Steering and roll-stabilizing device with retractable fins

Abstract

The system includes at least two units each contained in a watertight housing to be installed on starboard and on port side, each containing inside a blade or a fin having a moving device that retracts or projects the fin outboard when necessary for steering or stabilizing. In both cases the blades or the fins are maintained normally inside their housing to reduce sailing resistance and are extended right or left only when activated for steering or for stabilizing. The motion device essentially consists of a plate joined to the blade or fin tilting on a shaft pivoting inside the housing but holding out at least one end passing through a hub provided with a seal providing water tightness and supporting actuators, and capable of supporting remote monitoring systems that record the exact position of the blade constantly and automatic controls of course or an automatic stabilization system.

1 . An apparatus for steering or stabilization of a craft during navigation comprising:
 at least two units each contained in a watertight housing configured to be installed one on a starboard side and the other one on a port side,   each unit containing therein a blade or fin provided with a moving device configured to retract or to project the blade or fin outboard partially or totally when necessary for steering or for stabilizing, a slot being defined on the bottom of the housing, the blade or fin being maintained inside the housing to reduce sailing resistance, the blade or fin being protruded when actuated for steering or for stabilizing, a gradual movement of the blade or fin being obtained only by a degree of exposition or by an incidence angle and not by rotation on an axis of the blade or fin,   a plate joined to the blade or fin tilting on a shaft pivoting inside the housing but holding out at least one end passing through a hub provided with a seal to maintain the housing watertight and support an electric or hydraulic actuator working in a water tight and protected place and to support a remote monitoring system recording an exact position of the blade of fin constantly and automatic controls of course or an automatic stabilization system.   
     
     
         2 . The apparatus as in  claim 1 , wherein the blade or fin has a hydrodynamic profile constant or variable along the axis. 
     
     
         3 . The apparatus as in  claim 2 , wherein the blade or fin has a top plate at its extremity creating a limited asymmetric resistance on port or starboard side for navigation at low speed. 
     
     
         4 . The apparatus as in  claim 1  each unit, wherein the apparatus comprises more than one blade or fin connected to the plate parallel and disposed as a biplane providing greater efficiency with same dimensions. 
     
     
         5 . The apparatus as in  claim 1 , wherein the units are placed with a vertical axis abaft the craft. 
     
     
         6 . The apparatus as in  claim 1 , wherein the units are placed in a middle position of the craft to provide greater stability.