OK so - 21ft. Seasport 5.0 duoprop. I just got her back from a complete redo. I am getting 35-3600 rpm and 30 m.p.h. Using D3 props and she is topped out. Which is close to before the redo. Will a set of D4's give me more RPM and higher speed? Probably more economical too?
Volvo doesn't show anywhere that the pitch difference is.