How Is Bulk Cargo Prevented from Shifting? MCA Oral Exam Guide

The short answer

A solid bulk cargo is kept from shifting mainly by trimming: levelling it to the boundaries of the hold as the IMSBC Code requires. Grain has its own rules under the International Grain Code. Dunnage and battens belong to general and break-bulk cargo, not bulk.

Why shifting matters

A shifted bulk cargo gives the ship a list that may not come back, reduces her righting levers, and can lead to capsize. Examiners use this topic to check you connect cargo work with stability.

Trimming under the IMSBC Code

• Trimming reduces the chance of the cargo shifting and limits the air that can reach it.
• Holds are filled as full as practicable without overloading the tank top or tweendeck.
• The cargo is trimmed reasonably level to the boundaries of the space. The Code's individual schedule for the cargo may add requirements.
• Cargoes with a low angle of repose flow easily and need particular care.

Cargoes that may liquefy

Some bulk cargoes can liquefy if their moisture content exceeds the Transportable Moisture Limit (TML). Trimming will not prevent that. The shipper must declare the moisture content and TML, and the ship can carry out a can test if the cargo looks too wet.

Grain

Grain shifts easily, so the International Grain Code requires the ship to show she can withstand a grain shift, using her grain loading information and Document of Authorization. Measures include trimming and securing the surface of partly filled compartments.

Where dunnage does belong

Dunnage and battens protect general and break-bulk cargo: spreading load, allowing drainage and air flow, and keeping cargo off sweating steel. If the examiner asks about bulk, don't reach for dunnage.

What the examiner wants to hear

• Trimming, and the IMSBC Code by name.
• The link to stability: a shift causes a list and a loss of GZ.
• TML and moisture content for cargoes that may liquefy.
• The Grain Code for grain.