It is currently Thu Apr 17, 2014 6:37 pm

All times are UTC + 2 hours




Post new topic Reply to topic  [ 37 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: natural anchors
PostPosted: Wed Aug 03, 2011 2:36 pm 
Offline

Joined: Thu Jul 14, 2011 8:26 pm
Posts: 78
Location: Middelburg
Real Name: Frank de Souza
Could any one please give me some ideas on natural anchors. For instance, is a single tree enough for a top rope anchor. I wanna climb some cliffs near my house, but the cliffs do not have a "from the floor up start" as there is a river at the base of the cliff. So I wanna abseil in and climb out using a shunt as I don't have any one to belay me. I've done it a few times but dangling from a rope supported by a single tree really makes me more nervous than excited about the climb.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 3:00 pm 
Offline

Joined: Mon Nov 19, 2007 3:13 pm
Posts: 689
The general guideline is that the tree should be at least as thick as your arm, but that doesn't really give a good indication. Obviously it is your problem if it fails, so you alone should be satisfied that it is good enough. It is always better to have a backup. Are there more than 1 tree? Big rocks you can sling or tie a rope around? Good gear placements will also help. I've top roped quite a bit off only one tree, but I was 100% sure it was going to hold. Trees actually make good anchors because they perform remarkably well at absorbing shock loads. Just make sure you won't uproot the tree, it happens often in the Magaliesberg for example (usually after a storm).


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 3:12 pm 
Offline

Joined: Thu Jul 14, 2011 8:26 pm
Posts: 78
Location: Middelburg
Real Name: Frank de Souza
Its the only tree near enough for the gear I have. Its a bit of a hike, for me, so I don't take too much. Only the musts so it does leave me to improvise. The site has boulder I good use to second the tree. Will 6mm rap cord suffice? What would be the best and lightest way be to equalize the two?
Thanks man.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 3:21 pm 
Offline
User avatar

Joined: Sat Jan 08, 2011 10:25 pm
Posts: 176
Real Name: Wesley
I would also be careful not to put the sling to high up the tree to minimize the leverage on it.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 3:27 pm 
Offline

Joined: Mon Nov 19, 2007 3:13 pm
Posts: 689
I think the best way is to simply use the rope. Let's assume you have 60m of it and the cliff is let's say 40m high. That leaves you 20m to build an anchor and cover the distance from the anchor to the edge of the cliff. the best way I think would be to tie the rope to the tree, pull it towards where you want to build your equalization point, tie a figure 8 or alpine butterfly in the rope, take it around the boulder and tie a alpine butterfly and connect it to the first with a locking biner. Then you climb on the loose end. I haven't tested this idea, so rather don't just trust this blindly. :thumleft: I'm not a hundred percent fine with the biner in the middle, but I can't think of a save and easy knot to replace it right now.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 3:55 pm 
Offline

Joined: Fri Apr 08, 2011 12:28 pm
Posts: 16
Real Name: Norman
It all depends on the position of the tree to the boulder. If they are not too far apart, you could tie the cord around the tree using a thread through figure 8, then do the same arounf the boulder. Now pull the middle of the cord in the direction of the route you want to climb and tie a figure 8. clip a screw gate into the bight and there you go. 6mm is strong enough, but i'd use 7 or 8mm to be on the safe side.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 6:19 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
Dude, trees rock (as long as they are alive and thicker than your wrist, you'll be fine). I have even rapped off a bunch of saplings which collectively were thicker than my wrist in a moment of desperation. I would give a kidney to have some trees to use as anchors here on Gough. All the work we do uses galvanized poles driven in the ground backed up to Spartina tussocks (giant grass).

6mm cord is fine for anything that you will be doing, I carry a 8m length with me when tradding and use it to build belay anchors. Join one end to the rock and the other to the tree, tie an 8 in the middle and there you go. A nice, equalised anchor.

_________________
Happy climbing
Nic


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 7:16 pm 
Offline
User avatar

Joined: Fri Oct 15, 2010 9:57 pm
Posts: 24
Location: SUN CITY NW PROVINCE
Real Name: DYLAN FREEMAN
PLEASE EXPLAIN YOUR IDEA WITH THE SHUNT, WOULD THIS BE SHUNTING AS THE ENGLISH CALL IT? OR SOLO TOPROPING WITH A SHUNT. I HAVE USED A BASIC SYSTEM LIKE THIS WHEN SENDING LAPS ON A WALL I PRACTICE ON, WOULD YOU BE CONCERNED ABOUT CROSSLOADING THE BINER? AND A SAFETY ROPE WITH FIG 8S TIED TO CLIP IN FOR SAFTEY. KEEN TO HEAR YOUR THOUGHTS.

