VDR data - Lost before it is found?

Marine casualties still happen with alarming regularity and evidence that could be preserved is being lost.

Overview
In today’s world it is becoming increasingly desirable for mariners to have an in-depth familiarity with bridge equipment. It is therefore worthwhile exploring the wealth and scope of new bridge technology available to the mariner. In addition to exploring the capabilities (and limitations) of some of the latest technology, this article will also address the evidence preservation facilities contained within such equipment. In the event of an incident, the importance of understanding how evidence can and should be preserved can not be understated. Unfortunately, it is often when something goes wrong that a lack of understanding and in-depth knowledge of the equipment in question is exposed; but by then, of course, it is far too late and the vital evidence is lost. Bridge technology has a crucial role to play in the field of casualty investigation for loss prevention and litigation purposes – should the worst ever happen.

Voyage Data Recorder/Black box
Voyage Data Recorders (VDR), often referred to as “black boxes”, have been a common feature on aircraft for many years. They have only recently become mandatory in the maritime world under IMO legislation adopted in 2000 and which entered into force in 2002. As the name suggests, a VDR is designed to record data from a particular voyage and includes the following: a record of the vessel’s course and speed through the water, radar data, GPS positional data, transmitted and received voice communications, engine and propeller order and feedback responses, depth beneath the keel and rudder orders and responses. The more sophisticated versions may also record data such as the status of weathertight and fire doors, weather station data and hull stress. In a similar fashion to the familiar “black boxes” carried on aircraft, VDRs enable accident investigators to review the procedures and instructions that took place in the moments before an incident and help to identify the cause of an accident. Under the IMO performance standards, a VDR should continuously maintain sequential records of pre-selected data items relating to status and output of the ship's equipment, including command and control of the ship. This pre-selected data that needs recording is generally set up by the manufacturer to minimum IMO standards and owners’ requirements.

The data obtained must be automatically downloaded and stored into a brightly coloured, often orange, protective memory capsule that has been hardened to withstand extreme fire, shock and water pressure conditions. VDRs are required to maintain a record of all data for a minimum of 12 hours (Class often requires 24 hours and many manufacturers provide a longer period), after which the information will be overwritten. To ensure a VDR continues to record events during and after an incident, it should be capable of operating from the ship’s emergency source of electrical power. In the event that this fails, a VDR should, as a minimum, continue to record bridge audio from a dedicated reserve source of power for a period of two hours. After two hours, all recording would generally cease automatically.

During many incidents, however, power sources will not be completely lost and the VDR will therefore continue to record events in the normal fashion (i.e., for a minimum of 12 hours before being overwritten). For the purposes of evidence collection, therefore, it is essential to identify quickly whether a vessel is fitted with a VDR and for those on board to retain or download the information it contains as soon as possible. Should all power be lost (for example when a vessel sinks or is lost to fire), a VDR will generally retain the last 12 hours (or more if set up to do so) as a final recording medium installed in a protective capsule. This will remain fixed to the vessel or, in the case of a more sophisticated black box, float free and transmit its position, via an EPIRB type signal, for SAR aircraft and/or ships to detect. In any event, the capsule should retain the data for a period of at least two years.

VDR data has its uses outside casualty situations. The data can also be retrieved and downloaded at any time (providing those on board have the designated software) for training purposes (following a close quarters situation, for example). However, as with some electronic chart systems, VDRs will often require a manufacturer’s technician to attend in order to download the data. In a casualty situation, therefore, it is important that the master preserves the data and, if necessary, that a technician is brought on site to access the data as soon as possible. It is precisely this “grey” area that is causing the current loss of valuable information. Numerous manufacturers and various model types requiring different software versions to be able to view the data make it difficult for even the expert technician to retrieve the information, let alone the crew, who may not have received training in obtaining/preserving data. The important thing to do is to stop the VDR overwriting data – retrieving can always be done at a later stage either by the crew or a technician.

Electronic navigational charts
Electronic navigation, although still relatively new and unfamiliar to many, is becoming increasingly common on board vessels and is likely to completely replace the paper chart in the not too distant future. The true ECDIS system displays information from electronic navigational charts (ENC) and integrates position information from the GPS and other navigational sensors, such as radar, echo-sounder and Automatic Identification System (AIS). It may also display additional navigation-related information, such as Sailing Directions. Like the majority of other electronic navigation aids, electronic charts are likely to have a recording facility. In fact, it is a requirement that they have this facility for ships fitted with ECDIS. Clearly, any record showing a ship’s movements in relation to the relevant chart will provide useful evidence, particularly where ARPA and/or AIS data is also integrated and captured.

