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Static Line

This page is a chapter in 'BASE Wiki Jumping Techniques'

Static Line: A static line in BASE jumping works similiar to a static line in Skydiving in that it is a method to mechanically extract a parachute from a closed container. BASE jumpers use this method of deployment for a variety of reasons including but not limited to: allows for jumps from lower altitudes, provides almost instant deployment for longer canopy time to reach the intended landing area, substitutes for a PCA when jumping last or solo.



Basically a static line jump involves attaching your bridle or pilot chute to an object directly or indirectly using a piece of 80-pound break cord or some other weak link. Most jumpers prefer break cord to other items (such as tape, platic bags, etc.) since actual break cord has been designed and tested to hold until a load of 80 pounds or more is applied, then will break.

The sequence of events are typically as follows:

Jumper checks gear, gets to the exit point, attaches static line to object, double checks integrity of said system, then jumps. As the jumper leaves the object gravity causes him or her to accelerate. The force cause the bridle to payout, the pins or velcro to open, canopy extraction, line strecth, and so on till the jumper is at the end of his or her risers when the shock of their body weight causes the break cord to break releasing the entire system from the object.

Pros and Cons

Static line jumps have the disadvantage, relative to a good PCA, that the center cell is always stripped. In practice, this has a significant effect only for the lowest jumps — and even then, it is often inconsequential.

Static line jumps have the advantage that they do not require the presence of a second person, which can be helpful when access is difficult or a lot of work, when descent by ground crew would be dangerous, or when for other reasons the jumper would prefer that other people were not involved.

General Considerations

Static-line, old school
Although the pilot chute plays little or no role in a successful static line jump, a large pilot chute should nevertheless always be attached!! In the event of a premature break in the break cord, a large pilot chute will often suffice to deploy the canopy on time. If the break cord goes before the container opens, clearly a bridle without a pilot chute will do nothing. The jumper should also carry a hook knife to cut the break cord in case he or she can’t jump, but needs to get away after the break cord has been tied.

Early static line jumps, and many modern jumps, were done without the carry-on attachment described below. A number of very acceptable techniques can be used with systems such as that shown on the left; they generally share the disadvantage that they leave gear at the exit point which needs to be either cleaned up after the fact, or left there. More recently, a system has been devised which allows the jumper to take all gear with him, while not presenting a significant increased risk of hang-up or failure. This system is discussed in the next section.

Carry-Away Static Lines (CWY-S/L)

Carry-Away static lines are the most common type used today because they offer the jumper the benefit of pre-rigging at home and reduces the amount of time and exposure required at the object. They are easy to build using basic rigging skills, dacron line, a fid, and optionally rapide and/or quick links. If you lack the skills to build one you should have no problem finding someone to buy one from or who can build one for you. Accepted techniques for jumping without one exist, but are too varied and numerous to discuss in detail here.


The recommended procedure for a static line jump is largely common to jumps with and without a carry-on attachment:

  1. After the container is closed, pass a rubber band over the PC and slide it up the bridle to the container. You’ll use this later. For best results, use the same rubber band you would use to close your tailgate (and not the black ones!!)
  2. At the exit point find a suitable place to anchor the static line. Do not use a wimpy strap of steel, find something that looks strong and stout so you do not end up doing a 2-way with the chunk of steel that used to be attached to the object. Give the anchor point a strong tug to make sure it is solid.
  3. Tie the bridle or attachment to the object using a surgeon’s knot in a piece of 80 lb break cord (described below for the carry-on system).
  4. S-fold the bridle at the static line attachment point and stop about 24 from the container. Use the rubber band from step 1 to contain the s-fold. Don’t use a double wrap. This stow is not meant to hold anything. The only purpose is to keep the bridle neat and staged while you get into position and exit. The bridle should easily unfold as you fall away from the object.
  5. Ensure that the bridle runs straight from your container to the anchor without passing under or through anything that will prevent it from loading correctly. Also make sure no excess bridle can possibly entagle with your body, especially your feet.
  6. Climb into position so you are standing directly in front or next to the SL anchor. Try not to stand way off to one side of the anchor, as this may lead to heading problems.
  7. Once in position take a moment to look and/or feel your routing, if possible have it checked by another jumper. Exit with some forward movement so you clear the object, but don’t huck out there. Minimal forward movement will create less of a pendulum effect on opening and you’ll be able to control the canopy easier if you’re close to the ground.
Always be careful with your rigging. If possible, have somebody check it before you exit. The first static line jump is always a bit of an exercise in faith — if you’re unsure, a SL attachment setup can be easily tested on a balcony with a bridle and a weight.
Dexterbase Rigging carry-on S/L attachment

Carry-on Static Line Attachment

Bridle attachment of the carry-on system


Most carry-on static line attachments are similar to that shown above. Their use is straightforward:

  1. Girth hitch the white loop to the bridle/PC junction. Alternatively, the attachment can be tied to the bridle using break cord as shown on the left below.
  2. Pass the red end (away from the white end) over the anchor so that the white line faces away from the object.
  3. Tie the two red ends to the bridle/PC junction with a surgeon’s knot using a piece of 80lb break cord as shown.

Attachment to the anchor

TODO:

Combine:
http://www.blincmagazine.com/forum/w...ou_Static_Line

Then fix and combine:
http://www.blincmagazine.com/forum/w...Line_Evolution





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