HAPPY CLIMBING

DYLAN

_________________
"WHERE IS THE THICKET, GONE , WHERE IS THE EAGLE , GONE ..... THE END OF LIVING AND THE BEGINING OF SURVIVAL! "


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Wed Aug 03, 2011 7:31 pm 
Offline

Joined: Thu Jul 14, 2011 8:26 pm
Posts: 78
Location: Middelburg
Real Name: Frank de Souza
Yeah Dylon I use a shunt. The rope runs down double with the shunt running down the middle of the two ends. I normally tie my water bottle or backpack to the end of the rope when I climb, just to allow the shunt to run up easier. What I understand by you saying crossloading the biner, is when it turn in you harness and shunt in such a way that it is across in such a way that the screw en is to the shunt and the back of biner to harness or vise versa. I stopped using a biner when I noticed that the first time. I now use one of those small carabiners that look like a chain link except its got a screw gate. Ever since then I've not had it crossloading.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 10:29 am 
Offline

Joined: Fri Sep 22, 2006 1:45 pm
Posts: 558
Location: Aberdeen, Scotland
All I can add is just make sure you know what you are doing. If you are wandering off into the middle of nowhere on your tod, abbing in and then shunting out, the potential to end up in the shit is pretty large.

Think what you are doing, think everything through and have fun.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 10:58 am 
Offline

Joined: Thu Jul 14, 2011 8:26 pm
Posts: 78
Location: Middelburg
Real Name: Frank de Souza
All I can add is I'm not scottish


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 11:29 am 
Offline
User avatar

Joined: Tue Jun 26, 2007 9:38 pm
Posts: 780
Real Name: Greg Hart
This sounds similar to the toprope solo system I use a lot. The biner is definitely a concern, check out the new Black Diamond locking biners that have a small leg on the gate that closes the narrow end of the biner off (the shunt goes on this end), this eliminates the crossloading problem. The other big concern is obviously that the shunt was never intended as a belay device, the arm of the shunt is a cast piece which makes it prone to cracking. Scary as its almost impossible to back this particular system up satisfactorily (one can try a prussik of thick 8mm+ cord tied loosely above the shunt but Ive found this tended to jam the shunt unexpectedly on occasion, still worth considering if you are pushing your limits though). Ive found the system ok for climbing within my limits when there is little chance of a fall, but taking whippers onto it is blooming hair-raising! :o :shock:

The croll is supposedly designed for this type of belay, however as it has teeth similar to an ascender it shreds your rope slowly but surely. Whatever you use, try to back it up and always slide the device up every time you reach a rest and before tackiling difficult sections to minimize your fall.

Trees should be fine especially if they are biff looking but always have a second point (at least two! More if possible) of contact when setting a belay, the list of accidents caused by seemingly-solid single-point belays failing is long - and gory. Although its not so healthy for a lead rope, tying a fig8 in the rope at the top belay point gives you two independent ropes which is obviously safer than one. Always make sure the rope isnt going to get chomped on sharp edges at the crag top, use rope protectors (wrapping your empty pack or anorak around it works in a pinch). 6mm cord is strong enough but doesnt have the same resitance to cutting or abrasion that a thicker rope has, I use offcuts of old lead rope that are still sound (confidence inspiring) although static line is better as it doesnt stretch which can cause abrasion of the rope on the crag-top edge (your main [abseil/climbing] rope must always be dynamic however). If you use thin cord, always untie the knots when you get home (a mission with thin cord) to check for abrasion and wear inside the knot area.

Always let someone know where you are when heading out alone and when you intend to return, inform them of your return when back home safely. Make sure the person you tell has search and rescue phone numbers at hand.

Anyways thats my 2c worth, Ive been using this system to prospect new routes for over 20yrs and Im still here, hope the tips help keep you whole too! :) :thumleft: Well done for getting out there despite the lack of a partner!!


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 11:53 am 
Offline

Joined: Thu Jul 14, 2011 8:26 pm
Posts: 78
Location: Middelburg
Real Name: Frank de Souza
Finally. I get to learn some thing. Thanks to Xmod.

