Alpine butterfly? I find it runs well in wide crotches and with it's flat under side (running side?) would probably find its way through a biner too?
Knot for joining two lines for an SRT base-tie
- Thread starter southsoundtree
- Start date
southsoundtree
Been here much more than a while
- Location
- Olympia, WA
Sirnick, how is that used to join two ropes? Thanks.
- Location
- Carbondale Colorado
Attached is a picture of alpine butterfly it is a little tricky to tie good on the offset aspect. Also picture of sheetbend backed up by slipknot. The slipknot prevents the bight part of the knot pulling through as knud knoggin pointed out is its weakness.Best to leave sheetbend out of discussion of climbing knots as it has been established as not adequate. I do like it for other applications though for ease of tying and teaching. mostly comes apart easily by pushing up the bight part like a bowline and can be tied slipped too. But enough on that. I think I like the ashley bend best. Easy to tie considered secure and easy to untie and both tails on same side gives the offset.In reading up on bends I saw that the overhand bend aka euro death knot that started the discussion reduces strength by 50%.
Ashleys Zeppelin and butterfly are all interlocking overhand knots this makes it easier for me to see the construction.
Seems these are the 3 best options ?
Ashleys Zeppelin and butterfly are all interlocking overhand knots this makes it easier for me to see the construction.
Seems these are the 3 best options ?
Attachments
southsoundtree
Been here much more than a while
- Location
- Olympia, WA
I like that alpine butterfly bend.
Up 'til now, I only knew of an alpine butterfly on a bight, resulting in a clip in loop that can be loaded in either/ both directions.
Any idea on strenght reduction on ABB?
Thanks.
Up 'til now, I only knew of an alpine butterfly on a bight, resulting in a clip in loop that can be loaded in either/ both directions.
Any idea on strenght reduction on ABB?
Thanks.
SingleJack
Participating member
- Location
- W MD
It can be argued that the Alpine Butterfly Bend has 'essentially' the same strength as the Alpine Butterfly. Dr. Dave Merchant in Life On A Line, (2nd Ed., 2007, p42) states: "Isolating a damaged section of rope is best done an Alpine Butterfly Knot, which after all is intended for this type of loading." This knot used to isolate could be seen as effectively the same as 'bending' two lines together. Dr. Merchant further lists the Alpine Butterfly Knot with a; "Breaking strength: 60 - 70%" (p48).
Good book to have on hand - IMO.
Good book to have on hand - IMO.
southsoundtree
Been here much more than a while
- Location
- Olympia, WA
thanks
knudeNoggin
New member
[ QUOTE ]
Attached is a picture of alpine butterfly it is a little tricky to tie
good on the offset aspect.
...
I think I like the ashley bend best. Easy to tie considered secure and easy to untie and both tails on same side gives the offset.
[/ QUOTE ]
Neither of these knots is **offset** --both have "collars" around their
loaded ends ("main lines") which will impede movement over a rough
surface. (Yes, tails exit roughly perpendicularly, but that isn't the key
to being offset --knotted part lying entirely to one side of the axis
of tension.)
[ QUOTE ]
Also picture of sheetbend backed up by slipknot. The slipknot prevents the bight part of the knot pulling through as knud knoggin pointed out as its weakness.
[/ QUOTE ]
Actually, I wasn't so specific --only pointed to Richards's finding of slippage,
which, in fact, he found on both ends, in some cases.
(And, recall that Brion Toss did some testing of 5/32" 12-strand HMPE
cord (Dyneema, I think) in which a double bowline with tail stoppered
slipped by collapsing the eye, material just *flowing* out of the knot
via the double turns (!!).)
[ QUOTE ]
I saw that the overhand bend aka euro death knot that started the discussion reduces strength by 50%.
[/ QUOTE ]
And this matters, how? The indicated applications here (and esp. for the
rockclimbing use of abseil-ends joining) don't need great strength.
*kN*
Attached is a picture of alpine butterfly it is a little tricky to tie
good on the offset aspect.
...
I think I like the ashley bend best. Easy to tie considered secure and easy to untie and both tails on same side gives the offset.