A VDR screen.

Masters should be reminded, however, that the records will be overwritten (at times, once again, within 12 hours) if the data is not promptly saved. Masters would be well advised to familiarise themselves, and their bridge team, with the practicalities of data saving during quiet sea passages and include the saving of data as part of their emergency response procedures; such knowledge will need to be second nature in the aftermath of a casualty where time is of the essence. Owners/managers would also be advised to include such information within the emergency response section of the vessel’s Safety Management System (SMS). Often, however, the data will be saved in a format that is not readily accessible to a third party without the necessary software. Owners should check whether the information on their equipment can be readily downloaded or whether a manufacturer’s technician will be needed. If a technician is required, he should be put on stand-by to attend a casualty as soon as possible after an incident to extract the necessary evidence.

Some care should be taken when extracting the necessary evidence. Whilst preserving all available evidence, common sense should also prevail. For example, a common error is for a navigator to save the entire passage plan of a voyage, which may last some days, when the relevant section consists only of the last hour before the incident. Without wishing to discourage the extraction of evidence, it should be borne in mind that a huge data file, consisting of many days of voyage, is likely to crash the ECDIS during playback, or prove impossible to download without the aid of a technician when, really, it should be a task within the capability of those on board. One solution to prevent loss of electronic data is to have a simple A4 side instruction posted on the bridge, near the related recorder, e.g., the ECDIS. Further, when new officers join, this same instruction could be attached to their routine familiarisation checklist.

ECDIS system on board a vessel.

GPS
In the event of a casualty, GPS can be a valuable resource to the casualty investigator. GPS will not only provide a list of waypoints used in the voyage, but should also provide, if set up correctly, a valuable track history of the vessel. Such information can provide an investigator with extremely helpful data to determine a ship’s position and movements prior to the incident which may, in turn, dictate the direction of the investigation and any litigation. In the event that the GPS does not have a print-out facility, photographs taken of a GPS track history screen can be superimposed onto the working chart in question and provide a very clear picture of events. It can thereby provide an accurate plot of a ship’s movements in the event that VTIS or AIS, for example, is unavailable. It is important that GPS data is saved as soon as possible after an incident to avoid it being overwritten.

AIS
The AIS is a shipboard broadcast transponder system used by ships and Vessel Traffic Services (VTS) principally for identification and locating vessels. AIS works by integrating a standard VHF transceiver system with an electronic navigation system (such as a GPS or LORAN-C receiver), and other navigational sensors on board ship, which then continually transmit on a common VHF radio frequency. AIS provides a means for ships and VTS stations to exchange ship data electronically including identification, position, course, and speed. This information can be displayed on the unit screen or transposed onto the ARPA radar or an ECDIS display. AIS is intended to assist the vessel's bridge team in identifying nearby vessels and allows maritime authorities to track and monitor vessel movements.

As with GPS, in the event of an incident AIS is again an extremely useful tool in terms of evidence collection. Some AIS systems have a data recording facility and masters should be encouraged to check their sets and familiarise themselves with the use of this facility, if fitted. If preserved, AIS data not only provides information about your own ship’s movements, but also about other vessels in the area, including those who may well have witnessed the incident, even if not directly involved. In such cases, it is important that, where possible, AIS data (along with any other electronic information) is saved as soon as possible after an incident has occurred because, as we have seen above, it is common for most electronic navigation equipment with recording facilities to only save data for a pre-set time period, after which the information is overwritten. Some caution should be exercised with AIS, however, as it has not proved infallible and indeed many older existing sets are prone to inaccuracies and errors of various data fields.

Conclusion
Mariners should be encouraged to understand and familiarise themselves with the additional uses and benefits of the wide range of increasingly sophisticated electronic devices available to them, particularly in the event of a casualty. The quieter times on a sea passage can usefully be employed to ensure all electronic bridge equipment is correctly set up and that the procedures for evidence preservation during more stressful times are well understood. A poster on the bridge setting out the procedure, in easy steps, for preservation of evidence in respect of key electronic equipment such as the VDR, ECDIS, AIS and GPS, near the relevant equipment, should be encouraged. Owners/managers should consider including in their SMS and emergency response instructions/checklist procedures that can be employed in order to save data from all relevant devices on board within 12 hours of any incident.