base689 0 #1 July 27, 2004 > I wonder if it's okay to use a static line and have ground crew remove it as soon as the deployment is completed. Or you can use the "carry-with-you-SL" created (well, I got few inputs about it by somebody, yes... ) and patented (well, you know, not exactly yet patented, but I am on the way... ) by worldwide famous (well, at least my jumping mates and very few blokes abroad know me quite well... )by BASE #689. I haven't got yet tons of jumps with "carry-with-you-SL" system but the few times I used it, it worked pretty well indeed!!!! No trace left behind!!! Unless you witness the jump from proximity, you cannot say it was a SL jump (unless for the very high deployment).Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites
Faber 0 #2 July 27, 2004 so far do i have 20+ jumps from 180/165ft by the carry on SL(made after supervise from the master of this peice,thaks i dont know how to pay you backBesides that i can only say gooooood envention so far. Only thing i need is a thing that collect rubberbands and breakcord after the jump By the way Dexter that S is HIGH,your getting looooooooong canopy rides from there if you do it.. i personaly did 1 test jump off a 300ft A,then i were convinsed...just dont for get the PC Stay safe Stefan Faber Share this post Link to post Share on other sites
base689 0 #3 July 27, 2004 > so you use the length Carry on SL that fits for the object (so you minimize the risk of a SL hangup, which will ruin your canopy and the day). Well, indeed, if you followed LITERALLY my instruction, you must connect the "spare branch" of your "carry-with-you-SL" to the loop in your bridle via a loop of break cord, so the possibility of hang up is ZERO. In case of (temporary) hang up of "carry-with-you-SL" onto handrail/frame/object/whatever, after a split millisecond you will have broken such a link (it's just a second (=looser) loop of break cord, that some jumpers use it (the second break cord loop) when jumping off very low object where they DO NOT use the backup PC (scary!!!)). Yes, losing such an invaluable piece of equipment, yes, leaving traces, yes, but flying free toward freedom and not ruining at all your day (nor the canopy). P.S.: > i have 20+ jumps.... you have more jumps than myself using the device I created? I am jealous!!! P.P.S.: What about showing up at my places? What happened?Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites
NickDG 23 #4 July 27, 2004 From the photos the canopies appear to be 28-foot military surplus Cheapos, not 35-foot T-10s . . . All us "old school" folks made their first skydives with these. The bottom line is they are doing something very dangerous in that a first time jumper, doing a first time water landing, unless assured of being assisted, could find it difficult to deal with all those lines and all that material in the water. Nick BASE 194 Share this post Link to post Share on other sites
Faber 0 #5 July 28, 2004 Quote i have 20+ jumps.... you have more jumps than myself using the device I created? I am jealous!!! im living 5 mins away from this really nice 180/165fter which entertain me on wordkdays-nights...(night jump),actualy i got myself a bike as im too lazy to walk to the object,the bike has only been used for BASEBut hey we both wrote 20+ perhaps you have more than me anywaythink im about 22-23 or so Quoteyou must connect the "spare branch" of your "carry-with-you-SL" to the loop in your bridle via a loop of break cord, so the possibility of hang up is ZERO your using breakcord instead of a cornectorlink to secure the devise on your bridel? how can you then control that its the correct breakcord breaking first?I dont have anything my line can catch on the object im jumping at the time,but for future objects... Tom you perhaps want to Split the SL to another tread? QuoteWhat about showing up at my places? What happened? you never got my teksts or mails?We started Q about all the driving time down there and up back so we desided to wait untill we can book flight tickets and fly down there as i rater be there than sitting in a car,most of the time..Sorry if you didnt got the messegedesBut we desided to get more mony for such trip and actualy talked about getting them so we could plan a trip(that will work)next summer.sorry mate Stay safe Stefan Faber Share this post Link to post Share on other sites
DexterBase 0 #6 July 28, 2004 Wait a second guys! I don't mean to nitpick, but the device you are referring to as the "carry-with-you" static line bridle was actually my idea. I figured it out in a thread a little over a year ago. look here I'm sure someone has done it in the past before we brainstormed it. I emailed a leading BASE maufacturer to see if they had any interest and offered the idea to them. They thought it was a good idea and didn't see any problems with it. They asked me if there was a demand for it in my crew and I honestly replied, "No". So! If you're planning on patenting the thing, go ahead. I posted it here as a free piece of information for the BASE community. My offer to the BASE gear manufacturer was also free. Have a good day! Note: please don't take this post seriously! Share this post Link to post Share on other sites
