A cargo ship lost 34 containers off the UK after its crew became accustomed to dangerous weather conditions in the North Sea.

The UK Marine Accident Investigation Branch (MAIB) said the box-securing arrangements were overwhelmed on the 6,250-dwt Francisca (built 1997) on 31 October, 2020, near Duncansby Head.

The ship was on passage from Iceland to the Netherlands when severe weather conditions were encountered.

The deck cargo was affected when the Francisca was pitching heavily into the waves, causing stacks to collapse and containers to be lost overboard, the preliminary accident report reveals.

All but one of the boxes was empty and some debris from this laden container washed up ashore. None of the containers was recovered and Francisca suffered minor damage on deck. There were no injuries.

The MAIB found that the violent pitching and ploughing resulted in a rapid loss of speed and heading control, which exposed the deck to forces capable of overwhelming the maximum loading of the container-securing arrangements.

“Regular passages between Iceland and the Netherlands meant that Francisca’s crew had become accustomed to operating in the often poor weather in the North Atlantic, Pentland Firth and North Sea, and this had lowered their appreciation of the significant weather-associated risks,” MAIB said.

The preliminary assessment also identified that the absence of a protective breakwater at the vessel’s bow increased the risk of cargo loss in heavy weather.

Corrosion to the deck-cargo securing arrangements may have contributed to the scale of the loss, the report added.

As a result of the findings, MAIB has written to the vessel’s technical manager, VMS Ship Management, and the Dutch charterer Longship.

This was to advise them of the safety issues identified after the accident so that internal measures could be taken to reduce the risk of recurrence.