There are many mechanical oil spill recovery devices which have proved effective in cleaning up oil spills in calm, protected waters. These include disk, endless belt, robe mop, weir, rotary drum based on oleophilicity, and various types of suction skimmers. The industry, however, still faces the problem of recovery in conditions in which spills so often occur; in choppy seas, debris laden seas, in broken ice, and in the face of currents over 1 knot. When such conditions do occur, recovery efficiency of existing technology is greatly reduced or in some cases eliminated.
The COV was specifically designed to be capable of recovering oil in these conditions. The COV is rugged, simple to operate, has on boards storage for recovered oil which can be off-loaded without curtailing recovery operations, thereby reducing operating time lost for pump-outs. The COV is cost effective as to capital, operation and maintenance costs. Skimmers available on the market today are, virtually without exception, variations, of technology that has been in use for many years. There has been no basic “breakthrough” for many years.
Skimmers can be put into two basic categories, oleophilic and suction. Several variations or applications of each type are available. The oleophilic types are generally high efficiency- low volume skimmers that function best in calm water and in light medium viscosity oils. Suction skimmers will function in more adverse weather and sea conditions as well as in clam conditions and generally are capable of a higher volume recovery but at lower efficiency.
All skimmers available will recover oil form the water with some degree of success. Each one has a set of conditions under which it will function better or as well as any other. The need, fro an operator’s point of view, has always been to have a high volume skimmer that can recover oil efficiently in calm or rough sea conditions, can be operated in open ocean or confined harbour scenarios, is efficient in recovery of high and low viscosity product and can be used in zero current or in fast currents. With the exception of the COV, the industry has not yet been successful in developing such a machine. The COV has that potential and is arguably the most versatile oil spill recovery technology available, as detailed below.
The application of this technology in the COV is new and unique in that it allows the COV to operate in heavier sea conditions than most other skimmers and, unlike other ocean skimmers, can continue to recover liquids as conditions deteriorate with little or no reduction in efficiency. This is due to vessel stability and the recovery drums being immersed below the water surface. When the constant draft feature is factored in, the COV has distinct advantages over other ocean oil spill recovery technology. In addition, the COV can be efficiently operated as a calm water, harbour oil spill recovery vessel.
