It appears that the Louis Majesty ran into the heaviest weather as it transited from an area of force 7-8 SW’ly winds and seas into an area of Ely force 7-8 off the coast of Spain. The rapid backing of the winds likely caused a very confused sea where wave peaks coming from different directions added up to some freak waves.
Just before the incident at 1200z on March 3rd the surface analysis indicated an intense but weakening 1000MB low over the eastern North Atlantic, west of Portugal and a deepening 998mb secondary low over the western Mediterranean Sea. A sharp trough line extended from the secondary low WNW to the East Coast of Spain near 40N which is where the confused sea state was most likely.
Surface Analysis 12Z March 3rd (NOAA Unified Surface Analysis)
The unusual cold and snow of the winter in the eastern US and North Europe as well as the wet and stormy weather over the Med may be the result of a natural cycle called the Arctic Oscillation which has been in the negative phase most of the winter.