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landmissle

Semi-Stowless D-Bags

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I've been out of the sport for 10 years and am starting to prepare for my comeback...So, I call my local dropzone to purchase some new larger size rubber bands. I have a few left, but they are 10 plus years old and breaking a lot more frequently then I recall on my practice packing. Figured it's probably time to freshen them up. So guy in the rig shop says they don't have any rubber bands in stock to sell and, "besides, everyone has pretty much gone to semi-stowless d-bags. So we just give away the rubber bands."

I'm assuming they are "just giving away" rubber bands because the semi-stowless d-bags use half the bands. Besides feeling like a luddite and being behind the times, I have a few questions regarding these new fangled semi-stowless d-bags;

1) Are they really that popular and pretty much replaced the traditional (fully stowed?) d-bags?

2) I was always told that part of a good, soft opening deployment, was the methodical in sequence release of the lines from the stows. Stows too loose could contribute to a hard opening. Is having half the stows of any consequence for semi-stowless bags? Are they more likely to have hard openings?

3) Besides aiding in the speed of packing (fewer stows to deal with) are there any other advantages for using semi-stowless d-bags?

Thanks for any info folks!

 

 

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The way I see it, bands have two main tasks:

1) Non-locking: Keep the lines organized so they don't tumble around in the wind and get entangled with everything

2) Locking: Keep the container in the dbag until the line stretch.

Semi-stowless dbags replace the non-locking bands with a pocket. As far as I know (and can imagine) only if locking stows break before the line stretch you can get a hard opening, and that doesn't really depend a lot on semi-stowless vs "regular" (non-locking stows can keep the bag closed a bit as well if they're not on the closing flap of the dbag, but that's in the domain of luck I guess).

I find the line stretch from the semi-stowless cleaner as it keeps the lines from the wind while providing less resistance, meaning it's less likely to jam a bit and add a twist to the dbag. And the packing is faster of course because you have to replace broken bands less frequently.

I've heard of the semi-stowless dbags with magnets biting the canopy after extraction, so I prefer plastic tabs.

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Over here, they are somewhat popular, maybe a third of the jumpers use them. Openings are rather good, as they help reduce the linetwists, as the bag is.more stable when leaving the rig. Improvement in speed of deployment is marginal, and so is the improvement in speed of packing. My primary reason for using them is less line twists, and fewer rubber bands to change out.

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(edited)

Semi-stowless bags are the standard. Standard D bags are completely obsolete and provide absolutely no benefit. There are literately millions of skydives that have been conducted on semi-stowless bags. I have over 1200 on one myself. They are highly tested and highly proven. Also, reserves have used stowless methods for lines since reserves were in existence. Very few manufacturers use any form of direct stowing for lines. Also, ALL BASE canopies use stowless methods for the lines. There are no line stows in BASE jumping.

The only reason why standard D bags even exist anymore is just so manufactures can up sell to a semi-stowless. In reality, standard bags should be phased out of existence entirely.

Edited by 20kN

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(edited)

SunPath only sells semi-stowless bags for ZP canopies 150 sq ft and smaller. They are great and control the line extension better than rubber bands as there is no uneven tug from side to side to cause line twists. Also, fewer rubber bands to deal with, but, stowing the lines in the bag does take a little time to get used to.

Edited by BMAC615

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(edited)

1. Semi stowless bags are very popular now.  I don't know if they are more or less common than standard D Bags (ask your local gear dealer...) but I would not be surprised if they were more popular at this point for new gear.

2. Kind of.  Hard openings can happen for a variety of reasons.  There's a video from PD at PIA that talks about some of them for like an hour. 

The general gist is in modern canopies if you have a properly sequenced deployment within reasonable parameters (i.e. not going 200 mph, no line dump, no slider dropping prematurely) your opening should be fine.  The primary control of your opening is your slider.  The line stows were there to largely prevent line dump, not to slow down the speed of the bag.  That said, reserves and BASE have taught us over some decades that line stows are not the only way to prevent line dump.  Each of the semi-stowless bag designs should have some way to ensure a properly staged opening (hopefully...).

But staging/sequence is half the story.  The rubber bands do slow things down a little.  That's why PD keeps on with the "double stow everything!" diatribe.  Being in the sport long enough to remember switching from a standard D-Bag to a semi-stowless, I can tell you that the openings did become slightly more positive.  But the difference wasn't nearly the dramatic difference PD made it out to be.  Just a slight difference and I didn't mind it.  So technically, more likely - yes.  How much is the real difference?  Perceptible, but with a reasonable canopy you should be fine.

One other aspect - semi-stowless bag designs vary based on manufacturer.  Some really suck.  One design that really really sucks was just posted to this thread.  Talk to your rigger if in doubt.  My personal favorite is the old UPT design (still used by sunpath I believe).   I personally don't like the Chutingstar/RI design.

