BASE Article #9 - Setting Up a Skydiving Rig for BASE

Setting-Up a Skydiving Rig for BASE"

August 03, 1996

This is the seventh in a series of articles that I am posting about BASE jumping. This article examines a situation faced by most prospective first-time BASE jumpers--setting up a skydiving rig for BASE jumping. We'll take a look at setting up a rig to be used primarily for BASE jumping, then take a short look at preparing a
skydiving rig for Bridge Day in West Virginia.

The discussion in this article will be limited to the harness/container/reserve system.

Feel free to e-mail me (my e-mail address has changed--use ftr@hal-pc.org), 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 any more people hurt or killed while unknowingly re-inventing the sport.

In case, you're wondering about my background in BASE, I have made 60 BASE jumps, mostly freefalls from under 500 ft, from a variety of sites and I have been on the Bridge Day staff for the past few years, serving as Director of Safety and Training for BD '95.


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 a fool 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.

Is it OK to Use a Skydiving Rig on a BASE Jump?

In general, yes, but you must configure it for the site and for the type of jump you intend to make. Don't let the current hype about "BASE gear" vs. "skydiving gear" scare you. On any BASE jump, you'd better have gear that is properly configured for the site and the type of jump you will be doing. Often, modified skydiving gear is a good choice. Do some analysis and use the gear configuration that makes sense to you.

In my opinion, if there is sufficient altitude for a reserve deployment after experiencing a malfunctioned main, and there is no compelling reason to not carry a reserve, for example, weight or bulk considerations, then an appropriately configured skydiving rig is a better choice than a single- parachute system. I am not trying to imply that single- parachute systems are inferior to dual-parachute systems for BASE jumping. I have made the majority of my BASE jumps on single-parachute systems, but the
gear I choose to use on any given BASE jump is the gear combination that I feel will give me the greatest chance of survival.

One BASE jumping friend made this observation about the wide variety of gear combinations used in BASE jumping: "It all works, and it all (at times) doesn't work." For some BASE jumps, that makes a powerful case for using a properly-configured skydiving rig instead of a single- parachute BASE rig--skydiving rigs have reserves.

Do I Need to Modify my Skydiving Rig for a BASE Jump?

Not necessarily. I feel that the majority of attention should be spent on the main deployment system and the main canopy; if there is sufficient altitude for a reserve deployment, the reserve needs to be configured appropriately. Beyond that, if you are going to use a skydiving rig for BASE jumping exclusively, there are a couple of modifications that can increase your safety. These are covered next.

Harness/Container Modifications

There are at least two common BASE modifications to the harness/container system that relate to the main deployment system: Velcro tabs on the container and bridle, and a bottom-of-container (BOC) pilot-chute pouch.

Velcro tabs on the container and bridle are used to prevent the bridle from entangling with the jumper's body or gear. BASE jumpers face an increased likelihood of a bridle entanglement when launching with a pilot chute in their hand, as is commonly done for low-altitude BASE jumps. Before and during launch, and in freefall, a small amount of slack must be kept in the bridle to avoid prematurely opening the container if/when the jumper extends the arm that is holding the pilot chute. This is particularly true for standing BASE exits, where extending the arms far forward is an unconscious motion for many people. If too much slack is allowed, there is a small chance of the bridle becoming lodged under the container or under container flaps. On single-parachute BASE rigs, it is common to have at least one Velcro square on a container side flap, near the bottom, and a mating piece of Velcro on the bridle. This arrangement keeps the bridle away from the bottom of the container. Since the top flap on a BASE rig is usually tucked into the container, there is very little possibility of a bridle entanglement with the top flap. On skydiving rigs, some jumpers put Velcro on the containers and bridle, positioned to keep the bridle away from the bottom of the container, container flaps, and/or an externally-mounted reserve pilot chute, as is found on the Racer.

The bottom-of-container (BOC) pilot chute pouch, which is relatively common on skydiving rigs, has a dual purpose on BASE jumping rigs. For freefall BASE jumps where the jumper is leaving the pilot chute stowed in the pouch, its function is exactly the same as a BOC pouch on a skydiving rig. Additionally, the BOC pouch helps prevent a
premature deployment while the jumper is on the object. Since BASE pilot chutes are considerably larger than the typical skydiving pilot chute, most of them will not fit in a pouch designed to hold a skydiving pilot chute or if they do fit, they may be extremely difficult to extract. If the pilot chute is not well-secured by some other means, and it snags on an object or gets into the windstream, a premature deployment can result. On some objects, this is little more than a nuisance. On others, particularly antenna
towers, this is an extremely dangerous situation. For this reason, as well the fact that a BOC pouch drasticly reduces the possibility of a misrouted bridle, most BASE rigs, both single-parachute and dual-parachute systems, have a BOC pouch.

