SOLOIST TopRope Configuration - for review/comment
tradkelly
I'm looking for feedback - positive, negative, critical, constructive,
whatever - for some diagrams I am developing for Soloist operation.
I'd like to sound them off of you to see if they seem reasonable from
a general safety perspective. Obviously, solo climbing is not safe in
any way.
R.C and Dawn's FAQs have been useful in my understanding of a
(relatively) safe system for using the device consistent with the
manufacturer's intention. Would those who have some experience please
take a peek and comment as they feel appropriate?
I have not found any graphical illustrations of the proper use of any
solo climbing system anywhere, beyond those presented in the users'
manuals for the devices by Wren. I hope that this will be making the,
um, translation of your comments and instructions into a graphic
usable. I think better when I see a picture, sometimes.
http://www.geocities.com/tradkelly/pictures/soloist-toprope.jpg
(It's 125k, a little bigger than a normal full screen on most peoples'
browsers. There are lots of details, obviously, that need to be
covered.)
Does the diagram appear to illustrate the text-only commentary that
the group has replied with previously, for top-rope application of the
device in the manner intended?
I look forward to hearing your responses before producing a page for
open public consumption.
TIA.
Tradkelly
http://www.geocities.com/tradkelly
andy T.
<trad...@nospam.yahoo.com> wrote:
>Does the diagram appear to illustrate the text-only commentary that
>the group has replied with previously, for top-rope application of the
>device in the manner intended?
not knowing anything about the proper usage of the soloist device,
I'll comment that there's no way I'd be able to decipher your
hieroglyphics.
If you're intending to clean up the pictures and use normal fonts,
then maybe we're in buisness. Also- having normal <p> font will speed
up page loading by not having to load an image of the font. ( <p>
loads faster than <img> )
sorry that I don't have any comment on the usage of the Soloist
itself.
Andy T.
VikingBabe
> On Wed, 16 Oct 2002 02:42:02 GMT, tradkelly
> <trad...@nospam.yahoo.com> wrote:
>
>
>>Does the diagram appear to illustrate the text-only commentary that
>>the group has replied with previously, for top-rope application of the
>>device in the manner intended?
>>
>
> not knowing anything about the proper usage of the soloist device,
> I'll comment that there's no way I'd be able to decipher your
> hieroglyphics.
> If you're intending to clean up the pictures and use normal fonts,
> then maybe we're in buisness. Also- having normal <p> font will speed
> up page loading by not having to load an image of the font. ( <p>
> loads faster than <img> )
what a whiner! sheeeeeeeeesh. the graphics and written text were
fully legible to me tradkelly, and i don't even work for a doctor.
andy, maybe you should upgrade your 14.4 modem and 286, big spender.
>
> sorry that I don't have any comment on the usage of the Soloist
> itself.
> Andy T.
>
typical rec.climbing.
jenn (who also knows nothing about soloists, but am interested in
learning! so please shut it-some of us want to learn.)
Scott Grimes
> I'm looking for feedback - positive, negative, critical, constructive,
> whatever - for some diagrams I am developing for Soloist operation.
Thanks for taking the time to share with use your ideas. I had no problem
reading it
I've used the gri-gri and ascender in a similar manner. Using a dynamic
rope can have you scraping the ground with your feet or butt if you fall
early on in the climb. I'm not suggesting that you use a static line but do
consider the rope's elongation when deciding which rope to use.
I would stick with the cordolette arrangement and not use the sliding "X"
unless you take steps to limit extension of the sliding "X". This would be
an overhand knot that helps limit the amount of shock-loading the rest of
the anchor will have to deal with if one of the pieces should fail. Also, a
cordolette is not a multi directional anchor steps should be taken to
prevent the cordolette from being unevenly loaded during a fall. I've done
this by placing a directional anchor as close to the double-opposed 'biners
to prevent them from shifting across the rock.
I can't comment on detail number 5 because I've never used the Soloist but,
the use of the back-up figure 8 'fraidy knots is a great idea.
