relative speed of ss and alum

[jshoes52]

I have a 20 center console with a 90hp outboard. running a 13.75x15 Michigan vortex, the motor will spin up to about 5300 rpm with a light load. It's rated for 5150-5850 rpm. I also have a 14x13 alum Turning Point prop for heavy loads that will spin over 5800 rpm lightly loaded. A 14" pitched prop would be ideal, but I can only find one in stainless steel. How will a 14" pitche ss compare in rpm to the 13" and 15" pitch alum props?

 

[Texasmark]

Re: relative speed of ss and alum

If your Turning Point propeller is a Hustler I have one for my 90 hp in 23P.

I compared it to a 24P Ballistic SS and it cost me 3 mph and 600 rpm's........but you are supposed to increase rpm's when you drop pitch....right? Wrong.

The performance of the Ballistic is so superior to the Hustler even though the Hustler is marketed to have all the goodies SS has but without the cost.

In my case I think the blade thickness is the culprit but I haven't proven it. Course if you look at the blades on the Ballistic their shape is pretty radical.

My gearbox is 2.3 and I am on a lightweight padded boat so don't get hung up with the differences in your and my pitch values. With a 2:1 box and heavier boat I would be running in your area.

Mark