The automatic identification system (AIS) is a valuable tool that shares critical vessel information with other vessel operators. However, its usefulness depends on accurate data entry. In a recent Mars Report, not entering the vessel’s length correctly led to a collision, capsizing and several fatalities.
The Nautical Institute gathers reports of maritime accidents and near-misses. It then publishes these so-called Mars Reports (anonymously) to prevent other accidents from happening. A summary of this incident:
In the early morning, before sunrise, two towing vessels were approaching an almost 90° bend on a river in opposite directions. Neither vessel was broadcasting the correct total length of their vessel and tow to other AIS users.
The first vessel’s AIS broadcast showed 22 metres, yet the overall length of the vessel and its two-barge tow was 205 metres. The second vessel’s AIS broadcast showed 61 metres, but the overall length of the vessel and its 40-barge tow was 488 metres. As the vessels rounded the bend and completed their turns, they collided, causing the down-bound towing vessel to capsize and sink with several fatalities.
Advice from The Nautical Institute
- The accurate display of a vessel’s full length becomes particularly important in situations that prevent vessels from seeing each other until they are in very close proximity.
- While correct overall length is important for all vessels, tug and tow operations are particularly vulnerable to errors due to the changing value of their total length with each job.
- Incorrect AIS information will give a false mental picture to other vessel operators in the vicinity and can contribute to accidents.
Mars Reports
This accident was covered in the Mars Reports, originally published as Mars 202054, that are part of Report Number 336. A selection of this Report has also been published in SWZ|Maritime’s November 2020 issue. The Nautical Institute compiles these reports to help prevent maritime accidents. That is why they are also published on SWZ|Maritime’s website.
More reports are needed to keep the scheme interesting and informative. All reports are read only by the Mars coordinator and are treated in the strictest confidence. To submit a report, please use the Mars report form.
