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Hausse

Why are chest straps the way they are?!?

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A friend of mine just caught someone with a miss routed chest strap and it got me thinking.

Why are we using those weird buckles to fasten them???

Rigs are getting more and more fool proof and yet we still use a buckle that can EASILY be miss routed, no matter how experienced you are, and yes I agree people need to and should be careful but still, this seems to be something that could easily be changed and could very possibly avoid a fatality.

Why not use a metal clip that does not need to be routed correctly every time but that one can just adjust and click in like a B-12?

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B-12s and even quick-ejector snaps used to be fairly common on chest and leg straps, but fell out of favor between ten and twenty years ago. One reason is that the newer buckles are lighter, but the main reason seemed to be the fear that the snaps could come open accidentally even when correctly fastened. No system is perfect, but standard buckles are easy to route correctly, easy to check, and very reliable. Having said that, I have B-12s on both my rigs' leg straps, just because they make it so easy to put the rig on.

"Extraordinary claims require extraordinary evidence." - Carl Sagan

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Well there has to be some way with modern materials to make buckles that can't come undone (like the climbing ones that are screwed shut), are light weight, low bulk and easy to use. I would think that they would have an advantage over the current ones as they could not be miss routed.

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I doubt there's a system of any kind that a skydiver couldn't foul up. Heard a good line today: "We could give you guys bowling balls and you'd either break 'em or get 'em pregnant!".

So yes, what you're talking about may be possible, but mis-routed chest straps are pretty low on the list of fatality causes (only two in the last decade, I believe), so the effort would probably be better spent in other areas.

"Extraordinary claims require extraordinary evidence." - Carl Sagan

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I also started jumping back in the day when B-12s were common; and I also don't like the fact that a single mis-step like an easily mis-routed chest strap on modern gear can kill you.

Having said that, I do note, however, that the B-12s were used back in the day when harnesses had single-saddles, not (present-day) split-saddles; and belly-wart reserves effectively acted as a "second chest strap." Also, holding onto other jumpers' harnesses wasn't common back in the pre-freefly days. Nowadays, with AFF, freefly and hybrid, I wouldn't want another jumper getting anywhere near my leg straps or single chest strap if I had B-12s on them.

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Yes, something could be developed. But with very limited market I doubt it will happen.

B-12's or quick ejectors can be and are used for chest straps routinely. I have 7 pilot rigs in my basement and all have snap chest straps. If you want one see if the manufacturer will authorize the change.

But both B-12's and quick ejectors need routine maintenance and inspection. I jumped quick ejectors for several years but would do it now. B-12s any time they add another check to your pre exist inspection. "Click" the gates to make sure they aren't stuck.

But chest strap buckles are a problem that doesn't need fixing. If someone cant' put on their rig they have other issues. My first rig had 7 points for adjustment.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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This is not intended to sound condescending. It might read that way to some, so my apologies if it does.

Chest straps are easily misrouted which means they're easily routed correctly too. Climbers check that their webbing is doubled back. (slightly different but close enough for a proper comparison) Skydivers should too and not doing so is extremely complacent. It's so simple that it should never be misrouted yet they are. I always, and I do mean always, check mine multiple times. I always look at everyone else's I can see.

I have a very casual appearance when it comes to jumping however, it's due to the fact I am 100% certain my gear is fastened to my body.

There are 3 thread through type pieces of hardware. 2 leg straps, 1 chest strap. Check them every single time you put on your rig and then do it again before getting on the plane. chances are you should be doing it again before leaving the plane.

Check your hardware, check your handles.

6 points total to check on a very simple piece of equipment. 2 leg straps, 1 chest strap, Main handle, cutaway handle, then reserve handle.

When you get up to exit the plane, check your main hand one more time so you know it's in place and reachable before exiting.

