Slider off - primary locking stow

[BASE_689]

Let's state in advance that in all my slider off jumps, so far, I have always used the primary locking stow (locking a bite of lines with a tube stoe under the tail pocket).
By all my slider off BASE jumps I mean really all, ranging delays from 0.5 s (jump and throw) to 1-1.5-2-3 s, including also my SL jumps.
Now, I was wondering what the very experienced BASE jumpers do with their primary locking stow in case of very low freefall jumps and/or SL jumps.
I know that primary locking stow in case of slider off jumps is used to mitigate the outcomes of (possible) line dump: in fact, in case of line dump, the primary locking stow would keep slightly "closed", for a very short period, the canopy before reaching a proper line stretch, in order to avoid to have an open canopy above your head and THEN having line stretch: in case of a 3 s delay, that would hurt a little bit :-(
But in case of a "jump and throw" low BASE jump, a possible line dump would not be so dramatic, while the real "improvement" of NOT doing primary locking stow would be (hopefully) the one of speeding opening up.
Do the very experienced BASE jumpers out there avoid doing the primary locking stow when they do very low freefall jumps and/or SL jumps, in order to speed openings up?
Thanks
Stay safe out there
Blue Skies and Soft Walls
BASE #689 :D
e-mail: base_689@yahoo.com

[dexter]

That's an interesting question. I was actually going to post this question myself but I'm pleased to see someone beat me to it.

I actually do the opposite. I hardly ever use the primary stow for the slider down stuff. I'm very curious what the general consensus is from the experts out there. Sould you always use a primary stow? Sometimes? Doesn't matter?


Stay safe out there! ---Dex
dexterbase@hotmail.com

[Ghosty]

Very intresting question.
We here in Belgium jump always with the same configuration and never had 1 problem of this kind, based on more then then 2000 jumps all of us together. We make jumps from50m to all above freefall with always same configuration...idemdito for SL jumps. We not using a tube stoes but regalar small(rigging) elastics.

have Fun ;-)

[crwper]

I'm by no means an expert, but I've done s/l jumps as low as 111 feet and freefalls as low as 210 feet with the primary locking stow in place, without any problems. I use a large elastic on the stow, with just a single wrap. There's not very much force on there -- to be honest, I'm not convinced it does very much "holding together" of the canopy. I'd like very much to hear what configuration others are using on the primary locking stow.

Michael

[Rigalo]

I never use to use the stow on slider down, until I changed my packjob, and folding the stabilizers 45degrees up, before I get the packjob the size of the tailpocket. Why, because I thought that the stow would help very marginally to keep these stabilizers from 'grabbing' the air before the nose does. Some of my videos indicates that off-headings came from one side inflation first. Hence the above alteration.

I jumped it SL as well, and my Black Jack performs very well. No significant problems.

Off course, this is not scientific results, just an opinion with small test case. I walked away!

[eyespyeye]

How does the stow mitigate line dump? Even with the stow in place your lines can still be dumped out. The extra tension gained by the line stow will not help any more than the drag created by the canopy. I used to use the line stow on all but very low jumps until I thought about it, and asked a few questions, since then i've stopped using it.
Just my two cents.

[SBCmac]

I'm not an expert either but this is what I know and what I have been taught...

The stow that you are referring to is used for slider control and nothing else...

There are two types of slider control, direct and indirect. Direct slider control is when you use the stow on your center C-line to prevent the slider from falling down the lines before canopy inflation. Indirect slider control is when you use the stow underneath the tail pocket to prevent the slider from droping down the lines before canopy inflation. With that said and the fact that I use direct slider control, I never use the stow under the tail pocket.

You can go to BR’s site and read this info in the “BR Owner’s Manual” in the “Reference” section of their site.

Well I hope this info helps you out…

Thanks,

SBCmac

[BASE_689]

>The stow that you are referring to is used for slider control...
I know, I know that. And when I jump slider up, I use both direct (small rubber band) and indirect (primary line stow under tail pocket) slider control.

The main thread of this post of mine is referring ONLY to SLIDER OFF jumps.
I have been taught (in my First Jump Course) that when jumping slider off you'd better do a primary line stow under tail pocket in order to (in case of line dump) refrain parachute from opening up immediately while the lines are stretching. Worst scenario would be: no primary line stow, line dump, parachute prefectly open while lines are stretching: as soon as line are stretched, you get a jolly good "WHACK!!!!!!".

The reason of my post is to check what BASE jumper out there really do and HOW effective is such a primary line stow (slider off) in order to prevent (possible) problems caused by line dump.
And also to verify, if a good number of jumpers show up and say: "No, I never use primary stow in my slider off jumps", that without a (slider off) primary line stow there is NOT any problem on deployment.


Stay safe out there
Blue Skies and Soft Walls
BASE #689 :D
e-mail: base_689@yahoo.com

[BASE_689]

>How does the stow mitigate line dump?
Primary stow does NOT mitigate line dump, instead, possibly primary stow would mitigate the EFFECTS of line dump.

