A derrick is a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys. Most derricks have at least two components, either a guyed mast or self-supporting tower, and a boom hinged at its base to provide articulation, as in a stiffleg derrick. The most basic type of derrick is controlled by three or four lines connected to the top of the mast, which allow it to both move laterally and cant up and down. To lift a load, a separate line runs up and over the mast with a hook on its free end, as with a crane.
Two guy derricks at a granite quarry
Iron oil derrick
Stiffleg derrick performing high rise rigging on a rooftop
Wooden derrick (1917)
A guyed mast is a tall thin vertical structure that depends on guy lines for stability. The mast itself has the compressive strength to support its own weight, but does not have the shear strength to stand unsupported or bear loads. It requires guy lines to stay upright and to resist lateral (shear) forces such as wind loads. Examples include masts on sailing vessels, towers for telecommunications, meteorology, and masts on cranes, power shovels, draglines, and derricks, starting with the simple gin pole.
A guyed radio mast
The Sendeturm Jauerling is a partially guyed 141 meter tower built in 1958, consisting of a 35-metre-high free-standing steel framework tower, which carries a 106 meter guyed steel tube mast on the top
Zendstation Smilde, Netherlands, is a 303 m (994 ft) partially guyed tower that consists of an 80 m (260 ft) high reinforced concrete tower topped since 2012 by a 223 m (732 ft) steel lattice television mast
Mast guy line