The Alfa Lift crane vessel offers particular benefits for monopile installation campaigns. Monopiles will be transported transversely on the main deck with 148.40 m length and 8,310 m2 available cargo area. The ship’s large deadweight capacity means about 22,000 mt of monopiles plus 4,400 mt of transition pieces as well as mission equipment can be loaded for each round trip.
OHT’s philosophy is to minimize human intervention and to make a solutions that minimizes weather downtime. A fully automated system will transport the monopiles from the storage position on the main deck and into the upending frame at the forward end. The crane will upend the monopile and the pile gripper frame will take control of the lower end. At no point during this process will the pile be freely suspended under the crane.
During installation the vessel will primarily be relying on its dynamic positioning system, which will be working closely with the pile gripper frame’s control system to keep installation tolerances within limits. This allows for the shortest possible preparation time for each monopile installation avoiding time for jacking or mooring operations. As a backup the vessel will be outfitted with a DP assisted offshore mooring system.
The forecastle deck is prepared to carry cargo on a free area of 1,800 m2. This can be used for transition pieces, anode cages and mission equipment as required.