International Grain Code • Grain Heeling Moment • Grain Shift Heel • Residual Dynamic Stability • GM • GZ/KN Curve • Allowable KG • 2026 Special Compartments

Grain Stability Tool Grain Heeling Moment, Residual Area & Allowable KG

Cross-check bulk-grain stability against the International Grain Code using actual grain-shift heeling moment, righting-arm data and free-surface correction. Simple mode screens heel, residual area and corrected GM from a compact GZ curve. Advanced builds the grain moment from compartment VHM data, applies the correct vertical-shift treatment, generates GZ from KN and effective KG, numerically solves equilibrium heel and residual area, and reverse-solves the maximum allowable KG and required GM for the entered grain-loading condition.

Assessment data
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Need compartment VHM, KN curves and allowable KG? Click Advanced above.Advanced uses approved compartment volumetric heeling moments and the 2026 Grain Code special-compartment class, then solves the full residual-area and allowable-KG problem numerically.
Fast9 primary inputs
Three Code gatesHeel, residual area & corrected GM
ImportantApproved grain manual remains controlling

Fast Grain Stability Screen

Enter GZ values from the applicable approved loading condition after liquid free-surface correction. Enter the total corrected grain heeling moment in t·m. The tool creates the Code heeling-arm line with λ40 = 0.8 × λ0.

metric tonnes.
m, after liquid free-surface correction.
t·m.
m.
degrees; enter lower deck-edge immersion angle if it governs.
degrees; enter lower flooding angle if applicable.

Vessel Stability Condition

metric tonnes.
m above baseline.
m above baseline.
t·m.
m³/t, from loading facility / approved grain calculation basis.
degrees; use lower deck-edge immersion angle if applicable.
degrees.

Grain Compartment Heeling-Moment Register

VHM should normally come from the approved grain loading manual. For VHM rows: corrected heeling moment = VHM ÷ stowage factor × selected multiplier. Choose “Already corrected” to avoid double-applying a vertical-shift factor already built into approved data.

Compartment typeInput basisVHM m⁴Direct moment t·mVertical-shift treatmentCustom multiplier

KN / Cross-Curve Register

Enter sufficient KN / cross-curve ordinates for the actual displacement and trim. The tool calculates GZ = KN − effective KG × sinθ, where effective KG includes liquid FSC. Keep the curve dense around the grain-shift equilibrium and toward 40°/flooding.

Angle degKN m

Loading / Compliance Readiness Checks

Compliance limitation: this is a screening/cross-check tool and does not replace the ship’s approved Grain Loading Manual, Document of Authorization, approved maximum permissible heeling-moment tables/curves, approved loading instrument, Administration/class review or the International Grain Code itself. Compartment VHM values, KN/cross curves, flooding angle, deck-edge immersion and vertical-shift treatment are vessel/load-case specific. Do not substitute estimated geometry for approved grain data when making an actual loading decision.
International Grain Code basis: section A 7 requires the grain-shift heel to be no greater than 12° or, for ships constructed on or after 1 January 1994, the deck-edge immersion angle if lower; residual area between the grain heeling-arm and righting-arm curves must be at least 0.075 m·rad up to the least of the angle of maximum difference, 40° or flooding; and initial GM after liquid free-surface correction must be at least 0.30 m. Figure A 7 defines λ0 from the assumed grain-shift moment and λ40 = 0.8 λ0. The 2026 amendments in MSC.552(108) add the “specially suitable compartment, partly filled in way of the hatch opening, with ends untrimmed” condition and apply the 1.12 vertical-shift heeling-moment treatment to that class.
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