A derrick without a boom that uses guys from the top of the mast to permit leaning in any direction, raised by ropes reeved through top blocks, is called a(n):

A derrick without a boom that uses guys from the top of the mast to permit leaning in any direction, raised by ropes reeved through top blocks, is called a(n):

• A. Skeleton crane
• B. Gin-pole derrick
• C. Stiff-leg derrick
• D. Tower crane

Answer: (B)

Derrick configurations are distinguished by how the lifting assembly is arranged and how it supports and moves the load. When there is no boom, the lifting arrangement relies on a gin pole attached to the mast and guy wires from the top of the mast to permit leaning in different directions. The load is raised by lines reeved through top blocks that pull on the gin pole and mast. This combination—no boom, a gin pole for leverage, and guying to allow movement in any direction—defines a gin-pole derrick. Other crane types don’t match this setup. Skeleton cranes use a lattice framework with a boom and jib; stiff-leg derricks have fixed legs and a different load-raising arrangement; tower cranes are tall, fixed to a building, with a rotating jib, not a boomless derrick using a gin pole.

Derrick configurations are distinguished by how the lifting assembly is arranged and how it supports and moves the load. When there is no boom, the lifting arrangement relies on a gin pole attached to the mast and guy wires from the top of the mast to permit leaning in different directions. The load is raised by lines reeved through top blocks that pull on the gin pole and mast. This combination—no boom, a gin pole for leverage, and guying to allow movement in any direction—defines a gin-pole derrick.

Other crane types don’t match this setup. Skeleton cranes use a lattice framework with a boom and jib; stiff-leg derricks have fixed legs and a different load-raising arrangement; tower cranes are tall, fixed to a building, with a rotating jib, not a boomless derrick using a gin pole.