devils lake rack

hey, im starting to build a rack and top rope set up for devils lake but i live a tad too far to go scout out what cams i need, i was wondering does anyone had any advice to sizes and gear i should get?

A single set of cams to a #3 BD and a set of wires will get you up most everything. The harder the route gets, the more specialized gear you may want, like ball nuts and really small cams.

TR, get 20 feet of 9mm cord and two lockers and you are set if you will be using rock gear for anchors.

^^^ what he said... plus I usually carry a long piece of webbing (30'+) for when I have to tie off a tree really far back or want to sling a really big boulder. Really depends where you are going to TR, some places have ample places to place pro at the top others have turf up to the edge.

Keep in mind, don't girth hitch trees, it kills them slowly over time. A simple non-tightening loop will do to make a tree anchor.

A non tightening loop will put more force on a smaller area of a given tree and if repeated over time cause more damage then a girth hitch that is rigged with a slight return.

I always thought the tightening nature of the girth hitch was the worst of two evils. And that's how the trees on top of shovel point in MN died.

As for "more force", I would like to know the math before I can agree with that statement.

jon jugenheimer wrote:I always thought the tightening nature of the girth hitch was the worst of two evils. And that's how the trees on top of shovel point in MN died. As for "more force", I would like to know the math before I can agree with that statement.

If you look at a simplified free-body diagram a girth hitch acts like a pulley system.

If you assume all friction is between the webbing and the tree (no friction where the webbing goes through the loop), and that the girth hitch is positioned such that webbing going into and out of the loop are parallel, you end up with twice the tensile force being exerted on the end with the loop.

For everything to be static (no acceleration) you need all force vectors to cancel out. Also, (because we assume no friction in the loop) tension in the webbing is the same after going through the loop as it was before. So you've got the webbing coming out of each side of the loop exerting a force equal to the load you put on it, and since they are parallel this is all active force. This would put 2X the force on the end with the loop tied into it.

Of course, in reality there is friction between the loop and the strand of webbing you feed through it, so the tensile force in the webbing is reduced after it is fed through the loop, which reduces the force on the end with the loop tied in it. The strands going through the loop aren't perfectly parallel either, so the forces don't add in a perfectly linear fashion (see vector addition ). If the strands are parallel, then the strand going to the load is probably also rubbing against the tree, which reduces force on the looped end. So in reality the end with the loop tied into it ends up with a tensile force somewhere between the force being exerted by the load and twice the force exerted by the load.

I don't know if that was explained well. We're doing an anchors clinic on Sunday, and I might draw up a free-body diagram to help demonstrate that concept. If I do I'll scan it and post it to give you a visual.

So the girth hitch has somewhere between X and 2X then?

Use a basket hitch with slings or webbing on trees it increases the strength of the sling and does less damage to the trees. This may be what Jon is referring to by "non-tightening loop".

picture of a "Basket Hitch"?

Turd Ferguson! wrote: I once asked a guy what time it was and he spent the next ten minutes telling me how watches are made and thinking he was a really bright guy. In the end, he still couldn't answer what time it was.

Hey now. I can't climb worth a damn, but I can sorta explain some basic engineering mechanics. Don't take this from me, Turd.

jon jugenheimer wrote:picture of a "Basket Hitch"?

Single basket hitch:


Double basket hitch:


The double is useful in binding together loads with several elements. It's also useful to do two of them if you need to rig a load that would wobble around, or even slide completely off, if you just rigged a single basket to one point (for example, a beam), because it will help stop rocking and sliding. Downside is it takes up extra webbing, and increases the angles, hence it also increases tensile force exerted on the webbing, It's probably preferable to use the single basket for climbing applications.

Don't take this away from me, Turd. It's all I have. :)

Would a wrap 3 pull 2 webbing configuration be kinder to the trees?

^^^ image from: China Lake Mountain Rescue Group
kandicemurray.com/clmrg/str…

In the past I brought lots of webbing for this: a couple of 30 foot loops.

Any more, I bring smaller chunks of webbing and connect with static line which makes it easy for me to set the power point exactly where I want it. I will use w3p2 whenever possible; otherwise, I go with basket as described above.

Another kind-tree option is to be like the Arthur Dent character in The Hitchhiker's Guide to the Galaxy and bring a towel (to pad the tree).

