Final factory acceptance tests of a 900 metric tonne 'rope luffing knuckle boom' crane, which will eventually be fitted on Subsea 7's heavy construction ship Seven Arctic, have got underway at a production facility in Zhangzhou, China.
Once managers are satisfied the crane meets design requirements, it will be shipped to Hyundai Heavy Industries in Ulsan, South Korea, where it will be installed on Seven Arctic.
According to Huisman, the Dutch-owned firm that developed and constructed the crane, the hybrid boom design combines the advantages of regular pedestal cranes and traditional knuckle boom cranes. Due to its innovative design the main and knuckle boom have a low construction weight, so it almost matches the load curves of a pedestal crane with a fixed boom. With the knuckle boom in an extended position the crane offers a high lifting height at full lifting capacity, which is normally only available with a fixed boom. Furthermore, the hybrid design retains the advantages of traditional knuckle boom cranes, such as a low suspension point and reduction of load swing, which make it one of the most popular tools for offshore and subsea construction activities.
The crane is fully electrically driven, which enables precision control control over crane and load movements, with low noise levels, reduced maintenance and no risk of oil spills. A real-time heave compensation and shock absorbing system further increases the operational weather window for safe and accurate installation of subsea infrastructure components.