Cargo stowage is one of the most safety-critical operations in maritime transport. An incorrectly stowed load can create a list, reduce freeboard, or in extreme cases cause a capsize. The Stow It game in the Binnacle AI Arcade simulates container stowage on a Panamax container ship with real weight-distribution mechanics.
Stability principles in the game
The game models the relationship between the center of gravity (G) and the metacenter (M). When heavy containers are placed high in the stack or on one side of the ship, the ship lists. Players must maintain:
- GM (metacentric height) — must stay positive for the ship to be self-righting
- Free surface effect — partial ballast tanks reduce effective GM
- Longitudinal trim — fore-aft weight distribution affects propeller efficiency and steering
Hazardous cargo rules (IMDG Code)
The game includes IMDG (International Maritime Dangerous Goods) Code segregation rules. Class 1 explosives must be separated from Class 3 flammables. Oxidizers must not be stowed near flammables. Violations result in point deductions and failed inspections.
Understanding the IMDG Code's "separated from," "separated by a complete compartment," and "away from" segregation distances is essential for the USCG Cargo/Tankerman exams and is tested in the Stow It Perfect Stowage bonus mode.
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Binnacle AI Arcade has games for every aspect of seamanship, from cargo stowage to COLREGS to heavy weather. Free to play, global leaderboards, daily challenges.
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Frequently asked questions
What is metacentric height (GM)?
GM is the distance between the ship's center of gravity (G) and the metacenter (M). A positive GM means the ship is stable and self-righting. A negative GM means the ship will heel and potentially capsize. A GM that is too large (stiff ship) creates uncomfortable rolling.
What is the IMDG Code?
The International Maritime Dangerous Goods (IMDG) Code is an IMO standard for the safe handling of hazardous materials at sea. It classifies dangerous goods into 9 classes and specifies stowage, segregation, and documentation requirements.
What is 'trim' on a ship?
Trim is the difference between the draft at the bow and the draft at the stern. A ship trimmed by the stern (heavier aft) is the normal condition for most cargo vessels and is more efficient for propulsion. Excessive trim by the head (heavier forward) is dangerous.
What causes a list on a ship?
A list is a transverse inclination caused by an off-center weight — either from uneven cargo loading, free-surface effect in tanks, or damage and flooding. A list is a stability issue; a heel is a temporary inclination caused by external forces like wind.