Stiffleg Derricks

Somerset has designed Stiffleg Derrick lifting schemes for over 30 years. The Stiffleg Derrick is a lifting device that consists of a boom with a mast and two sills set apart usually by 90 degrees and two diagonal “stiff legs” that go from top of mast down to far end of sills. The advantage of a Stiffleg Derrick is that you can tie the mast and sills down to the structure that it sits on and it uses this as its counterweight. This makes the derrick a very efficient piece of equipment that can have a better lifting chart than conventional cranes.

Stiffleg Derricks cannot lift and travel with a load without a specially designed carriage and counterweight. Somerset has designed these travellers for many site situations. The usual set up for a traveller is that the derrick is tied down through the traveller and makes the necessary picks from one position then moves to a new position, tied down, and continues to erect.

Other situations that we have designed for are a “fixed” tied down position on top of a building or structure to do specific lifts and then removed. This has an advantage over ground based cranes with very long booms and jibs.  Somerset provides the engineering to check the supporting structure and the installation procedure for the derrick.

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