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January 2011 www.sname.org/sname/mt develop this concept further in order to build in buoyancy elements and attach all hoses through an umbilical on top of the skimmer. e LRB 150 skimmer is normally operated by an excavator crane and today is part of the oil spill contingency for ice- covered waters in Finland. Development of new skimmers. Several new skimmer concepts were evaluated by an international reference group, to stim- ulate development of new technology. Two brush-drum concepts were chosen for further testing supported through the Oil in Ice JIP and the Norwegian Research Councils DEMO 2000 Program. e rst was the Ro-Clean Desmi Polar Bear skim- mer, which consists of six brush drums in a hexagonal shape and is a further develop- ment of the Helix 1000 skimmer. An early prototype was tested in the SINTEF ice basin, and the nal prototype was tested during the 2009 eld trial. e other skimmer chosen was a brush- drum cassette built for the Framo skimmer, which was tested in the SINTEF Ice Basin. An early prototype of the skimmer also was tested during the 2009 eld trials. Combined basin and field testing. The target ice cover in the basin and field experiments performed was comprised of 30 to 70% broken ice pieces and oes. e results indicate a general trend that recovery e ectiveness decreases with the increased coverage of small ice, and that the actual ice regime will have a major impact on skimmer recovery e ectiveness. Among existing skimmers, the LRB skimmer represents state-of-the-art tech- nology for the recovery of oil spills in ice, but if it is going to be used under extreme arctic conditions, there may be a need for the fur- ther winterization of the skimmer. e results from the testing of the Polar Bear Skimmer, both in the ice basin and in the eld, indicate that it can be e ective in collecting oil in ice. The skimmer works best in the presence of low concentrations of smaller ice pieces and slush ice (less than 50%) and could also have the potential for application alongside larger ice oes. e skimmer has no thrusters and consequently must be repositioned by a crane or similar device during operation. The Framo Skimmer is still under development and focuses on basic skim- mer components such as brush quality and buoyancy in addition to minor general improvements, and the tested prototype exhibited good ice processing capabili- ties. e triangular shape of the skimmer, together with its thrusters, was a successful combination which enabled the skimmer to move in ice. Further development of the Framo unit was done in 2010 and the report will be available in spring 2011. Lessons learned The Oil in Ice JIP, with its focus on the testing of existing technologies and the further development of those technolo- gies, has improved our understanding of techniques for handling oil spills in ice. A number of important findings have resulted from the program. r 8 I F O D S V E F P J M J T T Q J M M F E B U T F B B O V N ber of natural processes occur that change the chemical properties of the oil. In ice-covered waters, this time- dependent weathering is significantly reduced depending on ice type, ice cov- erage, and energy conditions. is can be an advantage and can contribute to the enhancement of response e ectiveness for some oil spill scenarios. r &