The fact that the arm is a cast piece really did make my hair stand. I see what you mean about it cracking and most probably with no warning. Backing it up with the prusik makes perfect sense too but like you say it jams normally when you stand up fast. I normally try not to take unexpected falls, and try to lower before the fall. When I find my self on a piece out of my climbing ability, I place an ATC below the shunt and a long sling to the shunt. Move the shunt the length of the sling. Then pull up on ATC to shunt and repeat.

How much is one of those Black Diamond biner?

I got plenty old rope still in good nick. Cutting the good pieces with red hot thin knife should be fine, shouldn't it?

Thanks again. Xmod
Ps hey man my shunt doesn't have any teeth?


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 12:55 pm 
Offline
User avatar

Joined: Tue Jun 26, 2007 9:38 pm
Posts: 780
Real Name: Greg Hart
Ja using a thick (8mm) prusik helps stop the thing jamming in the mouth of the shunt. It also releases a lot easier after loading (a big problem with thin cord) and its safer.

Dont extend your shunt attachment, this is outside of design parameters and dramatically increases the chance of sever shock-loading. Just connect directly to your harness and rope as per standard practice. Rather use a short sling extension to your descender (a 60cm sling doubled over and tied to the belay loop with a larks foot knot works perfectly) which is then attached above the shunt. To change from abseil to climbing mode simply unweight the rope and remove the descender from the rope (it stays on your harness loop ready to use again easily). If you cant find a stance on which to unweight the rope attach the prussik (extended as necessary) above the descender, tighten it up and then pull slack up into the system to release the descender. This way your shunt always stays on the rope keeping you on-belay at all times - nifty and safe.

Ja shunts dont have teeth which is why Ive stuck with it rather than use the croll with its fangs. The arm may be cast but its beefy and Ive never heard of one cracking.

Biner was about R80 ?, cant recall offhand but well worth the bux. BD won design of the year with that biner. One of those simple effective ideas that make you go: 'Why hasnt this been done before?' - a sure sign of great design! Just make sure the shunt is in the smaller closed off end and dont use the biner for normal belaying as the shunt can cause nicks in the biner which will wear your harness loop unnecessarily (you may want two of these biners they are so cool, one for shunting, one for belaying).

Cut old rope with a sharp craft or stanley knife, seal with a lighter. Cut the lengths a bit longer than you think you will need to allow for knots etc. 6-10m lengths seem to be ideal but your situation may dictate otherwise. Rope is not heavy to carry in and it will greatly enhance your enjoyment knowing that the belay is backed up throughout the system and is totally overkill bombproof - confidence inspiring :thumright

Also remember you can escape a line that doesnt go by wrapping the rope a few times around your raised feet and then standing up sliding the shunt up the rope. Primitive but effective and it doesnt require any extra gear.

Yip, thats about all I got, have fun b safe! Stoked there are others out there, passionate enough about this, that they will go the solo route, pretty cool 'me' time exploring alone!


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 3:06 pm 
Offline

Joined: Fri Sep 22, 2006 1:45 pm
Posts: 558
Location: Aberdeen, Scotland
deSouzaFrank wrote:
All I can add is I'm not scottish


Neither am I, not that it's relevant.

I'm was just concerned for your safety that's all. Given your comment I kind of wish I hadn't been though. Given your questions you don't exactly sound experienced.

If you intend doing this kind of thing regularly it might be worth investing in a piece of kit designed specifically for self belaying.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 6:06 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
Hi

Shunts work fine on a lanyard, that is how we use them in rope access all the time, however for your needs they will work just as well when connected to your belay loop. It will also tangle less then.

I would not use a Croll, they are designed to be used when ascending a rope and using a chest harness. They are NOT designed for fall arrest. I would avoid using ANY toothed device (other than purpose built ones) to belay and arrest falls.

A Grigri would work, although possibly not as smoothly as a shunt. What you really want is a Silent Partner or a Petzl ASAP

_________________
Happy climbing
Nic


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 6:24 pm 
Offline

Joined: Thu Jul 14, 2011 8:26 pm
Posts: 78
Location: Middelburg
Real Name: Frank de Souza
Damn thanks Nic. Those look real nice. Do I understand correctly that the Petzl ASAP is even good for when angling the rope like for instance on an overhang. Overhang falls on to the shunt do worry me cause you fall a lot further. But this device is ok to load like that?


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 6:40 pm 
Offline

Joined: Fri Jun 27, 2008 8:38 am
Posts: 706
Location: Port Elizabeth
Real Name: Derek Marshall
Gavin Peckham shattered his foot climbing on a shunt. Can't remember the failour mode.

