From Narciki

The **maximum VCG curve** is a graphical plot of VCG vs. displacement, showing the highest values of VCG which will pass the given stability criteria. For reasons of expediency in calculation and ease of use, the graph may include a number of superimposed maximum VCG curves for varying sets of stability criteria: i.e., IMO intact stability criteria + ABS tow criteria + USCG weather criteria. Initial trim and heel are taken as level, as such load conditions play no part in the calculation.