I re-engined my Alpa38, 11 tons, 9 mt waterline that was equipped with a Perkins 4.108, inverter Hurt 250, with a BETA 60, TMC260 inverter with 2: 1 ratio, that will be delivered to me in late February.
I ask you if I can continue to use my existing propeller, a Max Prop three blades 18 ', and with how many degrees, or if I have to change it with one of a larger diameter, taking into account that I can be as high as 19'. My shaft is 35mm with Aqua Drive cvb 10.10.
Based on the boat specs that you provided I think that setting your current 18" Max Prop to 13" or 14" of pitch should work for you.
You will have to refer to Max Prop to convert inches of pitch to their settings in degrees. If you email PYI they will be able to help you her. There website is www.pyiinc.com/ and I have always found them to be helpful.