My only other concern is the area of transition. When you are pulling of
the lip of the cliff on to the ledge were the anchor is located, going from
on belay to off. Remembering the cordolette is not a multi-directional
anchor care must be taken when procceding to your walk-off that the anchor
system is still properly set.
Please exercise great caution.
Good Luck
Cheers,
SMG
Cartman
> Hey Everyone.
> I'm looking for feedback - positive, negative, critical, constructive,
> whatever - for some diagrams I am developing for Soloist operation.
Lose the background. The cliff looks more like another rope than the rock.
Why can't I do a single rope rappel?
Other than that I'm ready to go do some solo toproping.
loosaboy
The sketch made sense to me.
Question: when you weight the end of the rope at the base to allow for self
feeding of rope through the device (i.e. Soloist), does this make it a pain
to tie back up knots? I envision having to lift and hold that extra weight
when tying backups. Any suggestions?
PIECE
loosaboy
tradkelly
I'll work on that. Other modifications will be in order after I get
more commentary.
>Why can't I do a single rope rappel?
I assume you're talking about (step 6) in the diagram - because in
(step 1) you did do a single rope rappel. I would say that after you
have climbed the route (or lapped it however many times you wanted
to), you would want to take your rope home with you. Your options
here would be:
1. Double rope rap, pull the rope from the base.
2. Pull up the rope from the top, walk off.
3. Single rope rap, walk up to the anchors, and then choose either
method 1, 2, or 3. This is the least efficient of the choices, and
could lead to an endless loop of rappelling.
Am I reading your question correctly?
>Other than that I'm ready to go do some solo toproping.
This is not the only method - I've had a couple of other suggestions
on equally (un)safe setups and other methods and tricks that I will
think about, and possibly add to the diagram(s).
Thank you for your time!
tradkelly
trad...@nospam.yahoo.com
http://www.geocities.com/tradkelly
tradkelly
>feeding of rope through the device (i.e. Soloist), does this make it a pain
>to tie back up knots? I envision having to lift and hold that extra weight
>when tying backups. Any suggestions?
It could, on longer pitches, particularly if the bag weighed more than
a pair of tennis shoes. Also, it roughs up the bag a bit. I didn't
find the weight too much to deal with on half a rope on an 85deg slab,
with just my rope bag with hiking boots in it. Might be different on
more difficult terrain, though!
I've had a couple of other suggestions that I will integrate into the
next revision of the drawing - using a water bottle, clipping it to
your last back-up knot, and after tying a new back-up knot pulling up
the previous one, clipping the water bottle to the new one, and
untying the old knot.
It's still looking more like I'd have to hang weight on the rope to do
some of these things, though. I'm not really looking for that.
Not using the backpack as a weight is an option, but for awhile
starting the climb you have to manually feed the device.
Thanks!
tradkelly
trad...@nospam.yahoo.com
http://www.geocities.com/tradkelly
Bool
> I'm looking for feedback - positive, negative, critical, constructive,
> whatever - for some diagrams I am developing for Soloist operation.
Kelly, this is almost the exact setup I use to set routes at my local
gym. Granted we normally climb up with aiders but when we test the
last move set we climb with this configuration... on static ropes.
So, I think it looks pretty good... the weight at the bottom will
defiantly help with autofeeding... that is my largest problem with the
setup when I use it.
I've also heard of people attaching a second rope next to the primary
one you are climbing on. On that second rope about ever 10 feet or so
is an eight on a bite. Then you clip your harness into that second
rope as you climb... I've never tried this but I could see it adding
more security... if it doesn't create to much of a tangle.
Or, you could just get an autobelay.
tradkelly
>last move set we climb with this configuration... on static ropes.
Query, then. It would probably be appropriate to TR on statics,
because you're never going to be having rope out, or having slack in
the system (more than what's immediately above your device, anyway)?
Never, ever, on lead, for physics reasons, but could there be
drawbacks (other than possible rope stiffness and possibly poorer
feeding through the device) to using static for this setup?
