This is not advice, but a posting for historical reasons:

Setting-Up a Canopy for BASE

From: ftr@sam.neosoft.com (Walt Appel)
Newsgroups: rec.skydiving
Subject: BASE Article #5, Setting Up a Canopy for BASE
Date: Sun, 7 May 1995 16:50:56 UNDEFINED

This is the fifth in a series of articles that I am posting about BASE jumping. It gives general tips on how to set up a parachute for BASE jumps. In this article the focus, of course, is on skydiving parachutes, since canopies designed and manufactured specifically for BASE jumping should need no significant modification. I will be devoting the next several articles to canopies. Future articles will include more discussion on equipment, techniques, and general info. I will also discuss sources for gear and information.

Feel free to e-mail me, but don't ask me to recommend specific sites. I will not recommend specific sites, nor do I recommend BASE jumping. BASE, even though it has evolved a great deal over the past few years, is still somewhat experimental and I consider it to be an extremely dangerous activity. I am posting these articles because the lessons that have been learned about BASE have cost us dearly. I do not want to see anyone hurt or killed because they were unknowingly re-inventing the sport.

In case, you're wondering about my background in BASE, I have made 55 BASE jumps, mostly freefalls from under 500 ft, from a variety of sites. I make and sell BASE accessories, e.g., pilot chutes, bridles, mesh sliders, etc., and I have been on the Bridge Day staff for the past few years.

Disclaimer: I am not now, nor will I ever be, the final word on BASE jumping. Nobody is the ultimate authority.

BASE is an extremely dangerous activity. In my opinion, the best way to reduce your chances of injury or death is to talk with as many experienced BASE jumpers as you can, learn as much as possible, *think* about it, and jump in a way that makes sense to you. This article is written from one person's point of view (mine) and you'd be nuts to consider it the best or only point of view. There is a lot more to BASE than any series of articles can present. Use the information only as a starting point.

Attitude
Before I get to the subject at hand, I'd like to discuss attitude. BASE jumping is very psychological. Making your mind function properly in the presence of extreme adrenaline is not an easy thing. Because of this, you need to make the most of your preparation, including gear setup. Build in as much safety margin as you can. Humans are fallible, and you need to acknowledge to yourself that you are capable of making mistakes. Try to choose gear that will make up for your mistakes. Use the gear that gives you the highest probability of a safe outcome; it will give you a comfort level that you desperately need at the exit point.

Setting Up a Canopy for BASE Jumping
In previous articles, I've emphasized that BASE jumping gear needs to be configured for the site and the type of jump that it will be used on. In this article, I'll explain how to setup a ram-air canopy so it can easily be used for a variety of jumps and sites.

Note: I'm not going to discuss round canopies in this article because the rounds that are suited as special-purpose BASE canopies need very few, if any, changes. I'll point out a few things in a future article when I discuss packing round canopies.

Let's start by summarizing the features that a good ram-air BASE canopy will generally have, as discussed in the previous article.

# It will be a low aspect ratio seven cell, made of non-zero- porosity fabric;
# It will have dacron or nylon (not Spectra) suspension lines;
# It will have a very strong reinforcement scheme at the bridle attachment point(s) and all suspension line attachment points;
# It will have a very durable construction;
# It will have a surface area that is large enough to give soft landings even in deep-brakes approaches.
What more could you want? Here's a list. Bear in mind that I'm talking about setting up a canopy that will be used for BASE jumping at a variety of sites. You may not want or need all of these items:

# At least one BASE pilot chute and one BASE bridle,
# A mesh slider,
# A tailpocket,
# A riser/toggle combination that is secure but will release very easily, even under high loading on the steering lines,
# Multiple (2 or 3) brake settings, including deep brakes.
BASE Pilot Chutes and Bridles
You may have noticed that BASE jumpers put a great deal of emphasis on their pilot chutes. There is plenty of good reason for this. BASE jumping without a pilot chute that will provide quick deployment at low airspeeds is can quickly lead to a sudden, violent death. Don't do it. Most BASE jumpers have at least two BASE pilot chutes--one for very short delays, e.g., 0-2 seconds, and one for longer delays, e.g., 2-5 seconds.

