Start with the grain rules, not a generic bulk-cargo assumption
A parcel of wheat or maize may look like a routine dry-bulk fixture, but its loading plan needs a grain-specific check. The International Grain Code covers wheat, maize, oats, rye, barley, rice, pulses, seeds and processed forms that behave similarly to grain in its natural state. The IMO distinguishes bulk grain from cargoes governed by the International Maritime Solid Bulk Cargoes Code. Before treating a parcel as an ordinary solid bulk cargo, identify which requirements apply to its actual description.
The ship’s document of authorization is evidence that it is capable of complying with the Grain Code; it is not a substitute for checking the proposed loading condition. The document accompanies or forms part of a grain loading manual containing the information the master needs for the stability assessment. Grain loading stability data and associated plans belong on board as well. For a proposed fixture, an early, useful question is whether the intended distribution among holds can be assessed using that ship’s approved information.
International Code for the Safe Carriage of Grain in Bulk (International Grain Code) · Annex A: Requirements from SOLAS Chapter VI
Build a calculation from the cargo that is expected
Quantity alone does not describe a grain load. The planning inputs also include an accurate stowage factor, the intended distribution among compartments and the trimming methods available at the loading port. The Australian Maritime Safety Authority’s instructions advise obtaining these details from the local agent or another authoritative source and allowing for the possibility that the actual stowage factor will differ substantially from the expected figure. That makes a pre-loading calculation a working plan, not a promise that every hold will finish at its forecast level.
AMSA’s grain stability form asks for a cargo plan identifying holds, grain type, secured and unsecured surfaces, and ballast. Its instructions call for stability and shear-force and bending-moment calculations across loading conditions and voyage stages, with stability assessed for the worst condition that can occur during the voyage. In practical terms, the team should know which assumed hold fills and liquid quantities underpin the result. If the load changes materially, the assessment needs to reflect the condition that will actually sail.
Classify each hold by what the crew can see
The grain surface is an input to the calculation, not merely a finishing detail. The IMO’s outline distinguishes the assumed heeling moments for filled trimmed, filled untrimmed and partly filled compartments. AMSA likewise distinguishes those conditions in its loading instructions. A plan should therefore identify the intended condition of each compartment before loading and confirm the resulting condition afterward; calling a hold “filled” does not make it so if the observed ullage and surface do not support that classification.
AMSA says it cannot accept a compartment as filled when average ullage at the coaming exceeds the space needed for hatch-cover structure or 100 mm, whichever is greater. Its instructions also say untrimmed moments may be used only for filled compartments. These are Australian assessment instructions, not a universal measurement rule for every port. They illustrate why a small-looking difference at the hatch can change the calculation that is appropriate for the hold.
International Code for the Safe Carriage of Grain in Bulk (International Grain Code) · Calculation of Stability for Ships Carrying Bulk Grain
Check any exception before planning around it
A partly filled hold should not be casually treated as permission to leave an uneven surface. The Grain Code’s text provides for level free grain surfaces after loading in partly filled compartments, while describing a specific arrangement for a specially suitable compartment partly filled in way of the hatch opening with ends untrimmed. Under that arrangement, the grain must reach at least the bottom edge of the hatch end beams, and the surface in way of the hatch opening must be level.
AMSA’s form says it does not accept an untrimmed partly filled compartment unless it is a specially suitable compartment approved by the vessel’s flag administration and meets the Code’s defined arrangement. Its cargo-plan fields ask the master to identify holds with that approval. The practical checkpoint is documentary as well as physical: establish that the proposed compartment qualifies before relying on the arrangement, then verify the loaded level and surface against the condition used in the stability work.
Calculation of Stability for Ships Carrying Bulk Grain · International Grain Code: January 2026 Supplement
Close the gap between the plan and departure
Trimming capability belongs in the discussion with the loading port, not only in the final survey. AMSA advises masters to establish available trimming methods and makes the master responsible for ensuring the cargo is trimmed as required. It also says grain in a partly filled compartment should be evenly distributed rather than used to remove a list, and that any list should be corrected before sailing. These instructions keep a stability problem from being disguised by a change to the visible cargo surface.
The useful departure record is a consistent set of facts: actual grain quantities and distribution, the condition assigned to each compartment, the observed surfaces, relevant ballast and other liquids, and a calculation based on the ship’s grain information. Where those facts no longer match the intended load, revisit the calculation rather than carrying forward the original assumptions. The aim is straightforward: the ship that leaves the berth should be the ship described by its grain stability assessment.
International Code for the Safe Carriage of Grain in Bulk (International Grain Code) · Calculation of Stability for Ships Carrying Bulk Grain