For pro on a TR anchor it might be best to use passive stuff (stoppers and hexes and tricams (OH MY)). I'm paranoid about someone substituting passive gear for my cams if I use them for TR.

Sorry to drift from the OP's question, but has this ever happened? Or worse, has anyone had their TR pro or part of the anchor stolen while they were at the base of the climb and out of site of the anchor?

--Bill

Things you need to lead at the lake-
1. An acceptance of getting sandbagged
2. The abilety to climbing above spaced out pro
3. the desire to run it out close enough to the ground to possible hit it(the ground that is)
4. a big set of nuts... and hexes

The rock is slick, passive pro works more reliable then cams and the routes are mostly short so you can usually get by with a single set.

Devil's lake motto- Have fun or get hurt bad!

Top roping is very convenient, top access is never an issue and there are tones of trees at the top of just about every route(95%). If your top roping leave your rack in the car and bring 60-70 feet of static line(or webbing if your cheep)and 2 locking carabiners, learn to tie a speed bowline and a BHK and you will be building anchors in two min. or less.

Mike J. wrote:Top roping is very convenient, top access is never an issue and there are tones of trees at the top of just about every route(95%).

Very often, these trees are on the other side of a heavily traveled trail. Please do not use tree anchors if it means running webbing or static line across a trail. You will find gear closer to the lip, and maybe even boulders or pinches you can sling if you don't have gear.

This is a basket hitch as it would be rigged for a toprope anchor with a 4x4 deck post in place of a tree for this example. The webbing is tied into a loop with a re-traced figure 8.

basket hitch

basket hitch

I guess I should have been more precise. I have used both to tie off trees.

While for me a tree is always a last resort preferring hexes, nuts, etc the idea that one form of tie off is the culprit remains unproven. Both stress trees and both can cause damage if used improperly. Hopefully no single tree is used in isolation and as a part of a larger system the affects of either tie off will be muted. SInce both exert the same total amount of force on a given tree under the same conditions I should have said that a girth hitch will spread the load around the entire circumference while a basket hitch concentrates the load on roughly half. Compression of tissues occurs frequently in conditions such as the leeward side of a trunk flexed in high winds so I urge all climbers to use passive pro in the rock whenever possible.

The question of why a particular tree on the edge of a crag dies is far more complex than basket vs girth hitch. Erosion from traffic must be considered as well as necrosis from root tissues being exposed to air. Weakened roots due to roughly half of the trees structure not being well rooted is also an issue. I think of the two trees at the top of Sunken Pillar that surely have been girth and basket hitched for decades. SItting at the top of the crag the pine on the right has severe necrosis on the cliffside. Is this due to slinging or the fact that the roots on that side are exposed to the air?

So sling a tree if you have to but always strive for the lowest possible impact.

chris21 wrote:This is a basket hitch as it would be rigged for a toprope anchor with a 4x4 deck post in place of a tree for this example. The webbing is tied into a loop with a re-traced figure 8.

This anchor setup eliminates the redundancy of two biners...if one fails the whole shebang does.

"This anchor setup eliminates the redundancy of two biners...if one fails the whole shebang does."

don't use it as the sole anchor point (last time I checked one tree and one rope weren't redundant either) ... the two biners are so it would be clearly visible what the sling is doing for the illustration and so that one biner doesn't get cross loaded.

"Another kind-tree option is to be like the Arthur Dent character in The Hitchhiker's Guide to the Galaxy and bring a towel (to pad the tree)."

Padding the tree is a good idea.

when i went to the lake with an experienced friend she taught me to do three solid placements, one anchor in direct line with rope, and 2 at 30 degrees on each side of the primary. then equalize the load force between them. these can be build from crack placements, slinging around fixed rock, or a tree, etc. is that a pretty typical TR anchor at the lake?

Tito Krull wrote:when i went to the lake with an experienced friend she taught me to do three solid placements, one anchor in direct line with rope, and 2 at 30 degrees on each side of the primary. then equalize the load force between them. these can be build from crack placements, slinging around fixed rock, or a tree, etc. is that a pretty typical TR anchor at the lake?

That's a pretty ideal TR anchor for most any location. Of course, you're not always going to find 3 perfect spots at 30 degree intervals, so you use what you have.