So the short version, I don't think the chest strap fastener needs fixing. Just have a long enough chest strap and fasten it :)
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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Chest straps are sometimes misrouted because the owner probably has never been explained the function of the adaptor or if you want the way it works.
FUNCTION or HOW IT WORKS:

The chest strap adaptor has a frame and sliding bar. When you put a tension on the chest strap it has to force the sliding bar to squeeze the free part of the chest trap against the adaptor frame. More tension on the chest strap more squeeze from the sliding bar.
If it is misrouted the chest strap will slide almost freely in its adaptor when tension is applied. Try it and you will see.
Now how a chest strap is well routed ? The strap coming from the attached end has to go first behind the sliding bar of the adaptor then threaded between the sliding bar and the adaptor frame (on the adaptor side located toward the attached end of the chest strap). If it's not clear I will send you pictures, just tell me.
Learn from others mistakes, you will never live long enough to make them all.

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Having said that, I do note, however, that the B-12s were used back in the day when harnesses had single-saddles, not (present-day) split-saddles;



I've never had a rig with anything BUT B-12's...other than my 'Stylemaster' which had QE's.

IMO they are safer than thread through hardware in that you pretty much gotta be brain dead to 'mis-use' the snap.

Yes a bit more attention as far as not dragging the rig across the ground and occasional inspections...but you should be doing that with thread through too.

&

...ever try to get out of a step-through harness in a water jump?










~ If you choke a Smurf, what color does it turn? ~

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...ever try to get out of a step-through harness in a water jump?



Yep. Piece of cake :)

If I did a LOT of them then sure, i'd opt for something a little easier... maybe but i don't have issue with it.

Also, all but a handful of jumpers ever fully submerge themselves into deep water, especially on purpose.

That reminds me, I was part of a swoop in to a river demo for a bunch of boater folks. After I stopped, the dumbass steroid freaks on the boat I landed near, said how badass that was and handed me a beer. I still had toggles in my hands treading water.:D

"Yeah man it was awesome!!!! (must feign excitment for the crowd) Thanks for the beer bro, perhaps you can hold onto that until my feet are back on the dock" :) ... [Smile, thumbs up]

Oh... huh huh...
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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Also, all but a handful of jumpers ever fully submerge themselves into deep water, especially on purpose.




The 'on purpose' ones don't bother me either! ;)


Your river jump sounds like one I did in Peoria years ago...B|










~ If you choke a Smurf, what color does it turn? ~

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The chest strap flat type adaptor commonly used is both light and 500 lbs strong proof. The chest strap is not subject to a very important force at opening but you could fall out of the harness if undone. You certainly wouldn't like to have a plastic buckle made in ..... (like found on a lot of sport goods) or having a heavy thick quick ejector (with padding under) isn't it ? The chest strap adaptor you see on most of the modern rigs is a compromise between strength and light weight which is the sign of a sound design.
I let you go since I was taking a pause. I am packing my reserve !
Learn from others mistakes, you will never live long enough to make them all.

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Chest straps are sometimes misrouted because the owner probably has never been explained the function of the adaptor or if you want the way it works.
FUNCTION or HOW IT WORKS:

The chest strap adaptor has a frame and sliding bar. When you put a tension on the chest strap it has to force the sliding bar to squeeze the free part of the chest trap against the adaptor frame. More tension on the chest strap more squeeze from the sliding bar.
If it is misrouted the chest strap will slide almost freely in its adaptor when tension is applied. Try it and you will see.
Now how a chest strap is well routed ? The strap coming from the attached end has to go first behind the sliding bar of the adaptor then threaded between the sliding bar and the adaptor frame (on the adaptor side located toward the attached end of the chest strap). If it's not clear I will send you pictures, just tell me.



Ok at the possibility of getting flamed here, How the hell do you mis-route a chest strap? They aren't exactly rocket science to figure out. I'm simply curious as to how this happens.
Muff #5048

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There can be load there... was it a racer that tore lose all the stiching on one side of the chest strap? Memory is failing me. And I seem to recall hearing that Booth played with a single layer type 17 sewn in chest strap. I heard that he rejected it when he found issues durring asimetric openings on drop test.
Setting peel issues aside sence we know that tension is not much over 500 lb has any one looked at some of the para glideing hard wear? They have some nice alumanum quick releases. And they use those for there leg straps. It's a seat but you can still wind up with load on them.

