S.L. jump: maximum length of fixed rope

[BASE_689]

Object: E. Height: 40 m - 131 ft. Still I have got to check better its verticality (at least!), it's not so clear, I have got to hang out there another time with climbing harnes-rope-friend to check me (!), to check it properly and finally.
Exit would be about 5 m below the top of the wall, equipped with wooden handrail. Now, stated that I will NEVER tied my fixed rope (where to attach my break cord to) to such a wooden handrail (even if looks jolly solid...), my question is the following.
Granted that there are about 15 m (10 m horizontally and 5 m vertically) between exit point and the closest solid object (a tree), and I would fix my fixed rope to such a tree, do you think it is good/sound/safe/other to have something like 15 m - 49 ft of fixed rope to tie your break cord to?
I am a little worried about elasticity of 15 m - 49 ft of rope (even if it's a 10 mm - 13/32" diameter rope) that "could" be too much for the break cord...
Would the lengthening under load of 15 m - 49 ft of rope "dangerous" for the proper breakage of break cord?
Other issues that I am missing somewhere?
Thanks so much!!!

Stay safe out there
Blue Skies and Soft Walls
BASE #689 :D
e-mail: base_689@yahoo.com

P.S.: Do not even think about sticking a 10 cm - 4" climbing spit somewhere around exit point or elsewhere there around: in the area, all the wall/rock is really crappy and falling in pieces!!!

[JJ]

>Granted that there are about 15 m (10 m horizontally and 5 m
>vertically) between exit point and the closest solid object (a
>tree), and I would fix my fixed rope to such a tree, do you
>think it is good/sound/safe/other to have something like 15 m
>- 49 ft of fixed rope to tie your break cord to?
>I am a little worried about elasticity of 15 m - 49 ft of
>rope (even if it's a 10 mm - 13/32" diameter rope) that
>"could" be too much for the break cord...
>Would the lengthening under load of 15 m - 49 ft of rope
>"dangerous" for the proper breakage of break cord?
>Other issues that I am missing somewhere?

#689,

If you are so worried about climbing rope elasticity, why don't you use a static rope or a piece of webbing or something that will not stretch?

My experience with static line:
I have done 50+ static line jumps from sub 200 feet using a 10 foot piece of webbing or retired brake line as a static line and my 9 foot bridle. I would tie the breakcord in the middle with no PC. I tied one piece of break cord tightly, joining the bridle and static line and then a backup loop about 2 inches in diameter in the event the tight breakcord broke prematurely due to the snatch force/recoil of the bidle and static line. I had no problems with this configuration and video analysis showed no adverse effects or anything out of the ordinary.

Good luck, keep thinking, and test jumping...I mean BASE jumping.
JJ
:-)

[crwper]

You should be able to get static rope from any climbing store. This kind of rope has very little elastic stretch, and is perfectly suited to your scenario, I would think.

Michael

[bolder_1]

most dynamic climbing ropes stretch approx. 4% of their total length. it is easy to calculate stretch. i agree with the others though. static line has minimal stretch. webbing stretches a bit more than static line. there is my 2 cents.

[BASE_689]

>most dynamic climbing ropes stretch approx. 4% of their total
>length. it is easy to calculate stretch. i agree with the
>others though. static line has minimal stretch. webbing
>stretches a bit more than static line. there is my 2 cents.

Thanks so much to everybody!!!!! I have just bought 20 m of static rope!!!!!
Further investigation on verticality of above wall in progress!!!!
I shall let you know the results!!!!

Stay safe out there
Blue Skies and Soft Walls
BASE #689 :D
e-mail: base_689@yahoo.com

[tree monkey]

JJ, just to make sure I understand your set up.... you have two seperate loops of break cord( 1 tight, 1 slack inorder to be weighted at different times) and no pilotchute. thanks BASE 789

[BasejumperJeff]

I only have 3 SL jumps, all from the 200 ft. range. I was told that you must always have slack in your break cord when you tie around the bridle and static cord. I have always made about a 1-1.5 inch loop in the break cord, I was told this is for a more consistent break.

Let me know if I'm out of the loop here.

[d-dog]

First off, standard caveat: I am not an expert on anything related to BASE. I know alot about dogs and canine behavior, and I'm a damned good horseman to boot but that's not much to do with BASE now is it?

