Abstract: An arrangement for controlling movement of the grab bucket of a grabbing crane used for loading and unloading bulk material into and from ships is disclosed. Collisions of the grab bucket with the ship's superstructure and the hatch edges are avoided according to the invention by approaching the hatch edges with the grab bucket open and displaying the actual values so obtained as bars representing the horizontal position and width of the hatch on a display. To avoid collisions, the grab bucket drives are switched off if any desired value, set manually or by a marking line computer, exceeds an actual value.