Prop change? (help please)

[Floatsum]

18 ft parker, 130 2 stroke, estimated 3000# avg. load, clean trailer hull.

Presently have a SS 19 pitch (3 blade) rather sluggish comming out of the hole, top RPM 4900/5100.

Most of my cruising is in the 3400/3700 RPM range (ugh), and seems to love the fuel a bit too much. Slow manuvering speed is considerably faster than I'd like. Coming thru breachways,,, well, more oomph when needed would be nice.

Prop change;
Thinking a switch to a 3 blade at 17 pitch would help but perhaps I'd still be below the cruising rpm range that I'd consider efficient at 4200/4400

Theory of 2" pitch = 400 rpm change.

So, would I be better with the 15" pitch? Numerically it would seem appropriate for fuel consumption range, comfort, and power. Plus get me down to a better manuvering / trolling speed to boot.

Something inside my head says 16 pitch would be perfect,, but them little voices keep getting me into trouble.

Any thoughts on this?

 

[DaleH]

Pitch to 200-300 off max RPMs @ WOT. You lose RPMs in the Summer,so if your puppy is a 5500 RPM motor, I'd say a 17" pitch would be ideal.

 

[dave-j]

I sent an email to Robin at Parker asking the same thing about my 2000 23DVCC with Ox66 and got a reply within the hour from an engineer (Eric Denton). My recommended prop is a Yamaha black SS 15 X 17

 

[hwsiii]

Dave, the prop he reommended is their semi leaver prop, whih is an exellent prop, as it has very little blade surfae area and is very easy to turn. Just know that when you are running in formed seas it might have a tendeny to ventilate and lose tration if it is mounted too high on the transom.


H

 

[Floatsum]

Ended up with a Michigan 15 pitch cupped aluminum for realatively cheap.
Big difference. WOT is 5500 rpm @ 36 mph gps.
Not much time to toy with trim. Probably close though.
Definately much, much better all around.
Thinking the cup may make it behave more like a 16 pitch?
Gonna make a nice spare when I find the SS.