>I've also heard of people attaching a second rope next to the primary
>one you are climbing on. On that second rope about ever 10 feet or so
>is an eight on a bite. Then you clip your harness into that second
>rope as you climb... I've never tried this but I could see it adding
>more security... if it doesn't create to much of a tangle.
I've had this suggestion a couple of times as well. I'll give it a
try the next warm afternoon that I can scoot out of work early, and
see how I think it goes. I was thinking of posting a diagram of that
system as well, after I've tried it.
Thank you for the input. :)
tradkelly
trad...@nospam.yahoo.com
http://www.geocities.com/tradkelly
tradkelly
>rope can have you scraping the ground with your feet or butt if you fall
>early on in the climb. I'm not suggesting that you use a static line but do
>consider the rope's elongation when deciding which rope to use.
Would you see problems with using a static rope for a strictly top
rope scenario like this one, with a fixed top anchor? I saw that
possibility as well; extra backup knots nearer the bottom of the
climb, and not falling, should help this. I can't see another manner
with a dynamic rope, though. Proper selection of rope is a
consideration I'll think about.
>I would stick with the cordolette arrangement and not use the sliding "X"
>unless you take steps to limit extension of the sliding "X". This would be
>an overhand knot that helps limit the amount of shock-loading the rest of
>the anchor will have to deal with if one of the pieces should fail. Also, a
>cordolette is not a multi directional anchor steps should be taken to
>prevent the cordolette from being unevenly loaded during a fall. I've done
>this by placing a directional anchor as close to the double-opposed 'biners
>to prevent them from shifting across the rock.
The idea makes sense, as do the comments of shock-loading the anchors
on an X configuration. I think I'll leave anchor techniques to
another person, and change my comments to 'bombproof multidirectional,
and backed up again' or something like that.
>My only other concern is the area of transition.
Yeah, it's not representative of the climb I'm lapping right now, but
there are an endless number of possibilities. I'd hope that anyone
getting into soloing would know their rope, anchor, and self-rescue
skills well enough to figure out how to remain safe. Hope that I do.
:)
>Please exercise great caution.
>Good Luck
>Cheers,
>SMG
Thanks, Scott - I shall try. Cheers!
tradkelly
trad...@nospam.yahoo.com
http://www.geocities.com/tradkelly
Scott Grimes
> Would you see problems with using a static rope for a strictly top
> rope scenario like this one, with a fixed top anchor?
It would depend on how well the rope is feeding through the soloist. Let
say you have 2 feet of slack in the rope when you fall and the rope is a
static line, ouch.
But then again I am not familiar with the Wren Soloist. Mayhap it does not
have a problem with the rope feeding through it. Using the Gri-Gri as I
have, you have to stop and pull up the slack in the line and if I fell on a
static line before or while doing this it might hurt a little. The ropes
that gyms routinely use might be a candidate for what you're doing or just
your standard dynamic 11 mm fatty.
> and not falling, should help this.
when you perfect the not falling thing let me know.
> The idea makes sense, as do the comments of shock-loading the anchors
> on an X configuration. I think I'll leave anchor techniques to
> another person, and change my comments to 'bombproof multidirectional,
> and backed up again' or something like that.
Sliding X: equalizing anchor and multi directional but subject to shock
loading is an element fails
Cordollete: equalizing anchor but not multi directional but will not shock
load other components if one fails.
And, as Dawn pointed out in another post:
http://www.tradgirl.comclimbing_faq/advanced.htm#trsolo
Cheers,
SMG
andy T.
<I_dont_like...@all.com> wrote:
>what a whiner! sheeeeeeeeesh. the graphics and written text were
>fully legible to me tradkelly, and i don't even work for a doctor.
They weren't to me. That's the point.
I'm using Internut Exploder 6.0.26xxx which takes the pic ("a little
bigger than...full screen") and shrinks it to fit the screen by
default. This is only an issue when people post pictures of
handwriting. The text gets distorted in the process, and becomes
illegible. Faking the image via separate smaller pics and some
creative table cells alleviates the problem.
>andy, maybe you should upgrade your 14.4 modem and 286, big spender.
