Just caught up w/this thread...
Interesting history by Dave...not easy to follow, but interesting. Would love to read more from both Aggressor and other pump mfgs. ATM? Berkeley? Legend? Where are they on this important matter?
On Impeller blade (NOT vane or vein) pitch. The steeper Aggressor pitch no doubt the reason their blade leading edges extend to the edge of the shroud compared to a Berkeley impeller which falls short. Not merely an extended blade at the same pitch as HBjet proposed. More pitch means more aggressive or more bite.
So is more pitch or bite always good?
Does more pitch or aggressiveness automatically produce more flow and thrust? Not necessarily.
These ideas floating around the forum from post to post. I think the connection is pump efficiency curves (which no jet pump mfg seems to know or supply) impeller cut size and rpm. A function of power. Those factors most likely the basis of, "aggressive pitch is all good" claims. But the technical performance information (accurate flow measurements not material stress analysis) is lacking. Sure you don't want your impeller to self-destruct. But even more, you want performance.
Think of pitch and how it relates to prop performance. Does more prop pitch automatically guarantee more prop boat performance? Nope. Why not?
On "I've heard an Aggressor B is the same as a Berkeley A" Well, that was stated long ago (about a year or more) by Dave and incorporated in JPC pump curves. Also somewhat verified by real test data. From what I've seen I think it's true. So no wonder you heard it.
jer