Tuesday, August 27, 2013

Vertical Darwinism: Attachment Issues

"Are you attached?" This is more than a blunt way to check the dating status of an assumed Scorpio at a local watering hole. It is a crucial question that we should always ask ourselves when hanging out at a belay station. There are many ways to attach yourself to that all-sustaining MASTER POINT. But which method is right for you?

Let me count the ways...

A sling girth hitched to a harness can offer the security you are looking for. They work in your anchor and for slinging trees and chickenheads. So why not use them to attach yourself to an anchor? That is less of a hypothetical question than it seems. First off, girth hitching slings actually weakens their capacity. (See my "Slings and Things" post for more detail)  Secondly, slings can be loosy-goosey to deal with because of their length and lack of structure. This makes it difficult to adjust your distance from the anchor.  If you are using one you can tie limiting knots in them to add length options and give the carabiner a home base in the sling.

Daisy Chain- 
This is basically a hefty sling with sewn separations. It has more structure and seems more convenient than just using a regular old sling. So is it better? Organizationally, YES because there are a lot of little loops for you to use. Safety-wise, NO because tests have found that a high factor fall, like one from directly above an anchor, can cause stitching between the loops to fail. That is not surprising to find out because they were originally designed for use in Aiding and not intended for anyone to be falling on them. (Um... Neither are the above mentioned Slings...)

*Also note that, when using a Daisy Chain, if your carabiner is in two separate loops, you technically are in no loops at all because of Math. Topology would say that the letter B is the same as the letter O if the connector in the middle of the B gives way. A carabiner connected to both loops of the B is really hanging out in the bleak nothingness encapsulated by the O. So if you do use one, remember, "BO"...
Here is an excellent video illustrating this exact point.

Cord System- 
You will see some climbers have switched from the Daisy Chain to a wild system of cord that, using a combination of knots and magic,  can be extended to the desired length. This is a redundant system that can also be dynamic and absorb a fall depending on what type of cord you use. The only downside to this system is that it is a lot of cord hangin' out down there, which can get a bit messy and tangled. It is solid but just not as tidy as some other methods.

This multi-loop system consists of multiple loops. Yup.  Each loop is designed like a belay loop, where it is wrapped around itself twice, granting great strength in each segment. It is strong, compact, and stows away well. It also allows the climber to use more than one loop to attach if they deem it necessary since each loop is independent.

Cammed Webbing- 
I have also seen climbers using a strap with a camming device to adjust the length of the attachment. Mostly I see this used inside for route setting when you are tied into a rope as well. But hey, if it keeps a canoe on your roof rack...

Which Method is Best?
I don't know if there is a best, but I think there is a consensus that Slings and Daisy Chains are probably not the best. Personally, I use the PAS. I find that it is strong, lightweight, convenient, and compact. So run out and get one. Or I guess just head to REI and ask for a "climbing strap" and see what they hand you. But whatever method you choose, avoid taking falls onto anchors at close range. These falls are high fall factors which are not good for any of the above options. Anchor attachments should be for just that, attachments. They should not be dynamically weighted.

Regardless of your method, make sure it runs through your two strong points. NEVER on your belay loop.  Yes, I know the old PAS Packaging showed a picture of it but if you read the actual instructions you will see that they agree with me. Or I agree with them. Anyway, it turns out that not all graphic designers are personal safety experts. Is your belay loop not strong enough?  Far from it! But it is not designed to withstand the constant fabric-on-fabric action of a girth hitch or even a rope. The belay loop is a carabiner only zone. Don't believe me? check out this  excellent post from Backcountry Beacon for some interesting facts on belay loops.

Is chocolate too delicious?
No. It is the perfect amount of deliciousness.

Do I need more than one of these things to always be redundant?
You do not need to buy two attachment systems. Redundancy can come in many forms. You can even use the rope as your second attachment point. When you can't use the rope, like if you are setting up for rappel, just throw in another sling for good measure.

Does this make me look fat?
 I take the 5th.

Where should I store my attachment on my harness?
I shoot for a gear loop under my other gear. Some folk "keelhaul" it through their legs and right past their nethers. To me, that just seems like you are asking for it. Really this is personal preference. However, I value my reproductive capabilities. Maybe one day, someone else will as well. :(

Should I fear Clowns?

