hillbilly.. wrote:if there same what causes the loss of speed. just askin becsaue Im in need of a new blade for my boat got into the rocks and not sure of pitch im in need of
Different propeller efficiencies. One prop may have a little bit more cup, or a little bit different shape.
As far as choosing a prop for your boat, it is easy to find a prop that works pretty well for your boat, but takes testing several different pitches based on the normal load to ideally prop a boat. If there are any numbers stamped on your prop they will indicate the size and pitch, and if the boat ran fine with the propeller you had on it, I would use the same size.