Calculating power for a speed for a ship

The modern computative approach to calculating the power that is needed to move a ship at a certain speed uses a database of ships and then interpolates from the known values. In the past, to get a rough idea of the power required, the British navy used an empirical formula. They knew that they would need to do model trials to get a better power figure and to be able to generate a tentative power-speed curve. A third approach, developed by David Taylor, was to look up values from graphs from The Speed and Power of Ships, and then generate the data to provide a power curve. The U.S. Navy apparently had classified factors that they used to improve the results from the Taylor calculations, based on hull form. I have a program that runs in a game engine scripting language (which is unfortunate), that uses some data that both summarizes and extends what is in The Speed and Power of Ships. I also use, on the advice of Frank Fox, friction data from Gertler's book, A Reanalysis of the Original Test Data for the Taylor Standard Series (1954). This page has a picture of Morton Gertler with towing model of the submarine Albacore.