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B's version of Sherrill's Tree Frog

Burnham

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Frans and TreeRhino asked for some pictures of Tobe Sherrill's Tree Frog ropewalking SRT system, as modified by me. The changes I made are not substantial...the system works the same as originally marketed, but I "upgraded" it to my preferences. I replaced two components.

First, I got rid of the non-adjustable left foot loop tether, and went with a C&S jug strap that seems to no longer be on the market...any adjustable length foot loop would work, but I particularly like the velcro closure and elastic heel keeper on these old C&S loops. I think there is no way to fine tune any SRT system for max efficiency without setting tether lengths precisely for each individual's body and harness. And if you don't tune for max efficiency, then SRT is a waste of time for most climbers/most trees.

Second, I changed out the original left hand CMI Expedition ascender for the new double hand CMI Expedition. I found that I was always placing my right hand on the rope itself as I raised the left ascender, to keep my body as upright and parallel with the rope as possible. The best place to grap the rope to accomplish my objective was in the way of the ascender's path up the rope, and this also got uncomfortable for my hand on a climb of any significant distance. With the two handed ascender I just keep my hands on the ascender and find the efficiency much improved.

I probably never would have changed over to the TF from my modified Texas style sit-stand SRT system, but for Tobe's request that I review the TF when he first started selling it, and generously comping me the system to try out. I still think many folks don't prpoerly tune their sit-stand systems for ease and efficiency, but even so, I find the TF is a good system, with better efficiency and lessened dynamic loads generated on the anchor point, rope, and components due to the smoother ropewalking motion.

I think my upgrades are a distinct improvement, but they do run the cost up some...for me more than worth it.

First a pic of the system components, then one of the parts I discarded. I have several pics of the system all hooked up, but I had no photographer, and they are not really all that good. I hope they will serve.
 

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Frans

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I just looked at my adjustable foot loops made by OnRope1 and they do not have elastic heel holders. They are webbing.

Burnham, thanks for posting those pix. Have you tried the new CMI pantin?

It seems like it would work better especially for the novice who is flailing around...
 

Burnham

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I have not, but I think your point is well taken. I aid the flailer by putting a keychain biner through the hole in front of the cam...this restricts the cam's movement enough to keep the rope from accidentally escaping the nose of the Pantin. I also think it's good to be able to choose left or right foot model.

I never could understand why Petzl didn't use the same cam/latch configuration as the Croll on the Pantin, and make left as well as right models.
 
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TreeRhino

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Thanks for the pics. I seem to have all the components and i have things set about right. I guess i just need to practice with it a bit to get the rythm. My only modification was to replace the tether from the hand ascender to saddle with a 28Kn CMI closed pulley and running my DdRT systen through it so I could either descend if i needed to or to move around briefly once i was in the tree in order to get a decent tie in point.

Any suggestions on tuning the system? Specificly the foot loop portion.

Also, best way to attach chest ascender to a versatile.
 

No_Bivy

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I like the ascender lanyard set up....slick. Is there a trick for tying that?
 
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Greenhorn

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we got another "old school" tautline guy to try out the tree frog system a month ago at a certified tree worker seminar and he liked it!
 

Stumper

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Butch, SRT is pretty phenomenal.Going up gets several times easier that way......but, If it just a removal, less than 80 feet tall and you are good on gaffs then it is sort of a "Why bother " situation since set up time will be more that the "extra time" spent gaffing up.
If my TIP is less than 40 feet I'll just body thrust up even on a pruning. Burnham lives in tall tree country ..tall trees with few low limbs. SRT is the berries for that stuff...and worthwhile even in squatty tree country when TIPs are over 40-50 feet if the ascent is gonna be mostly rope dependent.(And the gadgets are fun.)
 
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Frans

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True Stumper. Guys get caught up in gear and forget the big picture
 

Burnham

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Yup, going up a 2:1 climbing system after you taste SRT can feel granny slow and inefficient.
 