However, I've spent nearly 20 years (ok, only 17) as a climber in disciplines ranging from pure bouldering to some moderately technical aid climbing. I cut my teeth on traditional leading, and was mentored and trained in anchor placement and rigging by several really good climbers.

Point being, I hope that I know a bit about the mechanics of rigging up "anchors," and that's what static line is: an anchor. Admittedly, it's an anchor that is supposed to fail. However, that failure is designed to happen at a specific tension, not more nor less, and it's set to happen as a result of the cord itself breaking - not the anchor coming undone, the cord being cut, etc.

The way in which one ties the break cord into the bridle and onto the anchor being used can have a material impact on the integrity of the anchor you are setting when you do a static line jump. Incorrect knotting will create a natural weak point in the system, and thus degrade the tension generated by the static line setup during shrivel flap removal/pin extraction, and subsequent canopy extraction.

Leaving "slack" in the static line loop will, depending on the anchor around which the loop is tied, dramatically decrease the efficacy of the setup; even a few inches of slack will almost certainly result in the cord breaking only at shrivel flap extraction, NOT at line stretch. This will change the level at which the canopy is pressurized and flying by AT LEAST 20 feet; on a low jump (150 or lower) that 20 feet could make a big difference in jump outcome.

I know of two fatalities directly attributable to incorrecly rigged static lines. I have personally seen very experienced jumpers rig static lines incorrectly on numerous occasions. Frankly, I am surprised there are not more static line-related fatalities, and I expect there will be more in coming years as more new jumpers get into static line jumps without enough rigging/anchor setup experience under ther belt.

Thus, I make the following plea: if you are going to be doing a good bit of static line jumping - particularly opening new objects, with tieoff points of various configurations - PLEASE get with an experienced climber and have them show you a bit about knots, tension, edges, etc. Most any city in the US or Europe has indoor rock climbing gyms. For a few bucks, you can go in and take a course or, better yet, just arrange for an hour of instructor time to go over the mechanics of anchors.

Three things will result in this time investment:

1. You will be more confident in your rigging of static lines, which will translate into more fun jumping and safer jumping as you are not worrying about the break cord at exit point;

2. You will rig safer static lines, including knowing how to "jump down" your break cord safely and thus not leave "pooty" (climbing jargon for crappy old slings left behind on routes) at exit. You will not die because you fail to rig a static line properly;

3. You will know enough to keep an eye out for how your jumping mates are tying their static lines, and you can share this knowledge with them. This will make them better, safer jumpers - and it might well save the life of one of your mates.


Someday I'd like to write up a white paper of sorts on static line rigging, as a stater for new jumpers. However, there's really no substitute for hands-on learning when it comes to rigging climbing anchors - a few minutes with a good, knowledgeable instructor is going to be worth much more than hours of book learning, hands-down.

So, again, my plea to folks: PLEASE take the time to learn about anchors before you really trust your life to those static lines. Experienced jumpers like JJ know enough to rig safely and do static lines without PCs. I agree that, for someone with that knowledge, there are situations where no PC is safer than having one to snag during the jump. However, for ANYONE with less than that knowledge, that's a fatality waiting to happen.

I'll also extend an open invitation: if you ever see me, or are jumping with/around me, and want to do spend a half hour or so going over anchor rigging. . . just ask! No matter what I'm doing, I'll be glad to take the time and share what I know so that we can all be safer in our jumping.

Static lines are really fun, and can be a safe part of BASE for many jumpers. However, doing them without some anchor rigging knowledge (not just urban legend lore passed down from one jumper to another) is stunningly dangerous. Climbers trust their lives to all sorts of funky anchors, all the time - there's a deep trove of super-solid knowledge to be gained from the climbing world, and it only takes an hour or so to get all that benefit. From there, you've got it for the rest of your jumping career and can share it with others.

Peace,

D-d0g

[d-dog]

<dupe post - sorry!>

[Baxter]

Tom wrote a very good article about static lines some time ago. I hope he doesn't mind that I have copied it below as I couldn't find the thread to post the link.

Baxter.