I think you're referring to my mention of the way to accelerate the dl
time. He mentioned it was 125k as if he was worried. Maybe he wasn't
worried at all. But my suggestion would speed up the dl, and that is
the biggest worry (next to content) in web development.
I'm running a 56k and a PIII 450, since you asked.
>typical rec.climbing.
>
>jenn (who also knows nothing about soloists, but am interested in
>learning! so please shut it-some of us want to learn.)
I'd say that your flame (which is equally if not more whiney than my
post) is more typical of r.c than anything I have to offer. He asked
for comments, that's what I had.
Damn, back to lurking for me.
biotch.
tradkelly
>bigger than...full screen") and shrinks it to fit the screen by
>default.
When you put your cursor on the image for a second or two, in the
upper left hand corner you have options to copy, save, print, and
something else. In the lower right hand corner there is a box with
arrows pointing out of the four corners - if you click that box, the
picture will expand to full size. Or, for offline viewing and review,
one could copy the image to a photo editor, or save it and do the
same.
>This is only an issue when people post pictures of
>handwriting. The text gets distorted in the process, and becomes
>illegible. Faking the image via separate smaller pics and some
>creative table cells alleviates the problem.
Yes, but it's way slower than sketching something out and then
'coding' in the correct page configuration, testing, and publishing
it. I was just looking (at this stage) for some feedback - and I've
had lots of excellent suggestions and discussions about it. Thank you
for yours. If it eventually goes onto an html page, I'll consider
doing what you're suggesting.
This is just a first draft based on some limited experience. The
finals should be much more clear in several regards.
cheers!
tradkelly
>say you have 2 feet of slack in the rope when you fall and the rope is a
>static line, ouch.
Okay, I'm convinced by thinking it through that statics are not the
way to go. Falling in a soloist failure would put you all the way
down to the most recent backup knot, up to 10-20 feet down. That
wouldn't be good.
We'll reserve the statics for jugging, hauling, and rappeling.
Thank you again!
>when you perfect the not falling thing let me know.
I'm working on that, right after the weather machine is finished. :)
>Sliding X: equalizing anchor and multi directional but subject to shock
>loading is an element fails
>
>Cordollete: equalizing anchor but not multi directional but will not shock
>load other components if one fails.
I'm thinking of deleting the anchor details and just saying 'build a
good anchor.' With a large disclaimer about the reader knowing what
one of those is, too. 'How to build a better anchor' should be (and
I'm sure is) another thread.
Cheers!
Tumblemark
It's been pointed out here several times that static ropes are still
stretchy. In the worst case (highest FF) they produce about twice the
impact force as dynamics. They should be fine for falls of factor one
or less (in the sense that any fall on any rope is "fine"). It appears
to me that you will never exceed a FF 1 fall, worst case (fall from
the anchors). I'd think that for your application you should give them
consideration. The reason is that they stretch about 1/5 as much as a
dynamic of comparable diameter. That means less liklihood of hitting
something, due to rope stretch. They tend to be stiffer, however;
would that affect your contraption?
tradkelly
>would that affect your contraption?
I think that it would, based on the statics that I've handled in the
past. The rope has to continuously wrap through and move through the
device, and in TR it makes a nearly complete loop - see the soloist
instruction manual, page 5, figure 3.
http://www.wrenindustries.com/soloistmanual.pdf
The right-hand image shows the typical configuration while TRing -
almost locked up, actually.
I do not have a static onhand to play with through the device, but
I'll borrow a friend's next time I'm up in Boulder, perhaps, and see
how I think it will go. I'm sure that it wouldn't be the better piece
of gear for leading on the soloist, but if flexy enough it might have
a place in some setups during TR. Probably not mine. YMMV.
I think that I've thought about, considered, and researched enough
such that for my own use I shan't use the static for the application.
The dynamic seems not to be a weak link in the relatively unsafe
system as it goes right now anyway.
Thank you.
N42461
>The dynamic seems not to be a weak link in the relatively unsafe
>system as it goes right now anyway.
Relatively unsafe? Compared to a grape smeared belayer? I dunno....
