Cargo ships secure containers with lashing rods and twist locks; heavier boxes generally sit lower, while turnbuckles and braces stabilize stacks. Containers can still fall overboard despite these precautions, and hatch covers protect cargo in the hold.
Lashing rods connect lower containers to raised fittings on the deck. Twist locks join stacked containers: a pointed locking head passes into a hole in the container above, then is manually locked. Stacking cones help keep cargo in the hold level, while bridges can brace adjacent stacks.
Route selection is another safeguard. The BBC reported in July 2022 that extreme Pacific conditions are particularly dangerous for the largest cargo vessels. Stavros Karamperidis of the University of Plymouth told the BBC that ultra-large vessels coming near the coast avoid big waves; he described the issue as one of stability.
