An important difference between what I am doing and what Rick Robinson's "Spring Style" program does

Rick Robinson's "Spring Style" program for warship design takes the approach that the designed displacement is sacrosanct, and that if you load the design up with large machinery, guns, and armor, that you will keep the displacement constant and start reducing the hull weight, even if it goes below what is feasible. Stability is another likely casualty, along with seakeeping and roominess.

My approach is to increase the displacement as you add weights. That will still affect the stability, and will increase the draft, and slow the speed. My plan is to calculate power curves for at the legend displacement and the deep load displacement, and not for the designed displacement that was desired. I do calculate a "designed draft" based on the "designed displacement", as that figure is required to do the weights analysis.