:idea: Admin edit: Click here for info on the Shunt Accident mentioned above.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 04, 2011 7:52 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
Quote from the Petzl website, ASAP page: For 10.5 to 13mm semi-static ropes certified with the device.

i.e. DO NOT use dynamic ropes with the ASAP, you can buy a shock absorbing lanyard for it that will stop you hurting yourself.

It works with top anchored lines that are under slight tension, allowing it to run up and down with you, only locking in the event of a fall. It should work under an overhang, I cannot see why not.

deSouzaFrank wrote:
Overhang falls on to the shunt do worry me cause you fall a lot further. But this device is ok to load like that?


You should hardly fall far unless the overhang is massive. The rope will take your weight as soon as you come off and you will fall twice the distance of your connection to the shunt plus the rope stretch. You will swing a lot though.

For your purposes and rope, the Silent Partner is your best option

Marshall1 wrote:
Gavin Peckham shattered his foot climbing on a shunt. Can't remember the failour mode.


Link to the forum post about Gavin's accident

viewtopic.php?f=17&t=4983&p=24180

_________________
Happy climbing
Nic


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Fri Aug 05, 2011 2:04 pm 
Offline

Joined: Fri Jun 20, 2008 12:08 pm
Posts: 126
Location: Durban
Real Name: Bruce Tomalin
Just to add my 0.5c worth:
I really enjoy this mode of solo "climbing" (some say its not climbing - whatever...),
its fast, no stress/fear factor and close to 100% safe if you think it all through (unless you're gavin peckham!). Great for working out moves, training or just chilling...

Its a fair bit of work to set up an anchor but I try to do it so I can play on more than one line per anchor and also usually climb each line more than once...
You can also climb reasonably off-vertical lines by placing gear on your way down (and running climbing line through a q/draw) - just note the pull on the gear will be different to what you are used to when placing gear on lead (more outwards and sidewards than expected).
I ALWAYS have more than one top anchor no matter how dik the tree - I link with static line, equalized and tied off with fig 8s...
Wrap trees low down with a sling (to protect tree from rope friction and also keep tree juices off your rope).
I also shunt on a double dynamic rope, each strand independently attached to the anchor - makes me feel very safe.
I usually attach climb rope ABOVE cliff top to anchor, ie. dynamic rope runs over the edge, therefore it is ESSENTIAL to protect the rope on the cliff edge (I use a v lekker rubber tube gizmo with velcro closure which I got from MMO).

I hold the shunt upright with a couple of elastic accessory cords over opposing shoulders and weight the bottom of rope so slides nicely - this reduces fall distance to virtually nothing .

Never thought about the shunt arm breaking! I'll just put that out of mind...

To me the most dangerous part of this process is messing around close to the edge...
I therefore set up the top anchor early and clip in with a long sling.

Oh and complacency - think it through, work out a routine that works for you and step through it every single time... I once started climbing at my limit with the shunt only attached by the elastic accessory cords - luckily snapped out of my dream while I could still downclimb...

And yes, always leave place, expected times, etc with some-one you trust (not your hung-over buddy)... Durban's Kloof gorge is great: the ranger has a sign in system and actually does look for us if we don't sign out...

C ya,
bruce

_________________
LCD SCUM


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Fri Aug 05, 2011 3:27 pm 
Offline
User avatar

Joined: Tue Jun 26, 2007 9:38 pm
Posts: 780
Real Name: Greg Hart
Nick et al, Ive used the Silent Partner a fair bit for soloing. It is not that suitable for this type of top-roping, the reason being that it gives a very dynamic belay which it achieves by allowing a LOT of slack to slide through the device before the knot tightens and you are caught. I tested it in France (leading) just to see what would happen jumping off with a bolt about a meter below my feet, I promptly flew nearly ten meters stopping inches short of the back-up knot. The device worked perfectly giving a VERY soft catch (better than most human belayers) that I barely felt through my harness. I was glad it worked ( :o :shock: ! - obviously!) but it was a wake up call to be vigilant with the back-up knots and not get bold with the gaps between knots. In top-roping the device will not lock if you want to just sit back a bit and rest, it requires a sharp hard pull on the rope to operate the brake. You can induce this but you fall quite far when you do (not ideal when youre trying to work out moves) and its a full on mission to loosen the knot when it tightens, more so if you are hanging free in space. I eventually sold the device as it did not offer me the freedom of movement I was looking for nor the instant brake the shunt offers.

