Basejumper.com - archive

Was wondering how many people still use the primary stow before they S-fold the supension lines in the tail pocket for slider off jumps. I have been free stowing my lines for over the past 200 jumps with no ill effects.
How about some opinions. Some manufactures say to make the primary stow, some say not.?

C-Ya

Medium size tube stow on all my jumps.

I do two wraps of a medium rubberband on a 3" stow always unless under 200 feet.

That stow is coming off when you hit linestretch. There's really not that much force required to pop that stow. Try stowing and then pulling it out. I'd be more worried that the stow isn't tight enough rather than be concerned with it slowing down the opening.

The primary stow is very important and is the best way to ensure your lines do not spread out and allow the bottom skin to inflate before you're completely at linestretch. Use it! Proper deployment sequence is good.

I did about 100 jumps before I started using a primary stow, but I was counseled by a very knowledgeable jumper who explained why I should use that stow.

I have done static line jumps well under 200 feet with two wraps of a medium rubber band. No problems.

I recommend doing a go-n-throw from a conservative height to see for yourself.

Yo !

I've done it both ways, and cannot see any difference in actual openings. Primary stow looks like a good idea and i use it when forced to do a low jump

Slider-down jumps suck ass.

bsbd!

Yuri.

Why not under 200 feet? Do you think that it will delay the opening? And if yes, how many feet would you guess will you lose?
Al my sub 200 feet jumps where static line and like you I also do a primary stow. I think this will not affect the time of the opening at all but will help to prevent that the lines fall out of the tailpocket before reaching line stretch.

I always use primary stow for all my jumps no matter the altitude.. i do a single wrap always..

Do you use a primary stow when slider up (with direct control) on terminal jumps?
I have heard conflicting views ....
I'd be interested to hear your current view........
(not directed at you Faber.......I know those lil' square things scare ya..... )

Yes, I always use both direct and indirect slider control on all my whole 14 terminal jumps.

Thanks for the replys, I'm always looking to learn or to compare techniques.

I thought a little tech stuff is good for this forum every once in a while.

I always do a single wrap of tube stow for all my jumps, no problems also under 40 meters...

he he i were about to reply as i saw the above

The purpose of the primary stow is not to keep the slider up.

The primary stow is used to stage the deployment of the parachute. Ideally, the canopy should move to line stretch before it begins to expand. The primary stow is intended to keep the canopy together while it moves to line stretch, inhibiting expansion until after line stretch is achieved.

If the canopy begins to expand prior to reaching line stretch, there are several potential negative consequences:

1) Slack lines are thrown back and forth as the fabric moves outward. The lines are still in loops as this happens. This can increase the chances of a tension knot.

2) Slack lines can be pulled out of the tail pocket toward the canopy. As the line attachments move outward, they draw line from the tail pocket toward themselves. This line has to come from somewhere, and it is pulled (it is unrestrained without the primary stow)from the mouth of the tail pocket simultaneously with the normal line deployment (the lines feeding out of the tail pocket, running to the risers). Two different parts of the same lines are now being yanked out of the same (relatively small) opening at high speeds. This, too, increases the chances for a tension knot.

3) If the canopy somehow reaches relatively full expansion prior to reaching line stretch, it can decelerate before the jumper hits the end of the lines. This stops the jumper more suddenly (but not in less consumed altitude, actually), greatly increasing the opening shock that the jumper perceives. In the most extreme case, this can injure the jumper and/or damage the canopy. Picture falling at terminal and suddenly having a fully inflated canopy for the most extreme case, but be aware that I have seen jumpers knocked unconscious by this kind of out of sequence inflation on delays as short as 2 seconds.




The primary stow stages the deployment to slow the jumper throughout the process (instead of all at once), and reduces the chance of a tension knot resulting from slack lines being thrown around, or pulled multiple directions, as the canopy moves to line stretch.

I do a single wrap at pretty much any altitude.

With what size rubber band? I have used (many times) a single wrap with a small rubber band but prefer a double wrap with a medium band.

Single wrap with the medium sized rubber band.

My reasoning goes like this:

The stow band is there to prevent the canopy fabric from moving sideways. If it gets pulled outward, and flexes a little, it's not really a big deal. But if it is already tight, and it gets pulled outward and breaks, then you lose the benefits of having it in place. I'd rather see if flex a little and allow the fabric to travel outward a centimeter or so than to see it break and lose the line control entirely.

