Design of the stabilization control system of a high-speed craft

Abstract

In this paper, the main causes of technical malfunction of a hydrofoil was analyzed. In particular, a preliminary analysis evaluates the economic impact for the navigation company of the periodical maintenance related to the keeping of the vessel in dry dock. The study demonstrated that the main critical points are focused on the fragility of the stabilization control system. The increasing of operating costs has motivated the realization of a study aimed at redesigning the stabilization system. The continuing failure of the stabilization system (usually in waterimmersed) severely limits the use of the high-speed craft. The proposed design solution considers the positioning of the control actuators of the flaps inside the hull. Therefore, a kinematic system constituted by a slider-crank mechanism that is driven by a double-acting hydraulic cylinder positioned above the waterline was studied and developed. In order to design the mechanical system, it was necessary to take into account of the critical factors related to the transmission of high torque loads with limited space available for the placement of the system components. In fact, in order to reduce the motion resistance and to optimize the hydrodynamic flows in the connection area of the wings to the central strut, it was necessary to design a double cardan joint of reduced radial dimension. Several numerical analyses conducted in ANSYS environment allowed to validate the proposed solution. Fatigue tests on an experimental prototype of the stabilization system allowed to ensure the integrity of the solution during the navigation.