Reserve System

There are several schools of thought on selecting a BASE reserve for a skydiving rig. The first, and probably the oldest, is called the "wad of garbage theory". In this scenario, a round reserve, dumped into a malfunctioned main without first doing a cutaway, should create additional drag, even if it entangles with the malfunctioned main and doesn't fully inflate--the ore "garbage" there is over your head, the slower your descent will be.

Along similar lines, some jumpers have opted to use a tertiary reserve, as is used by some CRW jumpers. The tertiary reserve is a front-mounted unsteerable round canopy attached to the jumper's harness via a single long Kevlar bridle. This bridle is intended to enable the deployment parachute to clear a malfunctioned canopy overhead. The canopy usually has no pilot chute and is hand-deployed; it can inflate very quickly.

Another school of thought is that a slider-down square reserve, with an appropriate deployment system, will inflate much faster than a round reserve, and may allow time for a cutaway.

I won't discuss the pros and cons of the different schools of thought in this article other than to note that my personal preference is a properly configured square reserve.

Whatever your preference is, if you use a skydiving rig on a BASE jump, you need to realize that while skydiving reserve configurations will work well in a variety of skydiving situations, a skydiving reserve configuration is applicable to only a select number of BASE situations. Here's why. Skydiving reserve configurations are designed to work properly at a variety of airspeeds--from low speeds, as encountered in performing a cutaway from a low-speed malfunction, to high speeds, as encountered when deploying the reserve at terminal after a total malfunction of the main. They can do this because of the assumption that there will be plenty of altitude for a deployment in either scenario. Because BASE jumps are typically performed from much lower altitudes, BASE jumpers do not have the luxury of being able to rely on one reserve configuration for all emergency situations. The question to be addressed is the altitude available for a reserve deployment, and how to configure the reserve to open within that distance.

Previously, we have looked at gear selection based on the site and the type of jump planned as critical factors in the selection of a main canopy and deployment system. For someone jumping a dual-parachute system on a BASE jump, the same analysis is extended to selection of the reserve system configuration.

To briefly review, when planning a BASE jump, we examine the site and the type of jump planned. There are several distances to consider:

The vertical distance from the ground (or other hazard) to the exit point. The distance required for a normal main-canopy deployment. The horizontal distance from the intended opening point to the landing area. Your canopy's glide will determine the minimum opening altitude that will allow you to safely reach the landing area. Glide will be affected by winds, wing loading, canopy condition, and other factors. You must be familiar with the flight characteristics of the canopy you will be using. The distance required for successful execution of emergency procedures. In the case of a skydiving rig, this will determine the minimum altitude required for a reserve deployment.

Notice that all of the distances except the AGL exit altitude are very gear-dependent. Normally, you will select a main canopy based on the site (or possibly select the site based on your canopy), then consider the minimum opening altitude required. Once that is determined, you will choose your main deployment system and freefall delay (if you choose to freefall the site), and reserve system. It is not nearly as complex as it appears, but it definitely requires more careful consideration than choosing gear for a skydive.

Unfortunately, most skydivers are not very familiar with their reserve systems, beyond knowing what the configuration is, i.e., the size and type of canopy and whether it is equipped with an AAD. If you are using a skydiving rig for BASE jumping, you need to be very familiar with your reserve system. If you plan to BASE jump a skydiving rig regularly, and you do not know how to pack the reserve, I recommend that you consider learning how from a rigger. This takes many hours of practice, so be prepared to
spend a lot of time with it.

If your rig has an AAD, you will almost certainly need to make sure it is either disabled or removed. If there is any possibility of a water landing, remove it. An AAD can be completely ruined by submersion in water.

Since most of us don't have a variety of reserve canopies available to us, we need to look at ways of ensuring that our reserve will deploy very quickly in case of a BASE emergency. First we will take a look at the deployment system, then we will look at both round reserves and square reserves.

Reserve Deployment System

Since virtually all skydiving rigs have spring-loaded reserve pilot chutes and ripcords, we will consider only that type of system. The first item to examine is the reserve pilot chute. For most BASE jumps, the reserve pilot chute needs to be capable of creating a lot of drag at low airspeed and be certain to immediately spring clear of the jumper's burble. There are commercially available spring-loaded pilot chutes designed for this, e.g., the Magnum, made by National Parachute Industries. You will find these in the
ParaGear catalog. They come in diameters of 36" F-111 and 40" F-111. I don't know of any larger spring-loaded pilot chutes, but on the same page is a Hot Shot spring-loaded pilot chute that is a 36" ZP. I have a custom-made BASE reserve pilot chute that is a 42" ZP. Note: don't expect your rigger to be willing to put his seal on a rig that has a reserve pilot chute other than one recommended or required by the harness/container manufacturer. Many riggers will be very reluctant to pack a reserve system for a BASE jump. Respect their decision, even if you find it irritating or inconvenient. You will be able to find a BASE-friendly rigger, so keep looking.