My choices for BASE pilot chutes are:

# A 42 inch diameter zero porosity PC for delays of 2 to 4 secs.
# A 46 inch diameter zero porosity PC for delays of less than 2 secs.
These choices are reasonably conservative in nature and I consider them to be a good starting point. You wouldn't want to go much larger on the pilot chutes unless you are using F-111 pilot chutes. In that case, I recommend a 45 or 46 inch F-111 pilot chute for 2 to 4 second delays and a 48 to 50 inch F-111 pilot chute for the shorter delays.

I could easily write an entire article on BASE pilot chutes, but that seems a little too detailed for the series right now. If you'd like more detail on PCs, e-mail me and I'll write an article.

A BASE bridle is about 9 feet long from the closure, i.e., closing pin or velcro shrivel flap, to the base of the pilot chute. Don't deviate from this length by more than 1 foot.

A BASE pilot chute costs from 50 to 70 dollars U.S., depending on size, F-111 or ZP, and the manufacturer. A BASE bridle cost about 10 to 15 dollars.

Mesh Sliders
Slider up or slider down? Depends; for short delays at low altitudes, I prefer slider removed. For 2 to 4 second delays, a mesh slider is an excellent choice--it will not give an explosive opening, like a slider down 4 second delay, but it will give a significantly faster opening than a normal skydiving (sail) slider. It also gives a more reliable opening, i.e., not as much chance of a malfunction, than slider down or slider removed. Every BASE jumper I know has one of these in their bag of tricks. If you plan on jumping at Bridge Day, this is a good thing to have. The setup part is pretty simple--just replace the regular sail slider on a canopy with a BASE mesh slider. I'll tell you where to get one when I discuss gear sources in a future article. By the way, this item costs about 35-40 dollars U.S.

The Tailpocket
As explained in Article 2 , the tailpocket is a pouch sewn to a ram-air canopy's center cell along the trailing edge. It provides a place to stow the suspension lines. The reason for having a tailpocket is to avoid "bag spin" or "bag lock", and to give a faster deployment than a normal skydiving deployment bag. Tailpockets also seem have better performance than bags as far as giving on-heading openings. Depending on the specific tailpocket, it may have rubber bands for stowing the lines, or may be designed for free-stowing the lines.

By the way, I'm not trying to give the impression that you absolutely need a tailpocket for BASE jumping--you don't--but if you start getting into the low stuff, it will give you a better chance at getting a fast straight opening than using a deployment bag. Don't get one of these just for Bridge Day, but if you have a canopy that you will be using regularly for low BASE jumps, I'd highly recommend this piece of gear.

Setting up a canopy with a tailpocket is not nearly as simple or quick as installing a BASE pilot chute and bridle, or a mesh slider. It needs to be sewn on. You can install one with a home sewing machine, but I wouldn't recommend it unless you have the right thread and the skills to do it properly. Your best bet is to have a rigger either do it or at least supervise it.

By the way, you can still use a deployment bag on a canopy equipped with a tailpocket. Just pack it as you normally do--it won't interfere with deployment.

The cost of a tailpocket is about 30 to 40 dollars U.S. Installation costs extra, roughly 10 to 25 dollars, depending on how it is installed.

The "Line Mod" and Steering Toggles
The steering line modification, referred to as the "line mod" by most BASE jumpers, was developed by Mark Hewitt. As simple as the line mod is, it ranks among the most important and controversial gear innovations ever in modern BASE jumping. It refers to routing a ram-air canopy's steering lines outside the slider grommets and the keeper rings on the risers and is used to clear a lineover malfunction.

