Fly rods, thin, flexible fishing rods designed to cast an artificial fly, usually consisting of a hook tied with fur, feathers, foam, or other lightweight material. More modern flies are also tied with synthetic materials. Originally made of yew, green heart, and later split bamboo (Tonkin cane), most modern fly rods are constructed from man-made composite materials, including fibreglass, carbon/graphite, or graphite/boron composites. Split bamboo rods are generally considered the most beautiful, the most "classic", and are also generally the most fragile of the styles, and they require a great deal of care to last well. Instead of a weighted lure, a fly rod uses the weight of the fly line for casting, and lightweight rods are capable of casting the very smallest and lightest fly. Typically, a monofilament segment called a "leader" is tied to the fly line on one end and the fly on the other.
Each rod is sized to the fish being sought, the wind and water conditions and also to a particular weight of line: larger and heavier line sizes will cast heavier, larger flies. Fly rods come in a wide variety of line sizes, from size #000 to #0 rods for the smallest freshwater trout and pan fish up to and including rods for large saltwater game fish. Fly rods tend to have a single, large-diameter line guide (called a stripping guide), with a number of smaller looped guides (aka snake guides) spaced along the rod to help control the movement of the relatively thick fly line. To prevent interference with casting movements, most fly rods usually have little or no butt section (handle) extending below the fishing reel. However, the Spey rod, a fly rod with an elongated rear handle, is often used for fishing either large rivers for salmon and Steelhead or saltwater surf casting, using a two-handed casting technique.
Fly rods are, in modern manufacture, almost always built out
of carbon graphite. The graphite fibres are laid down in increasingly
sophisticated patterns to keep the rod from flattening when stressed (usually
referred to as hoop strength). The rod tapers from one end to the other and the
degree of taper determines how much of the rod flexes when stressed. The larger
amount of the rod that flexes the 'slower' the rod. Slower rods are easier to
cast, create lighter presentations but create a wider loop on the forward cast
that reduces casting distance and is subject to the effects of wind.
Furthermore, the process of wrapping graphite fibre sheets to build a rod
creates imperfections that result in rod twist during casting. Rod twist is
minimized by orienting the rod guides along the side of the rod with the most
'give'. This is done by flexing the rod and feeling for the point of most give
or by using computerized rod testing.