Question MRS DdRT vs. SRS SRT

theatertech87 said:
In SRS you and the device move on the rope, whereas in MRS you and the device move with the rope.

SRS is much much more agreeable to multiple redirects, and not building of extra friction on the rope without extra gear (think twin shiv pulleys and slings, vs natural crotches)

SRS is easier to protect from rope damage due to sharp edges (think tying in over the ridge of a roof for storm damaged trees. A rope sleeve protector can be used on srs practically, but can't be used reliably on MRS)

SRS requires the same amount of cordage as MRS if retrieval is taken into account, however in SRS only ~half the length has to be rated for life support

MRS is the only rope system currently usable for rigging loads. There are ways of using SRS like rock climbers who rappel with a figure 8, however they require someone riding with the rigged piece to control it, or someone running the tail end in the drop zone.

SRS is the only rigging method usable for speedlines (though you can add a MRS control line).

MRS is mostly confined to use in the arborist industry, as most other industries, roofing, rope access, caving, rescue predominantly use SRS for life support and MRS for rescue

Most (if not all) SRS gear can be used both SRS and MRS, whereas MRS gear usually requires some device to add additional friction to the system (munter below the hitch, wrench above the hitch, or a purpose built device with increased friciton rope runner/petzl id/etc)

You can "easily" set 2 climbing sytems from the ground with 1 rope in SRS using less rope than you can with MRS. Shared anchor point only needs 1 retrieval line and 2 rated parts of rope for SRS vs 4 rated parts of rope for MRS. Though this may be more of a concern for the european folks and their 2 climbing system requirement. You can see an example of the 2 SRS systems in the video here

That's most of the ones I can think of there's some difference when it comes to rescue, but most of those are more setup dependent rather than climbing style differences and don't translate to text very well
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"In SRS you and the device move on the rope, whereas in MRS you and the device move with the rope."
So I think what you are saying is that in SRS the rope is not moving and in MRS the rope is moving, right?
I know that seems obvious but this I believe is the first mention, correct? It is supposedly the sole characteristic that defines these techniques. I have pointed in the past that the "Rope Master" setup to help people practice "rope walking" is indeed a moving, single and most often static rope.
 
Richard Mumford-yoyoman said:
Can you expand on this
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Sure Richard -

To me SRS is the perfect system, EXCEPT for all the #%*”&# fiddling with the tending: hook it up to climb; don’t forget to unhook it when you stop climbing; get it adjusted short as possible, for the least sit back, and you have to contort your self like a shrimp to get it hooked up again.

For a couple of years I was wearing a chest harness JUST for my SRS tending, but am now, thankfully, wearing a saddle specific top harness that does the job.

I think that avoiding device or hitch tending is one of the main reasons to choose MRS for beginners - it’s a study in its own right.
 
Someone else can do a better job explaining this than I can, but in the case of parallel core ropes, the tight bend radius can put uneven strain on the core, sort of like creating a tension/compression situation like a tree limb. The outside if the bend is seeing more stress than the inside of the bend. That's the theory I think.
 
Richard Mumford-yoyoman said:
Did I lie? Anyway, on the "17th real response" there will be a free Footie from Climbing Innovations LLC.
At this point I'm counting 10 real responses, differences between the systems. Of course we can always debate that as what would any thread be without some spirited debate. Maybe I'll have to give away more than 1 Footie. I would do a SAKA but I'm out of stock.
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Gosh darnit.....I guess I didn't really contribute anything g pertinent
 
Need a new Footie bad mines on the fritts and now it's getting hard to come up with stuff.
when climbing srs using a hitch based multicender, you must use something else like a RW or figure 8, fate revolver to supplement the friction on descent.
 
Richard Mumford-yoyoman said:
Did I lie? Anyway, on the "17th real response" there will be a free Footie from Climbing Innovations LLC.
At this point I'm counting 10 real responses, differences between the systems. Of course we can always debate that as what would any thread be without some spirited debate. Maybe I'll have to give away more than 1 Footie. I would do a SAKA but I'm out of stock.
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My bad rich I know your not a liar. I just thought it was some trick or joke. Wish I didn't say that. I'm an idiot. Please save me a hh bc I almost have enough $to buy one.
 
Richard Mumford-yoyoman said:
"In SRS you and the device move on the rope, whereas in MRS you and the device move with the rope."
So I think what you are saying is that in SRS the rope is not moving and in MRS the rope is moving, right?
I know that seems obvious but this I believe is the first mention, correct? It is supposedly the sole characteristic that defines these techniques. I have pointed in the past that the "Rope Master" setup to help people practice "rope walking" is indeed a moving, single and most often static rope.
Click to expand...
Yes, the rope moves vs does not move is the general concept. In my head it makes more sense to look at it from a progress capture device view point where MRS the rope moves with through (the termication end) and the rope moves through device AND is attached to the device, where SRS the rope only moves through the device
 
pete3d said:
Sure Richard -

To me SRS is the perfect system, EXCEPT for all the #%*”&# fiddling with the tending: hook it up to climb; don’t forget to unhook it when you stop climbing; get it adjusted short as possible, for the least sit back, and you have to contort your self like a shrimp to get it hooked up again.

