Abstract: Apparatus for recovering spilled oil in water infested with floating ice or other debris comprises a fence having an upper rail and lower rail encircling an area to receive an oil skimmer. A plurality of buoyancy units maintain the fence at an appropriate water level. An ice-deflecting cone covers the bottom of the fence when the apparatus is deployed. A plurality of cables may be attached to the upper rail of the fence to raise and lower the apparatus into the water. The fence is preferably circular, with a diameter in the range of 10 to 50 feet. The fence preferably includes a plurality of spaced-apart vertical supports between the upper and lower rails to keep chunks of ice or other debris from entering into the encircled area, and the lower barrier structure is perforated, with openings in the range of less than an inch to several inches.

Abstract: An axial flow pump for handling debris-laden viscous fluid flow, for example of the type encountered in cleaning up oil spills in off-loading stricken oil tankers. The pump includes a bell- or venturi-shaped intake, rotating impeller mounted in the intake, a fixed stator downstream of the impeller, and suitable hydraulic motor means for rotating the impeller to pull oil through the pump from the intake inlet to an outlet. The surface of the intake is specially contoured at a first region from the inlet to the throat or impeller face to reduce and compensate for cavitation and viscous boundary layer growth in that region. A second portion of the intake from the throat or impeller face to the impeller exit is also specially contoured to compensate for viscous boundary layer growth, but modified in view of the impeller-generated forces and debris concentrations in that region which affect viscous boundary layer growth.