No one says I'm right, though--this is just my current opinion and reasoning. My thoughts change over time just like everyone elses.

Well said Tom.

I just would like to add something.

IMHO, another good reason to always use the primary stow is to retard tail inflation. I am of the idea that the more, well to some extent, the tail is retarded (pun intended ) the better the opening is.

The primary stow keeps the tail centered and trapped until the lines are free. By then the nose is ahead in the inflation process.

I also pack by trapping the tail and upper center cell as much as I can. So instead of wrapping the center cell around the pack job I just roll it around itself. Then I fold the ends of the stabilizers 90 degrees up and finally completely trap the tail with the "big" three folds.

I use it for both slider up and down and so far so good.

I started using this method for packing reserves too.

As for the rubber band...I got a Prodigy 175 (older school CRW stuff). The "thing" has a tail pocket and a primary stow, of course it's free-bagged.

Well, ever since I started to use a medium size tube stows the openings have been more on-heading. I switched back to a medium tan rubber band and I saw a degeneration in the heading department with both one or two wraps!

So now I use it on all by BASE canopies as well. Again thus far thus good.

The above could be all placebo

Does it look like this?

As far as I can tell, yes

Logically it makes sense to me and again so good so far!

I use a single wrap on slow speed and a single or double for high speed depending on how I feel about the tension of the stow at the time, "this feels about right for this jump".Also I have been using the above packing method for a couple years now and like the results, slider up or down. High speed or low speed this appears to give consistant deployments and is pretty fast to pack.

I do.

Exactly like that

I double stow about a 3-inch bite of line into a standard rubber band for all delays. When using a slider and a long delay, it's good to make sure the rubber band is as close to the slider grommets (which of course will be right up against the slider stops) so the slider isn't allowed even a tiny bit down the lines before line stretch.

Keeping the bottom of the canopy together till line stretch is a very good Idea. Staged openings = less chaos. Tension knots suck so do every thing you can to avoid them You may not feel a difference on slider down short delays but it can be seen on video and frame grabs.

I pack like that too, well close. the method is the same but the outcome is slightly different, but I really try to make it neat. cant compete with hookitt and dexterBASE.

did you think of laying the fabric same way each time will wear your canopy at thouse spots,also clamps makes some ugly scars to the canopy.. Not to speak about the way you need to huck the canopy to get the air out..
Just needed to pick on you packing natzies

I pack like shit expect the worst each time and gets happy suprised more times than you guys gets dissapointed

Hope you guys are doing great..

Every on-heading opening feels like winning the lottery.

As my canopy is traveling to line-stretch, I am getting ready to turn the 180 around. If you EXPECT a 180 on every jump, you'll never be surprised when it happens. You may still hit the wall, but you'll be better prepared than the jumper who is betting in getting an on-heading and doesn't. Two different mindsets which I believe will yield two slightly different reaction times.

But that's just my half-cocked hypothesis

if you look at the vid from our trip,at the part were we jumped a legal cliff somewere just to find out that it wasnt that legal im using a 0.42 on that jump

nobody else's pack job looks like that...

I understand the pros of the primary stow, but could there also be a substantial con concerning the primary stow for slider-down/off jumps as well? My main concern or thought is this: Once the pack job is out and lines have stretched to the point of the primary stow, is there a significant chance that, if the pilot chute is not centered and/or is oscillating, it may use the primary stow as a pivot-point to rotate the pack job, thus creating an off-heading? If so, what would be the best remedy for this without forgoing the primary stow. Hope this was clear. Thanks for any input!

Two locking stows on either side of the tailpocket? The purpose is preventing bottom skin expansion, right? so this would only partially still accomplish that task. I've heard of using two tailgates on a rollover before.

That's a new one to me.

Why would one jump with an oscillating PC?
That seems stoopid.
Take care,
space

Which Manu says not?

I'm not sure about the official recommendations, but I know that Anne jumps without one, and at one point BR recommended not using it for slider down. I don't know what Apex's positions today though.

It is my experience that if your pack job is going to "rotate" around a single point it can happen at any point on it's way to line stretch. Not just at the primary stow. If you think about it your lines are always paying out from a single point. I have video showing my packjob being a full 180 within several feet from my container.
I have never thought twice about using it on every jump I have ever done but also jump with several guys who refuse to use it slider down.