base689 0 #7 July 28, 2004 > your using breakcord instead of a cornectorlink to secure the devise on your bridel? Yes, my friend, just have a careful look at my original photos (my special bridle is sort of green-blue colour and any piece of break cord is sort of whitish). > how can you then control that its the correct breakcord breaking first? It's very simple. The way the "spare branch" is made, makes it very long compared to the length of "really-going-to-break" break cord loop. The "linking-second-break-cord" loop has got at least 10 cm of slack. The first thing that happens when you jump off the object is that at line stretch you put force onto the "really-going-to-break" break cord loop and you break it. After another 10 cm of fall, you simply "finish" the slack of spare branch and you simply pull (giving a whiplash onto handrail) the "carry-with-you-SL" through the secondary break cord loop. When you pass the "really-going-to-break" break cord loop: 1) through first loop of main branch of CWYSL; 2) through second loop of main branch of CWYSL (the main branch of CWYSL is AROUND the handrail); 3) through loop of your bridle, you have a very tight "system". Such a "really-going-to-break" break cord loop is quite tight, perhaps 4 cm in diameter, all the (three) loops are quite close together. The spare branch is way longer that all the other parts and finally is physically connected to the bridle itself via "linking-second-break-cord" loop: there is a slack of at least 10 cm, reasonably about 15 cm. There is NO WAY to have the "linking-second-break-cord" loop to go under tension before or at the same time as the "really-going-to-break" break cord loop... ...unless you use a "really-going-to-break" break cord loop that has got a diameter of 20cm (using half a meter of break cord to form it)!!!!!!!! Normally, I use 25 cm of break cord to create the "really-going-to-break" break cord loop, of which length quite a bit goes into forming the knot, so ending to have a "really-going-to-break" break cord loop of 3÷4 cm of diameter, no more!!! Again, look carefully the original photos I sent you in high definition, got them zoomed and you will clearly see what I mean. In the mean time, take care!!!!!!Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites
Faber 0 #8 July 28, 2004 hmm i can rember alot of talking about it,and actualy thourght it were Andrea as he were the only one who actualy had made one,corret? Well i give both of you guys the credit,hell even all who responded to that tread Patent or not its so easy to make that if there is im making copyes for myself anyway I dont think Adndrea meant it serius aswell(as you said it your self its a year since) and dont come spoil my fun.. i like it weather who got the idea and so on.. i just jumps it(i really like the thing..) by the way from now on evrybody can call me lukey luke as i yesterday were abel to be so fast on my risers after pitching(had some funny winds so i expected funny shit to happen),that i couldnt find them as they hadnt left the harness yet luv ya guys(dont take that too seriously)by the way im on Dexters site,well atleast untill i get my gear home in 1 peice Stay safe Stefan Faber Share this post Link to post Share on other sites
base689 0 #9 July 28, 2004 > ...the device you are referring to as the "carry-with-you" static line bridle was actually my idea... > So! If you're planning on patenting the thing, go ahead. Probably it is the fact that English is NOT my first language and so my attempt of humor are not exactly taken the way they should be by native-English-speakers. Probably it is the fact that Italian humor is not exactly well understood by Americans. The only sure thing is the following: YES, Dexter, the idea of "carry-with-.you-SL" is YOURS!!!!!!! Perhaps I was the first to use it, perhaps not. Possibly I am the first to have used it AND to have posted about it and details of its setup. Furthermore, I must give credit to Michael-CRW for the idea (very smart indeed) of connection of "carry-with-you-SL" to bridle via a secondary break cord loop, just in case something got entangled, after a split millisecond you again free. Take care, my friend Dexter, where you are, try to come back in one piece and if you ever have the chance of coming to Italy, please drop me an e-mail that we can share few nice objects together.Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites
