ABSTRACT

An open-seas skimming means has been developed which is capable of skimming oil efficiently under typical offshore wind and wave conditions. The key to the effectiveness of this open-seas skimmer is a “quiescent pool” within the skimmer. This quiescent pool is achieved by flow diffusion of the water and oil entering the skimmer and of the water leaving it. The flow-diffusing baffle system floats independent of the catamaran hull support vessel and is hinged in order to conform to waves. Oil removal from the quiescent pool can be achieved by any of a variety of commercially available oil-removal devices such as belt, weir, or floating suction skimmers.

Design of the 90-foot-long catamaran hull skimming and oil-storage vessel was based on extensive model tests. Efficient oil collection and recovery is possible at vessel speeds up to 2 knots in either swells or wind-driven seas up to low sea state 4 (18-knot winds, 6-foot significant waves). Typical collection rates of 200 gpm with 80% oil in the collected mixture are projected. Also projected is a retention of the oil encountered at vessel speeds up to 2 knots.

The basic concepts used in the open-seas skimmer were initially developed by Shell. Further development of these concepts was sponsored by the American Petroleum Institute.

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