Torsional Stability of Offshore Hoists

The progression of lifting and lowering operations into ever-increasing depths of water has exposed a weakness in the long-established methods of assessing the torsional stability of multi-fall hoists. Instances of "cabling" have been reported on two-fall hoists despite using "low-rotation" ropes in situations where they were expected to perform satisfactorily.

The author explains how assumptions that worked perfectly well when heights of lift were a few hundreds of feet can no longer be safely applied to offshore operations in thousands of feet water depth. This article presents a new and more rigorous solution that reveals a secondary influence of height of lift on the torsional stability of multi-fall hoists. The revised theory is used to illustrate the severity of the problem faced by offshore operators and to examine alternative methods of solution.

For more information, please download this free white paper.

More About This Company