A cooperative multicrane lifting operation with two vessels is often selected to lift a heavy suspended load. As the mechanics in cooperative multicrane lifting with two vessels are more complex than a single operation with a vessel, a thorough understanding of the coupled dynamical mechanics is needed. Unfortunately, there are few research activities regarding the fundamental mechanics and the motion analysis in multicrane lifting operations with two vessels. Given these motivations, both experiments and calculations were conducted to investigate the dynamics during a multicrane lifting operation with two different displacement vessels, and the impact of the distance between the two vessels on the coupled dynamics is clarified.
Crane lifting operations in the ocean are crucial for constructing offshore structures and installing subsea facilities on the seafloor. The safety and availability of lifting operations must be analysed when planning construction. Wave-induced coupled dynamics between a vessel and a suspended load must be predicted for these analyses, as the coupled dynamics can result in more complex mechanics than just the dynamics of a floating structure. A cooperative multicrane lifting operation with two vessels is often selected to lift the heavy suspended load (van Winsen and van Dijk, 2019). The mechanics of cooperative multicrane lifting with two vessels are more complex than those of a single crane operation with a vessel. In such situations, the connection of the two vessels to the suspended load means that all actions taken on one vessel influence not only the motions of the suspended load but also the other vessel. Therefore, as a dynamic positioning (DP) system between these two vessels needs to be designed to optimally consider such characteristic mechanics for safety position keeping, a thorough understanding of the coupled dynamical mechanics is required when using cooperative multicrane lifting with two vessels.