Related to this, I received a request from a user to be able to filter to only see buoys and gear, as doing so can help to identify dark vessels. The user noted that buoys and gear such as FADs may be broadcasting AIS even when the vessel is not. He wants to be able to filter and only see buoys as he can inspect their location and pattern and evaluate the type of vessel that may be involved and whether further investigation is needed, such as deploying a patrol boat ("the vessel's going to come back at some point")