VDR is an equivalent of a ship’s black box in an aeroplane. It documents the events of a maritime accident, including the date and time of the accident, the location of the ship at the moment of the incident and its speed, course and so on. The information recorded is a valuable resource in identifying safety risks and improving the operation of the ship.
According to IMO regulations, the standard VDR must contain a range of data. This includes dates, times, and Coordinated Universal Time, vessel position (latitude and longitude, coordinate reference) along with heading and velocity, audio recorded by the bridge (voice messages recorded with one or more microphones located on the bridge for recording conversations and alerts that sound), Very High-Frequency Radio Communications (VHF) and radar data (a exact reproduction of the display that is on view at the moment of recording) including rudder and engine orders, watertight door status, and accelerations.
The system consists of an encoder that encodes and processes the data stream sensors that supply input to the concentrator and a final recording medium (FRM) designed to survive disasters and enable the retrieval of data from voyages. The FRM could be a fixed unit mounted on the vessel or a retrievable floating device that is connected to the EPIRB to allow for the identification of the vessel quickly in the event of a disaster.
The best way to be sure that a vdr functions correctly is to incorporate its use http://www.digitaldealdataroom.info/how-to-get-started-with-your-new-ideals-vdr-system/ in all bridge crew drills and training exercises. The saved data may also be used to identify areas in need of training, and to enhance bridge procedures and operational security.