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Hi all =]
I don't understand why in most of the inevitable water landings it is preferred to use round parachute,please help me understand
thnx all
Kimkash

- easier to get it out of the water / handle in the water
- can be jumped when wet
- can be packed very fast
- to scare the shit out of yourself if you are used to slider down openings

i dont think they are used for most inevitable water landings (but i actually dont have any numbers about that). they also have their downsides, like long openings on short delays and being not steerable, so youre not able to fly closer to the shore, etc...

i think the main reason to jump a round is because its fun to do so.....

ciao!
hirschi

Water landings are a lot harder on your gear.

Why put a $2000 Flik/Blackjack/Troll in the water when I can put a $150 Phantom in there instead?


Also, rounds dry out a lot faster because they have only one surface. You can basically "shake and bake" them until they are dry enough to pack, then rinse and repeat.

You wouldn't want to abuse your good (and expensive) BASE gear that way.

All good reasons for sure. Another reason is that when jumping from relatively short walls into a guaranteed water landing the consequences of a 180 with a round are *much* less severe than a 180 with a square.

Walt

Not that I'm doubting this but is it quantifiable in some way? Can some of the damage be mitigated in some way? Careful drying?

I know of no *easily* quantifiable characteristic related to water landings, but I'm quite sure that measuring the permeability (porosity) of your canopy's F-111 fabric would show a reduced performance after a water landing.

Years ago a rigger told me that some accuracy jumpers would wash a brand new accuracy canopy as soon as they got it. Their reasoning was that soaking the canopy would immediately increase its porosity to somewhere near its lifetime maximum and therefore give them consistent performance over the life of the canopy.

That's quite a statement. Not sure if its true but it is something to consider.

Check this out.

Walt
edited by waltappel on Apr 23, 2012, 11:53 AM)

I've always just agreed with the fact that even clean water can hurt an f-111 canopy but honestly it doesn't make much sense to me. Nylon climbing ropes are always washed because dirt causes more damage then water.

I know that nylon is much weaker when wet but once it is dried it should be the same strength, so I can't figure out why it isn't.

My guess is that it has more to do with the amplification of UV rays before it is completely dry. That and maybe the water helps dirt and other chemicals that are in the water get deeper into the fabric of the canopy causing it to loosen and become more porous.

(I'm probably way off and will regret writing my uneducated opinion on this friendly forum.)

No reason to regret posting it but I'm sure it will seem obvious as soon as you read the explanation.


This can be chemically explained by understanding the general formation of Nylon’s polymer base. Nylon is a semi-crystalline polymer consisting of both crystalline and amorphous regions which have intermolecular hydrogen bonds between the polymer chains. Water is primarily attracted to the amorphous areas of the structure, where it disrupts the hydrogen bonds, thereby effecting a decrease in the glass transition temperature (one characteristic of modulus) and the tensile strength of the fabric.


Seems obvious to me!

Not really.

That's from a white paper done by the Jump Shack years ago on the subject of saltwater contamination of parachute fabric.

Walt

Thank you Dr. Sheldon Cooper.

Here's a simple version of what causes water to increase its permeability.

Calendering is the process of running the fabric through heated rollers at high pressure. So, you have the super tight weave of ripstop nylon f-111. Running it through the heated rollers smashes the fabric causing the round fibers to be flatter and closer together. Now you have 0 to 3 CFM fabric

Just add water and the fabric soaks it up a little causing the fibers to fill and become a bit more round. That also increases the space between the fibers. Poof, more air can get through.

So, it has higher porosity, but completely jumpable!

Another consideration is that the thread in the whole canopy shrinks at a different rate than the canopy material. although BASE canopies are large/slow, there will be detrimental shrinkage no matter what you do during the drying process.

My personal experience with 2 different Black Jack 260's (one ZP nosed, the other all F111): i put 2 intentional jumps on both. The flares were notably weaker on both after 1 jump, worse after the second. I eventually shortened the all F111 BJ's brake lines 3" IOT get a tad more out of the flare (and bring it closer to a stall, unfortunately). My buddy's Flik has 1 water jump, 115 ish total jumps and doesn't flare for shit.

Water=bad for canopies.

-Harry

This thread makes me want to abandon 2 interesting water jumps I have planned...

I used to blame my canopy skills on water landings too...But then I hardened the fuck up and learned how to land my parachute.

my troll likes to take a bath now and again it got the sap off, but my backjack is scared of the water

Yeah I think my Dagger loves the water because it keeps aiming for it

haha... ok.. sounds like a pretty serious scientific experiment...

i've gotten my blackjack soaked a few times and still manage to land it in the accuracy circle hundreds of jumps later.

sounds like an excuse to me.

Accuracy=Skills
Good Flare=Ankles

I agree with what a few posters have written. I have several of the same size/make canopies , and have one that landed in a very deep canyon, and after a quick reline, and a new set of risers, it has never flared the same. Just my .02$
I bought a round setup from Morpheus just for H20 places. I must say .... it's one of the funner toys I own on hot summer days. YMMV

Round setup from Morpheus? Don't you mean Apex?
http://apexbase.com/...ct.php?product_id=51

Nope... I meant Morpheus..... Rob made me a Nano for my birthday a few years ago.... It's so small, it looks like a camelback . One of my favorite bridge tricks...

Wow! The more you know