If you get a lineover malfunction on a skydive, the procedure is to cutaway because, short of cutting the steering line causing the problem, there is nothing you can do to clear it. On many BASE jumps, there is not sufficient altitude to get a reserve out. Mark Hewitt's solution was to route the steering lines outside of the slider grommets and keeper rings so that simply releasing the brakes and letting go of the toggles would clear the lineover. It was (and still is) a clever, effective solution to a very dangerous problem, and no doubt has saved a number of lives and prevented serious injury. It does have its limitations and quirks, however:

1. You can only use it for slider down (or slider removed) jumps because it may hinder the slider from descending on a slider up jump.
2. Your canopy may handle differently when flying with the line mod. Personally, I prefer the way a canopy with the line mod flies.
3. You may need to shorten the distance between the brake settings and the steering toggles because the line mod changes a canopy's flare point--the steering line goes straight from the tail to your hand instead of going around a corner because of the keeper rings.
4. If you release the toggles to clear a malfunction, you must steer and flare with rear risers. This can be tricky on some canopies.
5. A toggle can accidentally release during deployment, forcing you to release the other toggle and steer/flare with rear risers.

Also related to the possibility of a premature toggle release is the need for a toggle that will release under very high loading, which occurs on a lineover malfunction. The most common solution is to use "Zoo toggles", which have been adapted to BASE jumping. A Zoo toggle has a loop made of suspension line (looks somewhat like a container closing loop), a straight stainless steel pin, a grommet near the top of the toggle, and a fold that is held in place by velcro (similar to what a lot of skydiving bridles have). The loop on the toggle is passed through the steering line's brake setting, then through the keeper ring on the riser, then through the grommet on the toggle. The brake is set by inserting the pin on the toggle through the loop. It's a good system that releases very easily, yet is fairly secure. The drawback is that if you pull on the toggles incorrectly, they will not release. They are not completely secure, either. Premature releases do happen, although not very often.

Zoo toggles will work with nearly any set of skydiving risers, but there are some BASE-specific risers made that have toggles designed to mimic the function of a Zoo toggle. They generally work well, and I'll be discussing them in upcoming articles.

Remember, the need for these toggles goes along with using the line mod. I recommend the line mod be used on all slider down (or slider removed) jumps. In the case a a jump with a single canopy system, the line mod *is* the reserve.

No need to buy this item just for Bridge Day, but if you will be doing any slider down jumps, get either a pair of Zoo toggles or a BASE riser/toggle system, and use the line mod.

Deep Brake Settings
Many BASE jumpers have multiple brake settings on their canopy. They come into play when jumping walls, e.g., cliffs or buildings. A canopy with deep brake settings has less initial forward surge during opening and lower forward speed after inflation. Jumping off a wall with a ram-air canopy and having a 180 degree off-heading opening is a worst-case scenario in BASE jumping. If it happens on a canopy with deep brake settings, the decreased surge during inflation and the lower forward speed after inflation give the jumper a chance of avoiding an object strike. If there is no line twist, simply flaring with the rear risers will stall the canopy and make it fly backwards. This is a very effective remedy and has certainly saved lives and prevented serious injury.

I personally don't have deep brake setting on any of my BASE canopies because I rarely jump walls, but I will be putting some on soon. To add deep brake settings to a canopy, take it on a skydive and experiment with deep brakes. Find a point where the forward speed of the canopy is *very slow*, but still above the stall point. Mark the steering lines (at the keeper rings) and recheck the setting. Have your rigger finger trap brake settings at that point. Two cautions: do not risk opening in a stall--always test new brake settings on a short-delay, slider-up skydive before using them on a BASE jump; also be aware that jumper weight makes a difference--a lighter jumper using the same brake settings could open in a stall.

More On Deep Brake Settings by Adam Filipino
There are a lot of details that I haven't covered in this article, but it does give a good overview of the common tricks that most BASE jumpers are using on their canopies. I'll include more details in future articles. Meanwhile, feel free to e-mail me with specific questions or comments-- especially suggestions for future articles.