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20_kN

Single or Double Stow the Locking Stows?

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My personal view:

I double wrap every stow, locking and otherwise. I use medium sized rubber bands (some people call them large, whatever isn't the small rubber bands) throughout. I do this because:

1) My master rigger mentor recommends double stowing the locking stows (and he has 50,000 pack jobs between packing-related malfunctions)

2) PD Recommends also double stowing all the way through (the previously linked video)

3) Keeping one size rubber bands makes things logistically easier

4) Once you get good at double stowing (doesn't take long) it doesn't take longer to double stow versus single stow

5) I'm not concerned about bag lock. It either doesn't happen because of double locking stows, or at the very least, incredibly rare and easy to cut away. I personally don't think a bag lock on a tandem system is a good comparison because of the many differences in the deployment sequence and other factors. But that's me personally.

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DJL

NOBODY has every died after properly cutting away from a bag log.

Earlier my S&TA shared a story of a bag lock he got on a tandem. Apparently some new packer started packing with double stows. Out of the first two tandems he packed, both had bag locks and my S&TA was the operator of one of them. He cut away but the risers did not release and he was not able to get them to separate in time. He ended up having to deploy his reserve into the bag lock. Fortunately the reserve cleared the mess and opened, but then the main opened afterwards. It sounded like some pretty sketchy stuff.

If the pilot chute doesent even have the ability to break a small rubber band, I could see how you might have trouble cutting away, especially if you have an RSL and the PC doesent generate enough force for the RSL to pull the reserve cable out.

So I guess the question would be then how does a PC not generate enough force to break a rubber band? It seems that even a very worn out PC would generate a large amount of force when flying through the air at 120 MPH. I could see a fully uncocked PC not breaking a band, but I dont really get how an inflated one cant.

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Hi 20_kN,

Quote

Earlier my S&TA shared a story of a bag lock he got on a tandem. . . . If the pilot chute doesent even have the ability to break a small rubber band



If the tandem rig was a RWS/UPT rig then the drogue collapses upon release. Very possible a collapsed drogue would not have sufficient drag to 'break a small rubber band.'

Jerry Baumchen

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He ended up having to deploy his reserve into the bag lock



That's why I said "properly cutting away from a bag lock." He was not cut away from a bag lock. You can manually pull the risers off your shoulders and it's part of a correct cutaway procedure to visually check the risers.

But yes, an inflated drogue will break a rubber band without hesitation. As the previous poster noted the drogue was likely collapsed.
"I encourage all awesome dangerous behavior." - Jeffro Fincher

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DJL

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He ended up having to deploy his reserve into the bag lock



That's why I said "properly cutting away from a bag lock." He was not cut away from a bag lock. You can manually pull the risers off your shoulders and it's part of a correct cutaway procedure to visually check the risers.

But yes, an inflated drogue will break a rubber band without hesitation. As the previous poster noted the drogue was likely collapsed.



My thought exactly.

However, my 2nd thought is, was the packer a rigger following the gear manufacturers instructions or was it a packer who was not being appropriately supervised.

At the DZ I jump at packers are observed/tested to ensure they pack the way that is standard at the dropzone. So all are packed in a consistent manner. Any rogue openings are tracked/recorded so we can observe any trends (whether canopy/packer...)

After the 1st bag lock, was the packing/gear investigated to determine cause and prevent a re-occurence.

Tandems are different from normal sport rigs. Strong tandems have some bungee cord stows. They need to be tight and even though the drogue stays inflated until canopy is open there is no way it will break bungee cord. These stretch or if broken and you let packers make a replacement they will make them longer to make it easier to pack - however they then fail to do what they are intended to do. For tandems, ensure that they are packed/used in accordance to manufacturers instructions.

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Double stow everything. If you have enough rubber band slack to double stow, do it and you'll be fine (in other words, if you simply can't do a double physically because there is not enough slack, you're probably fine to single stow but with a healthy bite of line (2").

Use the small bands for microline and the larger ones for Dacron. Don't use large bands for microline.


I jumped HP canopies for years, small bands, all double stowed. Never had a problem. Would rather have bag lock than line dump.

And you won't have a bag lock anyway with a properly functioning PC... the rubber band SHOULD break (there are no absolutes however which is why I recommend 2" stows).

