In this study, a series of model tests were performed for mating operations of a heavy topside module on a FLNG. Three experimental models, a floating crane vessel, a FLNG and a topside module, were introduced and the winch system with the four crane wires were utilized. To measure the dynamic forces between the topside module and mating deck, four leg mating units (LMUs) were modelled as linear compressive springs. The model tests were carried out at four mating stages. Both regular and irregular wave tests were performed. First, the motions of the lifted topside module were presented from the regular wave tests. Then, the transfer functions of the crane wire tensions and LMU forces are suggested at four different load transfer stages. Finally discussion is made on the dynamic responses of the wire tensions and LMU forces in irregular waves.
Regarding the installation operation using a floating crane vessel, the safety as well as the operability should be checked before real-sea operation. In the recent times, the nonlinear time-domain numerical simulations are widely used to validate the designed installation operation. Sometimes, related to new complex installation operations, model tests also can be used to ensure the safety of the operations. In particular, as for the cooperation operations by multiple floating vessels, not only the hydrodynamic interactions but also mechanical interactions from various mooring lines and fenders should be taken into account. Also, the motions of the floating crane vessel are affected according to the heading angles, the wave heights and other oceanic environment conditions. Consequently, the motions of the lifted object and the hoisting wire's tensions are altered according to the various oceanic environment conditions. Therefore, the evaluations of the installation operations using the model tests and the numerical simulations should be performed in various oceanic environment conditions, because selection of the suitable oceanic is very important for the installation.