The silent partner is ideal for lead-climbing long overhanging pitches below your limit which makes it appropriate for a very small segement of the climbing population if you consider that ovrehanging climbs usually check in at grade 24 and up. It also requires you to stop and tie in to a back up knot every few meters, the only practical way to do this is to clip into gear to free up your hands to work with the knots and free rope. Whilst you can toprope with it you need a second rope with fig8's pre-tied in it at intervals to clip into to back up the device The main rope is weighted to help it feed, similar to using a shunt, making it hard to tie back up knots in). Again you will want both hands free to do this effectively. Also the device is quite heavy and extremely bulky. Whilst the partner slides beautifully freely up the rope allowing free movement (even very quick moves like dynos) in between stops to mess with knots, all things considered its, a very awkward and fussy type of climbing.

Extending the shunt may work ok for access work where you can pre-lock it yet still need the freedom of movement the extension gives. Extending it is NOT a good idea when climbing however, it is designed as an automatic brake back up for abseiling and must be clipped directly to the harness. Ive had the extension wrap around the device before stopping it from operating resulting in some very anxious moments and an extended fall, stopping only because the extension loosened in mid-air, resulting in me coming to a slamming halt when the device finally activated. A shock load situation one should do everything to avoid. Not only can it cause cracks in the arm it may also result in rope slippage. The brake arms are small diameter and will create enough friction-heat to cut a rope if forced closed whilst the rope is flying through the device - remeber it is NOT a belay device!

The Shunt also may fail to operate on very overhanging rock where the angle exceeds the angle required to operate the lever arm. If you are exploring overhanging rock put a bunch of gear in on the way down clipping both lines into it to keep the rope coming as vertically as possible into the device. Failure to do this may result in rope slippage with disasterous consequences!

Another way of backing things up is to have a second rope hanging free next to the route with fig8's pre-tied at intervals which you can clip into with a locking biner as you reach them. Again this requires stopping to do so, also you want the knots level with decent rests preferably (presuming you want to free-climb smoothly up the face), judging where the knots must be tied on top of the cliff prior to abbing in is near impossible usually requiring that you stop on the way down to fine tune the rig. All of which is rather time consuming and fiddly - things I try to avoid in my climbing.

The shunt is not ideal by any means but until I find a similar better device, its what Im using (Im not familiar with the ASAP). I read that Iker Pou used one to rehearse moves on a multipitch alpine route as he did not wish to bore a partner to tears with the endless rehearsal needed for the 8b pitch. If its good enough for him.... BUT even he opted for a human belayer when it came to start linking the moves together as the shunt just did not offer enough safety margin on the overhanging rock. Im going to try running my SUM on a toprope and see how it performs but fear it will not feed very smoothly.

Anyways this is just the system Ive been using, and the advice I give is from hard experience gained through some very hary-scary moments which lead me to stick to the set-up I describe as its the safest and simplest, and stays closest to manufacturers recommendations for correct set-up (aside from the fact Im belaying with it). Solo exploration is a very satisfying thing to do, being totally self reliant is quite empowering, and Im stoked others are out there doing it. If anyone has a different system theyve used which works well please share! - Cool topic!

PS ditto what Bruce said about working on the cliff top, its often awkward and always dangerous clip yourself in asap.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Fri Aug 05, 2011 4:19 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
Tx Greg. Never used a Silent Partner so I can't comment. I just know that it is one of the few devices designed for soloing.

Incidentally, the failure mode for the Shunt on every drop test that I have seen the results of has been the body of the Shunt unfolding, releasing the rope, rather than the arm breaking.

_________________
Happy climbing
Nic


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Sun Aug 07, 2011 10:20 am 
Offline
User avatar

Joined: Tue Jun 26, 2007 9:38 pm
Posts: 780
Real Name: Greg Hart
Thanks Nick gd to hear that about the arm (altho not about the body! :?) of the shunt .

I dont want to put ppl off the Silent Partner, its amazing for leading, just lots of work and not really free flowing climbing due to the back-up story. Its also damn pricey and hard to get. If you want a new one you have to write a letter of motivation to the manufacturers giving your experience record and will probably have to sign a liability waiver before they will sell it to you, its not sold to the public generally speaking.

Of course if you are Hans Florine and are prepared to forego the back-ups that the manufacturers insist on, climbing with the Silent Partner can be very fast and free, Im not that brave though.

There's defintely a market for a simple do-it-all autolck belay/abseil/solo-belay device that feeds easily and is problem free. Any designers out there got a gd idea?