Couple of points:
In the diagram, you might want to hang the bag/balast. Takes some of the
stretch out of the rope as well.
Statics work good with an ascender rig. In a Soloist/Gri Gri set up they suck
bad if the rope is even a bit stiff..
Static is cool on a route you are going to dog to death. That way you dont blow
out the sheath on the knot that's rubbing on the rock by the fancy 3x anchor.
If you think you won't introduce any slack into a solo TR system you are on the
pipe. Self feeding is an ideal, not the rule, and many routes wander (though
not all are lost) and will require redirects. One of those blow out and you
have instant slack.
On a route that's tough off the deck, just yank yourself up a few feet 'till
you are out of ankle snapping range and get on with the day. It's bad style,
but better style than dangling in the wind for 3 months 'till elk hunters find
your corpse.
There are routes you won't want to try w/o a good belayer.
You can also climb 2000 feet in an afternoon from a single tre.....um...anchor,
so there are advantages too.
Have Fun
nathan sweet
tradkelly
Hmm, I'll have to explore how much some directionals might be required
in some TR problems relatively local here; I only have (literally) one
problem within about 45 minutes that's suitable, but I see your points
with respect to that.
Good point on static with a more resiliant sheath, despite other notes
I've made about them to myself. I'm planning on sticking to nice,
easy, mellow stuff that I'd be happy doing with some of my
less-experienced pardners rather than pushing the envelope, at least
for the time being. I've seen the 'protect the rope with xxx' comment
here too. Situation dependent, and I'll take it into thought.
And, aspiring to start some more-than-A0-cuz-I-can't-do-the-move
aiding as well, the style questions are less important to me on
practice or fun days. Performance days, like a trip to Indian Creek,
are always with a human on the rope to administer first aid when I
peel. :)
Nathan, thank you for taking the time. The more I hear, the more I'll
assimilate. I'll try and pass on the favour.
cheers,
kelly (soloing now - don't listen to me, I've got a death wish)
Jim Rock
> "tradkelly" wrote:
>
My only other concern is the area of transition. When you are pulling
of
> the lip of the cliff on to the ledge were the anchor is located, going from
yeah, I'm with you on that, scott. if you fell when climbing over the
lip, you'd hit the system with a lead fall, changing the dynamics
completely.
why not leave the belay back from the top and use a rope protector or,
hell, a t-shirt to save the rope over the lip? this is easier to set
up, removes the possibility of a dynamic fall, and allows for a much
safer abseil.
jim
Christian :?
> >... when we test the
> >last move set we climb with this configuration... on static ropes.
>
> Query, then. It would probably be appropriate to TR on statics,
> because you're never going to be having rope out, or having slack in
> the system (more than what's immediately above your device, anyway)?
> Never, ever, on lead, for physics reasons, but could there be
> drawbacks (other than possible rope stiffness and possibly poorer
> feeding through the device) to using static for this setup?
> tradkelly
> trad...@nospam.yahoo.com
> http://www.geocities.com/tradkelly
See comment above, and in archives, that if you think you can have a
slack free solo tr setup, you are very mistaken. Solo tr on static is
not a great idea...
You are heading up, there is a little kink in the auto feed, say a
foot, you fall... take a look at how that force is dissipated. (Many
things to factor into this such as slipping of the device. There is a
great study out there somewhere addressing this.)
This is also important to remember when tr soloing on a dynamic. As
you get closer to the top anchor, the rope is becoming more static
(not really precise, but it's overall ability to absorb force is
less). Falls near the top anchor will generate more force to the
body.
Also ask yourself about those nifty fig 8's... If you had to rely on
them, would you want to be on a static?
As to the other thread about the shunt, I am positive that I have read
an account of this device failing in solo-tr mode. I don't remember
where, but wanted to at least mention that. I didn't realize that
Petzel recommended it for solo tr, I thought that the only device they
did reccommend was the basic (which I think sux too, but for different
reasons).
Cheers,
Christian :?)
Tumblemark
> ... would you want to be on a static?
