DynaSorb or double braid?

Tom Dunlap

Tom Dunlap

Here from the beginning
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Retired in Minneapolis
My rigging philosophy has been built on using double braid ropes with low stretch. Design the system to take a calculated load and make the cuts and drops fit the system. Using low stretch ropes makes sense to me. It takes a variable out of the system that I left behind many years ago when I abandoned three strand synthetic ropes and moved to double braids.

I understand the design of DynaSorb and it makes sense if the goal is to reduce the load at the rigging point. There are other ways of reducing that load. It seems to me that trying to factor in rope stretch adds an unknown variable. The other, and more important issue about stretch, is how to account for the added distance the chunk will drop because of rope stretch. Again, many years ago I punched a hole in a garage roof because I didn't account for rope stretch when chunking down a large limb using three strand. That wouldn't have happened using double braid. Now, I wonder if it might happen using DynaSorb.

The crew that I'm working with likes DS but they haven't articulated a reason to like it over using DB rope.

By now there must be some feedback about using DS...what is it?

Thanks
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I've been using a similar DB rope product (polyester cover/nylon core) for approx 10 years. I like it for rigging. The little amount of extra shock absorption is nice for the climber, and the tree.
For rigging over structures in tight quarters, I use a polyester cover/dyneema core DB. A pricey rope, but it hardly stretches.
If the guys like the rope their using, you can always use a larger diameter, or take smaller pieces to help prevent roof holes.
 
We use Polydyne from Yale (same as DynaSorb??) and Husky Bull ropes. Husky seems like it has more stretch than Stable Braid, maybe due to the nylon core, but we like it a lot. We have not had any issues with stretch in tight areas with the Husky. However if things are real tight, we take very small pieces and use Yale 1/2" XTC. I do like Polydyne when chunking down bigger wood. It does soften the shake for the climber.

I think using Polydyne puts less pressure on the ground man to run a piece smoothly, which can be nice for less experienced people.
 
Tom D, I'm glad you brought this up, great subject.. Most of my rigging has been done with & 9/16 dynasorb. It didn't take me long to understand the stretch and absorbing capabilities of this rope. I was removing a Black Oak in the middle of an old deck, not much of a top, but the tree was all trunk. I only had to rope down one section of trunk, must have weighed a good 700 lbs, and then I could slice and dice to the finish. We had the device tied off as it had no room to run, and once the piece came off it stretched all the way down to the deck and hit bang-on flat, somehow causing no damage.
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I feel like it has saved my rigging point from failure on several occasions. I rarely feel any of my gear will be pushed to the point of failure, but shockloading a rigging point could mean disaster in certain takedowns.

Dynasorb works well with natural crotch rigging, the rope seems to hold up really well. I've also used this rope to skid heavy logs up and around hills, it works okay for that, but I was really able to see the stretch up close when pulling hard. Also, when working with groundmen that seem to have a hard time "letting it run" you can at least trust the rope to help you out.

It does have a bit of a bungee effect, this can work with you or against you. This rope, overtime, has allowed me to gain the confidence in lowering more and more weight, doing larger pieces safely, and has been a real time saver.

Unedited cell phone video of dynasorb in action on some pretty heavy stuff. Did this tree quite some time ago, not perfect work by any means, but just some clips to show ya'll for fun. The action is just at the beginning.

http://www.youtube.com/watch?v=sQFuhUZ_3TI&feature=plcp
http://www.youtube.com/watch?v=KUTuLi0sUr8&feature=plcp
 
I think that if you have the room and the tree is somewhat suspect to failure (basal defect, dead, etc.) dynasorb (Sherril's name for polydyne,same construction - polyester cover like double braid with a braided nylon core, same as husky. Different braiding techniques change degrees of stretch.)makes sense. For tight drop zones and lifting or pulling, Double Braid (braided polyester core) is perfect. I prefer to have the right tool for the job, whether or not it takes time to switch or not. 2 cents. Keep track of weights and force vectors and apply the tools that you have to achieve the best results.
 
The right tool for every job. Polydyne is not a panacea for the which rope? conundrum.

