What is a Stiffleg Crane?

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Stiff leg crane

The image above shows a TC15 stiffleg crane lifting the tubing reel for a CTU package. Our cranes are often deployed to support coiled tubing operations offshore.


What is a stiffleg crane and What are it’s features and benefits?


Our stiffleg crane is modular and portable, so we can transport the crane offshore via supply vessel and install it on both platform or FPSO temporarily in order to conduct specific lifts. Once the job is completed we can then demobilize and return the equipment onshore.


The advantage of the stiff-leg crane for offshore use is in the design of the crane itself: The crane has a mast and two skid beams set apart by 90 degrees and two diagonal “stiff-legs” that go from top of mast down to the end of the skid beams.


The stiffleg design means that we can tie the crane skid beams down to the platform or FPSO structure that it sits on and it uses this as its counterweight. This makes the stiffleg crane a very efficient piece of equipment that can have a better lifting chart than other types cranes of a similar size or footprint.


The stiffleg crane being fixed to the platform has safety and stability advantage over either the vessel or barge based cranes, which typically use a very long boom to provide sufficient hook height above the platform or FPSO deck.


Due to sea conditions, the vessel or barge crane may experience movement, and this movement is amplified at the tip of the crane boom which can cause a swinging load. Stiff leg crane installed on deck of a fixed platform will provide more precise lifting capability.


If a larger capacity modular and portable crane is needed we also provide pedestal cranes that can be temporarily mounted on the platform structure.


Would you like to learn more? Contact us if you have any questions or would like to learn more about Thunder Cranes’ offshore temporary rental crane services, lifting solutions, or lift planning services.