having a means of descent immediately available. These are two separate issues: back-up= protection in the event of a failure, having a means of immediate descent=a way to get away from trouble or a way to get to help.
Considering the following, the ITCC back-up requirement seems nuts: Ascenders are engineered for the purpose and manufactured and tested under strict standards. Friction hitches are manufactured in the field by whoever ties them, and they’re tested, if at all, according to whatever standard the user decides to use. Ascenders are hardware and have very uniform performance. The performance of friction hitches is highly variable and depends on any number of loosely regulated or unregulated factors: the type of cordage used; the length of cordage used; how the hitch is tied, dressed and set; whether the cordage is new or worn; whether or not there’s pitch on the rope; and whether the cordage is wet or dry. So, with very predictable performance on the one hand and with variable performance on the other, why is a back-up required only for the thing that has the reliable performance?
I need to emphasize that I’m NOT advocating that friction hitches be backed up all the time. There are certainly situations where it’s a good idea to have back-up. That’s why we use fliplines, double crotching, and M riggings. The position I’d like to push is that ascenders don’t need to be universally backed up in tree work and recreational tree climbing. For both friction hitches and ascenders, the need for back-up needs to be determined on a situation-by-situation basis by competent climbers. And, what we need to focus on for both ascender and friction hitch use is developing competent users. What we need to develop for ascender use is something similar to what’s been developed for Prusik use during a secured footlock: A set of limitations that takes into consideration and conveys how a Prusik works. This set of limitations gives a standard by which safe and competent use can be determined. The universal back-up requirement for ascenders that’s currently in place doesn’t allow for any competent, safe non-backed up use of ascenders. It’s a lowest-common-denominator-applied-to-all approach. And, it does nothing to foster knowledge about how ascenders work; what can make them fail and what can make them work well, and what should and should not be done with them.
I’d like to get one or maybe several threads going on these subjects. But, my participation will probably have to wait until next week some time.—My roof was leaking badly, and I need to finish my re-roofing project.
Hasta Luego,
Paul
There are a number of ways to back-up Mar-Bars that would probably be ITCC compliant. But, I still have to talk with the officials.
My personal opinion, based on lab tests, field trials, and use in actual tree work, is that just using an upper unit alone provides a very high level of safety, and if you use an upper unit together with a lower unit you <u>are</u> using a backed-up system. (I need to do an article, a video, or at least a detailed post about all this.)
I would like this discussion of MB back-up to take place in the context of a very vigorous and open-minded discussion of safety and the need for back-ups in general. It seems to me that we are developing a double standard with respect to the requirements for back-ups, at least at the competitions. Why should an ascender require a back-up but a climbing hitch not. The arguments I’ve been hearing aren’t very good:
• If the cam in an ascender failed, the climber could have a serious fall.—Well, if the eye splice or termination knot on a Prusik cord or the cord itself failed, you could have the same result. Why require a back-up for one system and not the other? Nobody seems to be looking at actual equipment failure rates. Just how “unsafe” are ascenders anyway?—I’ve used ascenders in tree climbing for about 25 years and never had a failure. I’ve certainly had friction hitches slip, run, or jam during that time.--Why should we expect an ascender to be more subject to failure than a friction hitch? Where’s the case for this?
• Ascenders are only for going up. Ascenders need to be backed up because if you encounter an angry bees’ nest, you’ll then have a means of quickly descending and getting out of harm’s way.—Well, what if you’re using a secured footlock entry. Where’s your instant means of descent. A footlock Prusik isn’t supposed to be used for descending. And, if taking a footlock or wrap on your boot to do an emergency descent using the Prusik only as a back-up is acceptable, why wouldn’t doing the same thing with an ascender as the back-up be o.k.? Also, the bees argument really doesn’t make a case for why ascenders need to be backed up. It makes a case for having a means of descent immediately available. These are two separate issues: back-up= protection in the event of a failure, having a means of immediate descent=a way to get away from trouble or a way to get to help.
Considering the following, the ITCC back-up requirement seems nuts: Ascenders are engineered for the purpose and manufactured and tested under strict standards. Friction hitches are manufactured in the field by whoever ties them, and they’re tested, if at all, according to whatever standard the user decides to use. Ascenders are hardware and have very uniform performance. The performance of friction hitches is highly variable and depends on any number of loosely regulated or unregulated factors: the type of cordage used; the length of cordage used; how the hitch is tied, dressed and set; whether the cordage is new or worn; whether or not there’s pitch on the rope; and whether the cordage is wet or dry. So, with very predictable performance on the one hand and with variable performance on the other, why is a back-up required only for the thing that has the reliable performance?
