vid666 0 #1 November 17, 2004 now that the whole NC story settles, perhaps we can go back to discussing BASE jumping .... a certain building. ~~ 252 ft to the landing area as you look at it, 186 feet to the bottom of the buildign - obviously we would like to open fast and fly long. an anchor point, about 2 feet from the edge. Seems solid, but feels a bit weary. Basically, it will definately hold throught getting a line stretch, but we have doubts it can hold on through too many 80lb pulls needed to break the cord. The cord is 7 strands - realistically we percieve if we cut a few ( to be determined ) strands, the breakforce needed is lowered, thus lessening the pull on the anchor point ( a 1 ft pole sticking out of the roof ). The question : is it advisible ? If so, how many strands can be cut to still ensure a safe linestretch ? ( i.e. - how much pull does it take to open a 2 pin rig and get the canopy to line stretch). Please post your thoughts/suggestions. Keep the flames in the other thread :) thank you. P.S. jumper1 Vented Flik 293/Vertex - going PCAd jumper2 Fox 245/Gargoyle - going SL Share this post Link to post Share on other sites
TomAiello 25 #2 November 17, 2004 QuoteSeems solid, but feels a bit weary. Basically, it will definately hold throught getting a line stretch, but we have doubts it can hold on through too many 80lb pulls needed to break the cord. If it breaks off, will it fall on your head and hurt? Or fall through your canopy and damage it (or knock it off heading?)? Serious stuff to think about. I'd take a long piece of 1" tubular webbing (about 40 cents a foot a climbing shop), and tie it to a more solid anchor further back. Then static line off of that. You might want to tie it up into a "take along" static line, depending on how much webbing you have to use (obviously, you don't want a 40' tail hanging off you). I'd definitely try to get it back afterward, if you don't take it along. But I'd take leaving it there (and potential damage to site access) over dropping a heavy anchor through my canopy/body.-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites
pBASEtobe 0 #3 November 17, 2004 QuoteSeems solid, but feels a bit weary. I don't know much but if I was even a little worried about my SL anchor breaking off I would find something else to use. I agree with Tom, tubular webbing at a climbing store is cheap. You can pick some up (here where I live) for $0.25/ft. Share this post Link to post Share on other sites
vid666 0 #4 November 17, 2004 QuoteQuoteSeems solid, but feels a bit weary. I don't know much but if I was even a little worried about my SL anchor breaking off I would find something else to use. I agree with Tom, tubular webbing at a climbing store is cheap. You can pick some up (here where I live) for $0.25/ft. You guys misunderstood me. I am not worried about the anchor point giving on this jump, I am worried about the fact that it can loosen up after a few jerks. I am 100% sure this one time it will hold with no visible damage or ill effects. The other point I was trying to get some help on was that the breakcord is 80lbs - i don't think it takes anywhere close to that force to get linestretch - so why not minimize the impact on the anchor if the anchor is the weakest link in this system ??? Again, these are my thoughts, and if they are wrong, I would like for somebody to point that out, and especially let me know WHY they think/determine so. tnx ! Share this post Link to post Share on other sites
bps 0 #5 November 17, 2004 Hello -- I believe Tom A., as well as the folks at Basic Research, did some research several years ago on the amount of pull force needed. I can't seem to find the threads, so I'm recalling this off of memory and my numbers may be incorrect. I want to say that somewhere in the neihborhood of 20 to 35 lbs was needed. However, it is important to note that there are SEVERAL variables that can drastically change this number. Some of these variables are (but not limited to): container being used, closing tension of the pins or velcro, size and weight of canopy, body position of the jumper, what your static-line is tied to, and even the wind can effect the amount of force needed. Bottom line, it would be real hard to narrow it down to a specific force each and every time. 80lb breakcord provides slightly more force than is needed, but in my opinion, that is a good thing. Even with that, 80lb breakcord has failed before, so it is not 100% foolproof. Personally, I would not cut strands on the 80lb breakcord to reduce its strength. If you really feel that less force is needed, maybe you could look into getting 50lb or 60lb breakcord for your project. Before using lesser breakcord, I'd make sure that I could get away with an unexpected freefall from this object in case the lesser breakcord prematurely breaks. You may also want to send an email (or phone call) to Apex Sports. The former BR folks may possibly have more experience than anyone in the static-line department and they might be able to provide more insight to your question. Good luck with your project! Bryan Share this post Link to post Share on other sites
peterk 0 #6 November 17, 2004 My opinion is that if I was SLing a 186' to impact building, I would want a very secure anchor that I had no doubt about, and at least 2 pieces of break cord. I get scared enough looking at one piece of fresh 80lb cord, at 220'. If this idea of using cut break cord onto a rickety anchor doesn't work at 186', things will suck pretty quickly for you...--------------- Peter BASE - The Ultimate Victimless Crime Share this post Link to post Share on other sites
