Cable fairing


A cable fairing is a structure attached to a towed cable designed to streamline the flow around the cable, primarily in marine environments.
Cables are faired primarily for two reasons: to reduce normal drag and thus achieve more depth for a given cable scope and speed; and to eliminate cable vibration caused by vortex shedding, commonly known as cable strum.

Types of cable fairing

There are several major types of cable fairing:
All cables have hydrodynamic loading functions. These describe the variation in drag coefficient as a function of angle with respect to the flow. As an example, the loading function for the normal drag coefficient of an unfaired cable, represented as a flexible circular cylinder, is .

Operational complexities

Fairing a cable can increase the complexity of the handling system. An unfaired cable can be wrapped many times on a winch drum. Some types of faired cable may only permit a single wrap.
Furthermore, many types of hard fairing require the use of anti-stacking rings. When under tension, the diameter of a steel-armored cable gets smaller. This in turn would cause the fairing sections to loosen and slide down the cable without the use of the anti-stacking rings.