A method and apparatus for processing underwater beds includes a plurality of polygonal hollow pipes arranged side by side, the upper ends of which form a horizontal, substantially flat working platform. Each hollow pipe has a horizontal projection with a flange extending vertically and a corresponding flange insertion aperture with a slot immediately above it running vertically and extending as far as the upper end of the hollow pipe, the aperture being further away from the upper end of the hollow pipe than the projection with the flange and having a greater horizontal dimension than the slot. Neighboring hollow pipes engage one another via a respective projection with a corresponding slot. The hollow pipes cannot be moved relative to one another horizontally. Individual pipes can only be pulled out individually in an upward direction at the platform outer edge.