The uppermost point on a curve of volumetric heeling moment
versus either depth of grain or ullage, in a partly filled compartment,
should be based on the void in the filled condition shifted 25°.
In other words, the curve of volumetric heeling moments for the partly
filled condition should not be terminated at the point, at
zero ullage, which represents the volumetric heeling moment based
on a 15° shift as the moment applies only to the filled condition.