Derricks are a type of crane used in construction and other industries. They are tall, vertical structures with a boom and pulley system that can lift heavy objects. Derricks are often used to lift large pieces of equipment or materials, such as steel beams, onto buildings or ships. They can also be used to move objects from one place to another. Derricks are an important part of the construction industry, as they make it possible to move large objects quickly and safely.