A stability booklet is a ship-specific, flag-state-approved document containing the hydrostatic data, sample loading conditions, and stability criteria needed to verify a vessel’s stability before every voyage.
What the Stability Booklet Contains
- Hydrostatic tables — vessel-specific data (KM, TPC, MCTC, and similar values) at various drafts
- Sample loading conditions — typical cargo/ballast scenarios with pre-calculated stability results, useful reference points
- Minimum GM and stability criteria — the specific thresholds this particular vessel must meet, which can vary based on the ship’s design
- Deadweight scale and capacity plans — supporting data for loading calculations
Why It’s Vessel-Specific
Every ship has genuinely different hydrostatic characteristics based on its unique hull form, dimensions, and design — a stability booklet from one vessel cannot be used for another, even a sister ship, without verifying it’s actually the correct approved document for that specific hull.
Mandatory Pre-Voyage Use
Before every departure, the Chief Officer calculates the vessel’s actual loading condition (cargo, fuel, ballast, stores) and verifies the resulting GM, trim, and stress figures against the stability booklet’s approved limits — a genuine, mandatory safety check under SOLAS, not an optional reference consulted only when something seems unusual.
Approval and Updates
The stability booklet requires flag state (or recognized organization) approval, and must be updated if the vessel undergoes structural modifications significant enough to change its hydrostatic characteristics — an outdated booklet after major modification is a genuine compliance and safety gap.
Exam Relevance
Stability booklet contents and its mandatory role in pre-voyage stability verification are core, heavily-tested Ship Stability topics across all levels of deck officer competency exams.