Technology from Europe:
Trimaran oil recovery vessel
Preliminary design work on the Oil Sea Harvester (OSH), a new anti-pollution trimaran capable of storing 6,000 t of oil, has recently been carried out by Les Chantiers de l’Atlantique (LCA), a subsidiary of Alstom Marine, with funding from CEPM, France’s Committee for Oil and Marine Research, and support from CEDRE, the French center for documentation, research and experimentation on accidental water pollution. Christian Gaudin, a French naval architect at LCA, proposed the construction of this trimaran, which measures 225-ft long and 105-ft wide. The aim is to design a vessel capable of responding more quickly and effectively to shortcomings that became apparent during the sinking of the Erika off the coast of Brittany in 1999. The new trimaran offers the ability to operate in bad weather in open seas, unlike present vessels, and it also provides increased storage capacity.
Specially designed oil slick recovery vessel features side hulls and 6,000-t storage, into which recovered oil is pumped.
The trimaran structure with a central hull, a large slender monohull, and two SWATH-type (small waterplane area twin hull) side hulls (see figure) gives the vessel a number of advantages, including directional, pitch and roll stability. These advantages enable it to operate in open seas without support, to withstand seas up to Force 7 and to provide two, 26-ft wide channels of calmer water between its hulls. The oil slick remains confined between the side hulls and the central hull. High-performance recovery equipment appropriate for the type of spill is placed within these two channels. This equipment can consist of a cyclonet centrifuge system, scoops, bucket wheels or traditional pumps. These different modular techniques can be chosen according to the viscosity of the product ascertained onsite.
The central monohull will be able to store up to 6,000 t (over 40,000 bbl) of oil, which is equal to its daily collection capacity. Its total capacity, taking into account distances and transfers, is estimated at 20,000 t per week. The trimaran would also carry tools and machinery for treating the oil, such as filtration, decantation, reheating and chemical processing, all optional depending on the problem to be resolved.
The vessel’s range of operation is important. Fitted with two pods – engines in nacelles, each with a power of 10 mW – cruising speed would be 20 kt, which would enable it to operate efficiently off any European coast. During the collection phase, this speed would reduce to 3 kt. For example, if it had been built before November 2002, the OSH would have taken only one to two days after leaving Brittany to arrive at the location of the sunken wreck of the Prestige off the Spanish coast.
Estimated cost of building the vessel would be about 100 million Euros. Its size, seastate capability and power make it possible to consider tasks other than recovering oil, such as search or rescue missions, maritime surveillance, recovering solid waste, recovering chemical products, fire fighting and offshore operations. Other projects are under consideration. One of them, also originating from CEPM and CEDRE, in collaboration with Doris Engineering, entails a less-powerful vessel open at the stern that would enable backward collection.