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

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.

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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.

Displacementmetric tonnes.

Corrected initial GMm, after liquid free-surface correction.

Total corrected grain heeling momentt·m.

GZ at 10°m.

GZ at 20°

GZ at 30°

GZ at 40°

Maximum permitted grain-shift heeldegrees; enter lower deck-edge immersion angle if it governs.

Flooding / upper residual-area limitdegrees; enter lower flooding angle if applicable.

Vessel Stability Condition

Displacementmetric tonnes.

KMTm above baseline.

Actual KG before liquid FSCm above baseline.

Total liquid free-surface momentt·m.

Grain stowage factorm³/t, from loading facility / approved grain calculation basis.

Maximum permitted grain-shift heeldegrees; use lower deck-edge immersion angle if applicable.

Flooding / upper residual-area limitdegrees.

2026 special-compartment provisions relevant?

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 type	Input basis	VHM m⁴	Direct moment t·m	Vertical-shift treatment	Custom 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 deg	KN m

Loading / Compliance Readiness Checks

Document of Authorization / approved grain manual checkedShip-specific approved grain stability data and plans are onboard/current. Compartment VHM source verifiedFilled/partly filled conditions match the actual loading plan. Vertical-shift correction treatment verified1.06/1.12 or alternative approved treatment is not double-counted. Liquid free surfaces reconciledFSM and tank states reflect the condition being checked. KN / hydrostatic basis verifiedCross curves correspond to the applicable displacement/trim. Flooding / deck-edge limiting angles checkedLower governing angles are entered where applicable. Departure / arrival / worst intermediate condition reviewedCompliance is required throughout the voyage. 2026 special-compartment rules checked where usedMSC.552(108) condition is applied only to qualifying specially suitable compartments.

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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