Angle of heel measured from upright.

Deck Slope / maximum slope

The maximum slope of an initially horizontal, flat deck at the resultant vessel heel and trim. i.e. combined effect of heel and trim.

Gust Ratio

Used for some wind heeling criteria, the Gust Ratio is the ratio of the magnitude of the gust wind heeling arm to the steady wind heeling arm.

g = 9.80665ms^-2

1998 CODATA recommended value for standard acceleration of gravity

Roll back angle

A negative heel angle change. Often a roll back angle is measured from some equilibrium position; the resulting heel angle after the roll back has been applied is more negative than the original. Commonly used in wind and weather criteria to account for the action of waves rolling the vessel into the wind. If a criterion uses a roll back angle, it is often necessary to calculate the GZ curve for negative angles of heel.