Basejumper.com - archive

Given several recent discussions on this topic
thought it'd be useful to get a rough idea of
the number of times people had problems.

Broken bridle.

I also saw one where a jumper caught a leg in the static line setup, resulting in a premature breakage with a closed container, which was very fortunately cleared in freefall.

I also know of one fatality that resulted from a bridle/jumper entanglement that should have been cleared prior to launch.

yep.

solo. casino. night.

something hung up, and it turned ugly. felt suspended, briefly, then a sudden release. spun wildly, watching the floors pass way too quickly. figured it would hurt.

PLF onto concrete. briefly knocked out. (a helmet surely limited a head injury to a concussion.)

extreme damage to the parachute. center cell A, B, & C lines popped off the bottom skin (6 lines) plus a wonderful new vent in the upper skin.

happy to assume a rigging error, but never returned to investigate.

Thanks all for the input, lesson, and link
regarding how force is applied to knots
and materials.

What makes you think it is?




The knot deforms the material. The material is strongest in it's uncompressed form, when all the component parts connect most evenly. Compressing and twisting it makes a segment that is weaker than the uncompressed and non-twisted parts.

sharp points, sharp angles, etc. tend to concentrate all stresses into a single point. for example, they tried rectangular windows in airplanes, until problems kept cropping up in the corners. knots seem to do exactly that.

I had the rest of the broken bridle pull-tested by a very reputable rock climbing manufacturer.

The simple results were:

no knots=bridle failure at slightly higher than rated
overhand knot=failure at slightly lower than full rating
slight cut (1/10 of bridle width) situated at knot=failure at cut around 400 lbs

Check this out. http://www.caves.org/.../nh/50/knotrope.html

According to this the alpine butterfly is the strongest knot to use for a loop.

As a tree removal expert and using 9000 lb up to 13,000 lb rigging lines for the last 21 years...any time you tie a knot in any type of line.....you decrees its tensile strength up to half

i always use it, works nice. leaves no marks on the bridle even.

http://www.animatedknots.com/...ww.animatedknots.com

Definitely one of my favorite knots. Easy to tie and easy to untie after it's been weighted too.

i read where a guy didnt tie his break away line either right or tight enough and it disconnected from the object when he jumped resulting in no deployment and he died.

I beleive i saw that on the WBFL.

one 4-6 in SL and a few feet long piece of 1 in flat webbing. jumping at 180 ft.

jumped... very hard opening... mushy flare... landed...


canopy had hole along middle center rib abotu 6 in long, severe tears on ribbs, x bracing was tore from bottom skin...

The first place I would quote is the BFL where 3 people have had issues with static line in the past:

http://splatula.com/bfl/


Then, I have consolidated these issue it types:
http://www.blincmagazine.com/.../Fatality+Statistics

More Static line articles

http://www.blincmagazine.com/...s/static%20line.html

I have even seen talks of using plastic grocery bags for static lines. This was an Aussie trick I think.

 

That's genius.

Not had any major problems other than tearing the mesh on a PC once and also having a 120 degree right opening.