What about a large party of followers?
Anchor stations get crowded. Consider putting your followers on a long leash of webbing or cord to get them to a point of safety and comfort, far away from the belay. They could always use their end of the rope as an attachment as well.
*Pro Tip: Have a distinct anchor carabiner marking for everyone in your party. The gaudier the better. My favorite so far was pink nail polish with Hello Kitty Stickers :) This way everyone knows who is attached where.

Where should I pee?
Check out this handy flowchart to determine the ideal urination location.

Climb Smart MN is a grassroots approach to climbing education based on community and charitable giving. For information on donation based climbing lessons visit ClimbSmartMN and follow us on Facebook. With over ten years of climbing instruction, coaching, and guiding experience,  Chris Hesselbein strives to better the climbing community through personalized technique and safety education.

Thursday, August 22, 2013

Vertical Darwinim: Slings 'n' Things

Recently, I was asked about the safety level of girth hitching a sling to a tricam in a top rope anchor. My gut reaction was that it is absolutely fine as I have done it many times before. Then that nagging feeling of doubt snuck up on me. Do I really know what I think I know?   So, I did my due diligence and found some research.

First of all, why would anyone girth hitch a sling to a tricam or other nylon slung piece of pro? Why not just use a carabiner?  The obvious answer is that it can get you out of a jam if you are short on biners and need to extend a piece. The less obvious situation is that your piece is positioned so that attaching a carabiner would position the biner on the edge of a rock. This is a very bad place for a biner as it may cantilever over the edge, possibly bending or deforming the biner. In this case it is much preferable to make a softer nylon to nylon connection and extend the piece around the corner. In the case of a cam a girth hitch directly to the stem will suffice, but in the case of a tricam, girth hitching nylon to nylon is unavoidable.

So, if that is the only option you have, is it okay? Will it greatly reduce the strength? I found some compelling and disturbing research posted on the black diamond quality control lab. As it turns out, girth hitching a sling to another sling can actually reduce the strength by up to 50%. (Just FYI, when it does break, it is usually the THINNER sling that breaks.) This shocking strength reduction might permanently turn you off to the idea of girth hitching slings altogether. But some simple math shows that there may be times when this practice is acceptable.

Let's break it down. We can assume that our master point carabiner can hold a maximum force of 22KN. We can also assume that a well equalized 3 point anchor should distribute this force among three points of protection leaving each piece responsible for roughly 7.33333333.... KN lets round up to 8KN to adjust for a low angle of attack. Note that a .75 Camalot is only rated to 9KN. Now consider taking a 22KN sling and girth hitching it to that Camalot to reduce its effectiveness by half.  The now 11KN sling is still stronger than the .75 Camalot which still more than handles the distributed overall fall force.  Then remember that this scenario deals with maximum forces and real forces in a top rope scenario are far less than 22KN.

In summary, in many cases even a weakened sling should be effective in sharing the load of a top roping climber. Furthermore, if the piece that you are slinging is rated to anything less than 11kn,  your piece will pop before your sling breaks. Of course all of this math is based on a new, full strength sling. An old sling will start at a disadvantage and therefore fail at a lower level of force. It is recommended that slings be replaced regularly as per manufacturers suggestions. (usually every 5 years)

I am currently looking into an alternative to girth hitching yet have not found any research to support my new strategy. Any engineers out there have a pull test machine that they would like to use to help out your climbing community?

What have we learned today?
  • Always make sure slings are in good shape and regularly replaced (about every 5 years)
  • Use a carabiner when you can.
  • If you cannot use a carabiner, directly girth hitch to the plastic cam stem.
  • If there is no cam stem, girth hitching is okay as long as you know your anchor can handle it.
  • Never girth hitch to a wired nut or hex. There are other ways to extend those pieces. Ask me about it.
  • Listen to your small voice of doubt. Do research. Ask questions. Know that you know.

Climb Smart MN is a grassroots approach to climbing education based on community and charitable giving. For information on donation based climbing lessons visit ClimbSmartMN and follow us on Facebook. With over ten years of climbing instruction, coaching, and guiding experience,  Chris Hesselbein strives to better the climbing community through personalized technique and safety education.