Surface treatment device for a vessel hull, comprising: a working head equipped with an application unit, said working head being fastened to an actuator device, which connects the working head to a rack and can move in at least two directions perpendicular to one another relative to the rack within a processing space, characterised by an electronic control unit which is connected by means of signal technology to the actuator device to control the movement of the working head along the at least two directions, the control unit comprising: - an input interface to read scan data of the vessel hull which plots the surface geometry of the vessel hull, - a filtering module designed to remove scan data located outside of the vessel hull, - a planning module which is coupled by means of signal technology to the filtering module and is designed to define a target surface covering the vessel hull from the filtered scan data using target surface data, wherein the target surface is defined by dividing the filtered scan data into a plurality of surface data sets in such a manner that each surface data set defines a surface which is free of discontinuities, - a work preparation module which is coupled by means of signal technology to the planning module and is designed to create a plurality of work surface data sets from the target surface data, wherein each work surface data set defines a surface which is smaller than or equal to the processing space, and - a control module which is coupled by means of signal technology to the work preparation module and is designed to create a control data set for the actuator device from each work surface data set, and - an output interface to output the control data sets to the actuator device and the planning module is designed to calculate a volume which is delimited by the target surface and the surface geometry of the vessel hull and the volume is minimised by virtually moving the target surface. a working head equipped with an application unit, said working head being fastened to an actuator device, which connects the working head to a rack and can move in at least two directions perpendicular to one another relative to the rack within a processing space, characterised by an electronic control unit which is connected by means of signal technology to the actuator device to control the movement of the working head along the at least two directions, the control unit comprising: - an input interface to read scan data of the vessel hull which plots the surface geometry of the vessel hull, - a filtering module designed to remove scan data located outside of the vessel hull, - a planning module which is coupled by means of signal technology to the filtering module and is designed to define a target surface covering the vessel hull from the filtered scan data using target surface data, wherein the target surface is defined by dividing the filtered scan data into a plurality of surface data sets in such a manner that each surface data set defines a surface which is free of discontinuities, - a work preparation module which is coupled by means of signal technology to the planning module and is designed to create a plurality of work surface data sets from the target surface data, wherein each work surface data set defines a surface which is smaller than or equal to the processing space, and - a control module which is coupled by means of signal technology to the work preparation module and is designed to create a control data set for the actuator device from each work surface data set, and - an output interface to output the control data sets to the actuator device and - an input interface to read scan data of the vessel hull which plots the surface geometry of the vessel hull, - a filtering module designed to remove scan data located outside of the vessel hull, - a planning module which is coupled by means of signal technology to the filtering module and is designed to define a target surface covering the vessel hull from the filtered scan data using target surface data, wherein the target surface is defined by dividing the filtered scan data into a plurality of surface data sets in such a manner that each surface data set defines a surface which is free of discontinuities, - a work preparation module which is coupled by means of signal technology to the planning module and is designed to create a plurality of work surface data sets from the target surface data, wherein each work surface data set defines a surface which is smaller than or equal to the processing space, and - a control module which is coupled by means of signal technology to the work preparation module and is designed to create a control data set for the actuator device from each work surface data set, and - an output interface to output the control data sets to the actuator device and the planning module is designed to calculate a volume which is delimited by the target surface and the surface geometry of the vessel hull and the volume is minimised by virtually moving the target surface.