I need to emphasize that I’m NOT advocating that friction hitches be backed up all the time. There are certainly situations where it’s a good idea to have back-up. That’s why we use fliplines, double crotching, and M riggings. The position I’d like to push is that ascenders don’t need to be universally backed up in tree work and recreational tree climbing. For both friction hitches and ascenders, the need for back-up needs to be determined on a situation-by-situation basis by competent climbers. And, what we need to focus on for both ascender and friction hitch use is developing competent users. What we need to develop for ascender use is something similar to what’s been developed for Prusik use during a secured footlock: A set of limitations that takes into consideration and conveys how a Prusik works. This set of limitations gives a standard by which safe and competent use can be determined. The universal back-up requirement for ascenders that’s currently in place doesn’t allow for any competent, safe non-backed up use of ascenders. It’s a lowest-common-denominator-applied-to-all approach. And, it does nothing to foster knowledge about how ascenders work; what can make them fail and what can make them work well, and what should and should not be done with them.
I’d like to get one or maybe several threads going on these subjects. But, my participation will probably have to wait until next week some time.—My roof was leaking badly, and I need to finish my re-roofing project.
Hasta Luego,
Paul
Mahk,
Thanks for the greeting.
I'd love to and need to gab with you about MBs, but it will have to wait until next week.
Paul
Thanks for the greeting.
I'd love to and need to gab with you about MBs, but it will have to wait until next week.
Paul
- Location
- Canon City ,CO
Paul, Even though you may not read and respond for a few days I'm going to post in hopes of generating some thought and discussion. In our local chapter TCC last week the judges agreed that anyone wishing to ascend SRT and switch over to a DdRT sytem hung on the SRT line-A "Floating False Crotch" system- would have to do so based upon either hanging the system on a Friction hitch with a "stopper" knot tied below it or by clipping into a loop knot tied in the ascent line.No hanging a "work system" off of mechanical ascenders was permitted. The reasoning for those rules is based on the nature of how mechanical ascenders and hitches each work and how they can fail.
Assuming a properly tied hitch with adequate stopper knots, tails or splices the hitch untying should not be an issue......but good hitches can slide. A stopper below provides security against a long uncontrolled slippage of the hitch.
Ascenders can fail in numerous ways. That does not mean that they are dangerous or inadequate for the purpose that they are designed for but the ways in which they may fail need to be recognized and systems designed to preclude ascender failure becoming a life safety issue. Side loading a mechanical ascender can cause it to detach from the line. Ascenders are adequately strong for the near static loads involved in ascent but a severe but survivable fall could physically break the frame of some ascenders. Ascenders can damage/shear the rope under loads that are under the nonsurvivable fall threshhold. All of these points make a case for not running a working system off of these devices. Ironically, while we love our gadgets (me too) and they DO make ascent easier than rope on rope sytems, when it comes right down to it, good old fashioned rope has some unique properties that enhance strength and safety.
If you are merely referring to the issue of backing up ascenders in ascent I do take your point-we allow and encourage footlocking with naught but a prussik....but then we add a seperate belay for speed competition.
FWIW our TCC also had a all climbers demonstrate their systems and hitches during gear check-Hitches had to demonstrably grab and hold when weighted.
Assuming a properly tied hitch with adequate stopper knots, tails or splices the hitch untying should not be an issue......but good hitches can slide. A stopper below provides security against a long uncontrolled slippage of the hitch.
Ascenders can fail in numerous ways. That does not mean that they are dangerous or inadequate for the purpose that they are designed for but the ways in which they may fail need to be recognized and systems designed to preclude ascender failure becoming a life safety issue. Side loading a mechanical ascender can cause it to detach from the line. Ascenders are adequately strong for the near static loads involved in ascent but a severe but survivable fall could physically break the frame of some ascenders. Ascenders can damage/shear the rope under loads that are under the nonsurvivable fall threshhold. All of these points make a case for not running a working system off of these devices. Ironically, while we love our gadgets (me too) and they DO make ascent easier than rope on rope sytems, when it comes right down to it, good old fashioned rope has some unique properties that enhance strength and safety.
If you are merely referring to the issue of backing up ascenders in ascent I do take your point-we allow and encourage footlocking with naught but a prussik....but then we add a seperate belay for speed competition.
FWIW our TCC also had a all climbers demonstrate their systems and hitches during gear check-Hitches had to demonstrably grab and hold when weighted.
- Location
- balancing on the edge . . . .
Pictures at 11 - i got is setup - maybe a video - if that looks ok
Almost dialed in.
video ( ok wrong tread area) take my rope for 5.
http://www.youtube.com/watch?v=SgG7NlGH4Tk
- picture on next post
thanks
jz
Almost dialed in.
video ( ok wrong tread area) take my rope for 5.
http://www.youtube.com/watch?v=SgG7NlGH4Tk
- picture on next post
thanks
jz
- Location
- balancing on the edge . . . .
Picture
- Location
- sunny Madison, WI
How does it work for you?
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What's on your mind? TCI Magazine wants to know
- Started by Tree Care Industry Assoc.
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Apr 09 (Free CEUs) & May 07 - 'Urban Forestry Today' Webcasts @ Noon (Eastern)- Started by UFT
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