I've tryed opimizing and found that the smaller the Cm as possible, the better

I need to change my attempt at optimizing hull form, and only optimize for Cp (prismatic coefficient). There is the issue that the best Cm is at 0.8, the lower end of what I tried. My take is that I just need to use the designed Cm and optimize Cp, only. It actually turned out that all I had to do was provide a flag to determine where to write the output to the log file, or not. That allowed me to repeatedly run the function for determining the actual speed for a given SHP, and use that in the optimization process.