This degree project has been carried out at FMC technology, Kongsberg, Norway. The aim of the project is to design turnbuckles that facilitate length adjustment of a sling during offshore lifting. Additionally, the design has to fulfil FMC technology safety requirements.

Further, the project also comprises of studies like material selection, numerical calculations, manufacturing and detailed drawings of all the components of the final design concept.

The final design concept presented in this report is based on a modification of an ordinary turnbuckle. Design improvements were carried out in order to fulfil the FMC technology requirements. A material selection has been performed according to DNV 2.7-1, and a suitable surface treatment of the material has been conducted. For the calculations, a safety factor has been taken in to account according to DNV 2.7-1.

The drawings of each component of the turnbuckle have been presented and are attached to this report.