The blades closest to the engine are typically larger in diameter and wider then the rear set of blades , but not always ! They have been tried in allot of different configs , some are better than others or work better in particular situations . more often then not the first set of blades has more surface area then the second set of blades . On my boat I tuned my props for the best of both worlds or a compromise , if you will , of speed & raw thrust . It is a monster of a boat and will run dry ground w/ a top speed of 60 MPH . In this size of a boat I have never really been ably to do both as well with a single prop set up .