A container ship is a merchant vessel purpose-built to carry standardized intermodal shipping containers, stacked in cellular guides below deck and secured in tiers above deck.
Measured in TEU
Container ship capacity is measured in TEU (Twenty-foot Equivalent Units) — a standard 20-foot container counts as 1 TEU, a standard 40-foot container as 2 TEU. Modern ultra-large container vessels can carry over 20,000 TEU.
Key Features
- Cellular hold structure — vertical guide rails that hold containers in precise stacks below deck
- Lashing systems — securing containers stacked above deck against rolling, pitching, and heavy weather
- High service speed relative to bulk carriers, since container trade prioritizes schedule reliability
- Gearless design on most large vessels — relies entirely on shore-based gantry cranes for loading/discharge, unlike smaller feeder vessels which may carry their own cranes
Operational Considerations
Container stability calculations, lashing verification, and stack weight limits are safety-critical — container ship losses from improperly secured or overloaded stacks remain a real industry concern, particularly during heavy weather.
Exam Relevance
Container stowage planning, lashing requirements, and stability considerations specific to container operations are covered in Cargo Work sections of deck officer competency exams.