The next item to examine is the bridle. As with the main bridle, it must have sufficient length to ensure that the pilot chute can clear your burble. If you are using a free-bagged reserve, it will have a bridle length that is more than sufficient. If you are using a different reserve system, this may not be the case. Make sure the bridle is at least 8 feet long.

Speaking of free bags, I do not personally see any problem with using a free-bagged reserve on a BASE jump, even though deployment bags are not generally used on BASE main canopies. They offer the distinct advantage of enabling the reserve to inflate even in the case of a horseshoe malfunction or failure to cutaway. I generally
free-pack my reserve instead of using a free bag, but only because I don't want to risk trashing the environment with a lost free bag and pilot chute. (Yes I know that is some weird reasoning.)

Square Reserves

As is the case with square mains, square reserves are generally easily configured for fast openings--simply replace the sail slider with a mesh slider and/or pack slider-down. I keep a mesh slider on my Raven I reserve. On jumps where I have lots of altitude and will be deploying my main canopy at or near terminal, I pack my reserve slider up. For jumps with more limited room for a reserve deployment, I pack my reserve slider down. For an unusually high BASE jump, like Angel Falls, I would probably use a skydiving reserve configuration, but it would depend on the altitude available for reserve deployment.

Round Reserves

Although there are some specially modified rounds that are capable of opening almost instantly, the vast majority of round canopies don't. There are a couple of ways to speed up the openings. The first is called "rubber banding the apex". The idea is to use rubber bands to constrict the canopy 1 to 2 feet below the apex. Depending on the thickness of that part of the canopy after it is flaked and folded lengthwise, I use either large skydiving line stow rubber bands or groups of several "pony tail" rubber bands that I have threaded the bridle through--you may need to remove the reserve pilot chute or bridle to do this. I slide the rubber bands down the canopy and usually constrict the apex in two places--about two feet below the apex, and a few inches below the apex. Supposedly, this trick will cause a round canopy to inflate more quickly. In my
experience it does seem to work, although any round inflation on a BASE jump seems to take forever compared to a slider-down square.

The other trick, and this should be fairly obvious to anyone familiar with packing rounds, is to not fold the skirt of the canopy parallel with the radial seems after flaking it.

How Should I Set Up My Skydiving Rig for Bridge Day?

Here's my analysis, but don't consider it to be anything more than one person's opinion--do the analysis yourself and use your best judgement. The New River Gorge Bridge is 876 feet high, and the exit point is about 250 yards (meters) from the designated landing area. Winds vary considerably in speed, but they are nearly always either coming straight up the river or down the river at the exit point. At ground level, wind speed and direction, and turbulence are unpredictable.

The typical jump is a 2 to 3 second delay. This takes about 60 to 140 feet. Deployment for a mesh-slider-up ram-air main canopy will take about 100 feet, maybe a bit more. So if you open without problems, you are at about 600 feet. If your canopy doesn't open normally, you've got a maximum of 600 feet to deal with it. For the typical skydiving rig with a square reserve, removing the AAD (a MUST since there is a potential water landing) and pulling the reserve slider down should be sufficient for the
reserve system, but I prefer to put a high-drag reserve pilot chute on also. Be aware that a slider-down reserve can be very dangerous to deploy at near-terminal or terminal
freefall speed. You must be very careful not to get into that situation!

For the main, a 40" to 44" BASE pilot chute and a 9 foot bridle should do the trick.

Here are some more tips. First of all, jump gear that you are willing to submerse in water. The dry landing areas on Bridge Day are tight and full of rocks and trees. The safest alternate landing area is the river. If you are insistent on staying dry, then jump a canopy that you can land slowly, softly, and accurately. Large, low-aspect-ratio seven cells seem to give consistently good results.

A Few Parting Remarks

I wish I could tell you the magic gear combination that will guarantee your safety on any BASE jump. There isn't one. Talk with as many experienced BASE jumpers as you can before you jump, analyze the site yourself, and jump with the gear and the plan that you feel most comfortable with. The time for considering all the "what if" scenarios is during the planning and preparation. The exit point on a BASE jump is a horrible place to experience gear fear.

Be smart, be safe, don't be afraid to say no to a jump, and if you learn any neat tricks along the way, pass them on to other jumpers to help them stay safe.