BASE813 0 #10 July 28, 2004 hey Andrea! hope all is cool with you! sorry still have not got hold of that video - but T is still moving around various relations for his rehab and has not returned home yet - I still have not got hold of my rig from him after 3 months! He is doing ok, but I guess with both legs fucked up it must be driving him mad! Nice to see ya back writting up - if your on MSN drop me a line (sms / email) and give me something to do during the day too! remember I am still in rehab but at least with one good leg!! Be cool Bro! Michael PS) I hooked up that guy with some numbers of people who will be glad to take him around on his visit (sorry I could not), just in case you did not know!! Share this post Link to post Share on other sites
TomAiello 25 #11 July 28, 2004 QuoteTom you perhaps want to Split the SL to another tread?/reply] Ah, well, here we go again...-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites Faber 0 #12 July 28, 2004 Quote Ah, well, here we go again... If any dont like that the carry on SL thing has been splitet by my request then speak up now or shut up for ever Its on my bill Tom,any agressions pointed at you by splitting this tread you can send my way and ill respond tem Thanks anyway... Stay safe Stefan Faber Share this post Link to post Share on other sites sum1sneaky 0 #13 July 28, 2004 For those of you who are looking, here's pics of base689's setup I was doing a bit of testing with one I made out of 850lb dacron and found some interesting stuff about knots. I've always tied my break cord in a circle using repeated square (surgeon's) knots - and this is what I've understood base689 to be using in the setup for the carry-on SL system. This knot is pictured in the first image (sl-carry-knot1.jpg) and the second (test1_knot.jpg). In all the pics, I've substituted the the bridle with a carabiner for simplicity of loading etc. I then piled weight onto the setup, very slowly and carfully so that no acceleration except for gravity is applied to the system. In this first test, the breakcord broke just after I took the picture (test1_hang.jpg). Go ahead and make fun of my weights. Then I piled all this junk onto the scale = (test1_weight.jpg) and the weight was 105 lbs at break time! The carry-on worked flawlessly and the breakcord broke in the middle of the loop. That seemed like a lot more than the 80 lbs it's supposed to be, so I decided to try another method, thus test2. In this test, the breakcord is tied to each end of the carry-on rig, and care would have to be taken to make sure there's not a lot of friction at the bridle attachment point (or else the force would be doubled!). The knots are detailed in (test2_knot.jpg). The weight is applied (test2_hang.jpg), and just after the last rock was added and that pic taken - it broke (test2_break.jpg). This time, the cord broke with 98 lbs. (test2_weight.jpg) - 7 lbs less than the previous method. This method would have a problem if the bridle bound the breakcord in any way - where as the circle/loop method used in test1 would always be free to break at the attachment to the carryon device. I also though someone might try to lower the force required by tying one end of the breakcord around the carryon device and the other to the bridle - leaving just one strand of breakcord in between. (test3_knot.jpg) This would be a BAD thing however, as when the cord breaks - the loop will still be tied to both sides of the carryon rig (test3_break.jpg) and force will then be doubled or worse. I'll be using it with the first method because it seems to have the lowest propensity for error. However, I would prefer it if it broke with less weight - any ideas folks? Share this post Link to post Share on other sites base311 0 #14 July 28, 2004 I'm curious to know what sort of 'thump' the weights made when they hit the floor? Gardner Share this post Link to post Share on other sites riggersam 0 #15 July 28, 2004 MIL-T-5661 Type I Plain Weave cord is designed to have a breaking strength of 80 lbs (minimum). That breaking strength is measured with one piece of material pulled in a straight line. Breaking strength will be reduced by any bends or knots used. The knots you have in Test 1 and 2 use a "loop" of the material, that is, two pieces. In theory, that would take the breaking strength to 160 lbs. As you found in your tests, the material's strength is reduced (and is weakest) at the knot, so that is where it broke (your test2_break.jpg). A 97lb breaking strength indicates the knot reduced the strength by 63 lbs or about 39%. That's par... Poynter's Manual, Vol 1, Section 8.6 indicates a 40% reduction can be expected with a bowline knot. I'd go with Method 1 as well - It keeps the whole sling from sliding around. And as you mentioned, I'd avoid method 3 like the plague... Mark Share this post Link to post