The 27hp Yanmar 3HMF in my 38' 15000lb boat will peg the tachometer at 4000 RPM and just barely reach hull speed (or maybe not quite). Right now I cruise at about 6.5kts @3500 RPM. I'd like to get the speed up to 7-7.5kts and the RPM down to 3000 or ?? not sure. Is that reasonable or possible? The prop is a two blade folder. I couldn't find any markings on it, so I'm not sure of the pitch. I thinking of re-pitching or replacing it, but I'm not sure at what RPM range I should be aiming. I race the boat, so fixed props are out.