posted 02-20-2002 11:05 AM ET (US)        

RPM----->MPH

14x17 Alum prop:
3400.....16.5
3800....21
4000....22.5
4200....24
4500....27
5000....30
5800....35 (WOT)

13x19 alum prop
3400....23
3700....24.5
3800....26
4000....29
4200....30
4500....34
5500....39 (WOT)

Pretty substantial I would say. I have never experienced 2 inches of pitch that made that much of a difference. Holeshot was great with both props. As some know I was slightly disappointed in my slow speed with the 70 over my 90 Yamaha....until now. I was running 3800 RPM with the Yamaha and doing 28 MPH. I then changed motors and at 3800 I was doing a measly 21 and it felt like I was falling off plane. Now I am running 3800 and doing 26...cool! The 19-inch had less bow rise than the 17-inch. The blades look different and the 17-inch blades are longer as in it would not fit in a 5-gal. bucket but the 19 did. I am gonna run these numbers by my prop shop (General Propeller) in Bradenton and see what he recommends as far as turning my 17-inch Yamaha SS prop into that would benefit me the best.

FYI with 4 people in the rig it popped on plane nicely with the 19-inch, cruised very nicely with the load and hit a respectable 34 but only at 5000 RPM (WOT). So in that respect it is a bit steep. A 18-inch would probably be ideal.

I was amazed that a 14x17 prop had a slower cruise. I assumed the larger diameter would give a better midrange but it did not. I guess 1-inch diameter is not enough to make a difference or the Montauk is light enough that a large diameter blade is inefficient.

I am gonna post my SS prop speeds when I get them and will also do now and jackplate up another inch or so.