As unsafe as it gets

[Condor 0]

I am writing a fiction in which the main character needs to open his parachute in the last instant and he lands in water. Then he’s going to have to base jump and land again (some very bad dudes are after him). Can someone tell me what the minimum height is that a person (about 170 pounds) can open his parachute from and land unharmed? Not minimum safe height but minimum possible height (under ideal conditions). Also, can you repack a wet chute and expect it to work 4 hours later wet?

[tunaplanet 0]

For your fictional story, in my professional opinion, you could pull at 300-400 feet. That would give you impact almost immediately. I have heard of people deploying at 500 feet safely. You would be pressed to safely pull at 300, but possible. Besides, in fictional movies/books you can take a .38 revolver and fire it 42 times in a row without reloading.

As far as repacking a wet chute...yes you can. It is not reccomended, but you can pack a wet chute.

Forty-two

[marks 0]

well the cypress fires at 750 ft roughly
that is the automatic activation device used as a last ditch effort... i would say 500-750ft ..

wet parachute...well ive got my parachute soaking wet in the swoop pond and took it out and let the excess water run off it then packed it up and jumped it 10 minutes later..... i jumped it to dry it out..... so ya you can pack and jump a wet parachute..

[BlackholeSon 0]

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well the cypress fires at 750 ft roughly
that is the automatic activation device used as a last ditch effort... i would say 500-750ft ..

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Because while the "very bad dudes" are chasing our fictional character it would be best, during all possible action movie based scenarios, for our character to activate his cypres while presumably running at top speed in the wilderness.

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Here's to cheating, stealing, fighting, and drinking. If you cheat, cheat death. If you steal, steal a woman's heart. If you fight, fight for a brother. If you drink, drink with me.

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[rjf98 0]

Jay jumped wet chutes all last night. Towards the end of the 24 hours the sliders were starting to stay up and they were not opening very fast, but they were working just fine being packed up soaking wet.

[FrogNog 1]

> Towards the end of the 24 hours the sliders were starting to stay up ... but they were working just fine being packed up soaking wet.

Are you saying that the sliders were "sort of staying up" or "staying partway, but not that far up" or "staying up longer, but still coming down in a reasonable length of time"? Because if it isn't one of those, then it seems to me that sliders staying up is not "fine".

Or maybe the deal is "toward the very end of the 24 hours, the sliders were starting to stay up, which is bad, but the rigs were working OK being packed up wet for the first few hours before that."

Not that this really applies to me, since I probably won't be jumping any really wet gear soon. Not 20 times an hour, at any rate. ;)

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Pull.

[diablopilot 2]

Because the lines were wet the slider encountered more friction moving down the lines. Occasionally it would "hang" just past the halfway point, but was easily brought the rest of the way down with a small tug on the rear risers.

It's a common occurrence on a lightly loaded, slow opening canopy with a low aspect ratio, and long(er) lines, like the Spectre.

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You're not as good as you think you are. Seriously.

[FrogNog 1]

> It's a common occurrence on a lightly loaded, slow opening canopy with a low aspect ratio, and long(er) lines, like the Spectre.

Makes total sense. OK, I feel all better now. :)

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Pull.

[ihateskydivers 0]

i had an opening so hard once that i think i went back up

so, about 5 feet would be acceptable

sounds like a mix of point break and terminal velocity...

[billdo 0]

Well, what do true HALO spec ops jumpers deploy at? Over water?

In a movie I saw once the jumpers begin discussing when to pull while in freefall at 1000 feet. Approximately 20 seconds elapses before the second guy pulls and he just opens before the water, so I'd say something like 500 feet

[FeMike 0]

That dude that did 535 jumps last night in 24 hrs did almost the whole thing in the rain...All his repacks were soaked. No malfunctions.

Mike

[tunaplanet 0]

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Well, what do true HALO spec ops jumpers deploy at? Over water?

HALOs are almost always pulled between 900-1,000 feet. This is actually a pretty standard number for almost every HALO. Halfway through a HALO the entire squad or platoon will link up to stay together.

Forty-two

[crwmike 0]

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I am writing a fiction in which the main character needs to open his parachute in the last instant and he lands in water. Then he’s going to have to base jump and land again (some very bad dudes are after him). Can someone tell me what the minimum height is that a person (about 170 pounds) can open his parachute from and land unharmed? Not minimum safe height but minimum possible height (under ideal conditions).

Depends on the deployment system and canopy. My PD Lightning with a tail pocket would open so damn fast, going in might be the less painful death. All kidding aside and assuming unharmed doesn't include 'very unhappy' (it won't be pretty but you'll be able to walk away from it) ...around 150 ft.

