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Hi everybody. I'm trying and flying my base canopy in skydive environment (Troll 225). After some hop 'n pop, I'm approaching opening close to terminal velocity. I'm experiencing a great snatch force on that deployments. Probably is common on slider down jumps.
I'm here asking some advice on how to reduce that force on slider up jumps (in a safe environment as skydiving is).
Could I put on a smaller PC (now I'm using a 32" ZP vented)?
Should I use a different slider (now I'm using a large mesh one)?
Thanks everyone for the advice

I heard that you can try rolling the nose, using a small mesh slider, direct control, maybe even double direct control. And the pc size probably doesn't matter as long as it's not huge (over 38", when center cell stripping can happen).

And.... Use a D-Bag, skydiving collapsible P.C. , get a full sail slider from the manufacturer(Or measure yours , and have one built to match), and don't wear a heavy alti..... Knocked out three teeth on a WS jump with a BASE canopy that opened fast. just my .02$

None of these things will change the snatch force.


Snatch force is the force exerted instantaneously by the PC at the moment of extraction. It has very little effect on the opening, aside from (in a skydiving context) possibly stripping the lines off the bag (if it is too great) or (in a BASE context) failing to peel the velcro (if it is too little) on a new velcro rig with wide velcro.


The only way to change the snatch force is going to be changing the PC size or the bridle length.


Naod, why do you want to change the snatch force? Or is that not what you actually want to do, maybe? Are you just wanting softer openings?

For softer openings, I think uer16 is on the right track. Put the canopy into a skydiving rig with a deployment bag, use the regular skydiving PC, roll the nose, tighten the direct control stow, and/or switch out the slider. A ZP slider will soften the openings a lot, but there are plenty of things you can do before buying a new slider.

Oh, right Forgot to mention this, but it was quite obvious he was referring to opening force while saying snatch force, since you can't really feel the "snatch force" directly and thinking it's too high.

i used a sail slider, d-bag, with a 32, and my back hurt for approx 2 weeks... i def. needed to get much bigger and less arched before i pitched... so... big de-arch!

Get out lower and pull higher.

Thanks for your advice. Just to clear my aim. I don't want to transform the base canopy opening sequence in skydiving canopy opening sequence. I want to test all the sequence of a canopy opening (in order to understand if my packjob works as expected, if the on heading is good enough, if the way I roll the nose is useful, etc...) - and once opened practice the needed skills under that.
So, I don't want use a d-bag, sail slider, etc...as someone suggested. I could, but it's not my goal.
But, because of I consider the snatch the part of the sequence that hurts me a lot (nor the snivel or the inflation does the same), I'd like to avoid it as much as I can (I consider stupid to have my back hurting like a did a 200 feet base jump, without doing a base jump ).
I'll try the option to put a smaller (or older) PC (in F111, if I find it). Not so small to have a PC hesitation, I guess . Probably i won't try a longer bridle, I'm already using the base bridle.
Thanks again for all suggestions

Shorter bridle would result in less snatch force. Longer bridle causes more snatch force. But, the snatch force is probably not responsible for the harder openings.


I'd recommend using tighter direct control on the slider, pulling more slider through the stow, and also trying a small mesh or sail slider (or even ZP).

I didn't know that... good to know now


I'm using two little rubbers on inner C-lines whit two wrap on the slider (as explain in the blog watchthybridle).

The fine mesh will be probably the better option, but I don't have...yet

Again, thanks

The easiest way to adjust the opening shock on a slider up opening is to change this around. Try using tighter stows (more wraps), or taking more of the slider into them.

It can make a pretty substantial difference, and is a technique you should be familiar with for different BASE jumps, as well.

You can also change out the rubber bands (for something bigger/stronger), but I'd stick with what you're using at first. The "half width" rubber bands are nice in this application because if there is a hangup they break more easily. You're already using two of them, though, so that may not matter much.

Rolling the nose helped me a lot. The result was an almost "soft" opening but it took a "lot" more time till I hung under a fully pressurized canopy.

