Derrick Crane VS Tower Crane

The Derrick Crane is installed in a fixed place. The mast and a jib are fasted to a slewing platform. The mechanism and electrical parts are also placed on the platform. The derrick crane is a large hoisting mechine similar to Tower Crane in most respects, except for its stationary foundation. BQ models of derrick crane includes 10T Derrick Crane 2533A, 6T Derrick Crane DCB20-6, 10T Derrick Crane DCB24-10, 12T Derrick Crane DCB30-12, 16T Derrick Crane DCB30-16, 18T Derrick Crane DCB42-18. 

A tower crane is an inverted L-shaped structure that is capable of lifting several tons of weight to precarious heights.
The most striking feature of this crane is that it is self-building and can allow a building to be constructed adjacent to or even around it.