OTGBOSTON

punk in drublic
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to clarify. I still prefer to footlock, but occasionally will do the srt thing especially on rec climbs with multiple climbers using an access line.

Haven't gotten into the srt to floating false crotch yet, but I do see it as the future mainly because a novice groundworker can perform a a rescue with five mins of training.
 

Burnham

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I like the ascender lanyard set up....slick. Is there a trick for tying that?
That is a slick set up. It came from Sherrill thataway, and when I changed ascenders I loosened it up and retied it the same way.

Basically, you loop the lanyard cordage through the ascender hole (using a plastic thimble), tie a clove hitch with the prusik cord around both legs snug up against the thimble, then tie an overhand knot under the clove with the running end of the lanyard capturing the legs of the prusik cord and the standing side of the lanyard (this part seems unnecessary to me, but that's the way Sherrill did it, and it does seem to keep the loop on the thimble from cinching up super tight, lessening both the radius of the loop and deformation of the plastic thimble), then tie a scaffold knot capturing both legs of the prusik cord.

Last, tie a prusik on the lanyard and close the prusik loop by tying a double fisherman's knot. Balance all the lengths out, dress and set, and there you have it.

Here's some pics to help cipher my description. I loosened things up a smidge to help you see what's what.
 

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Burnham

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Thanks for the pics. I seem to have all the components and i have things set about right. I guess i just need to practice with it a bit to get the rythm. My only modification was to replace the tether from the hand ascender to saddle with a 28Kn CMI closed pulley and running my DdRT systen through it so I could either descend if i needed to or to move around briefly once i was in the tree in order to get a decent tie in point.

Any suggestions on tuning the system? Specificly the foot loop portion.

Also, best way to attach chest ascender to a versatile.

The length of the foot loop needs to be such that when you have extended the ascender overhead a distance a little bit short of your maximum reach (the lanyard from ascender to harness should go snug at this point too), your foot is a little bit lower than the max you can raise it comfortably and still step down on the loop with repeated strength and smoothness of stroke.

Most people find that going for maximum step length on a ropewalking system is excessively tiring, though it is fastest up the rope. Somewhat shorter steps generally keep you more upright, in line with the rope, and that increases efficiency. Steps of a similar length to ladder rungs or stair risers may be about right, but that's a personal thing.

I started with an autolock biner between the Croll and my harness, but soon switched to a small stainless steel screwlink because the biner was big enough to deflect the run of the rope out the bottom of the Croll. I'd attach it that way to your Versatile. Fortunately, if I'm seeing things right looking at a catalog photo, the loops on the bridge of the Versatile are oriented correctly to allow the Croll to lay flat against your belly with the single screwlink as attachment. You need some sort of suspender to keep the Croll upright...I use the Petzl Secur, but you can mock that up with 1 inch webbing easily. Attach the suspenders to the small webbing loop at the rear of your Versatile. You want this as snug as you can be comfortable with.

The way you are setting up with built in DbRT is probably ok for emergency escape, but if you are tempted to work off that ascender setting, you need to think about backing the ascender up, maybe even getting the ascender out of the system altogether. There have been threads on this subject in the past. If you don't go with the DbRT attachment to the ascender, make sure to figure out how to change over to a rappel device while hanging on line without being able to step off onto a limb...carry said device and practice enough to be able to do it safe and clean. Once in a rare while you may discover something partway up that makes you decide to go back down right now! Bees come to mind. If you need help working that out, holler.
 
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Tom Dunlap

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Burnham,

Thanks for taking the time to illustrate the Frog Walker. That takes a lot of time.

There's one difference that I use but I don't have a clear picture.

The lanyard that attaches the handled ascender in your setup is attached to the bottom of the ascender. In mine I clip a locking biner around the rope and then through the holes in the upper part of the ascender. This traps the rope and adds just a bit more security.