Share on other sites riggersam 0 #16 July 28, 2004 When I did break cord tensile strength tests, I rigged the loop material up above my head with some webbing (hung it from my garage door rail anchor) and stood on the floor scale. As I pulled myself up using the break cord and webbing, I noted how much of my weight was REMOVED from the floor scale. That told me how much went to the breakcord. It was accurate enough... This worked because I weigh more than the breakcord was expected to hold... Mark Share this post Link to post Share on other sites sum1sneaky 0 #17 July 28, 2004 QuoteI'm curious to know what sort of 'thump' the weights made when they hit the floor? A "dull" thump - like the sound of my last post being deleted because it implied a threat of physical violence when comparing the thump the rocks made to other thumps that sometimes happen. Share this post Link to post Share on other sites TomAiello 25 #18 July 28, 2004 Oh, man, you crack me up. I really can't stop laughing right now.-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites TomAiello 25 #19 July 29, 2004 Do you know if it's possible to buy different strengths of break cord? Paragear only lists one kind, but surely someone, somewhere has needed lighter break cord for something.-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites NickDG 23 #20 July 29, 2004 Also consider that the application of force on the breakcord is not a static load, like the test method shown. Your all up weight is accelerating away from S/L at the moment that weight is applied to the breakcord. I'm not a mathematician, but this increases the forces applied considerably. I never seen, or heard of, a BASE jumper in tow (I guess we need a new phrase there) but the opposite, a premature parting of the breakcord, has occurred too many times. In the same vein, if you compared how we packed for BASE in the old days, when free packing was the rule, and how it’s done now, it’s like night and day. We used to be afraid of any type of reefing that could possibly (even though it was imaginary) hang up the opening sequence. We’d pack thinking, open, open, open. When we should have been thinking, don’t open, don’t open, don’t open. We learned the hard way it’s easier to pack in a way that could blow your stuff up, and much harder to do it in a way where it wouldn't open at all. One of the benefits of BASE specific gear, and BASE specific jumpers, is we don’t see much canopy damage anymore. I ripped the center cell rib completely out of a Cruiselite once time, and it scared me badly, but there were no BASE canopies available at that time, so I sewed it back together and kept on trucking . . . NickBASE 194 Share this post Link to post Share on other sites RayLosli 11 #21 July 29, 2004 I just can not decide if this is real or a hoax ? If this is on the level, there seems to be a Crap Load of extra variables added to a simple Tie-off static line. More variables = more chance of things Not Working. You maybe over thinking this one just a Bit ? Less is More Cant you *Simply* just tie off and jump ? Plain old Break Cord, Its Simple. It works. Share this post Link to post Share on other sites Faber 0 #22 July 29, 2004 sure you can,but then leaving a evidence at the object.. some objects its nice to have it removed soon as you jumped knowing that noone can see you were up there in the first place And that my freind is why the Carry-whith-you-SL were madeand actualy its faster to hook up than standard SL,i will preffere the carry SL anyday... Stay safe Stefan Faber Share this post Link to post Share on other sites base311 0 #23 July 29, 2004 QuoteI never seen, or heard of, a BASE jumper in tow (I guess we need a new phrase there) (stuff snipped) NickBASE 194 Object in tow?? I can't find it now, but I would swear I read of an incident once where some guy db'd or sl'd a B under construction and somehow the bag lanyard became engaged with the canopy/harness? and he swung back into the B and ended up grabbing steel or something.. then proceeded to unhook and climb down?? Maybe I'm just making this up... Tom: Dunno about the diff. break cord availability, but I built a sandwiched velcro version that does the same thing and the required force to release is infinitely adjustable (well, not infinitely - in the sense that I always managed to get it to release). My tests were not at all scientific, but based on my experiences with PCA-ing folks. Haven't had the occasion to jump it yet, but I would. Gardner Share this post Link to post Share on other sites base689 0 #24 July 29, 2004 > MIL-T-5661 Type I Plain Weave cord is designed to have a breaking strength of 80 lbs (minimum). > That breaking strength is measured with one piece of material pulled in a straight line. > Breaking strength will be reduced by any bends or knots used. WOW!!!!!! Really