Parachute cord (also paracord or 550 cord) is a lightweight nylon kernmantle rope originally used in the suspension lines of US parachutes during World War II. Once in the field, paratroopers found this cord useful for many other tasks. It is now used as a general purpose utility cord by both military personnel and civilians. This versatile cord was even used by astronauts during the 82nd Space Shuttle mission to repair the Hubble Space Telescope.
The braided sheath has a high number of interwoven strands for its size, giving it a relatively smooth texture. The all-nylon construction makes paracord fairly elastic; depending on the application this can be either an asset or a liability.
Current technical standards for the manufacture of cord for use in parachutes are published by the Parachute Industry Association. The US military MIL-C-5040H standard required the material to be nylon.  Similar styles of cord are manufactured with other materials such as polyester.
Despite the historic association of pararopes with airborne units and divisions, virtually all US units have access to the cord. It is used in almost any situation where light cordage is needed. Typical uses include attaching equipment to harnesses, as dummy cords to avoid losing small or important items, tying rucksacks to vehicle racks, securing camouflage nets to trees or vehicles, and so forth. When threaded with beads, paracord may be used as a pace counter to estimate ground covered by foot.
The yarns of the core (commonly referred to as "the guts") can also be removed when finer string is needed, for instance as sewing thread to repair gear, or to be used as fishing line in a survival situation. The nylon sheath is often used alone, the yarn in the core removed, when a thinner or less elastic cord is needed such as when used as a boot lace. Ends of the cord are almost always melted and crimped to prevent fraying.
In addition to purely utility functions, paracord can be used to fashion knotted or braided bracelets, lanyards, belts, and other decorative items. These are sometimes tied in a fashion that can easily be unraveled for use in a survival situation. Some companies use paracord in conjunction with other survival components to create everyday wearable survival kits.
The same properties which soldiers appreciate in paracord are also useful in civilian applications. After World War II parachute cord became available to civilians, first as military surplus and then as a common retail product from various surplus stores and websites. A given product labelled as paracord may not correspond to a specific military type and can be of differing construction, quality, color, or strength. Particularly poor quality examples may have significantly fewer strands in the sheath or core, cores constructed of bulk fiber rather than individual yarns, or include materials other than nylon.
Paracord has also been used for whipmaking. The durability and versatility of this material has proved beneficial for performing whip crackers and enthusiasts. Since nylon does not rot or mildew, it has become known as an all-weather material for whipmaking.
Hikers and other outdoor sports enthusiasts sometimes use "survival bracelets" made of several feet of paracord which is woven into a compact and wearable form. Such bracelets are meant to be unraveled when one needs rope for whatever purpose — securing cargo, lashing together poles, fixing broken straps or belts, assisting with water rescues, controlling bleeding with a tourniquet, etc.
Another use of parachute cord is in the stringing of mallet percussion instruments, such the xylophone, marimba, or vibraphone.
Additional uses for parachute cord are in the manufacture of items such as lanyards, belts, dog leashes, and key chains. This is becoming more popular as crafters are discovering this material.
US Military issue paracord was purchased with reference to a technical standard MIL-C-5040H, which was inactivated in 1997. This standard described six types: I, IA, II, IIA, III, IV. Types IA and IIA have no core. Type III, a type commonly found in use, is nominally rated with a minimum breaking strength of 550 pounds, thus the nickname "550 cord".
The US military specification for paracord gives strength and construction parameters to which the final product must conform, as well as requirements for packaging and marking. Although the standard contains specific denier figures for the sheath strands and inner yarns, there are no overall diameter requirements for the cord itself. Below is a table of selected elements from the specification.
|Type||Minimum strength||Minimum elongation||Minimum length per pound||Core yarns||Sheath structure|
|I||95 lb (43 kg)||30%||950 ft (290 m; max. 1.57 g/m)||1||16/1|
|IA||100 lb (45 kg)||30%||1050 ft (320 m; max. 1.42 g/m)||<no core>||16/1|
|II||400 lb (181 kg)||30%||265 ft (81 m; max. 5.62 g/m)||4 to 7||32/1 or 36/1|
|IIA||225 lb (102 kg)||30%||495 ft (151 m; max. 3.00 g/m)||<no core>||32/1 or 36/1|
|III||550 lb (249 kg)||30%||225 ft (69 m; max. 6.61 g/m)||7 to 9||32/1 or 36/1|
|IV||750 lb (340 kg)||30%||165 ft (50 m; max. 9.02 g/m)||11||32/1, 36/1, or 44/1|
The core (also known as the kern) consists of several yarns, the number is determined by the cord type, and each yarn is made up of two(commercial) or three(MIL-Spec) smaller nylon fibers twisted together.
Mil-spec Type III may be slightly thicker than commercial grade due to it often requiring three nylon fibers per inner core as opposed to the two fibers per core of the commercial version. Mil-spec cord will be closer to a 4 mm thickness, where commercial versions are closer to a 3 mm thickness. This will also vary if the Type III uses 7,8 or 9 inner cores. The most common on the commercial market is a 7 core. While the U.S. military has no overall diameter requirements in its specifications, in the field Type III cord typically measures 5⁄32 inch (4 mm) in diameter.
The inactivated military standard only describes sheath colors of "natural" or "olive drab" ("Camuflage Green"). Commercially, many colors are available.
The inactivated specification describes the requirements for the manufacture of compliant cords. The fibers for the outer sheath must be colored using an approved dye -the dye cannot compromise the structure of the fibers or the finished product. The undyed fibers are twisted tightly to make the inner yarns- 3 bundles of fiber per core yarn. The sheath is then plaited over the yarns(the number of yarns are determined by cord type, type III would have 7-9 yarns). The cord is steamed to tighten the cord. This step was crucial to parachute use since the extra bit of stretch helped to absorb the shock when the parachute was deployed.
The inactivated military standard referred to a color code used to identify the manufacturers of the cord. Manufacturers would insert several dyed strands, using a code assigned in MIL STD 905 (also inactivated) to identify themselves. This was so that in the event of cord failure it would be possible to find the source of the sub-par cordage. Type 1A cord and Type 2A cord would have the marking fibers on the sheath since the contain no inner yarns. Types 1, III, and IV would have yarns containing the marking color.
- Tom Nugent, "Blanketing the Hubble", University of Delaware Messenger, vol. 6, no.3 (1997)
- MIL-C-5040H, Military Specification Cord, Fibrous, Nylon
- http://www.thomasnet.com/products/parachute-cord-19822808-1.html Thomas registry "parachute cord polyester", retrieved 2014 04 03
- Bill Ganze, "Surplus Everywhere", Farming in the 1940s
- Samantha Grenier, Parachute Cord Craft: Quick and Simple Instructions for 22 Cool Projects Design Originals, 2013 ISBN 1574213717