Lee
Lee
[email protected]
www.velocitysportswear.com

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Most straps also have a catch at the end to keep them from sliding completely though the locking mechanism. I've seen plenty of rigs without them. Seems like that extra fold at the end of the chest strap solves (or mitigates) a large portion of the potential problem of the strap slipping back through the lock unexpectedly. Any comments on this?
I will be kissing hands and shaking babies all afternoon. Thanks for all your support! *bows*

SCS #8251

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The chest strap flat type adaptor commonly used ...!



The document is attached in case you do not have it.
Except it is now PS70101 since PIA took over the specs.

Notice that the specs say "reversible". This means you can thread your chest strap equivalent to the 1 inch wide chest strap in the picture.

(This always extends the thread quite a few posts!)

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That is true. Just for the record that is actualy rather important. The leg straps will be rolled and sewn with x number of passes of five cord of x length at x stiches per inch with a minimum number of stiches. or they'll be split and sewn on an old mill rig. It's actually written into the line drawing of there tso. DO NOT CUT OFF YOUR LEG STRAPS TO MAKE THEM SHORTER. DO NOT TRY TO RESEW THEM WITH E-THREAD. Don't laugh I've seen people do it. Oddly no one has ever seemed to make a big deal about chest straps. It's a lot less force. It doesn't seem to have slip issues like leg straps. That's probbably because we use such aggessive hardware on them. If we tryed to use that on a highly loaded leg strap it would probable cut it in half. The fact that it's almost a straight pull rather then the smaller diamiter of the leg helps too. I think you'll find that the ones that aren't rolled at all are double layer 17. I don't think it could slip and a roll might be a bit thick to slip through the adapter any ways.

Lee
Lee
[email protected]
www.velocitysportswear.com

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I'm not worried about messing it up, I was just wondering why there isn't a more modern alternative.



I think the KISS principle (keep it simple, stupid) is generally the best approach with higher risk endeavors. Chest straps are comfortable, work, and are easy to check - just tug.

Often the modern alternative is more about sales than actual improvement, and the gains are outweighed by new failure points. This is especially evident in diving, which is a bit safer than skydiving. While regulators improved greatly, BCs have regressed.

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Hi Gary,

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(This always extends the thread quite a few posts!)



Ok, I'll bite. :P You must like being a trouble-maker. B|

Quote

Notice that the specs say "reversible".



IMO, this means that it can be mounted in either direction; with the marking showing or with the marking towards the body. It has the same strength and is dimensionally the same either way.

Quote

This means you can thread your chest strap equivalent to the 1 inch wide chest strap in the picture.



You got me confused on this. Your photo is of a MS/PS70101 which is for 1 3/4" webbing. The photo looks like two layers of Type 8 webbing. What is really interesting about the photo is that he/she has threaded it in reverse so the the running end is towards his/her body. I've never seen that before but it is interesting.

Of all the hardware used in the construction of parachute harnesses this is the only piece that is stamped out of sheet metal; not forged. Because of it's thin material it is difficult to get the edges eased so that they do not damage the webbing.

Just my thoughts.

JerryBaumchen

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Your photo is of a MS/PS70101 which is for 1 3/4" webbing. The photo looks like two layers of Type 8 webbing. What is really interesting about the photo is that he/she has threaded it in reverse so the the running end is towards his/her body. I've never seen that before but it is interesting.



Yep, that's why I said "equivalent". The 1 inch hardware goes by another number I'm assuming.

I like bringing up the routing because it is amazing how many people see that picture and immediately think it is not safe. The hardware is reversible so it is safe, just not conventional.

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Why are we using those weird buckles to fasten them???



Because they work, they're easy to use and inspect, they contain one moving part and have a high degree of reliability.

Any type of clip or locking buckle will have at least two moving parts, twice as many as the current arrangement.

On top of that, you would still need a threaded portion for the jumpers who prefer to loosen their chest strap after opening. So now you still have the same old problems in addition to the new problems.

Furthermore, any type of spring used to close or secure a clip or buckle would be a failure point you couldn't inspect. The spring will break when the spring wants to break, what then?

Proper training (a must for safe skydiving) along with complete and frequent gear checks (also a must for safe skydiving) will solve the problem, and possibly many others at the same time.

I vote for training and gear checks.

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