A buoy device includes a first part having a first support structure and a second part having a buoyant body and a second support structure. The first and second support structures are connectable to form a rotatable connection between the first part and the second part. The buoyant body further includes one or more buoyancy elements releasably arranged on the second part. The buoy device may be a turret buoy, a CALM turret buoy, or a CALM turntable buoy.