The following 2 stability curves give examples of the variations in righting arms and points of vanishing stability (PVS) which can occur with different vertical centres of gravity (VCG).
This lift bulb keel racing yacht had an inclination experiment conducted, with the yacht in measured condition i.e. no loading, and the VCG of the yacht was established. The first curve shows the yacht with keel fully down in its unloaded condition. The bulb keel arrangement gives a very low VCG for the ballast.
The second curve shows the yacht loaded with all of the crew weight and gear weight for racing located at deck HEIGHT and on centre line. The PVS is still 139.2 deg with keel fully down.
2.8m lifting bulb keel - VCG 256mm below DWL - PVS 150.2 deg
2.8m lifting bulb keel - VCG 60mm below DWL - PVS 139.2 deg