The harness of a BASE rig is, in most respects, identical to that found on a skydiving container. The container, however, differs in several important respects:
- A BASE-specific container is generally designed to hold only one parachute. The rationale behind this is that there is generally insufficient time to assess a malfunction and deploy a reserve in the BASE environment, and that additionally the presence of a reserve complicates the system, a more complex system being generally less reliable.
- BASE containers are closed differently than skydiving containers. Although many modern BASE containers are pin-closed, like a skydiving container, they often use two pins instead of one, or velcro instead of pins all together.
Closure in a BASE container
Like a skydiving main container, a BASE container generally consists of four flaps, connected to the top, bottom, left, and right sides of a backpad. BASE containers differ in how these flaps are held together in the closed container. The three most common closure methods are listed below. None of these closure methods is inherently unsafe.
The Reactor 4, a velcro-closed container manufactured by Basic ResearchThe first BASE-specific containers were, in most respects, similar to a modern Velcro-closed BASE container. In a Velcro-closed container, each of the four flaps has a strip of Velcro on the outside, along the centerline of the container. These flaps mate with a shrivel flap, which holds the container closed and is fixed to the bridle.
The first BASE containers were closed using a strip of fabric with Velcro sewn to one side. This system was generally effective when used from a flat-and-stable body position. If the jumper found himself head low, however, the Velcro (which sheared, in that scenario, rather than pulled away from the container) would not reliably open. The shrivel flap, which shrivels if the Velcro does not immediately peel, resolved these issues.
The advantage of a Velcro-closed container is that, regardless of the details of the packjob, the armour being worn by the jumper, or his or her body position, the container will consistently open with the same (small) pull force. If necessary, as for very low jumps, the pull force can be further reduced by “priming” the Velcro. The method by which the bridle is attached to the shrivel flap makes it particularly easy to attach a length of cord, rather than a bridle, when doing static-line jumps, so that the bridle is not worn unnecessarily.
It is important that the jumper carefully maintain the Velcro on this type of container, since old or fouled Velcro is prone to becoming detached in the relative wind, leading to a horseshoe malfunction on a single-parachute system. Also for this reason, Velcro-closed containers are not the optimal choice for terminal BASE jumps, though a modern container with clean, relatively new Velcro can generally be safely taken to terminal. They are very strongly recommended against for slider-up aerials and wingsuit jumps.
Single pin containers
A single-pin container, like a skydiving container, is closed using a curved pin and loop near its center, the pin fixed to the bridle.
All pin-closed containers are sensitive to the bulk distribution in packing the canopy, as well as bulk from the jumper’s clothing or armour, and variation in pin tension due to body position. A container that had a low pull force when packed can attain a dangerously high pull force, for instance, if it was not sized for the armour worn and deployment is initiated from a tuck position. It is therefore ‘’critical’’ that the pin tension be assessed while the jumper is wearing what he or she will be jumping in, and for the anticipated body position. Furthermore, a jumper who is new to packing should pay particular attention to the effect of variations in the packjob on pull force.
Nevertheless, the fact that pins are hidden, on all pin-closed rigs, beneath a flap makes pin-closed containers more suitable than their Velcro closed counterparts for terminal jumps, slider-up aerials, and wingsuit jumps. Furthermore, pin tension can be deliberately reduced by adjusting the closing loop or replacing it with a Spectra loop, so that pin-closed containers can also be more suitable for very low freefall jumps.
In addition to checking pin tension before a jump, jumpers using pin-closed containers must be sure to leave a small amount of slack (usually a 1-inch fold) outside of the flaps, between the pins and the canopy, so that the bridle comes taut only after the pins have been pulled.
Dual pin containersA two-pin system is closed using two pins, threaded through two loops – one near the top of the container, and one near the bottom. The container is otherwise similar to a single-pin container, and shares its advantages and disadvantages relative to a Velcro-closed container. In a two-pin container, the pull force is split between the pins. Many jumpers find a dual pin container easier to close than a single-pin container.
Containers with a reserve
BASE containers are available which allow for the use of a reserve. In addition to the issues of simplicity and efficacy discussed above, jumpers considering the purchase of such a system should understand that the reserve, like the main, must be packed in a manner appropriate to the jump being done. A reserve packed slider-down could be fatal if used on a slider-up jump , and a reserve packed slider-up would be useless on a slider-down jump.
Even packed correctly, there are very few scenarios in which a reserve might be useful. A jumper with a reserve might be inclined to pull high, “just in case”, when in fact it is generally safer to pull lower, allowing more time for the jumper to gain distance from the object. Remember: Very few injuries in BASE are the result of a canopy malfunction; far more are the result of object strike.
BASE-specific canopies are designed to be reliable and stable, and are therefore almost immune to the spinning malfunctions so common on elliptical skydiving mains. Furthermore, even a relatively careless BASE packjob would be meticulous by skydiving standards, with most packjobs closely resembling those used for skydiving reserves. One jumper puts it this way: “I don’t jump without a reserve; I jump without a main.”
For these reasons, the use of a second canopy is extremely uncommon in BASE.