bridge - Rope vs Amsteel

[Brocky]

If the bury is long enough like its manufacturer suggests, that is all that is needed, a straight bury. Stitches are required so the buried tail can’t be pulled out under low, or no load.
Agree gradual tapers give the strongest results.

 

[mtsrunner]

Exactly. Really makes you wonder if people who make these products have any idea what they're doing. Tapers are overlooked on almost everything. Continuous loops are spliced without rebraiding the rope around the splice, so there's nothing but the bury holding the weight on most prusik adjustable bridges

I’m not arguing that you should use Amsteel for a bridge or prusik, but a straight splice is definitely stronger than ‘rebraiding the rope around the splice’ (assuming proper bury length with tapered strands). So, if I were to make a continuous loop as a prusik for an adjustable bridge, I would absolutely just do a straight splice. Once you make the 6 wrap prusik (or friction hitch of your choice), that splice isn’t backing out.

 

[Brocky]

The rebraiding is called a locked brummel, it does weaken the splice, but if the dyneema is strong enough, it doesn’t matter.

 

[mtsrunner]

The rebraiding is called a locked brummel, it does weaken the splice, but if the dyneema is strong enough, it doesn’t matter.

Correct. It just bothers me that in just about every discussion I see about splicing (I’m also on Hammock Forums a lot), people state that the locked Brummell is stronger than a correctly made straight eye splice. It’s just an incorrect statement that has been scientifically proven.

Having said that, there are definitely situations that a locked Brummell is a better choice, especially when the splice might see periods when it is not under any tension and is packed away.

 

[Brocky]

There is a thread on TreeBuzz about this, trying to convince them the locked brummel isn’t magical also! The LBs are good for hitch cords so shorter buries can be used, to be more flexible, now I’m wondering if enough stitches could replace the LB on hitch cords, to keep them stronger. The locking stitches will hold a straight splice together as well as a LB, when there is low, or no load.

 

[30coupe]

Correct. It just bothers me that in just about every discussion I see about splicing (I’m also on Hammock Forums a lot), people state that the locked Brummell is stronger than a correctly made straight eye splice. It’s just an incorrect statement that has been scientifically proven.

Having said that, there are definitely situations that a locked Brummell is a better choice, especially when the splice might see periods when it is not under any tension and is packed away.

I'm not trying to start an argument here, I'm just trying to learn something. How does a locked Brummell weaken a splice? Are people using the LB only to make the splice. I've always used a LB in conjunction with a tapered splice and assumed the splice did the holding while the LB kept it from loosening when not under tension.

 

[Fl Canopy Stalker]

I'm not trying to start an argument here, I'm just trying to learn something. How does a locked Brummell weaken a splice? Are people using the LB only to make the splice. I've always used a LB in conjunction with a tapered splice and assumed the splice did the holding while the LB kept it from loosening when not under tension.

Because it causes angles in the splice. Based on pull test we’ve done, it weakens it between 8 and 12 percent depending on the size of the amsteel…

 

[30coupe]

Because it causes angles in the splice. Based on pull test we’ve done, it weakens it between 8 and 12 percent depending on the size of the amsteel…

So in your testing the amsteel broke at the LB, or did it cause the splice to slip since it wasn't going straight into the center of the rope? Is this based on testing a closed loop? Is this the same for a loop at the end of a rope since the splice has to go through the braids rather than into the opposite end of the rope? Again, I'm just trying to educate myself here not doubting your word.

Also, 8-12 percent doesn't sound all that bad compared to the 20-40 percent one loses when tying a knot in a rope. On the other hand, it makes me cringe to see guys using 1/8" amsteel daisy chains to support platforms and sticks. I tend to err on the side of bigger is better though, so there is that.

 

[GeoFish]

So in your testing the amsteel broke at the LB, or did it cause the splice to slip since it wasn't going straight into the center of the rope? Is this based on testing a closed loop? Is this the same for a loop at the end of a rope since the splice has to go through the braids rather than into the opposite end of the rope? Again, I'm just trying to educate myself here not doubting your word.

Also, 8-12 percent doesn't sound all that bad compared to the 20-40 percent one loses when tying a knot in a rope. On the other hand, it makes me cringe to see guys using 1/8" amsteel daisy chains to support platforms and sticks. I tend to err on the side of bigger is better though, so there is that.