breaking load is with ONE SINGLE PIECE OF MATERIAL CONNECTING TWO PULLING HEADS?!?!?!?!?!? Until I read your post, I ALWAYS thought that, just because ALL THE BASE MANUFACTURERS were talking about 80 lb break cord and because our use in BASE (for SL jumps) is to tie such a break cord in a loop, the 80 lb breaking load was referred to the break cord ALREADY SET IN A LOOP!!!!!! So, finally, I discover that what we get is NOT the 80 lb break cord being little more robust than the "nominal" value, but actually is the opposite way around. What we actually rig for SL jumps is a 160 lb - 73 kg break cord but because the (surgeon) knot deteriorate (=sharp bending radius) 40% (I didn't imagine the deterioration was so HIGH) of the characteristics of the cord itself, we get something like: 0.6 · (160 lb - 73 kg) = 96 lb - 44 kg That's how comes the 100ish lb value of the tests of sum1sneaky!!!!! I justified the results coming from the tests starting from the wrong break load value!!!!!!! It's true: you never stop learning!!!!! But, honestly, I think that the BASE manufacturers SHOULD inform buyers of break cord about the real value of break load (so when you do a loop you simply get twice the break load) and about the high deterioration (40%) of doing the (surgeon) knot. I mean: it SHOULD be way more evident and way more clear in our world what we are EXACTLY using!!!! Thanks anyway, Mark!!!!Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites base689 0 #25 July 29, 2004 > ...consider that the application of force on the breakcord is not a static load... ...your all up weight is accelerating away from S/L at the moment that weight is applied to the breakcord... > ...but this increases the forces applied considerably Well, let's see. Our body in freefall WOULD exert a high force. Why "WOULD"? Simply because before break there no force applied anywhere (= not to a fixed point), gravity force is pulling you down and you accelerate, after break again gravity continues to pull you down. Your body does exert a force ON A STATIC/FIXED POINT only in the few split milliseconds you load the break cord and it breaks. Before putting tension on break cord and after break, there only gravity with no other force that opposes to it, simply it accelerates you. The bottom line is the above: even if your accelerating body would be capable of exerting a high force onto a fixed ppoint, the break cord cannot hold yourself more than its proper break load. Rather, I think an interesting argument is the following. Granted that 100 lb - 45 lb applied statically to break cord loop breaks it, what would happen to our break cord loop if a device capable of applying a variable force (=your body in freefall) actually start exerting an increasing force onto the break cord loop? When would the break cord loop break if such a variable force is applied dynamically/instantaneously to it? Would the break cord loop dynamically break BELOW 100 lb - 45 lb? Would the break cord loop dynamically break ABOVE 100 lb - 45 lb? I think the dynamic test can only be performed in a laboratory, putting break cord strings between the clamps of a dynamometer and setting it to pull at a fixed speed (perhaps few test at different speeds) and having it to record the load applied between the clamps, up to break of loop. And having a look at the results, especially reading the load AT break. If you take a 100 lb - 45 lb and apply it gradually to a break cord loop, at the very end of releasing it breaks the break cord loop. Given for granted that if you step "very fast" over a brick on the pavement, you exert onto brick twice your weight (=dynamic load) just for a split millisecond and then you exert just your weight, if you step "very slowly" over a brick, at the end of slowly process of releasing/loading weight you end up with your weight onto brick. So, if you take a 100 lb - 45 lb load and release it istantaneously onto a break cord loop, it WOULD exert for a split millisecond twice its weight, but simply our break cord loop cannot hold such a weight and it breaks exactly AT its (dynamic) break load. It would be really interesting to know if and how much the dynamic break load differs from the static break load of our 80 lb - 36 kg break cord. If you don't believe to the fact that instantaneously applying a weight onto a surface, the surface itself bear for a split millisecond bear a load twice the weight of the object, try the following. Take the scale you got at home. First test: put only one foot onto the scale and very slowly transfer your weight from the foot on pavement to the foot onto the scale: you will notice that the indicator on the scale increases up to your weight, without never exceeding your own weight. Second test: put only one foot onto the scale and transfer IMMEDIATELY, as fast as you can, your weight from the foot on pavement to the foot onto the scale: you will notice that the scale indicator will exceed your weight (you should read for a while twice your weight, but system itself could be not so fast in "chasing" the actual (maximum) weight value) and then, oscillating it will stabilize onto your weight. Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites Prev 1 2 3 Next Page 1 of 3 0