Keep in mind that a static imparts only about twice the impact force
as a dynamic in the worst case fall, but stretches only about
one-fifth as much. This means that a static should be OK for falls
with FF<=1. This is what the solo contraption is going to see, because
you never get above your anchor. With the Fig-8 backup knots, the
worst case fall will be from the anchors; the easiest would be at the
botton onto the first backup knot. The higher impact force of a static
doesn't seem to rule them out, no?
OTOH, a fall near the bottom on a dynamic could mean a grounder, and
anywhere up the climb would result in five times more drop due to
stretch than if a static were used. A dynamic stretches maybe 20-40%,
depending; imagine 30 xtra feet of drop on 100 feet of rope. You can
see this benefit in action at a gym that uses statics for belay (and
where max FF<1 also).
A static is also more durable as a result of having lower stretch:
less sawing abrasion on rock during falls.
The decision as to whether it is preferable to experience falls having
more impact force (but still UIAA safe amounts) or five times as much
rope stretch is one question the solo climber must address.
Hardman Knott
>
> Keep in mind that a static imparts only about twice the impact force
> as a dynamic in the worst case fall, but stretches only about
> one-fifth as much. This means that a static should be OK for falls
> with FF<=1. This is what the solo contraption is going to see, because
> you never get above your anchor.
I would caution against implying that factor 1 falls are "OK"
while top-rope soloing!
I experimented using a GriGri as a top-rope solo belay device.
Despite what's been reported here to the contrary,
there's no way to get this to self-feed without adding TONS
of rope drag. (I'm guessing at least 20 to 30 lbs)
This might be fine while running laps up some 5.6 jug-haul,
but is utterly and completely unacceptable when trying
something at your limit.
So for a real-world example, let's say you are trying a long,
sustained crux sequence with no place to pause to manually take in slack.
You are 7-10 feet below the anchor, and you fall with a few feet
of slack out; using a (relatively new) dynamic rope.
Guess what?
This is quite a shock to the body -- it makes for some very
gut-wrenching falls! My back was quite sore after just a few
of these. They were estimated to be roughly FF.7
The equalized fig-8 knot at the anchor was damn near
impossible to untie. (I later switched to a bowline-on-a-bight)
Now picture the above scenario using a static line.
Any volunteers?
Hardman Knott
ChrisFerro
safe. I don't use that second, backup rope that you have in your diagram, I
just tie into the rope below the soloist at various intervals to prevent
hitting the ground. You really can't die unless the anchor fails, the rope
fails, or your harness fails. It's probably the safest way to climb - even
safer than having a friend belay you because a friend can always make a mistake
and drop you. One key is that you must use a chest harness, though (or at
least a runner that functions as one).
tradkelly
I used the method you describe my first time out, and in the beta
version of the drawing on my website. I had comments about trying the
other manner, for having another rope available to escape onto, for
reducing some drag, and stuff like that, so I gave it a try. I'm not
yet convinced that one or the other methods work 'best' in all
circumstances, but for the stuff I'm TRing right now the double-strand
method seems to work best for me.
Both are feasible and probably have their place.
Tumblemark
> while top-rope soloing!
> I experimented using a GriGri as a top-rope solo belay device.
> Now picture the above scenario using a static line.
Your point is well-taken, but I reach different conclusions. And I
didn't mean to say factor 1 falls are OK; that's equivalent to bungie
jumping with a climbing rope: you go first! However, a fall with a few
feet of slack when ten feet below the anchors results in a FF of about
.2, not .7. FF .2 falls are fairly common, especially for sport
climbers. True enough, a fall near the anchors would be the worst (a
fall if you had just clipped your daisy chain to the anchors would be
the absolute worst). Conclusion: don't set up a self-belay with a crux
at the anchors.
I also hear you saying not to use a GriGri for self-belay. That's
certainly wise, as your Darwinian example illustrates! Conclusion:
only consider devices intended for self-belay.
