Cargo Operations and Dangerous Goods
What the exam tests
Cargo Operations and Dangerous Goods tests safe stowage, segregation, lashing, stability, ventilation and IMDG/IMSBC/Grain Code compliance. The exam expects a documentary and physical check.
Core rules and concepts
- IMDG classes 1–9; segregation depends on class and stowage category, not just labels.
- Dangerous goods declaration must include UN number, proper shipping name, class, packing group and flashpoint where relevant.
- IMDG segregation terms include away from, separated from, separated by a complete compartment or hold, and separated longitudinally by an intervening complete compartment.
- Container lashing: calculate forces from ship motion; check stack weight, twistlocks and lashing rods.
- Bulk cargoes: IMSBC Code group A liquefaction, group B chemical hazard, group C neither; check TML and moisture.
- Grain: Grain Code requires stability calculation and heeling moment; shifting grain can capsize a ship.
- Ventilation: prevent condensation and hazardous gas accumulation; never ventilate a fire without assessment.
Worked example
A 10 t container is subjected to a horizontal acceleration of 0.5g. The horizontal force is 10 × 0.5 = 5 t-force. If each lashing takes 2 t safe working load, at least three effective lashings are needed, plus a safety factor. Check deck fittings and stack height; never rely on twistlocks alone.
Traps
Accepting a DG declaration without flashpoint; mixing incompatible classes; using a lashing calculation without ship motion; loading grain without a heeling moment check; and ventilating a closed space without gas testing.
Key points: IMDG declaration; segregation terms; lashing forces; IMSBC groups; Grain Code; ventilation.