3. Much better heading performance.  Pretty night and day.  That's the reason everyone gets them these days.  A lot fewer line twists.

Edited by lyosha

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On 3/19/2021 at 10:13 AM, BMAC615 said:

SunPath only sells semi-stowless bags for ZP canopies 150 sq ft and smaller. They are great and control the line extension better than rubber bands as there is no uneven tug from side to side to cause line twists. Also, fewer rubber bands to deal with, but, stowing the lines in the bag does take a little time to get used to.

I would guess the 150 and lower is because of the length of the lines that would need to be managed in a semi-stowless environment. If everyone was a rigger this rule would not apply. I see zero disadvantages from a semi-stowless bag. I would get a semi-stowless bag direct from the manufacture. 

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On 3/18/2021 at 6:37 PM, landmissle said:

 

 

 

There are two stages of openings - the part where the lines stow out, and then when the parachute opens.  The first part is DEFINITELY faster with the semi-stowless - I am used to all double stowed rubber bands where my initial situp is super gentle  This week I did a couple jumps on a demo canopy with a semi-stowless -the initial part of the opening was jarring but the second part was soft (depends on the main.)  I would never jump a semi-stowless with my gigantic camera helmet - the non-stowed portion seems to fall out practically instantly causing a sudden jolt before the parachute does its part.  In reality the semi-stowless bags are just like reserve freebags which are designed to open super fast.  

I don't mind them on a normal jump where I have a light helmet on and my neck can take that initial jolt, but I would never have one when I jump my great big camera helmet.  My neck would not be happy   

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(edited)

Semi Stowless Bag Review by Sandy Grillet

I first started jumping the semi-stowless bag from UPT with the two locking stows and 4 tuck tabs, prior to them going into production because the designer wanted his design to
be field tested using mostly an everyday jumper with what he thought would be typical skydives and pack jobs.

I make 325-350 jumps each year. Roughly 1/3 of which are camera jumps - filming tandems. The rest are belly jumps as 4 and 8 way training, competing, coaching and FS organizing at boogies and events. I make use of packers for about 275-300 of my jumps
(one of the reasons for the designer to give me a prototype of his bag). I now have more than 2500 jumps on the semi-stowless bags using Katana 120s, Velocity 103s and Valkyrie 96s. I have zero jumps (that means none) on wing suits. So my opinion
is based on my personal experiences and my general knowledge of skydiving and deployment sequences.

I have nothing but good things to say about the semi-stowless bag. It is essentially set up the same as a reserve bag except it uses a flap with tuck tabs for figure-eighting the lines instead of sliding them down into a pouch. This allows the packer to see what the lines look like as they are being figure-eighted - a good thing IMO. As recommended by the designer, I use large rubber bands for the two locking stows and double wrap them
around no more than 1 1/2 inch of line bite.

Some people will tell you double wrapping is not a good idea and may cause bag lock. This is a myth (assuming the use of large bands and the proper maintenance of your pilot chute and kill line length). I've been double wrapping large bands for 18 years on all my stows (locking stows included) even before the semi-stowless bag).

I love the openings of the semi-stowless bag. I've had mostly very controlled on heading openings. Any off heading openings (90-120 degrees) usually happen on my pack jobs because I've been told I sometimes pack a bit hastily. Thank God for packers.
 

The bag does allow you to get to line stretch quicker and cleaner than a conventional bag. I like this because I believe the majority of line twists start and are caused before the canopy comes out of the bag. Most jumpers replace the rubber bands only when they
break or are extremely close to breaking. How many times have you wrapped a band around a line-bite thinking "come on don't break..... just hold for one more jump"? This means our bands are generating varying levels of force on our line bites. Some hold
better and longer than others due to better (newer) strength. This imbalance of line bite strength often initiates rotation of the bag as the lines play out causing line twists. I believe the single wrapping of line bites sometimes allow the lines to deploy out of sequence allowing one or more lines to sneak out early and wrap around another line bite which can and has caused bag locks and hard openings. I also believe too much line bite helps cause line twists and out of sequence line deployment which can also cause line
twists and bag lock.

I've seen footage of quite a few opening sequences using high speed cameras, which means you can slow the footage down by roughly 2/3 of a normal video camera slow motion. The footage is quite enlightening. I think most people would be shocked to see
how much bag dance and out of sequence line deployment is actually going on above our heads. Now, this doesn't mean that it happens all the time but it does happen pretty regularly. It also does not mean that it couldn't happen with the semi-stowless bag but the design is such, and testing along with hundreds of thousands of jumps has proven that bag dance and out of sequence line deployment is dramatically reduced to almost
nothing.