Zoter 0 #7 November 17, 2004 Could somebody explain to me how you attach a static line/PC to an object so that the PC holds through line stretch and initial deployment but then 'breaks free' without damaging the PC. Im not asking to put it into practice !! I have just seen it a few times on video and wonder how its done...... Are there ever any issues with the PC/bridal not releasing and causing some sort of hangup or deployment problems? just interested....... Share this post Link to post Share on other sites
SBCmac 0 #8 November 17, 2004 vid666, The other reason you don’t want to cut the break cord is because of dynamic force. I was taught about dynamic force and static line jumps when I took BR’s FJC a few years back. I don’t know the best explanation for dynamic force, but it is basically what “bps” stated in his post. You may be able to determine the weight needed to open the container and extract the parachute in perfect conditions, but there are too many variables that can change the pull force needed. The example that BR gave in their cours was to tie a 5lb weight to 80lb break cord and drop the weight from the height of a table, the 80lb break cord will break… The cord breaks because of dynamic force that is created from the acceleration of the 5lb weight. So it may only be 5 lbs but with acceleration it excerpts more pull force than 80lbs. Same thing when you are doing a static line jump. In a perfects scenario it may only take 20-30lbs to extract the parachute, but how much pull force are you really putting on that 80lb break cord on every jump??? Speaking of break cord... And I apologize for going off topic... But, I'm running out of my supply of break cord and I was wondering if anyone know where you can get break cord, other than a BASE manufacture/Rigger? I’m hoping to find somewhere easy like a hardware store Thanks, SBCmac Share this post Link to post Share on other sites
vid666 0 #9 November 17, 2004 Quote Speaking of break cord... And I apologize for going off topic... But, I'm running out of my supply of break cord and I was wondering if anyone know where you can get break cord, other than a BASE manufacture/Rigger? I’m hoping to find somewhere easy like a hardware store Thanks, SBCmac ??? http://www.paragear.com/templates/base_template.asp?group=33#T1055 ? Share this post Link to post Share on other sites
SBCmac 0 #10 November 17, 2004 Awesome!!! Thanks SBCmac Share this post Link to post Share on other sites
diablopilot 2 #11 November 18, 2004 QuoteBottom line, it would be real hard to narrow it down to a specific force each and every time. Isn't that one of the advantages of a velcro rig compared to a pinned rig? More consistant pull force?---------------------------------------------- You're not as good as you think you are. Seriously. Share this post Link to post Share on other sites
Skydawg 0 #12 November 18, 2004 If you're a bit wary of your anchor, you could try putting in a climbing bolt. Share this post Link to post Share on other sites
DexterBase 0 #13 November 18, 2004 Well, you can get some from me. If you ever get your ass over to our place. I'll even put out some beer to see if I can lure you over. Want to hang out and make a jump this weekend? Share this post Link to post Share on other sites
Faber 0 #14 November 18, 2004 QuoteI was trying to get some help on was that the breakcord is 80lbs - i don't think it takes anywhere close to that force to get linestretch mate.. you want a canopy outso you can fly and land in the safe LZ,a 80lbs brakcord dont dameged your gear now why would you then give your self more bad odds to making it safe to LZ? Personaly i jump whith a back up break cord each time i jump SL.(2 peices of 80lbs brekcord,one longer than the other) plus my min. 45 pc. at this point i have no # on how many SL jumps i made so far,but can tell that my setup never failed or dameged my gear due a jump(my latest acsident aint to blame my gear,only me..). i will strongly recomend you NOT to use weaker breakcord.. Stay safe Stefan Faber Share this post Link to post Share on other sites
SBCmac 0 #15 November 18, 2004 Hey bro Well I'm jumping my new little sweet spot this weekend if you want to join me... And it's near your part of the woods. It would be great if you could join me. I pretty much plan on being there from sun rise to sun set on both Saturday and Sunday. And the weather is supposed to be nice all weekend... So bring your packing tools, some warm cloths (layers preferably) and come out and play I’ll E-mail you the details… Just awesome… This weekend is going to be so much fun, can’t wait … SBCmac Share this post Link to post Share on other sites
Zoter 0 #16 November 18, 2004 QuoteCould somebody explain to me how you attach a static line/PC to an object so that the PC holds through line stretch and initial deployment but then 'breaks free' without damaging the PC. Im not asking to put it into practice !! I have just seen it a few times on video and wonder how its done...... Are there ever any issues with the PC/bridal not releasing and causing some sort of hangup or deployment problems? just interested....... .........anybody? Share this post Link to post Share on other sites