Survivable (maybe) and you'll be able to painfully 'walk it out' ..100 ft.


Also, can you repack a wet chute and expect it to work 4 hours later wet?

[mr2mk1g 10]

Your hero would presumably not have done any special modifications to his parachute and would simply be using an ordinary sport parachute... this would mean the opening height would have to be higher than is possible in the extreme.

Sport parachutes are deliberately designed and packed to open in slowed stages (120mph (freefall speed) to 0mph tends to hurt if you try to do it too fast).

Parachutes will generally open within about 1000ft leaving little safety margin... but then when your being chased by bad people I guess that doesn’t really matter... If you wanted to have your hero cut it even finer, anywhere down to 500ft would be plausible.

People above have mentioned his "Cypres" or AAD. This is a little computer which opens your reserve parachute for you if you are unconscious, (or dumb)… this activates at 750ft so if you are passing through this altitude without a parachute out, or with an opening parachute… it is likely to activate. Best avoid the whole concept of a Cypres as it complicates things… your hero either doesn’t have one or has not had time to switch it on (damn those bad people).

If you then want your hero to BASE jump to get away later in your book, post in the BASE category and get all the info you need there.

[elfanie 0]

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(120mph (freefall speed) to 0mph tends to hurt if you try to do it too fast).

*snort*
isn't that the problem with trying to land without a parachute?

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Elfanie
My Skydiving Page
Fly Safe - Soft Landings

[shedao 0]

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Parachutes will generally open within about 1000ft leaving little safety margin... but then when your being chased by bad people I guess that doesn’t really matter... If you wanted to have your hero cut it even finer, anywhere down to 500ft would be plausible.

Aren't BASE rigs and the typical sport rigs different for just this reason? It would be good to note that in the story. I doubt he would use the same rig to jump both unless he wants a severe case of neckbreakitis (using a BASE rig out of a plane) or the opposite (using a sport rig to BASE jump) groundimpacttoofastus.

[mr2mk1g 10]

if he used a sport rig he could do it... just depends on what he based...

If he wanted to BASE something really small in the sports rig he could pop the reserve and tie its pilot chute off to a hand rail or something... this ought to have it opening in about 80ft if we are to believe the skyhook tests.

[dont do this at home kids]

[waltappel 1]

The minimum survivable pull altitude depends in part on whether the jumper is at terminal or is falling slower. As a rule of thumb, at terminal (belly flying) a person will go 1000' in about 5 seconds. Even a fast-opening parachute will take 2+ seconds to completely decelerate a jumper from terminal. For a jumper opening from terminal, assuming a fast-opening canopy, my guess would be somewhere around 500 ft. For sub-terminal, as in a very low exit from an aircraft or fixed object, it would be significantly lower.

[deronde 0]

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if he used a sport rig he could do it... just depends on what he based...

If he wanted to BASE something really small in the sports rig he could pop the reserve and tie its pilot chute off to a hand rail or something... this ought to have it opening in about 80ft if we are to believe the skyhook tests.

[dont do this at home kids]

Taking this senario your hero doesn't have to repack at all! He (She?) lands in the water, cuts away the main chute (making sure he hasn't got an RSL which would automatically open the reserve) swims to shore, climbs up to where ever the badies chase him and uses the above mentioned method to deploy the reserve...

[mr2mk1g 10]

Yes actaully your right. Thats actually a far more plausable scenario too.

Can you imagine how hard it would be to swim to shore of wherever he lands with a parachute deployed in the water? I would doubt anyones ability to swim through deap water dragging an open parachute after them.

You could have him cut away from his main on hitting the water, swam out of the harness and then to shore using the reserve as a floatation device. This is actaully straight out of the manual and what you're supposed to do so no one could say its technically incorrect.

In this scenario you could still get in a tense few moments of drowning under the sinking canopy before a skillful escape which (no author) im sure could be made captivating.

Using the reserve to BASE in the next escape scene would eliminate the tedium of 15 minutes of packing he would need to go through (which must be something of a boring chapter in the book).

[billvon 3,089]

>Can you imagine how hard it would be to swim to shore of wherever
> he lands with a parachute deployed in the water? I would doubt
> anyones ability to swim through deap water dragging an open
> parachute after them.

I've done it. It's doable but very slow going (as you might expect) and any significant current is going to "win the battle."

[Soozie 0]

Nice.

[Condor 0]

Ya’ll have been very helpful. Thanks.

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[marks 0]

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Ya’ll have been very helpful. Thanks.

aww man.. i bet it is hard to swim in a wing suit

[hooligan 0]

in a wing suit? hmmm?

think maybe you could kick like a dolphin as you would while swimming butterfly??

dont make me buy a wing suit to try it!


adam