But, as I do the numbers for your scenario, taking a factor .2 fall on
static rope would only add about 40% to the impact force felt by the
climber (and anchor)--still less than a FF of .3 (which isn't so bad
or unusual). Conclusion: don't rule out static ropes in this
application simply because of impact forces, they may have offsetting
benefits.
jes...@westnojunkfailure.net
>> > ... It would probably be appropriate to TR on statics,
>> ... would you want to be on a static?
> The decision as to whether it is preferable to experience falls having
> more impact force (but still UIAA safe amounts) or five times as much
> rope stretch is one question the solo climber must address.
Another thought, what about a static rope with a yates screamer? It
wouldn't stop the OOF factor, but if one did get into a UIAA fall range it
would take the edge off, make the system more dynamic.
http://www.yatesgear.com/climbing/screamer/index.htm
I'm new at this so consider that suggestion a good way to kill yourself.
take care,
Jester
P.S. i am very concious of static Vs. Dynamic, having worked billboard
painting protected with static toprope & watching the other painter let
5-10 feet of slack build up... I told him he'd likely be paralyzed just
waering a sit harness, he didnt care so i shut up and cringed whenever he
did it.
--
***************************************************************************
If you see a mad professor in a minibus, just smile. --James Bond
http://westfailure.org
***************************************************************************
Dave Buchanan
> Your point is well-taken, but I reach different conclusions. And I
> didn't mean to say factor 1 falls are OK; that's equivalent to bungie
> jumping with a climbing rope: you go first! However, a fall with a few
> feet of slack when ten feet below the anchors results in a FF of about
> .2, not .7. FF .2 falls are fairly common, especially for sport
> climbers. True enough, a fall near the anchors would be the worst (a
> fall if you had just clipped your daisy chain to the anchors would be
> the absolute worst). Conclusion: don't set up a self-belay with a crux
> at the anchors.
While my numbers may not have been the most accurate,
.7 was given as a practical worst-case example.
Generally they would be in the .2-.5 range.
The main point is that regardless of the numbers,
these were quite unpleasant falls.
I can't imagine willingly increasing the forces.
(by using a static rope with a device which doesn't feed)
> I also hear you saying not to use a GriGri for self-belay. That's
> certainly wise, as your Darwinian example illustrates! Conclusion:
> only consider devices intended for self-belay.
I should clarify that the GriGri can certainly be used
by tying enough weight on the rope to force it to feed.
Perfectly acceptable when climbing something easy;
in fact, there might be some benifit similar to climbing
with ankle weights, ect.
> But, as I do the numbers for your scenario, taking a factor .2 fall on
> static rope would only add about 40% to the impact force felt by the
> climber (and anchor)--still less than a FF of .3 (which isn't so bad
> or unusual).
I am confused by your earlier statement that a static
would double the forces...
> Conclusion: don't rule out static ropes in this
> application simply because of impact forces, they may have offsetting
> benefits.
If you use a device such as The Ushba Basic Ascender,
or the Petzl Mini-Traxion -- both of which feed infinately
better than the GriGri -- you would generally never fall
more than a few inches at most.
If I could find a small diameter static that was reasonably
priced, I agree about the other benifits. (mainly abrasion
and sharp edges)
Hardman Knott
Tumblemark
> would double the forces...
It depends on the ropes, of course, but if you figure that the ratio
of the modulus of statics to dynamics is about 4:1 to 6:1 (which would
also be the 1/ratio of the stretch), the the ratio of the impact force
in hard falls will be square root of that, or about 2:1 to 2.5:1 .
Precision math isn't important--the static rope impact force would be
"about double" and the stretch would be "about one-fifth".
If impact force were the predominant consideration, that would suggest
using a half-rope as a single. Much softer falls but much longer
stretch. Probably no takers on this approach.
> If I could find a small diameter static that was reasonably
> priced, I agree about the other benifits. (mainly abrasion
> and sharp edges)
Possibly. 8 or 9 mm static line can be had from caver and rescue
supply dealers. It costs about half of what a dynamic does. Doesn't
come in cool colors, though. And you'd probably want to stay well away
from the 8 mm unless you knew that your belay contraption was designed
for dental floss.