During a company audit, it was noticed that the deck tanks used for ammonia storage had been loaded up to 98 per cent at a loading temperature of -22°C. The expected ambient temperature later in the voyage was 20°C.

The Nautical Institute gathers reports of maritime accidents and near-misses. It then publishes these so-called Mars (Mariners’ Alerting and Reporting Scheme) Reports (anonymously) to prevent other accidents from happening. This is one of these reports.

Deck tanks are high pressure vessels that require strict adherence to the cargo manual. In the case described above, the deck tanks should have been loaded to 89.5 per cent to allow for increased pressure when ambient temperatures increased.

Further inquiries identified that the cargo manuals had the appropriate loading curves, but their usage had not been properly explained to crew. Alternatively, the filling limits can be obtained through the formula as mentioned in IGC code, Par.15.5.1.

Also read: Do you know how unusual cargo may impact your ship’s stability?

Advice from The Nautical Institute

  • Be familiar with your cargo manual and don’t hesitate to ask questions.
  • Audits are invaluable tools in quality assurance, not exercises in finding fault.

Also read: No procedure for ship maintenance job – major consequences

Mars Reports

This accident was covered in the Mars Reports, originally published as Mars 202445, that are part of Report Number 382. A selection of the Mars Reports are also published in the SWZ|Maritime magazine. The Nautical Institute compiles these reports to help prevent maritime accidents. That is why they are also published (in full) 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.

Also read: LOTO lapse causes fatal ship repair accident