The use of oil-spill booms in the open sea is fine in theory and under good conditions. In reality, the challenges are often considerable.
Bohus Innovation, based in Uddevalla in Sweden, provides oil spill cleanup products and services. The company is particularly active in the design and manufacture of flexible booms to contain oil on the surface of rivers, harbors and in the open sea.
According to Finn Mathisen, Marketing and Sales director, the success of the company has been down to continuous innovation. "Oil spills are notoriously difficult to cope with, especially in rough seas, and you always need to be on the look out for better ways of tackling the problems."
Bohus has recently introduced a system for operation in larger rivers subject to strong currents of up to four knots. Mathisen claims that only a little further development is needed to make the system suitable for use offshore.
The present system employs a flexible boom, one end of which is attached to a specially designed floating vane. When launched from the shore, the vane is quickly carried by the current out into the stream, hauling the boom behind it. A single mooring line from the vane is used to control the final position of the boom relative to the current flow - no additional boats, anchors, or fixed installations are needed.
For best results, the angle of the boom to the stream is set at about 11 degrees. When deployed in this manner, oil is channeled into the 'cul-de-sac' formed between the boom and the shoreline. Under normal circumstances, much of the oil would ultimately escape beneath the boom at this point. However, a few years ago one of the company's leading figures, Captain Erling Blomberg, invented a simple, hydrodynamic separator that floats on the surface and dramatically increases the amount of oil that can be recovered. Under the influence of the current, the water and oil is guided into a rotational chamber where a slow-moving vortex is created that traps and concentrates the oil. Conventional skimmers and pumps may then be used to remove the oil to storage.
US approval
The system, which has been approved by the US Coast Guard, is being further developed by Bohus to be deployable from a vessel (and hence usable offshore. In a separate development, responding to the demand for booms that can be deployed very quickly, Bohus recently unveiled its Sea Sledge, a 6 meter by 2 meter barge carrying 300 meters of flexible boom folded-up in a zig-zag fashion. The sledge is towed at around 10 knots to the location of the spill and the boom automatically deployed in less than three minutes by throwing overboard a drifting anchor attached to one end of the boom. Following successful trials, oil terminal authorities in South Korea have bought 12 of the sledges.
For more information contact Finn Mathisen, Bohus Innovation. Telephone +46 522 980 80, fax +46 522 194 78 or e-mail: [email protected]
