The detection of vessels from the bright white pixels on the satellite images is done by an automatic algorithm and verified manually. There are some other features on the SAR images that could look like vessels but are not (e.g. rocks, icebergs, wave crests). Conversely, sometimes items such as offshore wind turbines are erroneously labelled as undetected vessels. Although the service providers have maps of permanent installations so that they can avoid making these mistakes, it is important for users to provide feedback when this occurs so that the service providers can integrate further information in their systems and improve the rate of correct detections.