ninelines

Ninelines is a term used in the context of skydiving and paragliding to refer to the lines that connect the risers of a parachute to the parachute canopy. These lines are typically made of strong, low-stretch synthetic materials such as Dacron or Spectra. The arrangement and length of these lines are critical for the proper inflation and stability of the parachute.

In a typical ram-air parachute system, there are usually two sets of ninelines, one for each side of the parachute. Each set consists of several lines, often referred to as A, B, C, and D lines, although the exact naming convention can vary. These lines are attached to specific points on the risers, which are then connected to the skydiver's harness. The canopy itself is attached to the other end of the ninelines.

The design and configuration of the ninelines directly influence how the parachute opens, its aerodynamic performance, and its maneuverability. Adjustments to the length or attachment points of these lines are part of the complex process of parachute rigging and can affect flight characteristics. The integrity of the ninelines is paramount for safety, as any failure could lead to a loss of control or an inability for the parachute to function correctly.