The Anatomy of a Slider

What a Slider Is, How it Works, and Why You Need to Understand It

Image © Apex BASE
Image © Apex BASE. Image © Apex BASE

What is a Slider?

A little hamburger. Obviously.

OK, fine.

A slider is a rectangular piece of fabric with industrial-strength grommets securely sewn into each corner. The slider is a reefing device that stages the deployment of a ram-air parachute in order to mitigate its opening shock, which -- if left unchecked in a terminal airspeed environment -- can damage the canopy and/or the jumper.

The slider is rigged to nest into the canopy at the top of the lines.

As the canopy deploys, the slider --well -- slides -- down to a resting place just above the risers. Air resistance slows the slider's descent, reducing the speed with which the lines spread to their flying configuration and leading to a "softer" opening.

Sliders in Skydiving

In a skydiving context, sliders are made of light, strong, opaque fabric.

Modern slider designs generally include a means of cinching the slider closed to reduce its drag and interference with flight after opening. Usually, this is achieved using two pieces of cord, which sit in sewn-in channels set equidistantly from the middle of the slider. Each piece of cord has a grabbable tag at one end and a notch-like extension of cord close to the other end. After the skydiver has deployed the canopy, he or she tugs the tags on both cords until the "notch" falls into place, locking the slider in a gathered-up position.

As a result of the dynamics of the fabric and its interaction with the skydiving canopy's more performance-oriented design, the sequence of deployment often takes over 500 feet to complete -- sometimes, more.

The high altitude of deployment allows for a design focused on comfortable, "soft" openings.

A slider can get stuck at the top of the lines, causing what can sometimes be a very serious malfunction that needs to be cut away.

Sliders in BASE Jumping

Naturally, BASE jumpers open lower than skydivers -- often, close to cliffs, buildings, or other hazards.

As a result, a BASE jumper requires his or her canopy to open quickly and on-heading over opening softly and sweetly. Therefore, BASE sliders prioritize opening performance and consistency over comfort. A hard opening is usually a much smaller problem than a long "snivel" (deployment sequence) that results in the jumper landing in a dangerous place or, worse yet, impacting the ground before full parachute inflation.

Depending on the specifics of the BASE jump, the jumper must choose to configure his or her slider to better control the canopy's deployment sequence. There are different slider types and configurations to choose from, depending on the freefall delay from the exit point. No uninformed decision should ever be made in regards to slider choice and configuration without the direct consult of a mentor or very experienced jumper.

Slider Types

There are two types of BASE slider: fine-mesh and large-mesh. Mesh sliders are mandatory for BASE, as the slower opening of a sailcloth slider is generally inappropriate in the BASE context (but can be used in very specific instances).

  • Fine- (or small-hole, or "marquisette") mesh resists the air more than a wide-mesh slider, slowing down the opening. For this reason, it is the less-common option and not appropriate for short delays.

Slider Configuration in BASE

The slider can be used in a slider-up or slider-down configuration. It can also be removed entirely. Slider configuration depends entirely on the specs of the object and the jump.

Apex BASE makes a slider that clicks on and off the canopy without the need to disconnect the risers from the canopy, which could be an excellent choice for a BASE jumper who moves between configurations often or does not wish to disconnect and reconnect his or her canopy if at all possible.

A BASE canopy's heading performance degrades as a slider is used on shorter and shorter delays. Never use a slider-up configuration on BASE jumps with a delay of less than three seconds from a strikeable object.

A mentor or experienced BASE jumper must teach you the process of configuring your slider, and instruct you in choice of configuration. With a one-parachute system, a misconfiguration could easily be fatal.


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Your Citation
O'Neil, Annette. "The Anatomy of a Slider." ThoughtCo, May. 5, 2016, O'Neil, Annette. (2016, May 5). The Anatomy of a Slider. Retrieved from O'Neil, Annette. "The Anatomy of a Slider." ThoughtCo. (accessed November 21, 2017).