Cargo Handling and Stowage
Cargo handling and stowage tests safe segregation, securing, cargo care and the documentation that proves the stow is compliant. The emphasis is on the IMDG Code, the CSS Code and the Grain Code.
IMDG classes and segregation
The nine IMDG classes are: 1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidizers and organic peroxides, 6 toxic and infectious substances, 7 radioactive material, 8 corrosives, and 9 miscellaneous dangerous goods. Segregation terms range from "away from" through "separated from", "separated by a complete compartment or hold" to "separated longitudinally by an intervening complete compartment or hold". "Away from" requires effective segregation with at least 3 m horizontal separation; "separated from" requires different compartments or holds, or an equivalent separation. Always check the segregation table and any special provisions.
Securing and cargo care
The CSS Code provides methods for calculating lashings and securing arrangements. Consider the cargo's mass, centre of gravity, friction, sea state and anticipated accelerations. Containers need correct stacking weight and twistlock arrangements. Heavy lifts need spreader beams and load-spreading plates.
Ventilation removes heat, moisture and dangerous gases. Surface ventilation removes air from the top of the hold; through ventilation moves air through the cargo. Use dew-point comparisons to avoid cargo sweat or ship sweat. The Grain Code requires the cargo to be trimmed, filled and secured so that the ship retains stability after grain shift.
Worked example: segregation decision
A consignment of Class 3 flammable liquid and Class 5.1 oxidizer is offered for the same hold. May they be stowed together?
The IMDG segregation table requires "separated from" for Class 3 against Class 5.1. Stowage in the same hold is therefore not acceptable unless the cargoes are separated by a complete compartment or hold or an equivalent arrangement. The correct action is to shift one cargo to another hold or to reject the stow. Record the decision and the segregation reference.
Traps
- Confusing "away from" with "separated from".
- Applying the segregation table only one way when the table is symmetric.
- Forgetting special provisions and the dangerous goods list.
- Using IMDG rules for bulk grain instead of the Grain Code.
- Ignoring flashpoint when assessing Class 3 stowage.
- Overlooking securing calculations for heavy lifts and containers.