Abstract: The invention relates to an unmanned underwater vehicle for localizing and examining an object, for example a pipeline, arranged at the bottom of a body of water. For this purpose, the underwater vehicle has object localization means and object examination means. The underwater vehicle has a sonar device with 3D underground sonar for collecting measurement data. The object localization means are designed for three-dimensional acoustic localization of local sections of the object which are arranged both above and below the surface of the bottom of the body of water by means of these measurement data while the underwater vehicle is simultaneously moving away over these local sections for the purpose of examining local sections of the object by means of the object examination means. As a result, the invention allows a pipeline to be simultaneously surveyed and inspected as it is traversed once.