device moejliggoera foer to anvaendning of oljefaella at strong stroem and deep water such as saa to water pressure paa oljefaellan between laensans edge and bottom won't be big foer, saa to laensan not foermaar to baera oljefaellan without drages down of stroemmen and device to foerenkla the accession of oljefaellan to laensans oeverkant