Safe, lifting and handling of goods on drill ships and other offshore rigs. With this solution of knuckle boom cranes the risk of swinging loads especially under rough weather conditions will become minimized. The lifted loads are under permanent hydraulic control. Special load control valves directly mounted on the cylinders guarantee that there are no uncontrolled movements of main boom or knuckle boom arms. Typical knuckle boom crane is operated with four cylinders in total: two knuckle boom cylinders and two main boom cylinders.
Certification according to DNV lifting appliances 2008, DNV standard for certification No. 2.9 hydraulic cylinders and DNV offshore standard E101/D101 or alternatively according to ABS rules for building and classing, steel vessel. Part 4, Lloyds register, GL or Bureau Veritas.