The aim of increasing the share of renewable energy sources to the total energy production has brought a significant increase of the interest in marine energies over the last years. Within them, tidal currents resources have been gaining ground for their advantages in terms of predictability, nonexistence of extreme flows, high load factor, minimal land occupation and visual impact. The authors, working in this field since many years, have been designing a new turbine able to work in the water like a kite, with no support structures, but easily connected to the coast by a rope. The constructive easiness, together with lower installation costs, are the main machine characteristics. Moreover it is able to overturn itself when the tidal current changes direction. The turbine equilibrium and mainly the transients related to the sink and surface phases, machine overturning, represent a critical aspect of the design. In the present work, starting from a phenomenological analysis, a simulation of the transients has been carried out in Simulink® environment. The study, related to the center of gravity, has pointed out the importance of the correct floating stabilizer design which helps the turbine to reach the equilibrium conditions even in case of flow instability.