Packing question: Tight or loose stows?

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According to the PD rep I spoke to last summer he said you want to, "Double wrap all your stows."

That being said I typically single wrap my first two locking stows because if I try to double wrap them they will snap on me.

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According to the PD rep I spoke to last summer he said you want to, "Double wrap all your stows."

Who was that?
And were they giving PD's advice or their personal advice?

[NickDG 23]

"Hey Man, Got Any Reefing?"

I think we are confusing line dump and bag strip. And, more importantly, the role of the slider in all this confusion.

Line dump isn't the end of the world as long the last two locking stows stay in place on the d-bag, and they usually do. They do because the upper part of a line set is where the cascades are and the extra bulk of the finger traps makes this section a bit thicker. So even someone who loosely stows their lines by not double wrapping the stow bands, or using stow bands that are too big, these initial locking stows are usually tight enough so they stay in place and keep the mouth of the d-bag closed.

So line dump is when the d-bag lifts off and some of the lines fall out of their stows and remain in the container. But bag strip is when all the lines fall out of their stows, including the locking stows, and then the bag is stripped off the canopy leaving the canopy and all the lines sitting in container momentarily.

But even in that extreme situation as long as the slider stays in place until full line stretch you aren't going to get an explosive opening. In order for that to happen, somewhere in this mix of line dump and/or bag strip you must also have a reefing system failure. And yes, you can have a reefing system failure without having either line dump and bag strip.

So what is reefing system failure?

As your canopy lifts off your back sans its d-bag in a bag strip situation the slider can begin to come, or more correctly fall, down the lines prior to full stretch. Because the grommets in the slider give it a bit of weight together with the fact there is really nothing holding the slider in place at the top of the lines, it's simply a matter of inertia.

And this is what causes hard openings. What you want is for the fabric in the slider to inflate in the relative wind (which makes it want to stay up) and as the canopy spreads that force has to act against the slider by pushing it down the lines. And this is what cancels out explosive openings.

So keep this in mind - line strip doesn't cause explosive openings, bag strip doesn't cause explosive openings, reefing system failure is what causes explosive openings.

And at one time free-packing rounds and squares was fashionable. In this method no line stows and no d-bag are used. With squares the lines were simply coiled and placed in the bottom of the container and a trash packed canopy (trash packing is the forerunner of pro-packing) is laid on top and the container is closed. How we avoided reefing system failure with the free-pack was by stowing the slider in its up position with stow bands, and in my case I would triple stow the slider to make damn sure the only way the slider could come down is when the opening canopy began to push it down.

Now that you know reefing system failure is the true culprit in explosive openings you need to know how to avoid it. And there are a few different ways to induce reefing system failure. Some of these will be simple mistakes students will naturally make, and some are just comically inept errors made by experienced jumpers.

For experienced jumpers (or packers) not un-stowing an already collapsed slider prior to packing gives you reefing system failure before you even set foot in the plane. This is an unthinkable mistake, but it does happen. Also not tightly wrapping the bottom of the canopy (which helps the slider stay in place without being stowed) is another.

Students who are first learning to pack are a whole different ball of wax. And the following is directed at Coaches and Instructors who teach packing. No matter if you're an Angel who makes it a point to give packing instruction for free, or if you're a extortionist who charges for it, it isn’t enough to just teach this fold goes here, and that line goes there without explaining all I've written above (and more) to your charges. The problem is I know many who can teach the how but not the why of packing. And if I can digress for a moment, in these days of paid packing, and money changing hands just to initially learn packing, I believe the teaching of packing to students should shift from Coaches and Instructors to rated Riggers. At least that way students will get the whole nine yards. And it would be another small income stream for Riggers and at the same time introduce students to Riggers and what they do. Another side benefit would be increasing the cache for a member of the skydiving community who mostly toils behind closed doors.

Also packing instruction shouldn't be done at the drop zone. It's too important to be imparted to a student or novice while they are contemplating their next jump in a few minutes, nor should it be done during the normal din, sights, and sounds of the DZ.