One more way of backing yourself up when using the shunt would be to simply pull up some rope below the device and tie a fat knot in that couldnt slide through the device, this will only work if the shunt failure hadnt severed the rope however, which is why I suggest the prussik above the device. Hard to beat a rope and knot for simplicity and reliability.


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Sun Aug 07, 2011 6:43 pm 
Offline

Joined: Wed May 05, 2010 8:05 pm
Posts: 82
Real Name: Jacques Breitenbach
Lots of trees in the magaliesberg kloofs. Me and my climbing buddy would ab off trees initially doubled up with pro, but not equalised. So the tree was taking all the weight. That way if the tree didn't pull out/fail the last guy down would take out the pro and come down on the so call "tested" tree. I realise now that if the tree ever did fail the shock on the pro could be potentially disasterous, thank goodness the tree's all held, it probably was not the best way to do things. Any acedemic thoughts on that?


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Mon Aug 08, 2011 9:17 am 
Offline

Joined: Mon Nov 19, 2007 3:13 pm
Posts: 689
jgb wrote:
Lots of trees in the magaliesberg kloofs. Me and my climbing buddy would ab off trees initially doubled up with pro, but not equalised. So the tree was taking all the weight. That way if the tree didn't pull out/fail the last guy down would take out the pro and come down on the so call "tested" tree. I realise now that if the tree ever did fail the shock on the pro could be potentially disasterous, thank goodness the tree's all held, it probably was not the best way to do things. Any acedemic thoughts on that?

I'm maybe not an academic, but I have a good deal of experience and I kinda like the idea of staying alive. I can't find fault in your plan. The idea of a backup is just that, backup in case the first anchor fails. If you equalise your backup, you won't know if the first anchor was strong enough. I don't think you need to worry too much about the shock load on the backup anchor in case the first one fails. Surely you build anchors strong enough to deal with a factor 2 fall. An anchor failure on an abseil will generate far less of a shock load on your backup anchor (methinks). :thumleft:


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Mon Aug 08, 2011 2:38 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
Hi

Shock loads are bad! The amount of force exerted by a shock load can be many times greater (dependent on a variety of factors) than that caused by statically (or slowly) weighting the anchor. Also, anchor failure can cause you line to move across the edge and sever it.

The best way to rig the system you describe would be to find a group of anchor points behind your tree, equalize those together, bring the rope forward and connect it to the sling on the tree using an alpine butterfly knot. Make sure that the weight is taken by the tree but also ensure that there is the least possible slack in the line running back to the equalized anchor. That will reduce the possible shock load as much as is possible.
If at all possible, try to get the point where you go over the edge, the tree and the equalized anchor in as straight a line as possible so that there will be the minimum of rope movement if the tree fails.
Ropes cut incredibly easily when running along an edge, I have seen 11mm static line loaded with about 150kgs cut by the edge of a brick in 3 swipes of the brick across the line...

_________________
Happy climbing
Nic


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Mon Aug 08, 2011 4:12 pm 
Offline

Joined: Fri Sep 22, 2006 1:45 pm
Posts: 558
Location: Aberdeen, Scotland
But what if the tree falls in a forest? :wink:


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Mon Aug 08, 2011 5:24 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
if it hits a mime, no one cares :jocolor:

_________________
Happy climbing
Nic


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 11, 2011 4:16 pm 
Offline

Joined: Wed Sep 02, 2009 3:32 pm
Posts: 11
This is a fascinating topic! I've been climbing for about 2 1/2 years but generally only simple stuff and only sport and would love to learn more about advanced topics. My regular climbing partner is always dropping me at the last minute for other non-important things, like a blind date for eg. Would be cool to still get out on my own and explore if the opportunity was there.

Does any1 do or know of any advanced courses with some sort of practical element? Maybe MCSA or something.. don't really know.

May be a good opportunity for some of you experienced types..


Top
 Profile  
 
 Post subject: Re: natural anchors
PostPosted: Thu Aug 11, 2011 10:11 pm 
Offline

Joined: Mon Apr 02, 2007 9:40 am
Posts: 726
Location: Stellenbosch
Real Name: Nic Le Maitre
Best thing to do: Find a traddie who needs a belayer and go climbing with them. Try your local climbing gym/crag/branch of the MCSA. Learning by experience is the best way.

I know that Venture Forth do run trad leadership courses if you are willing to pay. There are several others as well.

_________________
Happy climbing
Nic


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 37 posts ]  Go to page 1, 2  Next

All times are UTC + 2 hours


Who is online

Registered users: Bing [Bot], Google [Bot]


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group