Faber 0 #12 July 28, 2004 Quote Ah, well, here we go again... If any dont like that the carry on SL thing has been splitet by my request then speak up now or shut up for ever Its on my bill Tom,any agressions pointed at you by splitting this tread you can send my way and ill respond tem Thanks anyway... Stay safe Stefan Faber Share this post Link to post Share on other sites
sum1sneaky 0 #13 July 28, 2004 For those of you who are looking, here's pics of base689's setup I was doing a bit of testing with one I made out of 850lb dacron and found some interesting stuff about knots. I've always tied my break cord in a circle using repeated square (surgeon's) knots - and this is what I've understood base689 to be using in the setup for the carry-on SL system. This knot is pictured in the first image (sl-carry-knot1.jpg) and the second (test1_knot.jpg). In all the pics, I've substituted the the bridle with a carabiner for simplicity of loading etc. I then piled weight onto the setup, very slowly and carfully so that no acceleration except for gravity is applied to the system. In this first test, the breakcord broke just after I took the picture (test1_hang.jpg). Go ahead and make fun of my weights. Then I piled all this junk onto the scale = (test1_weight.jpg) and the weight was 105 lbs at break time! The carry-on worked flawlessly and the breakcord broke in the middle of the loop. That seemed like a lot more than the 80 lbs it's supposed to be, so I decided to try another method, thus test2. In this test, the breakcord is tied to each end of the carry-on rig, and care would have to be taken to make sure there's not a lot of friction at the bridle attachment point (or else the force would be doubled!). The knots are detailed in (test2_knot.jpg). The weight is applied (test2_hang.jpg), and just after the last rock was added and that pic taken - it broke (test2_break.jpg). This time, the cord broke with 98 lbs. (test2_weight.jpg) - 7 lbs less than the previous method. This method would have a problem if the bridle bound the breakcord in any way - where as the circle/loop method used in test1 would always be free to break at the attachment to the carryon device. I also though someone might try to lower the force required by tying one end of the breakcord around the carryon device and the other to the bridle - leaving just one strand of breakcord in between. (test3_knot.jpg) This would be a BAD thing however, as when the cord breaks - the loop will still be tied to both sides of the carryon rig (test3_break.jpg) and force will then be doubled or worse. I'll be using it with the first method because it seems to have the lowest propensity for error. However, I would prefer it if it broke with less weight - any ideas folks? Share this post Link to post Share on other sites
base311 0 #14 July 28, 2004 I'm curious to know what sort of 'thump' the weights made when they hit the floor? Gardner Share this post Link to post Share on other sites
riggersam 0 #15 July 28, 2004 MIL-T-5661 Type I Plain Weave cord is designed to have a breaking strength of 80 lbs (minimum). That breaking strength is measured with one piece of material pulled in a straight line. Breaking strength will be reduced by any bends or knots used. The knots you have in Test 1 and 2 use a "loop" of the material, that is, two pieces. In theory, that would take the breaking strength to 160 lbs. As you found in your tests, the material's strength is reduced (and is weakest) at the knot, so that is where it broke (your test2_break.jpg). A 97lb breaking strength indicates the knot reduced the strength by 63 lbs or about 39%. That's par... Poynter's Manual, Vol 1, Section 8.6 indicates a 40% reduction can be expected with a bowline knot. I'd go with Method 1 as well - It keeps the whole sling from sliding around. And as you mentioned, I'd avoid method 3 like the plague... Mark Share this post Link to post Share on other sites
riggersam 0 #16 July 28, 2004 When I did break cord tensile strength tests, I rigged the loop material up above my head with some webbing (hung it from my garage door rail anchor) and stood on the floor scale. As I pulled myself up using the break cord and webbing, I noted how much of my weight was REMOVED from the floor scale. That told me how much went to the breakcord. It was accurate enough... This worked because I weigh more than the breakcord was expected to hold... Mark Share this post Link to post Share on other sites
