Cargo on ships may undergo conditions much different from those that may occur on a train or in a semitrailer in New York. Even calm seas may cause significant shifting if goods are not secured, and often, there is settling of bulk cargo that may lead to a serious imbalance. When storms arise, the situation may become much less stable. However, with certain cargoes, the motions caused by choppy seas could lead to a new threat: liquefaction.
Marine Insight explains that agitation can cause some mineral concentrates and substances such as iron and nickel ores to suddenly turn from solids to liquids. Moisture content can also be a factor, and this information should be listed on the shippers declaration. It is the chief officer’s responsibility to review this document carefully before allowing any cargo to be loaded. During the voyage, levels of moisture may need to be checked repeatedly, if the load has unstable capabilities.
According to ChemInfo, the shipping industry has not paid as much attention to the threat of liquefaction as it should. Crew members may not be educated about the potential for the solid cargo to suddenly change to liquid through excess moisture content and motion, so loads are not secured in a way that would prevent them from tilting and causing a ship to capsize. Experts believe this may have been the fate of a bulk carrier transporting 266,000 tons of iron ore, which sank suddenly and has not yet been recovered. Twenty-two of the 24 crew members are currently still missing.