http://www.digitaldealdataroom.info/what-is-the-purpose-of-a-data-audit

VDR is the equivalent to a black box in an aircraft. It captures the details of an incident at sea which includes the time and date of the incident, the location of the ship at the time of the accident and its speed, location, course and more. The data recorded can be used to pinpoint the potential hazards to safety and to improve operations.

According to IMO regulations, the standard VDR is required to record an array of data. These include: date and time referenced to Coordinated Universal Time (UTC) vessels’ position (latitude, longitude, coordinate reference) as well as speed and heading bridge audio (acquisition of voice messages recorded by a microphone or two placed on the bridge to record conversations and sound alarms), Very High Frequency radio communications (VHF) and radar information (a exact replica of the radar display that was on view at the time of recording) the rudder’s order and response, engine order and response watertight doors, their status, and accelerations and hull stresses.

The system is comprised of a concentrator that encodes and processes the data stream, sensors that provide input to the concentrator and a final recording medium (FRM) designed to survive disasters and enable the recovery of voyage data. The FRM may be a fixed device mounted on the vessel or a floating retrievable device that is connected to an EPIRB to help locate the vessel quickly in the event of a catastrophe.

The most effective way to ensure the integrity of the vdr system is to make its use an integral part of all bridge crew training and drills. The data saved can be used to determine areas where training is needed and also to enhance bridge procedures and operational safety.