[/ QUOTE ]
Neither of these knots is **offset** --both have "collars" around their
loaded ends ("main lines") which will impede movement over a rough
surface. (Yes, tails exit roughly perpendicularly, but that isn't the key
to being offset --knotted part lying entirely to one side of the axis
of tension.)
[ QUOTE ]
Also picture of sheetbend backed up by slipknot. The slipknot prevents the bight part of the knot pulling through as knud knoggin pointed out as its weakness.
[/ QUOTE ]
Actually, I wasn't so specific --only pointed to Richards's finding of slippage,
which, in fact, he found on both ends, in some cases.
(And, recall that Brion Toss did some testing of 5/32" 12-strand HMPE
cord (Dyneema, I think) in which a double bowline with tail stoppered
slipped by collapsing the eye, material just *flowing* out of the knot
via the double turns (!!).)
[ QUOTE ]
I saw that the overhand bend aka euro death knot that started the discussion reduces strength by 50%.
[/ QUOTE ]
And this matters, how? The indicated applications here (and esp. for the
rockclimbing use of abseil-ends joining) don't need great strength.
*kN*
- Location
- Carbondale Colorado
Knud Knoggin Seems you have a lot of info on knots and rope. what would you recommend in this application?
As far as 50% strength reduction I would consider it significant in that if the srt/access line serves as a rescue line ideally it would have twice the rating of normal climbing rope for anticipated 2 person loads not half.
Obviously we don't require that rating for day to day work but those standards exist for a reason.
I see what you mean about the offset aspect now. I don't think that is a very significant factor passing the knot through a tight crotch though. My throw line to rope connection jams up often enough and that is far more streamlined.
The main point here is creating a reliable set up to lower a climber from the ground using a srt line. It seems adequate rope length is really the best overall.
I also found the discussion useful in identifying some better bends for general use. I have only used double fisherman, sheet bend and bowline on bowline. I have learned some good stuff here thanks.I have to reconsider my use of sheet bend (can you tell I like it). I have placed very high loads on the slipped double sheetbend and bowline on bowline in 5/8 12 strand pulling logs uphill with a truck and it has always worked well.
As far as 50% strength reduction I would consider it significant in that if the srt/access line serves as a rescue line ideally it would have twice the rating of normal climbing rope for anticipated 2 person loads not half.
Obviously we don't require that rating for day to day work but those standards exist for a reason.
I see what you mean about the offset aspect now. I don't think that is a very significant factor passing the knot through a tight crotch though. My throw line to rope connection jams up often enough and that is far more streamlined.
The main point here is creating a reliable set up to lower a climber from the ground using a srt line. It seems adequate rope length is really the best overall.
I also found the discussion useful in identifying some better bends for general use. I have only used double fisherman, sheet bend and bowline on bowline. I have learned some good stuff here thanks.I have to reconsider my use of sheet bend (can you tell I like it). I have placed very high loads on the slipped double sheetbend and bowline on bowline in 5/8 12 strand pulling logs uphill with a truck and it has always worked well.
- Location
- Carbondale Colorado
Not to get to far off the topic but I am curious what others think about this set up.
I found this on sale for 228$
New England Ropes KM III Max 11mm Rope Black 11mm x 300 ft
in combination with petzl rig would make for a rescue rated srt access/rescue system. I use the rig and ascender in RAD configuration but typically switch out to ddrt once I have reached my TIP. Been considering the rope wrench and pantin but haven't used it yet. Does the km111 work well with rope wrench?
Here is a link to petzl website info on RIG rescue applications. Very informative
http://www.petzl.com/us/pro/product-experience-and-technical-notice/rig#02_01
I found this on sale for 228$
New England Ropes KM III Max 11mm Rope Black 11mm x 300 ft
in combination with petzl rig would make for a rescue rated srt access/rescue system. I use the rig and ascender in RAD configuration but typically switch out to ddrt once I have reached my TIP. Been considering the rope wrench and pantin but haven't used it yet. Does the km111 work well with rope wrench?