I like my lines to come out quickly and cleanly (like a reserve) so my canopy can hit the air with the greatest chance of an on heading deployment from the bag. After that, it's a matter of how well you packed and placed the canopy in the bag (especially the control of your slider), how well your canopy is in trim (lines), your body position during deployment and the design and wing loading of the canopy.

As I mentioned earlier, you do get to line stretch quicker but it does not cause faster or harder openings. The openings are controlled by the slider and the packing (and canopy design). If a person gets a hard opening it's usually because the slider was not well
controlled during the packing and bagging process. There can be other factors but it's almost always the slider. The semi-stowless bag does not affect the hardness or softness of the openings. It only affects the speed to line stretch which I like. It also allows the
lines to play out in a more orderly fashion. We must remember, we only use rubber bands to keep the lines in place until they are needed and then to allow them to play out in a relatively orderly fashion in what is otherwise a fairly chaotic couple of seconds. But those bands can and do create other issues as I mentioned above. The semi-stowless bag does exactly the same thing but simply allows the lines to play out more consistently.

All of this can and has been debated by those who are naysayers. And I believe healthy, sensible, civil debate is good and necessary for further development of ideas in our sport and gear. And I welcome the debate by those who have actually given some rational and original intellectual thought to this or any subject.

Of course this is just my humble opinion –

Sandy Grillet

Full disclosure >> I am a UPT Vector dealer.

 

 

Semi Stowless bag open.jpg

Semi Stowless bag closed.jpg

Edited by Skydivesg
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11 hours ago, Skydivesg said:

 

I don't like the big initial jolt - I definitely agree that you are more likely to be on-heading but when I open with all of the lines double stowed, the first stage of the opening is slow and soft, and then the second stage is all about the parachute and its pack job.  With the semi-stowless bags the initial jolt is much more abrupt, and I would be afraid to jump with my heavy camera helmet on one.  Even on normal jumps with a standard helmet, the semi-stowless bags always have me going UHH on the first stage of the opening because its so much faster - like a reserve opening.  I definitely get if you are on a super tiny canopy where heading control is crazy important I think it could be good.  I jump more 'traditional' canopies which are nowhere near so sensitive to minor issues compared to the sub-100 stuff and I'd rather have the softer opening in exchange for more off heading than the brisk first stage.  

 

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On 3/19/2021 at 12:06 AM, 20kN said:

"Also, ALL BASE canopies use stowless methods for the lines. There are no line stows in BASE jumping."

Interesting outlook.

I've been doing fixed object skydiving since 1981.

Every BASE specific canopy I've bought since about 1987 has had a tailpocket (for stowless line control) that also incorporates  the capability to add a single rubber band controlled stow for what is known as indirect line control.

I think that qualifies as a line stow for base jumping.

Craig

 

On 3/19/2021 at 12:06 AM, 20kN said:



 

 

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On 3/21/2021 at 9:15 AM, Skydivesg said:

Semi Stowless Bag Review by Sandy Grillet

I first started jumping the semi-stowless bag from UPT with the two locking stows and 4 tuck tabs, prior to them going into production because the designer wanted his design to
be field tested using mostly an everyday jumper with what he thought would be typical skydives and pack jobs.

I make 325-350 jumps each year. Roughly 1/3 of which are camera jumps - filming tandems. The rest are belly jumps as 4 and 8 way training, competing, coaching and FS organizing at boogies and events. I make use of packers for about 275-300 of my jumps
(one of the reasons for the designer to give me a prototype of his bag). I now have more than 2500 jumps on the semi-stowless bags using Katana 120s, Velocity 103s and Valkyrie 96s. I have zero jumps (that means none) on wing suits. So my opinion
is based on my personal experiences and my general knowledge of skydiving and deployment sequences.

I have nothing but good things to say about the semi-stowless bag. It is essentially set up the same as a reserve bag except it uses a flap with tuck tabs for figure-eighting the lines instead of sliding them down into a pouch. This allows the packer to see what the lines look like as they are being figure-eighted - a good thing IMO. As recommended by the designer, I use large rubber bands for the two locking stows and double wrap them
around no more than 1 1/2 inch of line bite.

Some people will tell you double wrapping is not a good idea and may cause bag lock. This is a myth (assuming the use of large bands and the proper maintenance of your pilot chute and kill line length). I've been double wrapping large bands for 18 years on all my stows (locking stows included) even before the semi-stowless bag).

I love the openings of the semi-stowless bag. I've had mostly very controlled on heading openings. Any off heading openings (90-120 degrees) usually happen on my pack jobs because I've been told I sometimes pack a bit hastily. Thank God for packers.
 

