Boat Prop Blade effeciency

[ReddyWatts]

I was reading "Performance Boats magazine Sept. 2010 page 12" about props.

They say "The reason you will see so many four-blade props is that they are more effecient.". "The props have less slippage". " They even see alot of go fast boats with 5 and 6 blade props".

[Shooter]

Interesting. I guess it depends on how you define efficiency (at low or high rpm).

I always thought that multi-blade props were more drag at higher rpms.

For instance, some ski boats have 4 blade props for better "hole shots", but they end up losing a little top end.