I use a medium rubberband and one wrap for slider down, I use a medium band a two wraps for slider up, along with direct slider control (half small rubber band on C line attachment point taking a bite of the top of the slider)
then wrapping the lines in the slider

Firstly, I think you need to stop and seriously consider your posts before posting.
Secondly, If 1 stow could cause off headings, How could 2 stows not cause more off headings?

I seem to remember Tom once saying that he had video that shows a difference between no stow and primary stow deployments. But that on video there was no discernible difference between 1 wrap primary and 2 wrap primaries. I can't clearly remember so hopefully he chimes in.

I can clearly feel a difference in the openings. one stow spanks me, two and my old neck can handle it.

I'll concede up front that you have way more jumps than me and probably an order of magnitude more years of doing this. So conventional wisdom says I should sit here and ask you to fill my brain with all the awesome things you learned. But I don't really like conventional wisdom, so I guess you'll just have to put up with my crazy ideas.

If you want to consider the system as a rigid body, then you should refer to the concept of rotational inertia, and note that by changing where the lines are attached to the canopy, you are moving the mass further from the center of the body, lengthening the moment arm and increasing the force needed to rotate the body by the same degree. But I think it's a little naive to think that our parachutes can be considered as rigid bodies, especially when they are hooked up to different attachment points (the two different theoretical locking stows). You could at the very least consider it as two different bodies, rotating on separate axes. In this case, there will be one of two outcomes (which one is about as random as your off heading being to the left or right). These two bodies will either attempt to rotate in the same angular direction or opposite angular directions. If they rotate in the same direction, the forces will effectively cancel each other out. If they rotate in opposite angular directions, they will cause the packjob to bow in or out, but they aren't going to allow the body to rotate on a single axis (which is the theoretical problem of a locking stow). If a locking stow is creating a pivot point, and turning it into two pivot points doesn't help, how is turning it into 32 pivot points (all of your line attachment points) going to help? I guess I should really seriously consider all of this though.

I know I probably sound like a condescending asshole, and I really shouldn't be condescending to someone more experienced than me (or anyone for that matter). But the guy asked for a solution to the pivot point while maintaining the primary stow. Do you have any ideas that fall within that criterion? Two primary stows might not work, but it isn't some un-thought-out bashing on a keyboard either. If you think I'm wrong, feel free to tell me why. I would rather post something, look like an idiot, and find out why I'm wrong than wait to be spoon fed everyone else's ideas. If you just want to reject any attempt at original ideas, then what's the point of having a discussion in the first place?

And all this to say, I think the idea of the locking stow being a pivot point is a little silly in the first place. What do you think your bridle is?

And if we concentrate on keeping our shoulders level during deployment, all of this becomes mostly moot, yes?

Well, I think the idea of it being a pivot point is mostly moot in the first place. And having your shoulders not level is going to cause problems regardless of a locking stow. And your perfect body position would have to be coupled with an ideal pilot chute, with left/right symmetrical pilot chute and bridle attachment points. And a perfectly equal length of line taken for the bight on every jump. Then it would be mostly moot.

Someone once told a friend of mine not to worry about brake settings or riser turns, because all you needed was good body position. I'm a little skeptical about that.

Well you can cut that shit out. Plenty of people out there have way more jumps than I do. Unfortunately gear knowledge doesn't come from jumps. It comes from somebody taking the time to educate themselves on the subject.

Sometimes conventional wisdom is backed by 50+ years of parachute deployments.

You wouldn't be creating 2 points working to balance the system. You would simply be adding a 2nd single pivot point for your canopy to spin on. This is one of the leading causes for spinning line twists in skydiving. Every single time a line stow has to release it creates an opportunity for the pack job to spin. The 32 points you refer to is inline with your thoughts but that is only because they are all evenly loaded at the same point in the deployment.

Read my last post. Adding more line stows does nothing to change the fact that your lines are still going to be reduced to the tail pocket opening. And it is my belief that the majority of offheadings are caused on the way to line stretch not at the primary stow. Do I have any ideas on how to improve this? No. I think freestow pockets are probably as good as it is going to get for us.

You would have to be very very creative to have an "original" idea when it comes to inflated nylon. These answers already exist and have for a very long time.

