flows into the container 5 in the layer thickness as set and in the desired oil water ratio according to another possibility only the overflow wall 7 is provided with means not shown for adjusting only the wall 7 in that case for height the schematically indicated means m for guiding and vertically adjusting the collecting container 5 are manually driven in some cases but usually they are driven hydraulically or possibly pneumatically and they may be operated by remote control suitable pressure and or current velocity sensors connected to the adjusting means m may be provided near the overflow wall 7 and or in the collecting container 5 for influencing the influx of the floating layer momentarily by adjusting the height of the collecting container 5 accordingly fig5 shows the separate u2014 detached u2014 collecting container 5 which may be provided with a lifting eye via which the container 5 can in principle be adjusted for height by means of a hoisting device the container 5 as shown herein is provided with a hinged grid r which in the raised position thereof collects debris floating on or in the layer of oil in fig5 the grid r is shown in lowered condition when it is lowered a little further however the collected debris will be carried along by the current under the container 5 and thus be removed from the inlet into the container the skimming system 1 is provided with one or more pumps that are connected to the collecting container 5 the pumps 8 may be present on one or more of the guide.