sum1sneaky 0 #17 July 28, 2004 QuoteI'm curious to know what sort of 'thump' the weights made when they hit the floor? A "dull" thump - like the sound of my last post being deleted because it implied a threat of physical violence when comparing the thump the rocks made to other thumps that sometimes happen. Share this post Link to post Share on other sites
TomAiello 25 #18 July 28, 2004 Oh, man, you crack me up. I really can't stop laughing right now.-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites
TomAiello 25 #19 July 29, 2004 Do you know if it's possible to buy different strengths of break cord? Paragear only lists one kind, but surely someone, somewhere has needed lighter break cord for something.-- Tom Aiello [email protected] SnakeRiverBASE.com Share this post Link to post Share on other sites
NickDG 23 #20 July 29, 2004 Also consider that the application of force on the breakcord is not a static load, like the test method shown. Your all up weight is accelerating away from S/L at the moment that weight is applied to the breakcord. I'm not a mathematician, but this increases the forces applied considerably. I never seen, or heard of, a BASE jumper in tow (I guess we need a new phrase there) but the opposite, a premature parting of the breakcord, has occurred too many times. In the same vein, if you compared how we packed for BASE in the old days, when free packing was the rule, and how it’s done now, it’s like night and day. We used to be afraid of any type of reefing that could possibly (even though it was imaginary) hang up the opening sequence. We’d pack thinking, open, open, open. When we should have been thinking, don’t open, don’t open, don’t open. We learned the hard way it’s easier to pack in a way that could blow your stuff up, and much harder to do it in a way where it wouldn't open at all. One of the benefits of BASE specific gear, and BASE specific jumpers, is we don’t see much canopy damage anymore. I ripped the center cell rib completely out of a Cruiselite once time, and it scared me badly, but there were no BASE canopies available at that time, so I sewed it back together and kept on trucking . . . NickBASE 194 Share this post Link to post Share on other sites
RayLosli 11 #21 July 29, 2004 I just can not decide if this is real or a hoax ? If this is on the level, there seems to be a Crap Load of extra variables added to a simple Tie-off static line. More variables = more chance of things Not Working. You maybe over thinking this one just a Bit ? Less is More Cant you *Simply* just tie off and jump ? Plain old Break Cord, Its Simple. It works. Share this post Link to post Share on other sites
Faber 0 #22 July 29, 2004 sure you can,but then leaving a evidence at the object.. some objects its nice to have it removed soon as you jumped knowing that noone can see you were up there in the first place And that my freind is why the Carry-whith-you-SL were madeand actualy its faster to hook up than standard SL,i will preffere the carry SL anyday... Stay safe Stefan Faber Share this post Link to post Share on other sites
base311 0 #23 July 29, 2004 QuoteI never seen, or heard of, a BASE jumper in tow (I guess we need a new phrase there) (stuff snipped) NickBASE 194 Object in tow?? I can't find it now, but I would swear I read of an incident once where some guy db'd or sl'd a B under construction and somehow the bag lanyard became engaged with the canopy/harness? and he swung back into the B and ended up grabbing steel or something.. then proceeded to unhook and climb down?? Maybe I'm just making this up... Tom: Dunno about the diff. break cord availability, but I built a sandwiched velcro version that does the same thing and the required force to release is infinitely adjustable (well, not infinitely - in the sense that I always managed to get it to release). My tests were not at all scientific, but based on my experiences with PCA-ing folks. Haven't had the occasion to jump it yet, but I would. Gardner Share this post Link to post Share on other sites
base689 0 #24 July 29, 2004 > MIL-T-5661 Type I Plain Weave cord is designed to have a breaking strength of 80 lbs (minimum). > That breaking strength is measured with one piece of material pulled in a straight line. > Breaking strength will be reduced by any bends or knots used. WOW!!!!!! Really breaking load is with ONE SINGLE PIECE OF MATERIAL CONNECTING TWO PULLING HEADS?!?!?!?!?!? Until I read your post, I ALWAYS thought that, just because ALL THE BASE MANUFACTURERS were talking about 80 lb break cord and because our use in BASE (for SL jumps) is to tie such a break cord in a loop, the 80 lb breaking load was referred to the break cord ALREADY SET IN A LOOP!!!!!! So, finally, I discover that what we get is NOT the 80 lb break cord being little