SBCmac 0 #17 November 18, 2004 Zoter, There are several ways to do it; this may be why people are hesitant to answer... Not to mention, if done incorrectly (and even when done correctly) SL jumps can fail/release prematurely. So again this may be why people are hesitant to provide an answer. An example of how difficult of an answer in what you’re asking is like asking people how they fold their PC’s… Theirs the general concept, but everyone does their own thing that they think makes it open better… So please do plenty of homework prior to coming to a conclusion in how you go about doing SL jumps… I was hoping that BR still had their diagram on their site but they don't. I also went to CR's site and couldn't find anything on their site either. I'll post the way I do it but again realize that just like everything, everyone has their way of doing things. So I'm simply going to provide the way I do it, which is more or less the general concept... I'm at work so it's going to take me a little bit to draw up a raw diagram... SBCmac P.S. Again remember, I’m only showing you one of many different techniques… And not to mention, their are a lot more people that have more experience than me with SL... So those people please help me guide this person in the right direction. I'll at least provide the theory on one technique and maybe people can expand on it... Thanks Share this post Link to post Share on other sites TomAiello 25 #18 November 18, 2004 You always risk some PC damage. You have to try to adjust PC hang location to the specific anchor point (and snag hazards). I wrote up a "how to static line" bit a while ago. It's on another computer, but I'll see if I can find it and post it this afternoon. Or maybe DexterBASE still has it floating around?-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites Zoter 0 #19 November 18, 2004 Tom, SBCMac.... Thanks....Im just looking for the general 'principles' as I have no knowledge of it whatsoever.... And as already stated....its just for my own clarity...I m not going to try it !...so whatever you got is all good ... cheers Share this post Link to post Share on other sites SBCmac 0 #20 November 18, 2004 Zoter, Ok... Again I don't know how to draw so I hope you can understand the attached diagram Also, I'm more or less just trying to at least demonstrate the concept. So please do more research and talk to people with a lot of SL experience before attempting a SL jump. The one thing that the diagram doesn’t demonstrate is how you manage your bridle when standing at exit point. I personally “S” fold the bridle and use a rubber band to manage the access that is left over. Again be careful how you manage your bridle; there are many things that can go wrong with just your bridle… Again, get advice from others that have lots of experience on how they manage their bridle…. I can’t say it enough… Do your research and ask people questions, then come to a conclusion on what will work for you… I hope I helped a little SBCmac Share this post Link to post Share on other sites DexterBase 0 #21 November 18, 2004 If I can find it I'll post it. I'll look. Edit: ~elapsed time:10 minutes... I have no idea where I put it. I know I have it around somewhere. Probably won't be able to find it for a while. Share this post Link to post Share on other sites Zoter 0 #22 November 18, 2004 Thats a great picture...thankyou.... So from the diagram I am assume that the break cord 'breaks' (duh !) "releasing the PC and Bridal attached to the PC. Does the bridal attached to the structure serve a purpose?...ie is it designed to be able to break should a problem occur with the 'break cord' attachment. On alot of the videos I have seen the canopy is released from the container and the lines at line stretch before the PC is released ( ie before the break cord breaks).........if thats the case...why do you even need a PC attched on these jumps? Couldnt you attach the canopy bridle to the structure via the break cord directly? Excuse an idiots naiveity if there is a simple answer to these questions Share this post Link to post Share on other sites DexterBase 0 #23 November 18, 2004 The purpose of the webbing/rope/bridle/spectra sling/other stuff tied to the rail, is to keep the breakcord itself away from the anchor point. If the rail or beam or whatever is sharp or rough or has a small radius, and you tie the breakcord to it directly, the breakcord could part at a much lower load than desired. This could leave you in freefall with a closed container at a very low altitude. You want the breakcord attached until you're at linestretch- all the way at linestretch- before it parts. Let the super, overkill, strong piece of webbing take the abuse of the rusty jagged handrail and let the breakcord do it's job. Using a sling wrapped around the anchor point gives you more consistancy. When you're getting low, consistancy is the name of the game. Edit:clarity Share this post Link to post Share on other sites K763 0 #24 November 18, 2004 Hi All! Right off the bat, I would recommend the person asking the question be very wary of weakening their break cord. If it breaks prematurely and your canopy is not deployed, you'll be in a very dangerous position. I also have always used 2 loops of break cord, one tied tightly and the other a larger loop, so they break one at a time, one after the other. I will also always leave a minimum 45 ZP pilot chute on the end of the bridle. Pilot chute damage is not a concern for me on a static line jump; my life is definitely worth the $70 replacement value for the p/c. We are updating our website right now, and there is an excellent piece in the Tech News about a new bridle extension. This was created specifically for the Superbowl jumps, where we did NOT want any accidents to occur. Basically, this extension gives you 2 places to tie break cord, so you have 2 completely separate attachments to ensure deployment. This along with your pilot chute gives you 3 chances for deployment on a static line jump. Overkill? Probably not. It only takes on failed break cord loop to end your life. Break cord and the bridle extensions are available at Apex BASE Perris. Break cord is 50 cents a yard. Our phone number is 951-940-1324. Be safe, have fun, and soft landings! (oh, and reliable static lines, as well!) Karen Share this post Link to post Share on other sites ZegeunerLeben 0 #25 November 18, 2004 >>Is it true you started making break-cord to keep MM from SL'ing stuff with peices of string he pull-tested? 