Viscous-drag-reducing cladding
OwnerMicheal O'Ceallaighinventor
Life of this patent
Estimating the term…
Abstract
A viscous-drag-reducing cladding for a ship's hull whereby the wetted area of the hull is reduced by interspersing air between the hull surface and the water. A substantial portion of the submerged area of the ship's hull comprises densely packed air pockets. The dimension of the air pocket is less than twice the capillary length of water. Each air pocket is supplied with pressurised gas by means of a restrictor. The pressurised air is supplied to each air pocket by means of a network of corrugated channels.
Claims18
A viscous drag reducing cladding comprising an outer surface with a plurality of air pockets therein, each air pocket having an air inlet and an outlet;
- wherein
- the cross-sectional area of each air inlet is less than one tenth of the cross-sectional area of the air pocket's outlet, wherein the radius of each air pocket is less than twice the capillary length of water.
An air distribution system for a cladding system on a ship comprising:
- at least two corrugated sheets, at least one of which comprises multiple perforations;
- wherein the at least two sheets are arranged so that the ridges of the corrugated profiles of at least two sheets are substantially orthogonal to each other thereby creating at least two air chambers each in communication with each other via the perforations.
A tape for coating the hull of a ship comprising:
- a hydrophobic backing film, comprising a front side and a back side, wherein
- the back side of said tape is configured for adhesion bonding, and
- strands of thread comprising two ends, whereby one end is attached to the front side of said hydrophobic backing film, and
- wherein the other end is unattached, and
- wherein the outer surface of the thread is hydrophobic, and
- wherein the inner core comprises a hydrophilic material, and
- wherein the hydrophilic core is exposed at the unattached ends of each strand.
A method of forming a metal sheet with conical holes comprising:
- perforating a metal sheet with cylindrical holes;
- stamping each cylindrical hole with a forming die having a conical base;
- coating the inside of each hole to reduce the size of the hole at the tip of the cone;
- applying a tape to the metal sheet and pressing the tape into the conical holes;
- and
- perforating the tape to further reduce the size of the hole at the tip of the cone.
A viscous drag reducing cladding comprising an outer surface with a plurality of air pockets therein, each air pocket having an air inlet and an outlet;
- wherein the cross-sectional area of each air inlet is smaller than the cross-sectional area of the air pocket's outlet, and wherein the pocket outlets overlap.
A viscous drag reducing cladding comprising an outer surface with a plurality of air pockets therein, each air pocket having an air inlet and an outlet;
- wherein the cross-sectional area of each air inlet is smaller than the cross-sectional area of the air pocket's outlet, and wherein the outer surface of the viscous drag reducing cladding comprises a plurality of loops of hydrophobic thread where the loops are attached to said surface at both ends.
Dependencies are inferred from the claim text.