Operational Limitations and Operational Guidance

Operational limitations and operational guidance are the two alternatives the Second Generation Intact Stability Criteria offer a ship that cannot demonstrate compliance by calculation. They are not interchangeable. A limitation constrains the ship, and guidance informs a decision, and the distinction decides who carries the residual risk.

An operational limitation is a restriction written into the ship’s approved documentation, such as a bound on significant wave height, on the range of headings relative to the sea, or on speed in a defined sea state. It applies whether or not the master agrees with it. Operational guidance is advisory material supplied so a bridge team can recognize a developing hazard and act on it, typically presented as tables or polar diagrams of safe combinations of speed and heading against sea state.

The full article will cover the approval route for each, how each reaches the ship and the bridge, the way guidance products are generated from the underlying assessment, the practical problem of keeping advisory material usable in heavy weather, and the interaction with the master’s overriding authority under the ISM Code.