SRT's

Re: SRT\'s

Pretty much the same idea, I had a set made and I bought a set from Greg.

Now that I'm thinking of it...

I made up one set with the CMI ultrascender, they work great, still looking for the ideal backup for it.

I also have a pair of ISC ascenders that I "made" the bars it using a PVC shim like Nick did all those posts ago http://tinyurl.com/38qk2p <- there are some pics in this old thread

How did the ISC's work for you Nick?

My understanding of the system is that the CMI's work better because, with the single top hole, you can easily get the rope set in the lower ascender and still use a foot strap for the lower that runs through the top hole.

Somebody also told me that the ISC ascenders were of the appropriate ANSI rating, as the CMI's are not. I didn't check this for myself and have continued to backup my system with a microscender...

What if, work with me here, I used the ISC as the upper (just the handle bars) and the CMI as the lower set up with a foot strap.

My problem with using the ISC as the lower would be getting the rope into the cam. Nick came up with a soulution by making a loop of throwline and passing the foot strap through the loop. When I looked at the opening this created, I said "dogs in a bathtub!" No way those will go in there. So this brought Justin and I to say "why not just use a CMI lower and an ISC upper.

I slipped old bigshot tubing over the handles to achieve several things.
It:
Made the bars a little bigger and easier to hold on to
made the bars not so freaking cold in winter
made the bars not so slippery with muddy/wet/snowy boots


does any of this make sense? I'll try to get pics this week
 
Re: SRT\'s

[ QUOTE ]
Mar Bars is sort of a generic name. They are pictured in On Rope but I've never read the origin of the name.

[/ QUOTE ]

Charles Townsend first demonstrated a Mar Bar on a modified Jumar ascender in 1966 using what is now called the Inchworm method of climbing.
 
Re: SRT\'s

[ QUOTE ]
Thanks Bob!

What is the origin of the name "Mar Bar"? Did Mary or Marvin come up with the idea?

[/ QUOTE ]

The "Mar" comes from Jumar. For at least ten years, Jumars were the only ascenders that were suitable for attaching a crossbar. The CMI ascenders, with their large holes, are more suitable for a crossbar.
 
Re: SRT\'s

I agree with you however I have only seen one system that you can bail out with and it is a very bulking system to climb with. Most systems that I am aware of are no faster and acutally slower to switch from ascend mode to descend mode than mine. My system all you have to do us clip into a descender and unclip one biner to ditch the ascender system. This by no means will get you away from bees or something, but IMO that is one downside of climbing SRT. I maybe wrong here. Please show or tell me your solution to this problem. Thanks.
 
Re: SRT\'s

EMR,

Today I took a bit more time to look at the setup in post #79800. The rope that you're climbing on is a half inch rope, right? The Petzl ascender isn't rated for that diameter rope. What is the rating on the runner? Most of the smaller slings like that are over 22kn but some aren't.

These points are nit picks I know. The issue is consistency. It would be unlikely that either of these shortcomings would lead to an accident. But...either could be a basis for an OSHA or company safety policy violation. When there are tools that do meet standards available it is going to be hard to defend the use of ones that don't meet the standard.

Something to think about...or, shift to smaller diameter rope to solve one issue :)
 
Re: SRT\'s

The rope in the pict is not what I climb on. I currently use Poison Ivy, which is 11.7mm. I checked the specs on Petzl's site and they say that ascender takes up to 13mm which should cover 1\2" rope... correct? Your second concern was about the webbing. That webbing was purchased from Sherrill and in their catalog it says its rated at 27kN. I dont even use that anymore, now I use a shorter loop which is still rated at 25kN. I appreciate the feed back on my picts. One thing that I am very concerned with is making sure everything meets ANSI standards.

Kevin, are you not concerned about the increased friction on that hitch if you should have to decend rapidly? If you need to bail quickly you might burn though your cord. Is this a common practice in SRT? I personally would be scared to try it out.
 
Re: SRT\'s

I've been using a Pantin and a Jumar for ascending single or doubled. The jumar has a foot loop for my left foot and an adjustable tie-in to my center harness ring. When on doubled rope the knot is my backup for the Jumar; on single rope, which is most of the time, I have no backup on the ascender. I think I'll try a footlocking prusik above the ascender next time.

Once I'm up, I work on Ddrt.

So, I have a really stupid question. Why doesn't it work to use a single rope with a friction knot?
 
Re: SRT\'s

EMR,

Half inch rope is just sliiightly larger than 13mm depending on what conversion factor you use to go from MM to inches. A small nit to pic on small diameter arbo rope but not when a rope like True Blue is used.

Hitches on single ropes will work. But 100% of the climber's load is on the hitch instead of being shared like in DdRT. I spent a lot of time trying to find a hitch configuration that would work on SRT. They all lock down but many configurations don't release and slide too well. I think that there is more to be done on this topic. It seems like the solution will be if a ring or carabiner is incorporated into the wraps of the hitch. This would increase the diamter and add a bit of smoother grip.

RAther than having a back up above the handled ascender see about incorporating a back up at your harness. This will keep the backup seperated from anything that could potentially cause your primary attachment to fail.
 

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Re: SRT\'s

I use a distel on SRT just about on every tree I take down.
All depends on how many wraps you have on the hitch.
I don't have a friction problem and the descents are slow and controlled.
If you get going too fast it will generate more heat.
 
Re: SRT\'s

Wouldnt using a hitch for descent on a static line be just the same as using a prussik to descent on a doubled static line?
 
Re: SRT\'s

[ QUOTE ]
EMR,
RAther than having a back up above the handled ascender see about incorporating a back up at your harness. This will keep the backup seperated from anything that could potentially cause your primary attachment to fail.

[/ QUOTE ]

I just got a Microcender that I intend to use as a back up for my SRT right on my saddle. I noticed a few interesting things about it while reading the paperwork that came with it. On the body of the ascender it says it accepts ropes 9-13mm and 3/8-1/2" ropes. Since the way this works is different than the hand ascenders is it safe to use on 1/2" ropes? The second thing that I noticed is that the breaking strenght is only listed at 18kN or about 4000lb. This really supprised me since all catalogs sell this as an ascender or as an adjustment for a laynard. Should this tool be used in these applications since they dont meet ANSI standards?
 
Re: SRT\'s

Top,

A Prusik is likely to slide and not grab again. This was confirmed by some testing done in Australia a while ago. Choosing another hitch that's configured with spiraling wraps is a better choice. Another difference is the cross section of two ropes vrs. one. The round cross section seems to make it easier for the hitch to lock off when it's loaded.

EMR,

It's been years since I looked at the ratings on the MC. Hmmm...

This is an issue with almost all ascenders. Most ascenders are not rated for over 5k# but will slip on the rope at a much lower rating. So...what standard is used? During this revision of the Z133 this issue will be on the table. The discussion has already started.
 
Re: SRT\'s

So you are saying it would be safe to descend on a double static line if say a distel were used vs a standard prussik?

I disagree, I think descending on any static line with just a hitch (without a descender in conjunction), is just asking for catastrophe. Id be willing to bet if the hitch didnt grab right off the bat and you slid down the line a good distance that it wouldnt grab at all, much like a prussik in a FL situation.
IMO, it aint so much the type of hitch used but the use of it on a static line that is the problem.
 
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