Just like in Airplanes, a ship is also provided with a black box known as Voyage data recorder. It is said that the accident rate of ship is higher than that of an air plane, as the former is bigger in size and carries several machineries in a harsh environment, which makes it extremely important to have a voyage data recorder on board.
What is VDR?
A VDR or voyage data recorder is an instrument safely installed on a ship to continuously record vital information related to the operation of a vessel. It contains a voice recording system for a period of at least last 12 hours. This recording is recovered and made use of for investigation in events of accidents.
A ship’s VDR is far superior to a black box of an aeroplane as it store variety of data and that too for not less than a period of 12 hours. The data records covering the last 12 hours are continuously overwritten by the latest data.
A VDR is capable of withstanding heavy weather, collisions, fires and pressure conditions even when a ship is at a depth of several meters in water.
How VDR Works?
There are various sensors placed on bridge of the ship and on prominent location from which the required data is continuously collected.
This collected data which comprises of voices, various parameters, ships location etc. are then fed to a storage unit where the whole input is recorded and saved for at least12 hours.
There is also a record button provided in the bridge unit so that after pushing button (say during starting of any incident like collision or grounding), the recorder will start recording new set of information from that period of time.
The collected data by VDR is digitalised, compressed, and is stored in a protective storage unit which is mounted in a safe place. This temper proof storage unit can be a retrievable fixed or floating unit connected with EPIRB for early location in the event of accident.
Regulatory requirements for carrying VDR
The requirement for carrying VDR under IMO came into force on 1st July 2002 for all the passenger ships constructed after 1st July 2002 and vessel other than passenger ship above 3000 GT.
All the mandatory requirements are stated under Reg- 20 of SOLAS Chapter V, under safety of navigation.
On December 2004, an amendment was adopted for above regulation for carrying simplified voyage data recorder or S-VDR and it entered into force on 1st July 2006.
A S-VDR is a simple data recorder which stores less but vital data as compared to a standard VDR; however the storage criteria is same.
The VDR at least must record the following:
- Date and time
- Ship’s position
- Speed and heading
- Bridge audio
- Communication audio (radio)
- Radar data
- Post display data
- Echo sounder
- Main alarms
- Rudder order and response
- Hull opening (doors) status
- Watertight and fire door status
- Speed and acceleration
- Hull stresses
- Wind speed and direction
You may also like to read-Marine Radars and their Use in the Shipping Industry