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I've been BASE jumping for several years, and I have several hundred jumps. About 90% of my jumps have been 3 or less second delays with no slider.
When I was taught how to pack, I was told that you only use the primary stow (that short bite of line that you rubber band under the tail pocket before you stow your lines in the tail pocket) when packing slider up, as an indirect control for the slider.
I have never used the primary stow on slider down/off jumps, but almost everyone I see packing uses it. When I ask why, the predominant answer is "because that's the way I was taught."
What's the technical reason for that? If you use it for slider down/off, why do you do it? If you don't use it, I'd like to know why also.
I feel like it's a waste of time and it doesn't do anything positive for the opening. On the other hand, I feel like it COULD be a possible cause for delaying an opening by having an over wrapped or too strong rubber band.

Thoughts???

I feel that maybe the extra second it holds onto your lines, holds the tail back for that split second longer to allow the nose some extra inflation clearance?

2 wraps, every jump,
helps prevent your lines a dump.

(Im not a poet)

Yeah. I've heard that one before, but I don't really see how you can get line dump on a 3 or less second delay unless your tail pocket velcro is completely worn out and it won't hold at all. Could you elaborate?

Clearance from what?

Something like that, I guess. I don't know. I'm not a BASE jumper, just a guy who BASE jumps.

Keeping your Tail-Pocket Velcro in good form is a must for every jump . no Slider or up-Slider .

For Slider-Down it makes no difference either way for using a primary stow .

Slider-up . it is a necessity for a good line-stretch and you use it for a Canopy opening delay tool .
You can completely control your opening all the way to a snivel with just the number of wraps used in Primary Stow in conjugation with Direct Slider control .
.

It could be possible that keeping the lines stowed in the primary stow just below the canopy keeps the canopy inflation process from moving too far along before the jumper reaches the end of the lines, thus preventing an uneven inflation/loading of the risers, which I believe might be the cause of some offheadings.

In other words, inflation is theoretically somewhat delayed by the primary stow until the jumper reaches line-stretch and loads everything evenly... thus forcing the canopy open more evenly than it might open on its own without the driving force of the falling jumper.

If the canopy begins expanding on its own, it might pull the lines out of the tailpocket causing line dump to some degree... or out of sequence deployment, pulling lines from the other end. I think the primary stow might restrict the canopy just enough to prevent this in most cases... but I'm not really sure.

That's just my theory on why it's done... but I've tried both methods and haven't seen much difference. My regular method, though, is the primary stow always.

I'd be interested to see if anyone can verify my guesses better or show contrasting theories/reasons/evidence. Anyone?

Hi,
The primary stow is not (only) undirect control of slider, in fact it is not the main way of. The way is to give to the lines all the same lengh during the end of sequence when they are going out of TP, preventing some asymetric pull in the canopy deployment... so it could prevent some off heading. I use it all the time, 2 turns, SD and SU. This way was taught to me by Eric Fradet one of the most advanced jumper in all skydive and base jump equipment.
No delay problems, I use it for SL too.

Slider-OFF = 1

Slider-UP = 2

I think it helps to stage the deployment
as in getting to line stretch before my
big vented parachute starts to inflate.

To clarify, I use a standard flat rubber band not a tubular. 1 turn is not enough = same as not using it. But with a tubular 1 (but I prefer the first one). After each one should find its way and make its own test in vivo, that is the good way of practicing BASE.

I think it's oversimplifying to talk about the number of wraps and expect it to be the same for every canopy.

The line bundle will be greatly varying thickness, depending on the canopy. The difference between the thickness on a new Apex canopy (400 dacron lines) or an ultralight canopy with spectra lines and a canopy with an old school 600 lb dacron line set is very noticeable. Using the same number of wraps on those will give very different tension/holding to the stow.

You are right Tom, it depends on what kind of canopy and what kind of rubber band you use too. I just saw jumpers doing only 1 wrap on Troll with a standart flat rubber band than I have (cf picture) and it was the same as doing nothing. The strength at the opening is very strong (enough)! But sure you should adapt to own your equipment and understand the way and what you expect. So try and see.

I don't think it makes any difference whether you use it or not on slider off jumps. I've used one wrap stows, double wrap stows, and no stow at all depending on how I have felt over the years and have never experienced any difference at all in opening characteristics.

With slider down/off on a Blackjack 280, I use a standard Dacron rubber band, cut in half length wise, with a double wrap on the primary stow. Works for me.

 

1 wrap slider down troll245
2 wraps slider up troll245
flat rubberband

I always use a primary stow, from 120'SL, 200' free-fall to terminal. Full rubber band with 2 wraps. I've never had a problem relating to the primary stow not releasing or a hesi in releasing, the forces involved are just too strong.

Here's a video of what happens when you don't use a primary stow:

https://drive.google.com/file/d/1W0lRroKoP97sn7KsT4yQ2_C7TKulyPdF/view?usp=sharing

Interesting,
Does that jumper use a 'bury the tail' method to pack?
It doesn't look like it and I think a bury the tail method would alleviate this effect to some degree...

I think his body position "method" might also be part of the problem*
But I totally approve of the "jumping without pants" method which I swear to god it looked like he was doing the first time I watched it.

*I've done worse

That's an interesting video, best I've seen of tail pocket wrap around lines. But the wrap happens before the line stretch reaches the primary stow so I don't understand how one is related to the other? Can you explain?

I'm posting this video to show that about a foot or more of line comes out of the tail pocket from the canopy side before all the lines are unstowed and full linestretch is achieved. Around the 16 second mark you can see how the lines are feeding out of the tail pocket from both sides. As was hypothesized is post #8 in the thread.

What do you mean by tail pocket wrapping around the lines? I don't see anything that could be described like that happening in this video. You say it happens before line stretch reaches the primary stow, but the jumper in the video isn't using a primary stow...

I can't picture how a tail pocket would wrap around lines before the primary stow is unstowed..

Does anyone have a side-view, slo-mo video of a deployment that utilizes a primary stow, that they could post? To make a side-by-side comparison, would be nice to see.

Thanks in advance.

edit to add: pants optional

https://drive.google.com/...JA-/view?usp=sharing

Thanks! Do you know how many wraps on the primary stow, that jumper used?