Rich wrote:

I've been talking to a prop shop about changing from a 14.5 X 19 X 3 alum.
to a 4 blade SS prop. The shop recommended a 14.5 X 17 X 4 but said that I
would loose 3-5 mph from the top end, I guess because of the drag of 4
blades. Is there any other size 4 blade that won't cut the top speed?

TIA
Rich




Not really, for the same reason that you give up some top speed going
from a 2 blade to a 3 blade. 1 blade props would give you best top
speed, but they are extremely difficult to balance.

4 & 5 blade props are very smooth and have good initial bite, but for
most applications the 3 blade is the best compromise. You are usually
better off going to a similar ss prop if you are going to make the step
from aluminum to ss. In ss grinds, there are so many different blade
designs, with different surface area, blade shapes, rakes, trailing and
leading edges, diameters, blade thicknesses, & so on, the better
question would be "which 3 blade?". A prop with larger surface area and
a double cup can be run higher on the transom.

Also, two apparently identical props out of the box will usually act
somewhat differently on the boat.

Rob