Abstract: A low-cost viscous-drag-reducing cladding for a ship's hull comprising airbags whose outer surfaces are adapted to be water repelling. Each airbag comprises a plenum that comprises substantially open space, which does not obstruct the flow of air through it. The airbags are inflated with compressed air to a pressure higher than the adjoining hydrostatic pressure. The airbag material comprises a reinforcing fabric, which is adapted to withstand the forces encountered during operation, and is sealed with a sealant so as to be made substantially impermeable to air. The outer water-repelling surface of each airbag is connected to a plenum by means of restrictor holes. Air flows from the plenum through the restrictor holes into the water-repelling layer.

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.

Abstract: A low-cost viscous-drag-reducing cladding for a ship's hull comprising airbags whose outer surfaces are adapted to be water repelling. Each airbag comprises a plenum that comprises substantially open space, which does not obstruct the flow of air through it. The airbags are inflated with compressed air to a pressure higher than the adjoining hydrostatic pressure. The airbag material comprises a reinforcing fabric, which is adapted to withstand the forces encountered during operation, and is sealed with a sealant so as to be made substantially impermeable to air. The outer water-repelling surface of each airbag is connected to a plenum by means of restrictor holes. Air flows from the plenum through the restrictor holes into the water-repelling layer.

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.