If there is a roof below, and you are rigging close to it, polydyne is not the rope to use.

Why polydyne (dynasorb)? This video pretty much sums it up:

http://www.youtube.com/watch?v=WDIo-WZkSaM

Call it idiot-proof (well, probably idiot-resistant, I have seen a 5/8 piece broken in a SEVERE shock-loading incident), that is why I like to use it. New groundman? Get ready for a ride. Reduce that ride with polydyne.

If you have a rope that will reduce shock on the tree, the climber, and the rest of your gear, and you have the room to stretch a little bit, this is a good thing. It really doesn't stretch THAT much - not like you have account for it on every piece you rig.
 
The industry has made a few strides since you put a hole in that roof Tom. We are able to pre-tension lowering lines to take the stretch out or even lift a piece off a cut if needed...

Using balance point tie offs and side notches with pretensioned lines allows us to swing large horizontal limbs 90º+ before they drop..

Maybe it depends on the amount of room you generally have to work with, but seems to me that the DS or TB should be the everyday workhorses..
 
I feel dynosorb, and the like, is just another tool that has its place in tree work and it is up to the operator to make the right decision on which line to use and how it fits into the rigging scheme. I don't think there is anything, tool wise, in this biz that is a one size fits all for every tree.
 
Tom, I think Polydyne is excellent for negative blocking and less complex rigging in which the rope should absorb as much of the "shock" as possible. Once you disperse the load with properly placed, multiple blocks blocks, or find yourself pre-tensioning/lifting, a DB with less stretch is great. In the end, it's all about cycles to failure (including the tree) and chosing the right tool for the job.

Polydyne is sure nice in the hands once it wears in...heck, even when it's new. Super nice to tie knots with.
 
Static loads, not really gaining anything Tom....but blocking, it even 'feels' a lot less severe, especially if the groundworker messes up and locks the load. This was our first test-run a while back: http://www.youtube.com/watch?v=iCavP5I_-wc

The ground shots from that tree are right at the end of this vid: http://www.youtube.com/watch?v=BjqJs7YYnMo

Ignore the text that pops up, it was part of something else and I couldn't erase it.
 
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One of my all-time RC favorites... is that the 5/8 yellow dynasorb in the vid?

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Thats right 5/8, but for some reason they look bigger than normal DB 5/8
 
The bigger look is comforting to see on that bigger wood. I really like how you took the time to double the yellow one up, really safe. I sure do miss those videos when Gus was on the rope... you and him seem to always be on the same page.

How did you feel about lowering that much weight above that large cavity lower down on the tree? Long time ago I know but a tree you wouldn't forget i'm sure.
 
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How did you feel about lowering that much weight above that large cavity lower down on the tree?

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Nothing at all really, until I got to rest my feet in the hole for the log cut just above, felt better then.

Another climber had actually topped out the tree but but couldn't finish the logs, thats when I got called. A little rigging cant compare to what the wind loading must have been in years gone by.
 
Ahhh, I didn't realize your feet were in the hole! (4:25 second vid) I just always thought you were kneeling down... nice and comfortable. It sure did look like some solid wood.

Did you finish it off with the block driver?... speaking of which, whatever happened to the block driver? I want one. Anyone ever start manufacturing it?

Also, I've heard you explain it before, but if you could again, the small carabiner placed right above the rigging block and through the eye. When is it necessary to use this added safety precaution?
 
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What was the knot you used to attach the rigging line to the piece at 3:02?

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With the 2 lines? Cows hitch on I'd say. Dont know about the pull line.
 
A lot of the work we do is in the woods or places where we have plenty of vertical clearance. Stretch might not be critical until we get to the lower trunk portions.

After reading the thread I think that I'm going to stock up on some larger diameter DS or Polydyne for the big pieces up high. then, I'll have some DB for lifting, pulling or working low where we need to control stretch.
 
I recently bought a 150' of polydyne... Only used it a couple of times so far.. used it on some larger limbs where I had to negative rig them. I loved it, took a lot of the bounce out of the stem I was tied into. I normally use the stable braid which has become my go to rope. But its nice to have a good shock absorbing rope for those certain situations.
 
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