Patent ID: 7434527
Filing Date: 2008-10-14
Classification: B63B

Abstract:
1. A retractable fin device for steering or stabilizing a motorized watercraft having at least one hull, said retractable fin device comprising: at least two operating units each having at least one retractable fin, said retractable fins of each operating unit being contained in tubular watertight casings open on the bottom and located for their prevailing portion inside the hull, one on the starboard side and the other on the port side; an actuator associated with each of said operating units for moving said fins outwards and inwards out of the hull during the navigation for a variable extent in the water; and a guide part coupled to the root of said retractable fin sliding outward and inward into said watertight tubular casing; wherein said tubular casing and said sliding guide having both prevailing rectangular or prismatic section in order to avoid any tilting rotation of said fin along its axis when moved: wherein each of said fins being connectable to said guide closed at the base and open at the top, characterized in that said guide can slide within said tubular casing and has a section similar to that of said tubular casing, said guides being reduced in scale to said tubular casing permitting the eventual interposition of suitable anti-friction elements fitted to said guide; wherein said tubular casing of said operating units is made from a generally rectangular section made from material suitable for the type of hull, said casing being provided with at least one flange on its top to receive a watertight cover and an additional flange for its secure fixing to the hull, said additional flange being provided with a slot to allow the movement of said fin with a clearance which is sufficient to allow the water to flow out and in.