What does the International Grain Code require, and what are its stability criteria?
Short answer
| Criterion (Grain Code Part A §7.1) | Limit |
|---|---|
| Angle of heel due to the shift of grain | not greater than 12°, or the deck-edge immersion angle for ships built on or after 1 January 1994, whichever is less |
| Residual dynamic stability | not less than 0.075 metre-radians up to 40°, the angle of flooding or the angle of maximum difference, whichever is least |
| Initial GM after free-surface correction | not less than 0.30 m |
- Hazard: grain settles by about 2% and shifts when the ship heels; the grain heeling moment lists the ship and cuts her righting ability.
- Instrument: International Grain Code, MSC.23(59); SOLAS VI/8 defines grain, VI/9 makes it mandatory with a Document of Authorization (Part A §3) and approved grain loading information.
- Criteria (Part A §7.1): heel from the shift not greater than 12° (or deck-edge immersion for ships built on or after 1 January 1994, if less); residual area not less than 0.075 metre-radians up to 40° or the flooding angle; initial GM not less than 0.30 m after free-surface correction.
- Anti-shift (§10): trimming to level all free grain surfaces; partly filled compartments secured by overstowing or bundling, strapping or lashing, wire mesh or the saucer method.
- As Chief Engineer: fuel and ballast set the KG the heeling-moment margin is measured against; honest soundings keep GM above 0.30 m and the heel within 12°.
Full answer
The full answer explains each point step by step, with the regulations and figures behind it and the discussion from other candidates. It is in the MEO Class I section of the Marine One forum, open to members enrolled for the MEO Class I exam.