Stability & Cargo Safety Flashcards

What is the purpose of the vessel's Stability Booklet?

Answer: To provide the master with pre-calculated loading conditions and minimum stability criteria approved by the MCA — ensures the master can verify stability for any cargo arrangement

The Stability Booklet contains MCA-approved stability information, sample loading conditions, minimum stability criteria (GM, GZ values), and instructions for calculating stability for actual loading. Masters must use it to verify compliance before departure.

What is 'trim' of a vessel?

Answer: The difference between the forward draft and aft draft — a vessel trimmed by the stern has greater draft aft than forward

Trim is the difference between the forward draft (at the bow) and aft draft (at the stern). A vessel trimmed by the stern (aft deeper) is the normal trim for most vessels. Trim affects propeller efficiency, manoeuvring, and steering.

What is the significance of the ship's hydrostatics table?

Answer: It gives displacement, centre of buoyancy, KB, BM, and KM for each draft — allowing calculation of actual GM when combined with the loaded KG

Hydrostatic tables (or curves) give values of displacement, TPC (tonnes per centimetre immersion), KB (keel to buoyancy), BM (buoyancy to metacentre), and KM (keel to metacentre) for each draft, enabling calculation of GM from the actual loaded KG.

What is a 'grain loading document' and when is it required?

Answer: A document authorising the carriage of grain in bulk, confirming stability meets the International Grain Code requirements — required for bulk grain cargoes

Bulk grain cargoes are particularly hazardous because they can shift. The International Grain Code (under SOLAS) requires vessels to hold a Grain Loading Document (issued by the flag state) confirming the vessel's stability meets the special requirements for bulk grain carriage.

What is 'broken stowage' and how does it affect cargo planning?

Answer: The unused space in a hold between irregular cargo pieces — it represents lost cargo-carrying capacity and affects weight distribution calculations

Broken stowage is the space wasted between irregularly shaped packages that cannot be efficiently filled. It is expressed as a percentage of hold volume and must be factored into cargo plans because the actual cargo stowage factor differs from theoretical calculations.

What action must a master take before loading a heavy lift cargo?

Answer: Calculate the effect on GM, trim, and deck/hold strength; obtain a heavy lift plan and ensure appropriate lifting equipment is rigged; check weather windows for loading

Before a heavy lift, the master must calculate stability effects (change in KG), trim changes, and verify that deck or hold strength is not exceeded. A heavy lift plan should be prepared, appropriate lifting gear rigged, and a suitable weather window identified for safe operations.