"Static lines are pretty simple. All they really entail is using some kind of breakable cord to attach the bridle to the object. Here's a rundown on one fairly standard method. While still at home, starting with a packed rig: 1) Find a relatively cheap sling, and a carabiner you can afford to lose (you can replace these components with all kinds of stuff—I know one jumper who uses sailing lines and clips, and BR used a stainless steel cable and clip on the HOPE building escape rig--just make sure the gear you use is bomber, because if it breaks, you'll end up riding the white bus with the flashing lights). You'll leave these at the exit, and will either have to abandon them, or retrieve them after the jump. 2) Tie the break cord through (a) one end of the sling, and (b) the PC attachment point on your bridle (attach it to the bridle itself, not the PC, as it will load straighter, and be less likely to break prematurely). Use the standard static line knot. You can learn it from anyone who has packed static line rigs or teach yourself—I have attached a diagram below. Use this knot to minimize bends (weak points) in the line, to ensure consistent breaking tension.3) Use a tailgate rubber band to control the bridle (S fold the bridle into the rubber band, so it will slide out easily). 4) Pack your PC with the whole mess (static line, carabiner, bridle, etc) all inside the PC, where you would normally stow the bridle. This step isn't critical, but it does make it much nicer to get the whole setup to the exit point. At the object: 5) Put on your rig normally, with the PC still stowed. This avoids confusion with the bridle, and possible misrouting. 6) Unstow the PC, and have a friend check the bridle routing. 7) Use the carabiner to girth hitch the sling onto the exit point (hand rails are pretty good for this, but you may have to improvise). Sometimes, it helps to bring along a long sling or piece of rope/cord and some protection, so you can create an anchor to S/L off of (I used half my rack, and two forty foot slings creating the anchor for one 150' cliff, and I know that someone got so sick of building anchors at one popular static line cliff that they sank two bolts to static line off). 8) Climb onto the exit a few feet away from the static line, so that you don't tangle with it. Be careful to control the whole setup while you climb over. 9) Always have someone check the routing of the S/L and bridle before exit. Some people actually hold the bridle and or PC loosely in one hand (as if PCAing themself). I only do this in high wind (to keep the PC deflated), though. 10) Exit, and get on the opening fast. You won't have much time to fly. Notes: 1) Leave the PC attached to your bridle. People have died taking their PC off, when the break cord broke prematurely. 2) Get your break cord from one of the gear manufacturers, or from a drop zone (it's the same stuff they use for student static line rigs). I don't recommend using electrical tape, shopping bags, condoms, or reeds (all of which I've seen used at various times, mostly by folks with funny accents and a tendency to say "no worries, mate!") 3) You will want to practice your S/L off something else (like a nice high span) to make sure you've got it straightened out. 4) I'm sure I missed something. Feel free to contact me via email, or post questions, if you want clarification. ___________ --Tom Aiellotbaiello@ucdavis.edu" :D :D :)

[Skinflicka]

Why s/l without a p/c?

I use the same system as JJ in principle but I have a p/c too.

I've videoed a breakloop failure (single loop - actually a zip tie not a cord) and the resulting "freefall". I nearly pissed myself laughing but it could've been nasty.

Skysquatch would be dead today if not for that p/c.

My .02 - always use a pilot chute. As DDog will tell you...redundency in rigging is a beautiful thing.

Now go do something dangerous.

;-)

[imported_Tom Aiello]

I've attached the most current version (it's still a year or so old) as a .pdf file.

I hope this works...

--Tom Aiello
tbaiello@mac.com

[BasejumperJeff]

Just to clarify things, befor my first static line jump, I did do the reserch and read Tom's artical on how to rig it, and talked to a few jumpers that had experince with SL. My question is,
when you tie the break cord, should the loop be tight around the bridle and sl or should there be a little slack?

Thank-you

[imported_Tom Aiello]

I tie the break cord tightly. This seems to be working for me. I'd love to hear what other people do.

I haven't ever really thought about leaving any slack. It seems like the loop of slack would allow a few inches of give, increasing the "shock load" force on the break cord at bridle stretch (before you want it to break), thus encouraging premature breakage.

To me, it sounds like JJ's system is best (a tight "primary" loop with a slack "back-up"), since it offers redundancy in the system. I do generally leave my PC in place, though, since for anything but super-low (I'm thinking Canadian altitudes), in the case of a premature break, the PC could make the difference in which bus you take your next ride in (the white one with the flashing lights is my personal preference, rather than the long black one).

--Tom Aiello
tbaiello@mac.com

[BasejumperJeff]

Thanks Tom, as of present I always left a little slack in the loop, never had any problems but that doesn't I won't someday. I am going to experiment with the tighter loop as well as the back up loop, that idea does make alot of sense. Since I am a Canadian, the low stuff is everwhere.