Don't use tube stows. They might not break (although I did double stow everything with tube stows for awhile as well... the only reason I switched back to small bands was they are cheap and I liked how they gripped the lines more than tube stows).

If you are thinking along the lines of "well I should single stow cuz what if my PC doesn't work so great" then you are being lax in your gear maintenance IMO.

Also IMO if people are telling you to not double stow anything cuz of bag lock possibility, I would submit that they don't appreciate what its like to come to the end of line slack with a partially opened canopy (it SUCKS).

Now having read my post over I need to point out that there will always be exceptions to things. For example, if you are stuffing a canopy into your bag that is too small (or just suck at bagging canopies) then its entirely possible that a single stow might have enough tension on it to be ok (since the stows will be tight since they are the only thing holding the whole mess together).

__________________________________________________
What would Vic Mackey do?

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crapflinger2000


And you won't have a bag lock anyway with a properly functioning PC... the rubber band SHOULD break (there are no absolutes however which is why I recommend 2" stows).

What does a rubber band breaking have to do with 2" line stows? Anyway, I double stow all my locking stows (semi-stowless bag). However, I tend to go with a bit smaller line bights. I prefer around 1.5" and my reasoning so far has been that I can get 12+ lbs of tension (I measured it) fairly easily with a double stow. However, some of the bag lock photos I've seen occurred when a bight of line got trapped inside the loop of a stow, which in effect required the PC to break the band to release the stow, which in effect caused the bag lock. So I figured that going with slightly smaller stows reduces the diameter of the loop and thus reduces the chances of some random lines getting wrapped up in a stow, but because I double stow I still maintain the 12+ lbs required to release the stow.

Thoughts?

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The packers at my home DZ apparently normally single-stow. I was having “brisk” (as in “woah wtf was that?!”) openings until today, when my rig was packed double-stowed, and my openings were smooth as butter. It’s a Silhouette, so still not slow, but a whole lot more comfortable.

Give me double stows or give me death! (not actually unlikely)

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Just my 2 cents. I have been a packer for 7 years 4 of them full time. Plus my almost 2000 skydives I packed for myself, and 2 summers packing tandems in Sweden, and I have never had a hard opening, nor any of my customers. I actually had some people tell me the openings were a little too slow, could I speed them up a little. I jump two completely different canopies, 1 being a triathlon 135 and the other is a crossfire 2 119. I dont double wrap my locking stowes on MY canopies. I only double wrap the locking stowes if one wrap leaves them very loose,or the owner of the rig request it. There are other things that can be done to slow an opening and several factors that can cause a quick/hard opening.

Sorry you had a bad experience, glad you are ok.

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benlangfeld

The packers at my home DZ apparently normally single-stow.

I think that's common. I only know one packer that double stows. I suspect the main reason is packers are in it to get the job done efficiently and quickly as they have many loads to turn. Single stowing is faster and easier than double stowing and since it seems to work most of the time they go with that. Also, I suspect most packers are going to do what they are shown, so if they were shown to single stow at the DZ then that's what they will do.

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To summarize: most of taboos against double-stowing were invented when bulky Dacron lines were fashionable. Now that bulky lines have disappearred from most DZs we need newer methods to stow lines. Stowing methods vary with THICKNESS of lines.

All the tandem ma its turrets have invented different solutions to a common problem: line slump/dump. Strong added an Anti-Line-Slump flap - secured with bungees. If you use fewer than (factory recommended) 3 bungees - or bungees that are too long - openings get harder.
Both Parachutes de France and Jump Shack added extra (standard-sized) locking stows. Extra lock it stows reduce the risk of any single failure dumping lines or letting the canopy out of the bag prematurely.
UPT tandem d-bags can be packed with three different sizes of rubber bands: standard, double-wide and triple-wide. Even though UPT discourages them, standard rubber bands work well with the skinny Spectra or HMA lines in Icarus canopies. I always double-stow those. UPT recommends double-wide rubber bands on civilian tandems and triple-wide on military tandems. Hint: military tandems often start with 500 pound barrels.

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I suspect the main reason is packers are in it to get the job done efficiently and quickly as they have many loads to turn.



The other reason is that if you double wrap you are at least twice as likely to need to replace the band on the next pack job. Double wrapping itself does not take a good packer very long at all. Replacing bands does.

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