Here is a link to petzl website info on RIG rescue applications. Very informative
http://www.petzl.com/us/pro/product-experience-and-technical-notice/rig#02_01
- Location
- under grace
i use a Zepplin bend but the knot is very heavy........it kinda feels like ......welll uh....LED!! ok sorry!! now back to your regular thread!!
TC
Participating member
[ QUOTE ]
a zeppelin bend?
[/ QUOTE ]
In this vid I'm using tying/using a Zeppelin for joining two ropes together at 1.10 - 1.22
http://www.youtube.com/watch?v=1cwc20FGdbk
my SRT ascent system needs seriously updated, keep meaning to find the time to try the frog setup.
singlejack's maillion rapide idea is good.
a zeppelin bend?
[/ QUOTE ]
In this vid I'm using tying/using a Zeppelin for joining two ropes together at 1.10 - 1.22
http://www.youtube.com/watch?v=1cwc20FGdbk
my SRT ascent system needs seriously updated, keep meaning to find the time to try the frog setup.
singlejack's maillion rapide idea is good.
livefreeordie
New member
- Location
- Contoocook, NH
i use a zeppelin bend alot of the time when connecting two lines....it is one of my favorite knots for sure
RopeShield
Carpal tunnel level member
- Location
- Ontario, Canada
I use Santa Claus Knot or false sheet bend but with a full back up.
Easiest to tie and untie.
I ahve never seen it slip.
Supposedly used to tie wet, icey leather. Santas reindeer.
Oh the other name is Lapp Knot for Lappland the land of reindeers.
Warning for life situation use a full back up!
Easiest to tie and untie.
I ahve never seen it slip.
Supposedly used to tie wet, icey leather. Santas reindeer.
Oh the other name is Lapp Knot for Lappland the land of reindeers.
Warning for life situation use a full back up!
Attachments
knudeNoggin
New member
[ QUOTE ]
I use Santa Claus Knot or false sheet bend but with a full back up.
Easiest to tie and untie.
I have never seen it slip.
Supposedly used to tie wet, icey leather. Santas reindeer.
Oh the other name is Lapp Knot for Lappland the land of reindeers.
Warning for life situation use a full back up!
[/ QUOTE ]
Wrong knot. The Lapp bend should be essentially a reversed sheet bend
which should have the tails on the same side, not opposite sides as you show.
(YMMV on what you find in the literature, but same-side knots are more
common, and to my mind more secure.)
After folding the one end into a bight (U-turn), bring the other end across
the bight so that it turns <u>around the tail</u> --thus strongly nipping that.
I'm a fan of extending this basic Lapp bend by taking a 2nd or 3rd wrap
of the hitching line (i.e., not the U-turn'd one), from its initial tuck down
through the bight/u-turn, back around itself and that side of the u-turn.
This gives one a secure-when-slack knot, yet with some hope of untying
it by pulling the bight legs apart and thus prying out a little bit of the
hitching mainline, enough to untie the knot. (YMMV w/material & loads.)
*kN*
I use Santa Claus Knot or false sheet bend but with a full back up.
Easiest to tie and untie.
I have never seen it slip.
Supposedly used to tie wet, icey leather. Santas reindeer.
Oh the other name is Lapp Knot for Lappland the land of reindeers.
Warning for life situation use a full back up!
[/ QUOTE ]
Wrong knot. The Lapp bend should be essentially a reversed sheet bend
which should have the tails on the same side, not opposite sides as you show.
(YMMV on what you find in the literature, but same-side knots are more
common, and to my mind more secure.)
After folding the one end into a bight (U-turn), bring the other end across
the bight so that it turns <u>around the tail</u> --thus strongly nipping that.
I'm a fan of extending this basic Lapp bend by taking a 2nd or 3rd wrap
of the hitching line (i.e., not the U-turn'd one), from its initial tuck down
through the bight/u-turn, back around itself and that side of the u-turn.
This gives one a secure-when-slack knot, yet with some hope of untying
it by pulling the bight legs apart and thus prying out a little bit of the
hitching mainline, enough to untie the knot. (YMMV w/material & loads.)
*kN*
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