I actually believe that the bridle is a serious pivot point and beat it into students to ensure that their bridle is tight and centred when packing. I feel if your bridle is not centred it allows the canopy to initially be pulled from the container un-evenly which can then go on to cause bigger problems. Especially when you take into account the initial snatch of the PC and the weight of your canopy and the forces required to get it moving. I think this all combines for the optimal chance of causing off headings.

It seems like we actually agree on quite a bit. From the feeding out of the tailpocket and the effect of the bridle.


I realize that the people who came before us have improved our systems to the point that it's nearly impossible to make truly revolutionary changes these days. But that's not going to keep me from trying to figure out different stuff on my own. A year or so ago, conventional wisdom tried to tell me (on these forums) that attaching a static line at the end of your bridle was black death. So I did the calculations, and went to an object that was tall enough to take a 3 second delay on and tested it out. I proved to myself that conventional wisdom was at best misinformed. NOTE: I'm not advocating attaching a static line at the end of your bridle, just providing an example of conventional wisdom being flawed.


I don't think I adequately explained what I meant. I'm not thinking of putting all of the lines into two different bights in series (like a deployment bag). I'm saying take the left lines, and put those in one bight, and the right lines, and put those in another bight. These stows will load simultaneously. I realize this isn't doing us any favors for preventing line overs.


What about coiling the lines into the packtray? That HAS to have been done before. I have definitely seen it done on rounds.

I would hardly call that one conventional wisdom much less "Black Death". It is just the current trend. As you found out static lines work fine at the end of your bridle even if maths says you should halve your bridle length. Another trend was when people were attaching their static line to the bridle attachment on the top skin of their canopy. I prefer attaching static lines at the end of the bridle.

I would like to see the success rate of those loading evenly. It would also be interesting to see how half the canopy shakes off half a stow x 2. Also what if one releases before the other? Seems like more ways to create more off headings.

People stopped doing that on skydives due to it causing a variety of malfunctions. You would also probably still want some sort of Primary stow to prevent inflation before line stretch. So you would still have the issue of the Primary stow or run the risk of premature inflation. I cannot comment on the round you saw (were the lines just tossed in or rubber banded?) but these days most rounds still have some form of control to keep the skirt closed until line stretch.

I believe this was stopped in skydiving due to the possibility of the lines hitching on the open container flaps, resulting in a horseshoe malfunction.
There are systems in use where the lines are stowed in rubber bands in the container rather than on the canopy / bag, mainly in emergency rigs I think.

To use, or not to use, the single “primary” stow under the tail pocket...that is the question.

It has become a very personal thing. Some jumpers swear by it and others swear against it, as is evident in this thread. In the very early days of BASE tail pockets all of the lines were rubber band stowed. Yes, a full stow tail pocket. Then free stow tail pockets came along and having that one single stow made some feel better.

I’ve made a couple hundred jumps using the single stow. But since then I’ve made 4 times that many jumps without. I personally decided to stop using the primary stow on no slider jumps for a few reasons:

1- Any stow will not release all the lines at the same time. Any lines that are not in direct contact with the rubber band (the inner lines) will escape the stow first. The lines in direct contact will be released later. I didn’t like that.

2- With a single bridle attachment there is no counter force to the lines pulling the tail down. Try it. Open a pack job. Anchor the bridle and pull the container away from the canopy and see what happens. The primary stow will pull the tail down and distort the pack job. I didn’t like that. Now, try it again this time without the primary stow. Pick the one you like best.

I stopped using the primary stow on no slider jumps. Once the tail gate came along it was a better solution (in my mind). The gate is open or closed. All the lines are either trapped or freed at the same time. This was in contrast to point 1. The Multi provides the resistance that I believe is needed to eliminate point 2.

On a rare occasion (like when jumping a canopy with ZP) or when I really need one more reefing device to slow an opening down I might use the primary stow. But first I would much rather use several wraps of direct slider control (on slider up jumps).

For a no slider jump I believe the primary stow is not necessary, but a tail gate is.

For slider up- keeping the slider at the base of the stabilizer until line stretch is complete is very important. If you don’t direct stow the slider then the primary stow is the next best option to achieve that goal.

These are the observations that have impacted my packing decisions, but I understand and respect that other jumpers may prefer a different packing style. For this reason Apex BASE continues to put a primary stow on all of our canopies so the jumper can have the option if they believe it is of benefit to their style of packing.

Question for you-
Do you put a stowless bight of lines under the tailpocket, or go directly to coiling the lines into the tailpocket?

Straight to the tail pocket.