more robust than the "nominal" value, but actually is the opposite way around. What we actually rig for SL jumps is a 160 lb - 73 kg break cord but because the (surgeon) knot deteriorate (=sharp bending radius) 40% (I didn't imagine the deterioration was so HIGH) of the characteristics of the cord itself, we get something like: 0.6 · (160 lb - 73 kg) = 96 lb - 44 kg That's how comes the 100ish lb value of the tests of sum1sneaky!!!!! I justified the results coming from the tests starting from the wrong break load value!!!!!!! It's true: you never stop learning!!!!! But, honestly, I think that the BASE manufacturers SHOULD inform buyers of break cord about the real value of break load (so when you do a loop you simply get twice the break load) and about the high deterioration (40%) of doing the (surgeon) knot. I mean: it SHOULD be way more evident and way more clear in our world what we are EXACTLY using!!!! Thanks anyway, Mark!!!!Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites
base689 0 #25 July 29, 2004 > ...consider that the application of force on the breakcord is not a static load... ...your all up weight is accelerating away from S/L at the moment that weight is applied to the breakcord... > ...but this increases the forces applied considerably Well, let's see. Our body in freefall WOULD exert a high force. Why "WOULD"? Simply because before break there no force applied anywhere (= not to a fixed point), gravity force is pulling you down and you accelerate, after break again gravity continues to pull you down. Your body does exert a force ON A STATIC/FIXED POINT only in the few split milliseconds you load the break cord and it breaks. Before putting tension on break cord and after break, there only gravity with no other force that opposes to it, simply it accelerates you. The bottom line is the above: even if your accelerating body would be capable of exerting a high force onto a fixed ppoint, the break cord cannot hold yourself more than its proper break load. Rather, I think an interesting argument is the following. Granted that 100 lb - 45 lb applied statically to break cord loop breaks it, what would happen to our break cord loop if a device capable of applying a variable force (=your body in freefall) actually start exerting an increasing force onto the break cord loop? When would the break cord loop break if such a variable force is applied dynamically/instantaneously to it? Would the break cord loop dynamically break BELOW 100 lb - 45 lb? Would the break cord loop dynamically break ABOVE 100 lb - 45 lb? I think the dynamic test can only be performed in a laboratory, putting break cord strings between the clamps of a dynamometer and setting it to pull at a fixed speed (perhaps few test at different speeds) and having it to record the load applied between the clamps, up to break of loop. And having a look at the results, especially reading the load AT break. If you take a 100 lb - 45 lb and apply it gradually to a break cord loop, at the very end of releasing it breaks the break cord loop. Given for granted that if you step "very fast" over a brick on the pavement, you exert onto brick twice your weight (=dynamic load) just for a split millisecond and then you exert just your weight, if you step "very slowly" over a brick, at the end of slowly process of releasing/loading weight you end up with your weight onto brick. So, if you take a 100 lb - 45 lb load and release it istantaneously onto a break cord loop, it WOULD exert for a split millisecond twice its weight, but simply our break cord loop cannot hold such a weight and it breaks exactly AT its (dynamic) break load. It would be really interesting to know if and how much the dynamic break load differs from the static break load of our 80 lb - 36 kg break cord. If you don't believe to the fact that instantaneously applying a weight onto a surface, the surface itself bear for a split millisecond bear a load twice the weight of the object, try the following. Take the scale you got at home. First test: put only one foot onto the scale and very slowly transfer your weight from the foot on pavement to the foot onto the scale: you will notice that the indicator on the scale increases up to your weight, without never exceeding your own weight. Second test: put only one foot onto the scale and transfer IMMEDIATELY, as fast as you can, your weight from the foot on pavement to the foot onto the scale: you will notice that the scale indicator will exceed your weight (you should read for a while twice your weight, but system itself could be not so fast in "chasing" the actual (maximum) weight value) and then, oscillating it will stabilize onto your weight. Stay safe out there Blue Skies and Soft Walls BASE #689 - base_689AT_NO_123_SPAMyahoo.com Share this post Link to post Share on other sites
