Cargo Handling and Stowage: Safety and Planning
Core cargo knowledge
You must understand the difference between bulk, breakbulk, container and heavy-lift cargo, and the stowage factors that govern space and weight. Know the meaning of centre of gravity of a cargo, why heavy cargo goes low, and how to avoid overstressing the deck or tank top. Understand the IMDG Code classes and segregation requirements, and the purpose of the Dangerous Goods Declaration and the Container Packing Certificate. Know the terms of the Hague-Visby Rules on carrier liability and the significance of a clean bill of lading.
Traps in questions
A common trap is confusing stowage factor, which is volume per unit weight, with relative density. Another is assuming that all dangerous goods can be stowed together; segregation tables must be consulted. Watch for questions on the difference between a shipped and a received bill of lading, and on the effect of a claused bill on the shipper's ability to claim. Also be alert to the hazards of cargo liquefaction in bulk concentrates and the need for a cargo declaration of moisture content.
Worked rule of thumb
To check whether a hold can take a bulk cargo, multiply the volume by the stowage factor to find the weight that fills the space, then compare with the permissible tank-top load. Example: a hold of 2000 cubic metres with a stowage factor of 1.5 cubic metres per tonne holds about 1333 tonnes. If the tank top allows only 1000 tonnes, the hold is weight-limited, not volume-limited, and you must leave space or distribute the load. Always verify the ship's stability and stress after loading.