VDR is the equivalent of a blackbox in an aeroplane. It captures all the information about an accident on the sea, including the date, time the location, speed and course of the ship. The data recorded can be used to determine the potential hazards to safety and to improve the operation of the ship.

According to IMO regulations, the standard VDR must store a variety of information. These include the following: date, time and Coordinated Universal Time, vessel location (latitude and longitude, coordinate reference) along with heading and velocity audio messages from the bridge (voice http://www.digitaldealdataroom.info/ messages recorded using one or more microphones on the bridge to record recording conversations and alerts that sound) VHF, Very High-Frequency Communications (VHF) and radar data (a faithful representation of the display that is visible at the time of recording) as well as rudder and engine position and status of the watertight door, and accelerations.

The system is composed of a concentrator, which encodes and processes data streams, sensors that input data to the concentrator and the final recording medium (FRM) which is able to survive accidents and permit the retrieval of the voyage data. The FRM can be fixed to the vessel or a retrievable floating unit that is connected to EPIRB to provide a quick location in the event of an accident.

The best way to ensure that a vdr functions correctly is to incorporate its use in all bridge crew training exercises and drills. The saved data can also be used to identify areas where training is required and as a means to improve bridge procedures and operational safety.