I found that a tracking suit can help a great deal with opening force. Pitch in full flight, flying the suit for maximum time, not max distance. It does change the opening dynamics a bit (pack job comes out of the tray at an angle) but the ~20mph difference in deployment speed really cuts down the opening shock. Not exactly the same as what you get from a belly fly opening, but much easier on the body if you plan on doing a day of it.

I agree, except I'd say you get an even better opening if you go to a flared belly to earth type position for one to two seconds before deployment, think like you are approaching a formation really hot and need to put on the brakes. Deploying in full flight may be better practice for BASE, but I hardly think it matters and the older I get the bigger I am on limiting punishment on the body, that shit catches up to you. Also, a sail slider really helps to slow the opening and does not burn as much altitude as you might think. I've taken 12sec from a big A with a sail slider and still had over 30 sec canopy ride.

I don't mean to call you out on this, but I call bullshit.In my experience pitching from full flight in a tracking suit does not equal a softer opening at all. In fact it is just the opposite. You're head low when in full flight and the canopy is extracted behind you toward your feet which means it is pulling more the opposite direction causing you to whip around instead of just saddling you out 90 degrees. I have had visible bruises on my shoulders from this. And I'm black, so bruises don't show unless they are bad.

thats because hayes gets gets like 4 to 1 ratio on a track suit to get some buises from pulling in a track to get that kind of pull force wich normal white folk dont do

Do you have any (outside/ground camera) pictures of this? I'm asking because I've never seen it, but I havn't seen a lot and maybe people can track that good at pull time :)

Well if you're head low during a good track(which you are), it's quite obvious the canopy will extract towards your feet:

All true. 4.5:1 if I shave my palms.

agreed.

in my experience, pulling in a track will hurt you, and provide less dependable heading performance.

maybe if you're a featherweight, you can get away with it, but i don't know.

An efficiently flown tracksuit seems to yield a total lower airspeed then a regular terminal boxman. I have put about 200 jumps on my tracksuit and can tell you from skydiving that a pull from full flight will yield a significantly less positive opening then a pull from terminal boxman (My pro track registers fall rates in the low 60s to high 50s consistently). My Storm snivels like a crossfire when I take it tracking. Openings are more akin to a hop n pop then a terminal jump with the suit. The same result holds true for my base canopy ...so much so that I am thinking of throwing on a 38 and getting rid of my small mesh (this goes first) for terminal jumps with the suit. Currently I jump a vented 266 sqft FOX (4/7) with a 36 and small mesh (use direct and indirect control with two wraps respectively). I weigh 160lbs.

Plus: the swing forward due to horizontal motion with the suit seems to also "soften" the opening due to dispersion of energy into a swing rather then a smack downwards.

Also: Heading does not seem to suffer (much?) I have gotten line twists very rarely (statistically similar to regular box man deployments?) in my 200 plus jumps with the suit (always pull from full flight).

well, i will justify the combination of my results & your findings with the fact that i am certainly not an "efficient" tracking suit flier.

I jump a vented flick 220 and I experienced the same problems when I first started. Smaller canopies slam and thats the way it is. Best advice I can give you is reduce the number of degrees your body moves after you reach line stretch. Get as head high as possible in relativity to your presentation to the wind. I dump in a full track and once PC is out arms get big, feet go a little negative, you'll sit straight up and roll into your opening instead of getting snatched into it. That and single stow with small rubber band direct control and a 38' pc bring me soft on heading opening's time and time again even at terminal velocity. Changing your body position will help a lot without the risk of changing your gear or packing witch will be a bigger deal in base than skydiving. There is my useless opinion.

Try jumping CRW gear your views of hard openings will quite quickly change

So, finally the weekend came and I was able to did some jumps trying the advices given.
I can firmly assure that the rolls on the nose and the rubber bands (small ones with two wraps) as slilder direct control on the Cs (taking as much slider as you can) really slow down the inflation!!!
On the other side, the snatch force has been reduce a little by changing the PC. I tried a PC a little bigger and older with small mesh. It helped not so much as I was hoping, but enough to consider the snatch acceptable.
I didn't try the small mesh slider, but I think it would influence most of all the inflation (that in my case is slow enough).
Obviously, the positions which suggested to not have so much degrees in the angle from box position to canopy flying are useful (but I consider them not specific for base).
Thanks all for their suggestions