Q) Write a short note on VDR. (Jan-18, Nov-18, Nov-17, July-17, Jan-17, Nov-16)
Ans:- VOYAGE DATA RECORDER (VDR) :-
Explanation:-
A VDR or voyage data recorder is an instrument 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.
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.
Working:-
There are various sensors placed on bridge of the ship and on prominent location
from which the required data is continuously collected.
This 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 least
12 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 data collected by VDR is digitalised, compressed, and is stored in a protective
storage unit which is mounted in a safe place.
This tamper proof storage unit can be a retrievable fixed or floating unit connected
with EPIRB for early location in the event of accident.
Main Components:-
Data Management Unit: It acquires data from various sources using interfaces,
processes and stores the data in a specified format.
Audio Module:
o It consists of an audio mixer for recording audio from microphones placed in
the wheelhouse, bridge wings, ECR and various other locations.
o VHF audio signals can also be interfaced with this unit.
Final Recording Unit:
o This is a fire resistant, pressure tight storage medium to store recorded
data.
o The capsule is resistant against shock, penetration, fire, deep sea pressure
and immersion. Housed in a highly visible protective capsule which can
withstand high temperatures (1100OC) and deep sea pressure of 6000 m.
Remote Alarm Module: This is a small panel connected to the Data Management
Unit that will sound an alarm should any error or fault develop in the equipment.
Replay Station:
o This is an optional module for downloading and replaying the recorded data.
o The data when played back can help in casualty investigations as well as for
self analysis.
Information Recorded:-
o Date & Time from GPS every 1s
o Position & Datum – Lat/Long and datum from GPS, Loran-C etc. The source
of data is identified on playback.
o Speed (water / ground) recorded every 1s to 0.1k resolution
o Heading (gyro or magnetic) is recorded at intervals of 1s to a resolution of
0.1 deg
o Depth under keel from echo sounder to a resolution of 0.1m.
o Auto pilot settings for speed, latitude, rudder limit, off-course alarms etc.
o Bridge audio in real time, both internal & external (150-6000Hz). The mic
test beeps every 12 hrs & this is recorded.
o Radar image recorded every 15s includes range rings, EBLs, VRMs, radar
maps, parts of SENC & other essential navigational indications.
o Wind speed/direction from the Anemometer is recorded & stored individually
with time stamps.
o VHF communication from 2 VHFs are recorded for both transmitted and
received audio signals. Audio is compressed and labeled VHF 1 & VHF 2.
o Hull openings & watertight doors status is received every 1s and stored with
time stamps
o Hull stresses are received and stored with time stamps.
o Thruster status (bow/stern) can be recorded for their order and response
o Rudder order and response angle is recorded to a resolution of 1 deg
o Engine order and response from the telegraph or direct engine control with
shaft revolution and ahead and astern indicators are recorded to a resolution
of 1 rpm
o AIS target data is recorded as a source of information regarding other ships.
o Alarms are recorded with time stamps. All IMO mandatory alarms as wells
other audible alarms are stored individually by the bridge audio
microphones.
Q) Explain the purpose of VDR, list the data recorded on VDR/ S-VDR and
data retrieving procedure in case of a collision. (March-20, July-19, May-19,
Sept-18, March-18, May-17, March-16)
Ans:- Purpose of VDR:-
The main purpose of VDR is to record and store ship‟s critical parameters to
facilitate reconstruction of the incident for the purpose of analysis
Additionally navigator can use this for self-analysis, as lessons-learning tool and
thus improvement of procedures in the future.
VDR can be used to identify cause of an accident and thus make major
contribution to maritime safety.
o The benefits are:
o Promotion of safe practices
o Accident investigation and enquiry
o Response assessment and study
o Training aid and support
o Reduction in insurance costs
o Statistics generation
VOYAGE DATA RECORDER - DATA ITEMS TO BE RECORDED:- IMO Performance
Standard (Res. A.861(20)) and
IEC Information format (IEC 61996).
DATA ITEM SOURCE
Date & Time Preferably external to ship (e.g.GNSS)
Ship‟s position Electronic Positioning system
Speed (through water or Ship‟s SDME
over ground)
Heading Ship‟s compass
Bridge Audio 1 or more bridge microphones
Comms. Audio VHF
Radar data- post display Master radar display
selection
Water depth Echo Sounder
Main alarms All mandatory alarms on bridge
Rudder order & response Steering gear & autopilot
Engine order & response Telegraphs, controls and thrusters
Hull openings status All mandatory status information
displayed on bridge
Watertight & fire door All mandatory status information
displayed on bridge
status
Acceleration & hull Hull stress and response monitoring
equipment where fitted
stresses
Wind speed & direction Anemometer when fitted
SIMPLIFIED VOYAGE DATA RECORDER (S- VDR) - DATA ITEMS TO BE
RECORDED:- IMO Performance Standard (Res. MSC.163 (78)) and IEC Information
format (IEC 61996).
DATA ITEM SOURCE
Date and time Preferably external to ship (e.g. GNSS)
Ship's Position Electronic Positioning System
Speed (Through the water or Ship's SDME
over the ground)
Heading Ship's compass
Bridge Audio 1 or more bridge microphones
Communications audio VHF communications
Radar data: post-display Master radar display
selection
AIS Data AIS to be recorded if it is impossible to recordradar data.
If radar is recorded AIS may be recorded as an
additional source of information.
Other items Additional items required for VDR (Res.A.861(20))
when interfacing available.
Recovery of VDR: Recovery of the VDR is conditional on the accessibility
Recovery of VDR: Recovery of the VDR is conditional on the accessibility of the VDR
or the data contained therein.
a) In the case of a non-catastrophic accident, recovery of the memory should be
straightforward. For example, in some VDRs it can be accomplished by removal of
a hard disc from the VDR unit. This action will have to be taken soon after the
accident to best preserve the relevant evidence for use by both the investigator
and the ship owner. As the investigator is very unlikely to be in a position to
instigate this action soon enough after the accident, the owner must be
responsible, through its on-board standing orders, for ensuring the timely
preservation of this evidence in this circumstance.
b) In the case of abandonment of a vessel during an emergency, masters should,
where time and other responsibilities permit, recover the memory and remove it to
a place of safety and preserve it until it can be passed to the investigator.
c) In the case of a catastrophic accident, where the VDR is inaccessible and the data
has not been retrieved prior to abandonment, a decision will need to be taken by
the Flag State in co-operation with any other substantially interested States on the
viability and cost of recovering the VDR balanced against the potential use of the
information. If it is decided to recover the VDR the investigator should be
responsible for co-ordinating its recovery. The possibility of the capsule having
sustained damage must be considered and specialist expertise will be required to
ensure the best chance of recovering and preserving the evidence. In addition the
assistance and co-operation of the owners, insurers and the manufacturers of the
VDR and those of the protective capsule may be required.
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