>The extra tension gained by the line stow will not help
>any more than the drag created by the canopy
In case of line dump, lines are free, they are NOT pulling the canopy down, canopy travelling down but only at a "small" speed, being its speed the speed it had at the moment of container opening, plus a little bit more speed caused by acceleration under its (=canopy) own weight. In this case (of line dump) the scenario is that your body is travelling down jolly fast and still accelerating, the canopy (not yet "mechanically" connected to your body because of "not-stretched-lines") travelling down not as fast as your body, but it is made of fabric and even a small air speed gets it started to inflate/expand. And this is a clear, granted and known phenomenon.
Now, the point is:
In case of line dump (jumping slider off), HOW effective is the primary line stow to refrain parachute from opening fast BEFORE line stretch?
Because, if such a primary line stow would sort a very neglectable "refraining" effect on opening of parachute in case of line dump, it would be perfectly useless to continue to do such a primary line locking stow jumping slider off.... ;-)

Stay safe out there
Blue Skies and Soft Walls
BASE #689 :D
e-mail: base_689@yahoo.com

[imported_Tom Aiello]

On very low freefall jumps (less than 1 second delay) and static lines, I don't use the locking stow.

I experimented with leaving the locking stow off on longer delays a while back. Most of the time it seemed to work just fine. However, after experiencing what you describe as a "jolly good whack" (I lost consciousness briefly--obviously the potential for disaster existed there) on a 2 second delay, I have returned to using the locking stow on everything but go and throw and static line deployments.

--Tom Aiello
tbaiello@mac.com

[SBCmac]

Since you know it so well, why are you using both direct and indirect slider control for slider jumps??? Do you really think two methods are better than one? Why don’t you use two pilot chutes just in case???

Again read my last post again and understand what is being said before you just pass it off as knowledge that you already have…

First off, you will never have anything less than a line dump, with or without the locking stow used. The only devices on your parachute that control the behavior of the lines are the tail pocket and tailgate… In other words, there are no tension stows that actually slow down the lines on deployment therefore preventing what we call line dump in skydiving. In BASE jumping, we want line dump to occur to open the canopy as quick as possible… That is why you have Dacron lines to help absorb some of the opening shock caused by line dump openings… The tail pocket merely allows the lines to be “line dumped” in a clean manner. And the tailgate, the only other line controlling device on your parachute, is used to encourage the nose to inflate before the tail. The tailgate also holds the control lines in the rear while the nose of the canopy inflates to help prevent a line over malfunctions.

So again, the stow under the tail pocket is for slider control… It does not prevent line dump or control the way the canopy opens on slider off jumps…

Take the time to go to either BR’s or CR’s sites to get info… Don’t just take what people have told you as the right way to do things… BR and CR are great people, I’m sure they would be happy to answer a question or two if the info is not already posted on their sites…

Again I hope this info is useful…

Thanks,

SBCmac

[imported_Tom Aiello]

>Since you know it so well, why are you using both direct and
>indirect slider control for slider jumps??? Do you really
>think two methods are better than one? Why don’t you use two
>pilot chutes just in case???

>Take the time to go to either BR’s or CR’s sites to get info…
> Don’t just take what people have told you as the right way to
>do things… BR and CR are great people, I’m sure they would be
>happy to answer a question or two if the info is not already
>posted on their sites…

You might want to re-read your above two pieces of advice. Last time I asked CR, they recommended I use both methods of control.

In the BR owner's manual, available, as you suggest on their web site, the section on slider control reads:

"3.3-2 Stowing the slider, direct control.

-2a Lift the center of the slider so that it puts equal force on all four grommets against the stabilizer stops. Fold the top of the slider, so the slider is now only 1-2 inches (2.5-5 cm) beyond the rubber band located in the C line attachment tab.

-2b Place a stow(s) of slider in the rubber band. The resistance placed on the slider by this rubber band will very due to type and size of rubber band, number of wraps on rubber band, individual methods and deployment speed. Drawing 3.6-1

-2c Continue with Section 2.3-5."

Referring to the packing instructions, from 2.3-5 on, we find:

"2.3-7b Optional with slider “indirect control“- Using the single stow (located between the Tail Pocket and the canopy). Grasp lines 6 inches (10 cm) below Tail Pocket. Pull the lines toward the Tail Pocket creating a bite. Locate the single stow between Tail Pocket and canopy, place line bite in rubber band creating a single stow. Drawing 2.6-10 Then tuck the stow between the canopy and Tail Pocket."

Based on my three minutes of research on their web site (thanks tons for the suggestion), I see that BR presents double control as one option for packing their gear.

Dissing people because they want to start discussions about gear configuration seems mildly counterproductive. Suggesting that they refer to manuals which disagree with the point on which you are dissing them is just plain foolish.

--Tom Aiello
tbaiello@mac.com

[dexter]

While there is valuable information posted on the sites you refer to, most of that information is very general in nature and is intended to cover as broad a group of jumps and jumpers as possible.

Your argument about two methods of slider control being unnecessary (and then combining that argument with a rediculous two-pilot-chute example) makes me wonder if you really understand what happens in that time between releasing the PC and unstowing the toggles.

Admittedly, my own understanding of this process is not without its shortcomings. I know that there are several jumpers out there who are jumping their asses off and thinking outside the box. There are a couple people I know who are willing to jump an equipment configuration that is not the "textbook method" to see what happens and to possibly uncover potential problems. These jumps have also lead to techniques that expand our already small margin of safety on many jumps. Where would we be without this?

The manufacturers have forgotten more than I will ever know about rigging, but there are jumpers out there who know A LOT about BASE. Listen to them with an open mind, that's the only point I'm trying to make here. Don't write their information off without knowing who you're talking to.


Stay safe out there! ---Dex
dexterbase@hotmail.com