I'm doing all this empirical work to calculate volumes

I finally have my calculations for engine room size working, on a "per engine basis". I have been studying WWI ship engine room volumes. I have thought that you necessarily have to base the size on the "SHP/ton of machinery". It is not linear, as you might expect, although I am using a piecewise linear solution for part of the equation. I am using the equation for a line (y=mx+b), but I am computing the m and b using the SHP/ton weight basis. That seems to be working. Last night, I was really concerned that the engine room sizes were going to be so large as to be not workable. The next step will be to estimate boiler room sizes.