Bowstring

Lore & Background

Most bowstrings may be described as either simple, reverse-twisted, or looped. Simple strings may be made of any fiber, twisted into a single cord; they have been used in many parts of the world and are still effective and fairly quick to make, but tend to be weaker for their weight and may come apart if not kept under tension. Reverse-twisted strings are traditional in Europe and North America for most natural materials such as linen and hemp; the form is also used for modern materials. A reverse-twisted string is made of separate bundles, each twisted in one direction, then the entire group twisted in the other direction, resulting in greater strength for its weight than simple or looped strings. The traditional 'Flemish' string has a laid-in loop at one end, easier to fit over the nock when stringing and unstringing. The Japanese bowstring is made by reverse-twisting in different directions in the core and outer layers.

Looped strings are made of one or more continuous loops of material. Modern strings are often made as a single continuous loop, then served to give final form. In many parts of Asia, traditional strings have a single loop in the center, with ends made of separate lengths tied on using a special knot, allowing extra fiber at the ends where wear is more likely. Traditional materials include linen, hemp, hair, sinew, silk, and rawhide; sinew and hide strings may be seriously affected by water. Modern materials include Dacron, liquid crystal polymers such as Kevlar and Vectran, and ultra-high-molecular-weight polyethylenes such as Spectra and Dyneema. Modern strings are often made from composite fibres to gain advantages of both.

Reader's Guide

The bowstring is a fundamental component of archery, directly influencing arrow speed, durability, and bow longevity. Its design and material choices reflect centuries of practical refinement across cultures. The distinction between simple, reverse-twisted, and looped forms shows how different construction methods address trade-offs between ease of manufacture, strength, and wear resistance. The observation that mass at the string's center has disproportionate effect on arrow speed has guided material selection and serving placement. Traditional natural fibers like linen, hemp, sinew, and rawhide remain effective on traditional bows, while modern synthetics such as Dacron, Kevlar, Vectran, Spectra, and Dyneema offer greater strength per weight and water resistance. Dacron's stretch reduces shock to wooden-handled recurves, making it common on beginners' equipment and older bows. Liquid crystal polymers and ultra-high-molecular-weight polyethylenes provide faster arrow speeds. Serving—wrapping additional thread at nocking points and on looped strings—protects against abrasion, a practice also applied to compound bow cables. The legacy of bowstring design is one of incremental innovation, balancing weight, strength, and wear to meet the needs of different bow types and archery traditions.

Did You Know?

• 1 g of extra mass in the middle of the string slows the arrow about as much as 3.5 g at the ends.
• Njál's saga describes the refusal of a wife, Hallgerður, to cut her hair to make an emergency bowstring for her husband, Gunnar Hámundarson.
• The author of Arab Archery suggests the hide of a young, emaciated camel for bowstring material.

Anatomy of the String: Forms and Construction

A bowstring is the essential link joining the two tips of a bow stave, converting stored energy into the launch of an arrow. Over centuries, string builders worldwide have converged on three principal construction methods. The simplest is a single cord of any fiber twisted into one strand. Quick to make and still effective, it remains the weakest option for its weight and can unravel if not held under constant tension, with its ends secured by a round turn and two half-hitches. The reverse-twisted form, a European and North American tradition for natural materials, is more sophisticated. Individual bundles are twisted in one direction, then the entire group is twisted in the opposite direction. This counter-twist produces a cord that is stronger per unit of weight, holds together more reliably, and presents its full thickness at the nocks—the zone of greatest abrasion. The Flemish variant incorporates a pre-formed loop at one end for easier stringing, while the Japanese approach twists the core and outer layers in opposing directions. Looped strings, whether a modern single continuous loop or the Asian design with a central loop and separately tied end pieces, trade some fiber at the wear-prone tips for a different structural logic, often compensated by additional serving.

From Sinew to Spectra: The Evolution of Materials

The materials used to make bowstrings span an enormous range. Traditional choices include linen, hemp, other vegetable fibers, hair, sinew, silk, and rawhide. In dire circumstances, virtually any fiber will do—a detail preserved in Njál's saga, where Hallgerður's refusal to cut her hair for an emergency string led to her husband Gunnar Hámundarson's death. The author of Arab Archery even recommends the hide of a young, emaciated camel. Natural fibers, however, are vulnerable to water, and sinew or hide strings can be seriously damaged by moisture. Modern synthetic materials have transformed performance. Dacron, a polyester with a per-strand strength of 22.5 kilograms and 2.6 percent stretch, remains popular for beginners' and wooden bows because its elasticity cushions shock. Liquid crystal polymers like Kevlar and Vectran offer 31.8 kilograms of strength per strand with only 0.8 percent stretch, yielding roughly two metres per second more arrow speed. Ultra-high-molecular-weight polyethylenes such as Spectra and Dyneema push strength to 45.5 kilograms per strand at 1.0 percent stretch, are lighter and faster than Kevlar, and enjoy a significantly longer service life. Many contemporary strings blend fibers—Vectran with Dyneema, for instance—to capture the best qualities of each.

Physics on the String: Mass, Stretch, and Speed

The performance of a bowstring is governed by a few key physical properties: light weight, tensile strength, abrasion resistance, and water resistance. Among these, mass distribution is particularly consequential. A single gram of extra weight at the center of the string retards an arrow approximately as much as 3.5 grams placed at either end. This means that even minute additions of serving or nocking material at the midpoint carry a disproportionate penalty, while the same mass at the tips is far less costly. Stretch is the second critical variable. Dacron's 2.6 percent elongation absorbs shock—valuable for wooden-handled recurve bows—but costs speed. Kevlar and Vectran, at just 0.8 percent stretch, transfer energy more efficiently, gaining roughly two metres per second in arrow velocity. Dyneema sits between them at 1.0 percent stretch while adding the advantages of lower density and longer lifespan. The interplay of these properties explains why no single material dominates: the ideal string balances stiffness for speed against enough give to protect the bow, all while keeping every gram accounted for.

Serving, Knots, and the Art of Maintenance

Serving is the practice of wrapping an additional thread around the main string at its most vulnerable points. On a bowstring, this reinforcement is concentrated at the nocking points, where the string contacts the bow's tips and the arrow's nock—areas of the greatest abrasion. On looped strings, serving also serves a structural purpose, holding the two sides of the loop together. The same technique is applied to compound bow cables, wrapping the sections that repeatedly pass over cams, cable slides, or roller guards to minimize wear. The choice of knot reflects the string's construction. Simple strings are typically tied with a round turn and two half-hitches at each end. Reverse-twisted strings more commonly use a timber hitch, also called the bowyer's knot, at each tip. The Flemish loop, by contrast, eliminates the need for a knot at one end entirely, as the pre-formed loop simply slips over the nock. Maintenance considerations vary by material. Dacron strings are noted for their ease of care and can last several years with minimal attention. Natural-fiber strings, while still effective on traditional wooden or composite bows, demand more vigilance against moisture and their performance degrades more quickly than their synthetic counterparts.