Weight Estimation and Static Stability Calculation for a Floating Kuroshio Turbine

The purpose of the present study is to clarify the weight, center of gravity (CG), buoyancy and center of buoyancy (CB) of a 20kW rated Floating Kuroshio Turbine (FKT), as well as its metacentric height variation in the submerging process during deployment operation, so its transition stability can be confirmed. In order to estimate the weight and CG of the FKT in more detail, some of modules and elements including buoyancy engine are designed in the present study. Besides, accomplished designs of other modules or elements conducted by the FKT R&D group are also aggregated. A program basing on MATLAB software is developed to calculate the weight, CG and moment of inertia of the FKT as a whole unit. An existing program for calculating the buoyancy and CB of the FKT is also extended to be able to calculate the transition stability corresponding to the operation of buoyancy engine. The extended program is applied to calculate the metacentric height variation of the 20 kW FKT in the submerging process from two different initial floating conditions, one is trim by stern and the other one is trim by bow. Calculation results show that the longitudinal stability is lower than transverse stability, and more attention needs to be payed to longitudinal stability in operating buoyancy engine during deployment. Transition stability of the floating condition with initial trim by stern is lower than that of the floating condition with initial trim by bow. Therefore, the longitudinal positions of CG and CB need also to be considered for avoiding too significant initial angle of trim by stern. However, longitudinal metacentric height and transverse metacentric height of both these two initial floating conditions are not lower than 0.70 meter in the submerging process, and this value is higher than the IMO criteria of 0.15 meter for ships. It can be confirmed that the 20kW FKT with detailed weight estimation has sufficient transition stability for deployment operation.