The Sterling site list the minimum breaking strength of Amsteel 1/8" at 2,300 lbs. Even with the loss for a lB, why is that not strong enough for a stick daisy?

 

[30coupe]

The Sterling site list the minimum breaking strength of Amsteel 1/8" at 2,300 lbs. Even with the loss for a lB, why is that not strong enough for a stick daisy?

It probably is, but the MBS of 3/16" amsteel is 4900 pounds. For that 1/16" difference, I'd go with 4900. Then again, I'm old and don't heal as fast as I used to, so I prefer not to test the MBS. If you are comfortable with it, go for it. One of the things that makes me a bit nervous about the 1/8" stuff is watching guys on youtube twisting the sticks sideways to get to one more loop then camming it back. I have to wonder how many times one would have to do that before the amsteel got tired of it and started to come apart. By that I mean some of the fibers breaking due to repeated stress. Camming over your platform likely does the same thing. MBS is static weight as far as I know, and it's done on a new rope. Granted, fibers can also break on 3/16" rope, but there are a lot more of them there. Each of us has to do what makes us comfortable and keeps us safe.

 

[raisins]

So in your testing the amsteel broke at the LB, or did it cause the splice to slip since it wasn't going straight into the center of the rope? Is this based on testing a closed loop? Is this the same for a loop at the end of a rope since the splice has to go through the braids rather than into the opposite end of the rope? Again, I'm just trying to educate myself here not doubting your word.

Also, 8-12 percent doesn't sound all that bad compared to the 20-40 percent one loses when tying a knot in a rope. On the other hand, it makes me cringe to see guys using 1/8" amsteel daisy chains to support platforms and sticks. I tend to err on the side of bigger is better though, so there is that.

I use double brummel lock daisy chains for steps and platforms, even though this use is rare or non-existent outside of hunting and hammocking, it seems.

I know it isn't a proper splice, but I do not at all consider my sticks or platforms life support at all. The way I hunt, any of my daisy chains could fail catastrophically and I would be fine (my lineman's would swing me into the tree and then I would slide down onto my tether made with a dynamic rope...and I would end up a maximum of 2 feet, or one step height, below where I started). I would never throw a daisy chain around a tree and then clip onto a link in a way that if it failed I'd fall (for one example).

 

[mtsrunner]

I'm not trying to start an argument here, I'm just trying to learn something. How does a locked Brummell weaken a splice? Are people using the LB only to make the splice. I've always used a LB in conjunction with a tapered splice and assumed the splice did the holding while the LB kept it from loosening when not under tension.

No worries, I think we all learn a lot from these discussions. Yes, the fact that the splice turns back on itself causes the weak spot, but that is relative. That’s why I’m sure it’s fine if you use the appropriate safety margins. I have used plenty of self made 1/8” daisy chains (a whole bunch of locked Brummels) for sticks and steps. I have also exploded a 1/8” daisy chain when camming over a buddies big platform (TL Mission, I think?). I definitely prefer at least 3/8” for platforms, even my little X-Wing. Camming exerts a significant amount of force.

 

[Fl Canopy Stalker]

So in your testing the amsteel broke at the LB, or did it cause the splice to slip since it wasn't going straight into the center of the rope? Is this based on testing a closed loop? Is this the same for a loop at the end of a rope since the splice has to go through the braids rather than into the opposite end of the rope? Again, I'm just trying to educate myself here not doubting your word.

Also, 8-12 percent doesn't sound all that bad compared to the 20-40 percent one loses when tying a knot in a rope. On the other hand, it makes me cringe to see guys using 1/8" amsteel daisy chains to support platforms and sticks. I tend to err on the side of bigger is better though, so there is that.

It broke behind the brummel approximately 3/8” behind it where the angle sees the most stress, as the rope “kinks” at the bend exiting the brummel. The tag end eventually finger traps just with a slight dog leg in the rope. I tested an eye splice not a continuous loop, but I’d imagine it being similar as long as the ends were tapered, the brummel is the weak point. Either way the splice is undoubtedly stronger than most if not all knots. I much like you, am not a fan of going smaller than 3/16” amsteel simply due to degradation over time and also due to its lack of shock absorption.