Line Info

Base-specific concerns here

General

There are 4 line types in common use:
The number beside a line type is its breaking strength in pounds (when new).
- E.g. new Vectran 750 is rated to 750 lbs
- Higher number means stronger, thicker/bulkier, longer lifespan, and more parasitic wind drag
When differentiating between types of lines here, we are comparing the same weight
- E.g. new Vectran 750 vs. new Dacron 750

Uses: Found on BASE canopies and some brands of tandems.
Appearance: White and thick. Sometimes colored black on BASE canopies, and red on CRW canopies.
Trim: Holds trim better than Spectra, but worse than Vectran.
Tradeoffs:
- High bulk (increases pack volume by ~1 size e.g. a 150 packs like a 170)
- Higher drag

Also known as Microline, Dyneema, and UHMwPE

Uses: Reserve closing loops, pilot chute center lines
Trim: Loses trim significantly over time.
The most abrasion resistant of the line types
- UV, water, and abrasion (dirt/dust/sand/salt) resistant
- Stays smooth as it ages
- You can put a thousand jumps on a set that still looks fine
Tradeoffs:
- It goes out of trim. Lines shrink unevenly, and after several hundred jumps some may be inches shorter than new
- Not a problem on large conservative canopies, but...
  - Modern sport canopies are designed around a stable trim.
- Outer lines shrink relative to center ones, which will pull slider stops out of position
- Lifespan is limited by trim, rather than wear (opposite of Vectran)
  - ~50% of trim can be recovered by manually stretching the lines.

Also known as Technora

Historical, no longer in use.

The first low bulk line, adopted in the late 70s and early 80s as canopies got smaller and faster
Abandoned because it had too short of a lifespan
- Lines failing at 20-50 jumps
- Abrades itself where lines cross

What can decrease line life expectancy:

Dusty/sandy/costal environments
- Estimated to wear lines ~20% faster
Not collapsing your slider
Removable sliders
- The rings on removable sliders are heavier than on standard sliders
- An RDS is estimated to wear lines ~15% faster
- A full RDS also means more tension on the slider and lines, and the slider may clatter longer
Hard openings, line twists, and asymmetric deployments
Worn/sharp slider grommets
- JYRO estimates ~80% of strength loss to grommet abrasion, and ~20% to the load cycle of each opening
Exit weight

Heavy wear samples are well past the point they should have been replaced, charts by Performance Designs