Twin bridges on treemo

LordFarkwad

Well-Known Member
Anchor Bend.. ya mean another double fisherman's with a ring stuck through the double wrap?
I just recently went through the ordeal of differentiating some of these knots, John, and I think I see where you are coming-from/going with this. Anchor hitch, double overhand, (double) fisherman's, poacher's, scaffold...all related, kind of variations on a theme.

I was scratching my head for a while last week trying to figure out why my anchor hitch looked different than the ones in the book even tho it had a double wrap around the biner, and the difference ended up being that the tail of the line exited perpendicular to the biner, instead of inline with the biner going through the wraps. Small difference, but it totally changes how the knot handles a load.

In other words, a double overhand knot, an anchor hitch, and the so-called hitchhiker stopper knot are all the same knot/hitch, just tied in a different order (e.g., big loop then two wraps around the loop, or form two small loops and place tail through them) or dressed differently. It really is mind-blowing how profound these little differences can be...and a little scary.

Edit: This came across as waaay more authoritative than I have a right to be speaking, especially considering the experience and wealth of knowledge some of the members of this forum possess who might be reading this post. I will leave the contents intact, but if anyone sees any misinformation, misunderstanding, it miscommunication in there, I welcome being corrected; please do.
 
Last edited:

LordFarkwad

Well-Known Member
Yeah, they showed it with an accessory cord I think. Just wanted to make sure it was understood what they used for tying onto the bridge. I'm not normal a fan of the anchor hitch but it works well with that particular rope bridge, partially because the ends have a stiff flat stitch that keeps the anchor from working out too far.
What's up with the anchor hitch? Does repeated loading/unloading work it loose or something?

I've been connecting biners on a scaffold, but was playing with the idea of an anchor hitch for bridge purposes.
 

John@TreeXP

Well-Known Member
What's up with the anchor hitch? Does repeated loading/unloading work it loose or something?

I've been connecting biners on a scaffold, but was playing with the idea of an anchor hitch for bridge purposes.
I think both the Anchor Hitch and Scaffold knot are good ways tie onto a d-ring, when properly tied, dressed and set. While the Anchor puts the two wraps on the D-ring, the Scaffold uses only one. It's like tying knots on fish hooks, except we're the fish.
 
Last edited:

Mowerr

Well-Known Member
It's redundant only if you cut the "outside" bridge. If you cut the inside bridge through the small holes, the outside bridge simply pulls out and you fall. It's only redundant if the outer bridge fails.
I wouldn't consider that redundant ... not in a holistic sense of redundancy that two separate bridges offer you.
Not what I meant... Forget it
 

evo

Well-Known Member
I like that, I’m going to have to create a business for that name “Holistic Redundancy”
 

DSMc

Well-Known Member
Anchor Bend.. ya mean another double fisherman's with a ring stuck through the double wrap?
There is an entire branch of science dedicated to understanding the seemingly unimportant differences in knots. It is a forensic science. That should give you a clue as to how important small changes can be.

Take the time to understand what you are using and why.
 

TallTreeClimber

Well-Known Member
What's up with the anchor hitch? Does repeated loading/unloading work it loose or something?

I've been connecting biners on a scaffold, but was playing with the idea of an anchor hitch for bridge purposes.
In my mind, it is kind of like using a bolt with a nut for a critical application, whereas using a bolt with a locknut (scaffold knot) would be a safer alternative. I love the anchor hitch, I use it on my short climbing lines all the time, but I never use it without a stopper knot. Not that I've ever seen evidence of it needing one, but I've read that it needs one, and the anchor hitch sure is easy to undo, so I feel infinitely safer when life support is in play, using additional security with my anchor bends.
 

LordFarkwad

Well-Known Member
10mm Ocean poly, Platinum 10.5mm, or 1/2" Arbormaster for redundant bridge?

I've found these recommended by various individuals around the buzz at various times, and know @yoyoman has done extensive testing on bridges, and so I'm wondering if there is a clear front runner at this point for rope bridge material?

I'm considering adding a secondary to my TM Light, secured to the lower D's with scaffold knots. I lean towards the smaller diameters in the interest of keeping the termination more compact, but if something like Arbormaster is the clear hands-down winner, then that's fine as well.

@Jimmycrackcorn, is this an acceptable question? Or should I be waiting until I fall to ask about redundancy/backups?
 

Mowerr

Well-Known Member
10mm Ocean poly, Platinum 10.5mm, or 1/2" Arbormaster for redundant bridge?

I've found these recommended by various individuals around the buzz at various times, and know @yoyoman has done extensive testing on bridges, and so I'm wondering if there is a clear front runner at this point for rope bridge material?

I'm considering adding a secondary to my TM Light, secured to the lower D's with scaffold knots. I lean towards the smaller diameters in the interest of keeping the termination more compact, but if something like Arbormaster is the clear hands-down winner, then that's fine as well.

@Jimmycrackcorn, is this an acceptable question? Or should I be waiting until I fall to ask about redundancy/backups?
I think most would say the later 2 choices would be better than o.p. Try stuff out and keep your bridge new. One thing to consider is the elasticity in the rope you do choose, because if you do happen to take a fall that dyneema and o.p might not be so forgiving. I just grabbed some samson velocity bc its 11 mm so it fits in the holes of the low d's on your tm, cheap, light, and it has a nylon core so its got a little more stretch. Buckingham uses it on some of their saddles. So far I like it.
 