The downside of clipping above is that the cords aren't quite as fair. Getting my setup fine tuned has taken some work but I like the little extra security.

Nice idea to use the CMI double handled.

After teaching several SRT classes I've gotten reports about the CMI double. The thumb tab that limits the cam movement can get caught which allows the cam to open. The rope can then fall off the rope. The guys who had this happen immediately trimmed off the tab that sticks out from the ascender frame. Without the tab it is just a little by awkward to unclip but worth the extra effort to have more security.
 

Burnham

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Burnham,

Thanks for taking the time to illustrate the Frog Walker. That takes a lot of time.

There's one difference that I use but I don't have a clear picture.

The lanyard that attaches the handled ascender in your setup is attached to the bottom of the ascender. In mine I clip a locking biner around the rope and then through the holes in the upper part of the ascender. This traps the rope and adds just a bit more security.

The downside of clipping above is that the cords aren't quite as fair. Getting my setup fine tuned has taken some work but I like the little extra security.

Nice idea to use the CMI double handled.

After teaching several SRT classes I've gotten reports about the CMI double. The thumb tab that limits the cam movement can get caught which allows the cam to open. The rope can then fall off the rope. The guys who had this happen immediately trimmed off the tab that sticks out from the ascender frame. Without the tab it is just a little by awkward to unclip but worth the extra effort to have more security.

Good point about the cam release on the Expedition...I have no idea why CMI didn't use the same cam latch design as on their Ultracender...that one I like better, by quite a bit.
 

OTGBOSTON

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Burnham, the way it was explained to me is not only does the 'biner up top capture the line, there is also more "meat" to hold onto. Not that the lower hole will fail but the upper hole is double, FWIW. I'll post a pic b/c it also allows for a good spot for a friction hitch back up. My .02
 
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TreeRhino

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I. Fortunately, if I'm seeing things right looking at a catalog photo, the loops on the bridge of the Versatile are oriented correctly to allow the Croll to lay flat against your belly with the single screwlink as attachment. You need some sort of suspender to keep the Croll upright...
So attach to the bridge? Or the belt? Or both?
 
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Tom Dunlap

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Burnham,

I've never used the CMI with a footloop so I don't know how fair things would be up top after clipping through the double holes. On all of the other handled ascenders that I've used I like the way that the rope is kept just a bit more fair to the top of the cam. Your cowcatcher phrase makes sense too.

The tether from the biner that we're discussing to the harness can add a bit of a jumble at first. There are several routes to use for the tether. In the last couple of days I've been pondering one made with a shock cord inside. On the other hand, New England Tech Cord is so small that it fits into some places were webbing or other cordage would get balled up.

As our climbing systems get more complex it's important to keep them as simple as possible. Otherwise there are more things that could go wrong. Complexity requires a higher knowledge to understand, awareness to monitor and deeper pockets to buy.
 

Burnham

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Burnham, the way it was explained to me is not only does the 'biner up top capture the line, there is also more "meat" to hold onto. Not that the lower hole will fail but the upper hole is double, FWIW. I'll post a pic b/c it also allows for a good spot for a friction hitch back up. My .02
The upper and lower holes are in identical stock on the CMI, both the Ultracender and the Expedition. If you're using the Petzl Ascention, which is one of the worst ascenders ever built imo :), you are correct. Same with the Kong Double, it also has twice the stock at the top. Of course, we know that if we manage to load a toothed asender even a small portion of the level needed to cause a frame failure, the cam would have long before severed the rope. Worrying about frame failure, i.e. using the "meatier" hole, is pointless imo.

I can't see that there is a way to get a fair tether drop from the upper hole on the CMI two handed ascender using a biner for attachment. Look at my pics...there isn't room for a biner to lay downward if it's attached up top. It would set at nearly 90 degrees to the rope and you'd torque the ascender sideways badly loading it.

I'd like to see your pics, thanks. I'm still working on best practice for backup to my two handed ascender on double rope when footlocking.
 
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