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TomAiello 25 #18 November 18, 2004 You always risk some PC damage. You have to try to adjust PC hang location to the specific anchor point (and snag hazards). I wrote up a "how to static line" bit a while ago. It's on another computer, but I'll see if I can find it and post it this afternoon. Or maybe DexterBASE still has it floating around?-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites
Zoter 0 #19 November 18, 2004 Tom, SBCMac.... Thanks....Im just looking for the general 'principles' as I have no knowledge of it whatsoever.... And as already stated....its just for my own clarity...I m not going to try it !...so whatever you got is all good ... cheers Share this post Link to post Share on other sites
SBCmac 0 #20 November 18, 2004 Zoter, Ok... Again I don't know how to draw so I hope you can understand the attached diagram Also, I'm more or less just trying to at least demonstrate the concept. So please do more research and talk to people with a lot of SL experience before attempting a SL jump. The one thing that the diagram doesn’t demonstrate is how you manage your bridle when standing at exit point. I personally “S” fold the bridle and use a rubber band to manage the access that is left over. Again be careful how you manage your bridle; there are many things that can go wrong with just your bridle… Again, get advice from others that have lots of experience on how they manage their bridle…. I can’t say it enough… Do your research and ask people questions, then come to a conclusion on what will work for you… I hope I helped a little SBCmac Share this post Link to post Share on other sites
DexterBase 0 #21 November 18, 2004 If I can find it I'll post it. I'll look. Edit: ~elapsed time:10 minutes... I have no idea where I put it. I know I have it around somewhere. Probably won't be able to find it for a while. Share this post Link to post Share on other sites
Zoter 0 #22 November 18, 2004 Thats a great picture...thankyou.... So from the diagram I am assume that the break cord 'breaks' (duh !) "releasing the PC and Bridal attached to the PC. Does the bridal attached to the structure serve a purpose?...ie is it designed to be able to break should a problem occur with the 'break cord' attachment. On alot of the videos I have seen the canopy is released from the container and the lines at line stretch before the PC is released ( ie before the break cord breaks).........if thats the case...why do you even need a PC attched on these jumps? Couldnt you attach the canopy bridle to the structure via the break cord directly? Excuse an idiots naiveity if there is a simple answer to these questions Share this post Link to post Share on other sites
DexterBase 0 #23 November 18, 2004 The purpose of the webbing/rope/bridle/spectra sling/other stuff tied to the rail, is to keep the breakcord itself away from the anchor point. If the rail or beam or whatever is sharp or rough or has a small radius, and you tie the breakcord to it directly, the breakcord could part at a much lower load than desired. This could leave you in freefall with a closed container at a very low altitude. You want the breakcord attached until you're at linestretch- all the way at linestretch- before it parts. Let the super, overkill, strong piece of webbing take the abuse of the rusty jagged handrail and let the breakcord do it's job. Using a sling wrapped around the anchor point gives you more consistancy. When you're getting low, consistancy is the name of the game. Edit:clarity Share this post Link to post Share on other sites
K763 0 #24 November 18, 2004 Hi All! Right off the bat, I would recommend the person asking the question be very wary of weakening their break cord. If it breaks prematurely and your canopy is not deployed, you'll be in a very dangerous position. I also have always used 2 loops of break cord, one tied tightly and the other a larger loop, so they break one at a time, one after the other. I will also always leave a minimum 45 ZP pilot chute on the end of the bridle. Pilot chute damage is not a concern for me on a static line jump; my life is definitely worth the $70 replacement value for the p/c. We are updating our website right now, and there is an excellent piece in the Tech News about a new bridle extension. This was created specifically for the Superbowl jumps, where we did NOT want any accidents to occur. Basically, this extension gives you 2 places to tie break cord, so you have 2 completely separate attachments to ensure deployment. This along with your pilot chute gives you 3 chances for deployment on a static line jump. Overkill? Probably not. It only takes on failed break cord loop to end your life. Break cord and the bridle extensions are available at Apex BASE Perris. Break cord is 50 cents a yard. Our phone number is 951-940-1324. Be safe, have fun, and soft landings! (oh, and reliable static lines, as well!) Karen Share this post Link to post Share on other sites
ZegeunerLeben 0 #25 November 18, 2004 >>Is it true you started making break-cord to keep MM from SL'ing stuff with peices of string he pull-tested? Share this post Link to post Share on other sites