The bag does allow you to get to line stretch quicker and cleaner than a conventional bag. I like this because I believe the majority of line twists start and are caused before the canopy comes out of the bag. Most jumpers replace the rubber bands only when they
break or are extremely close to breaking. How many times have you wrapped a band around a line-bite thinking "come on don't break..... just hold for one more jump"? This means our bands are generating varying levels of force on our line bites. Some hold
better and longer than others due to better (newer) strength. This imbalance of line bite strength often initiates rotation of the bag as the lines play out causing line twists. I believe the single wrapping of line bites sometimes allow the lines to deploy out of sequence allowing one or more lines to sneak out early and wrap around another line bite which can and has caused bag locks and hard openings. I also believe too much line bite helps cause line twists and out of sequence line deployment which can also cause line
twists and bag lock.

I've seen footage of quite a few opening sequences using high speed cameras, which means you can slow the footage down by roughly 2/3 of a normal video camera slow motion. The footage is quite enlightening. I think most people would be shocked to see
how much bag dance and out of sequence line deployment is actually going on above our heads. Now, this doesn't mean that it happens all the time but it does happen pretty regularly. It also does not mean that it couldn't happen with the semi-stowless bag but the design is such, and testing along with hundreds of thousands of jumps has proven that bag dance and out of sequence line deployment is dramatically reduced to almost
nothing.

I like my lines to come out quickly and cleanly (like a reserve) so my canopy can hit the air with the greatest chance of an on heading deployment from the bag. After that, it's a matter of how well you packed and placed the canopy in the bag (especially the control of your slider), how well your canopy is in trim (lines), your body position during deployment and the design and wing loading of the canopy.

As I mentioned earlier, you do get to line stretch quicker but it does not cause faster or harder openings. The openings are controlled by the slider and the packing (and canopy design). If a person gets a hard opening it's usually because the slider was not well
controlled during the packing and bagging process. There can be other factors but it's almost always the slider. The semi-stowless bag does not affect the hardness or softness of the openings. It only affects the speed to line stretch which I like. It also allows the
lines to play out in a more orderly fashion. We must remember, we only use rubber bands to keep the lines in place until they are needed and then to allow them to play out in a relatively orderly fashion in what is otherwise a fairly chaotic couple of seconds. But those bands can and do create other issues as I mentioned above. The semi-stowless bag does exactly the same thing but simply allows the lines to play out more consistently.

All of this can and has been debated by those who are naysayers. And I believe healthy, sensible, civil debate is good and necessary for further development of ideas in our sport and gear. And I welcome the debate by those who have actually given some rational and original intellectual thought to this or any subject.

Of course this is just my humble opinion –

Sandy Grillet

Full disclosure >> I am a UPT Vector dealer.

 

 

Semi Stowless bag open.jpg

Semi Stowless bag closed.jpg

Sandy,

           What's the difference between the "U" and "V" bags? Not much info I've found. You're using the "U" bag pictured? I need that! 

~Tim 

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On 3/21/2021 at 8:15 AM, Skydivesg said:

I've seen footage of quite a few opening sequences using high speed cameras,

I've captured one opening so far at 240 fps on my GoPro 9. I hope to capture a few more on this rig with rubber band stows, and then I'll be switching to my new Vector3 with semi-stowless in April. Maybe I'll end up with some useful data.

 

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11 hours ago, kleggo said:

Every BASE specific canopy I've bought since about 1987 has had a tailpocket (for stowless line control) that also incorporates  the capability to add a single rubber band controlled stow for what is known as indirect line control.

I think that qualifies as a line stow for base jumping.

 

 

 

Yes of course, all BASE canopies do. But they dont have direct line stowing like on a standard D bag, which is what we are talking about. As you said in your own post, that is stowless line control which is what a semi-stowless bag uses. I am merely pointing out that stowless methods have existed forever and they work fine.

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(edited)
On 3/21/2021 at 6:15 AM, Skydivesg said:

Semi Stowless Bag Review by Sandy Grillet

<snip>
Of course this is just my humble opinion –

Sandy Grillet

Full disclosure >> I am a UPT Vector dealer.

 

 

 

 

Sandy, thanks for the informative post.

Edited by kleggo

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16 hours ago, 20kN said:

Yes of course, all BASE canopies do. But they dont have direct line stowing like on a standard D bag, which is what we are talking about. As you said in your own post, that is stowless line control which is what a semi-stowless bag uses. I am merely pointing out that stowless methods have existed forever and they work fine.

 

On 3/19/2021 at 12:06 AM, 20kN said:

Very few manufacturers use any form of direct stowing for lines. Also, ALL BASE canopies use stowless methods for the lines. There are no line stows in BASE jumping.

 

LOL

If you want to be seen as an authority on a subject, you may want to consider not utilizing hyperbole or declarative statements which are contradictory.

Or not.

BSBD.

 

Craig

 

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