Some aspects of consistent design and interrelated engineering solutions in hydromechanics of complex unsteady flows optimizing controlled motions of flexible blades and rigid wings of fin thrusters and hydrodynamic stabilizers are considered, including issues of general layout of special mechanisms for recreating hydromechanics processes with useful force reactions, and especially for induced and external manifestations of gradient and eddy currents, with solution of the problem of flow disruption and shock loads on the fence