Abstract: A solution is provided for the problem of holding an apparatus against a metallic hull of a vessel or an offshore unit. Described is a holding means, comprising: at least one magnetic means for exerting a pushing force on the apparatus to-wards the metallic surface; and a moving means for moving the apparatus on the metallic surface, in which the moving means is arranged to bear the pushing force from the at least one magnetic means, on the metallic surface. Also disclosed, is an apparatus including such a holding means. The holding means allows to bear the pushing force from the magnetic means, on the metallic surface, at the same time it allows the apparatus to move on it.