For a couple of years I was wearing a chest harness JUST for my SRS tending, but am now, thankfully, wearing a saddle specific top harness that does the job.

I think that avoiding device or hitch tending is one of the main reasons to choose MRS for beginners - it’s a study in its own right.
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Honestly I think that's more a limitation of the harness choice than a limit of SRS vs MRS. A ventral attachment on a harness (think rock climbing style with the loop at the waist) kee[s the attachment to the climbing system very fixed and the only slop introduced to the system from a sitback standpoint is however long the attachment carabiner is. That kind of attachment is great for up/down, but not so great for a work standpoint. No different than the difference between a rope bridge vs the old style 4 d ring harnesses
 
I'll take a stab at the doubled over but not moving rope too, though it's honestly not something I'm terribly familiar with.

Has spefically designed for it gear that is unsuitable for use in a srs/mrs system. Petzl shunt and dual cam hand ascenders come to mind; they specifically state in the manual they are not to be used on a singe part of line.

Can utilize multiple anchor points simaltaneously. Within the limitations of the spread of the rope legs getting to be too wide to be utilized with which ever climbing device is used.

You are generally limited in your decent vs ascent options requiring a change over of system once you reach the tie in point. Besides the TRT technique that there is very little information still floating around about, ascent and descent are not easily possible on the same device. Ex. Ascend footlocking with a prussic, but need to ues a figure 8 to decend.

Can be setup with a chocking anchor such that you can cut either leg of line and not fall out of the tree (girth hitch capturing both legs of line) though it requires additional rope/cordage for retrieval, whereas MRS/SRS would require am additional system to be employed for this redundancy.

2 legs of rope makes foot locking easier (more rope to grip with your boots vs mrs/srs), 2 legs of rope makes dual foot ascenders possible instead of needing a knee ascender. however tending slack below the foot ascender can be more cumbersome and a smooth rope walking ascent may not be possible without extensive practice

Back to MRS vs SRS

SRS doesn't require you to return the end of the rope to yourself when advancing (think captains hook). Where as MRS does

MRS has 2 attachments to the climber, the end of the rope as well as where the friction devices attaches to the rope. SRS has only the friction device attachment. This is important as it allows us to split those attachments into 2 seperate locations on our harness giving us the all important side d rings for lanyards, which allows for closer work positioning that a single attachment on a rope bridge for example

SRS or doubled rope requires the motive force for raising the climber to be entirely provided by the climber, where with MRS a ground hand can pull on the tail of the rope to "assist" the climber.
 
Tom Dunlap said:
Ooops...need to clarify

SRS=Stationary Rope System=formally known as Single Rope Technique. Rope doesn't move, climber moves on rope.

Doubled Rope=DdRT=traditional system for treeworkers from early years of twentieth century to aughts of 21st century.
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I think he meant a stationary doubled rope. Dang old terminology
 
We are getting a pretty good list and it has helped me understand the general mindset and some good learning and conversation for a weekend.
Let me add one I don't think was mentioned although elongation gets close.
In a Doubled Moving rope and even in a doubled non-moving rope, the load bearing capacity is nearly doubled, depending on the bend at the support point.
Also, even if the load bearing capacity is increased the vulnerability is still one line. With SRS there may be greater vulnerability do to the travel between the climber and the anchor. Base anchor and groundmen, base anchor back side of the tree hidden by vines, other climbers contacting your line, rigging lines burning thru your horizontal line for all the cool redirects that were done.
 
Saying Mrs. DDirt with a stutter has become a thing since the need to distinguish SRT from it occurred.:)

Or invent the new word Sechnique. :)
 
In a more earnest answer, the earlier post about tip forces bark roughness tightens of crotch becomes an equalizer, not distinct to either system - in DRT it grinds your rope, impedes your ascent and determines how much load your hitch sees, in SRT it determines the basal rope leg loading - exact same math/physics.
 
I think some very good points were made. Please feel free to discuss it further and let me know if you would like a correction to this PDF.
All are very valuable points. What I was looking for is the concept of tending which was mentioned. I think everyone knows this and to that point I want to add a couple of thoughts.
When climbing MRS/DdRT the climbing device will self tend AND very importantly self configure or remain properly oriented. When ascending SRT the device must be tended and importantly, maintained in proper orientation. Slop or slack in the system must be controlled. For example when walking up the rope there is likely zero load on the bridge or anchor attachment to the climber. While ascending the rope, the climbing device is completely passive but must be manually or consciously maintained in a 'ready' position. When a climber transitions from a MRS special attention should be, and I think is made, to this fact. It is not enough to just say, "put on a chest harness so you don't have to lift your ascender". The device must remain clear and functional. Tending straps or even the chest harness should not be allowed to contact the ascender. Just like working in a shop, loose clothing etc should not be allowed to impede the performance of a the device. Every device responds differently to these factors, some are more vulnerable than others but that does not make them unsafe, they just need to be understood and operated with that in mind.
Lastly, IMO the most defining characteristic of the two main techniques we use is that of the anchors. SRT has one anchor that is out of the direct control of the climber and supporting points elsewhere. MRS, both anchors are in direct control of the climber with a supporting point or points elsewhere in the tree.
 

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