High speed drag reducing ventilation for marine vessel hulls
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorYoung T. Shen
Life of this patent
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Abstract
Spaced cambered wedges having flow diverting surfaces thereon are deployed from retracted positions within the smooth surfaced sides of a marine vessel hull undergoing water travel above a high speed, under which air ventilated cavities are established by the deployed wedges along the sides of the hull, imposing drag on the hull sides of a substantially reduced magnitude as compared to that otherwise imposed directly by the water alone.
Claims11
In combination with a marine vessel having a hull exposed to water below a water surface level during travel, a system for reducing drag resistance imposed on the hull at high speeds of said travel comprising:
- a plurality of wedges having flow diverting surfaces;
- and means mounting said wedges on the hull spaced from each other in direction of said travel for displacement between retracted and deployed positions wherein the flow diverting surfaces thereon are respectively flush with the hull and extend therefrom at an angle in direction of said travel;
- each of the flow diverting surfaces including:
- a trailing end portion extending from a retention recess in the hull from which the wedge is displaced to the deployed position without exposure of the retention recess to the water.
In combination with a marine vessel having a hull propelled in a direction of travel through a body of water imposing drag on opposite vertical sides of the hull below a surface level of said body of water during said travel at speeds below and above a predetermined value;
- means for reducing the drag imposed on said sides of the hull at the speeds above said predetermined value, including:
- flow diverting means displaced from retracted positions within the hull for cavitationally establishing ventilated cavities within the body of water along said sides of the hull, thereby avoiding water flow to impose drag substantially less than that otherwise directly imposed by the water alone during said travel above the predetermined speed value, said flow diverting means comprising:
- a series of cambered wedges spaced from each other in said direction of travel and respectively extending vertically above the surface level of the body of water;
- each of said wedges having a water flow diverting surface extending toward a trailing end of the wedge in said direction of travel at an angle to one of the sides of the hull, said trailing end being thereby exposed to one of the ventilated cavities when the wedge is deployed from the retracted position within the hull.
In combination with a marine vessel having a hull subject to drag resistance by water in contact therewith which substantially increases during travel of the vessel above a predetermined high speed, a system for reducing said drag resistance imposed on the hull, comprising:
- flow diverting means mounted in the hull for displacement therefrom to cavitationally induce air ventilation precluding water flow in contact with the hull;
- and
- deployment means for effecting said displacement of the flow diverting means only during said travel above the predetermined high speed, said flow diverting means including:
- a plurality of movable surfaces spaced from each other along the hull and extending vertically above a surface level of the water.
Dependencies are inferred from the claim text.