RBJtree

Well-Known Member
I just added a second bridge on my tree mo not as redundancy, specifically to use with captain hook that I just got. I used 8mm ice. It looks bigger, but they say it's 8. But hey, it's 8000lbs tensile and pure technora so effevtively zero stretch. I used a scafold knot on one side and an anchor on the other with about a foot of tail daisy chained for a stopper/ room to adjust. Because the anchor hitch will actually come out without a pry bar, I could adjust it in tree with my extra daisy chained length. I attached it to the lower d's a couple days ago and it hasn't gotten in the way of my lanyard at all. Plenty of room for me. I'll get my first chance to use captain hook tomorrow and see how it works with the ice bridge.
 
Last edited:

RBJtree

Well-Known Member
By the way, I agree that the anchor hitch should have a stopper knot for life support, and I also have never had one work it's way out. It just seems like it could because it doesn't lock up. If I like having a second bridge I will probably pick a length and scafold both sides eventually.
 

LordFarkwad

Well-Known Member
The single red stitch encompassing the double-overhand stoppers on each end of the treeMOTION's bridge...is there any other purpose to it than, perhaps, as an indicator that the knot is creeping/slipping, or as a factory 'seal' of sorts, to indicate that the bridge has been tampered with?




@Jimmycrackcorn: Okay, okay, I've probably done it and totally crossed a line with this question, being that this question probably qualifies for mind-numbing and should be 100% totally self-evident and obvious to anyone with more than a clump of nerve cells for a brain. Maybe I should have put this disclaimer at the beginning of this post, even.
 

Brocky

Well-Known Member
RBJ, technora is an aramid and not suitable for a bridge. Bridges made from Ultratech, which has a technora core have failed in the past. The damage wasn’t visible because of the cover, but I don’t think I would trust it even if you can visibly inspect it.
 

Jehinten

Well-Known Member
The single red stitch encompassing the double-overhand stoppers on each end of the treeMOTION's bridge...is there any other purpose to it than, perhaps, as an indicator that the knot is creeping/slipping, or as a factory 'seal' of sorts, to indicate that the bridge has been tampered with?




@Jimmycrackcorn: Okay, okay, I've probably done it and totally crossed a line with this question, being that this question probably qualifies for mind-numbing and should be 100% totally self-evident and obvious to anyone with more than a clump of nerve cells for a brain. Maybe I should have put this disclaimer at the beginning of this post, even.
The red stitch is to keep the core from slipping out of the rope jacket. If the core were to slip the knot would have no holding power.

Side note, I'd ease up on Jimmy, no sense in calling him out in every post. His post may have been harsh towards you but it actually had very good intentions. The purpose that I got from his post was to keep yourself from getting seriously injured or killed. Now we all start from somewhere and I personally didn't have a clue when I started out and still have a lot to learn, so there's no fault in being new, just take it slow.

There are times in climbing and removals/trimming if you get to that point that you can create dangerous situations without even realizing it unless you have that experience. I'm certainly not saying that you shouldn't climb, ask questions or learn in fact I encourage it. Just trying to help you see where he was coming from.
 

RBJtree

Well-Known Member
RBJ, technora is an aramid and not suitable for a bridge. Bridges made from Ultratech, which has a technora core have failed in the past. The damage wasn’t visible because of the cover, but I don’t think I would trust it even if you can visibly inspect it.
Any idea why the failures occurred? I'm not set on the ice rope, I just had a piece around and it feels nice. I figured good abration resistance and strong equals good. Is it bad with point loading?
 

Brocky

Well-Known Member
It’s self abrading and the small bend radius of the ring, which is a majority of the time positioned in the center area of the bridge, caused it to wear through. I don’t know, but maybe the strands could wear away between and inside, and still look good on the outside.
 

Mowerr

Well-Known Member
Any idea why the failures occurred? I'm not set on the ice rope, I just had a piece around and it feels nice. I figured good abration resistance and strong equals good. Is it bad with point loading?
Your gonna wish there is some cushion if you ever fall on those aramids...and what do you mean by point loading? Any arborist rope out there and beyond will work for a bridge...you need to research the characteristics of the fibers and constructions of the rope Then decide what you want out of your bridge. Another big thing is to know how to inspect the rope used and also keep replacement lengths so you always got a strong bridge.
 

Mowerr

Well-Known Member
Check out samson velocity, its cheap, 11mm 24 strand that fits through the holes on your low ds, polyester jacket with nylon core and its very light and cheap. That nylon in the core give it some more elasticity to help dissipate some of the forces generated in a fall,
 

RBJtree

Well-Known Member
From what I have read so far since Brocky's warning, amarids are more brittle when bent at a sharp angle than poly. Yes there have been some failures. That's enough for me. I will switch to a poly or poly/nylon.
I can't imagine 24 inches of bridge rope is going to give you anything in the way of cushion in a fall situation. Samson velocity for example. 6000lb tensile, 3.2% stretch at 20% load. 200 lbs with gear climber falls 5 feet and creates 1000 lbs of force, a little less than 20% but let's go with the 3.2%. 24 inches of bridge stretches .7 inches. Now say you are climbing on that rope, and you are 10 feet below your canopy tie. That will stretch 3.5 inches. Multiply on up for rope in srt system. So, much more cushion from your choice of climbing line.
 
Top