advantages of a surface drive?

[milespm]

each prop blade has same pitch meaning distance screwed through the water every revolution. each blade uses hp and less blades in the means more
efficiency. fastest prop would have one blade but would also obviously be totally unbalanced. fast race boats like hydros have two. surface drives hhave many blades to smooth chopping into the water but only use those in the water
each of those pushing the same rate of pitch.

[powerabout]

still cant see the advantage of this over a sterndrive with propshaft mounted level with hull as many are now
( less on huge diesels as they can take the torque)