So back to Coaches and Instructors. Before you dare teach a student to pack, you must not only fully understand packing yourself, you must also understand the psychological aspects of new jumpers. When a student packs, with every fold, flake, and stow, it's natural in their minds to be thinking open, open, open. So they make everything loose, open, and airy. What they should be thinking while packing is don't open, don't open, don't open. This is the fundamental principal of reefing. You must make the canopy work hard to open. But students won't do that by themselves and it's the reason you must explain all the above to get them even close to doing it.

Lastly a word about line entanglements and another problem called over-reefing.

Upboard several people mentioned line entanglements and their connection to line dump or bag strip. And they were wrong on both counts. Generally you need to have two things happen to have a line entanglement. You need something to happen out of sequence (remember, proper reefing is a staged series of events that happen in sequence) and then something else has to happen to hold the tangle in place. Most line entanglements (we'll talk about tandems in a moment) that cause solo skydivers to cutaway happen below the slider. And that second thing is the pressure of a still trying to descend slider providing the pressure that holds the entanglement in place. Solo skydivers who have a line entanglement above the slider are rare and are either the result of an improper initial assembly and as you pull the slider up during packing you unknowingly push the tangle up the lines. You could also push a step through up the lines using the slider. And this is the reason you should always do a four line check before starting any pack job (You guys who are teaching packing are including four line checks, aren't you?)

Tandem canopies do sometimes exhibit line entanglements above the slider, but tandem canopies aren't simply bigger canopies than solo jumpers use. And it would be another whole page of typing to explain their issues of bad behavior. I'll leave it by saying any tandem packer who worked under me that caused a line entanglement either above or below the slider which caused a cutaway could stand by for an ass kicking.

On over-reefing? Ever see a guy who says his canopy snivels for a thousand (or sometimes more) feet? On a personal level I feel that an awful long time to be completely out of control in a crowded sky. Most times if you watch these guys pack even though they have an already slow opening canopy they will still roll up and bury the nose in their pack jobs. Or packers will do it to every canopy they pack because today's jumpers equate a fast opening with a hard opening. That's dangerous thinking. Look at it this way. In freefall you are under control and under canopy you are under control. But during the opening sequence you are basically a living breathing sack of potatoes with no control at all. So you want that phase of the jump to pass as quickly as is comfortable.

So what's a young and beginning jumper to do? I'd say look to a Rigger for your initial packing instruction. I'd also say don't discount the B.A.S.E. side of the house. Your average B.A.S.E. jumper with just a hundred jumps will generally understand the principals of reefing and packing better than many skydivers with thousands of jumps.

But, in any case, be proactive. And don't fall for the common wisdom that gear isn't something to worry about in the beginning of your skydiving career. Today's climate sort of allows for that, but if you were the type that follows the crowd you would never have started skydiving in the first place. So don't get sucked into doing it now. So at the very least show up at your local rigger's loft with a broom or a rake or some paint and brushes and offer to do anything possible to get schooled. The great equalizer in skydiving is no matter how you fly, free or belly, or whatever else new we come up with, we all have to land under a functioning canopy. So getting hip to that part of the sport is your job number one . . .

Oh, and if you want to sound like you know what you're talking about there are no "rubber bands" in skydiving, there are only "stow bands."

NickD

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Nick, thanks for all that typing! Hopefully a number of people/riggers will read and learn.

Bag strip is indeed much different than line dump, but I can't even get people to understand line dump, so I don't even try to go further....

[NickDG 23]

No thanks necessary, Gary. Especially from you. You've done your bit with all the stuff PARACHUTIST has printed. They never use the stuff I send them as it's a bit too blunt for them so I gave up.

BTW, I was working at Square One in the early nineties when you came out with that computer canopy coloring program for Windows 1.1. If Tony Domenico had given you a just small piece of every canopy we sold because of that program (the rubes were lined up out the door for a go at it) you'd be a richer man today . . .

NickD