Prop Selection

[Kenny Benoit]

I've been monitoring my loads and boats performance to select a new prop and here is the info. Any feedback is appreciated. Mr. Bob suggested a High Five just needed this info for a pitch selection.



Boat: 2007 Nitro 189 Sport

Motor: 2007 Merc 150 EFI

Current Prop: Laser II 21p

Load: Averaged around 1200 pounds with persons and gear.



Top Speed GPS 45mph. The WOT concerns me though, if I trim up to a point where I feel it should be fine I can easily exceed the safe WOT of 5800RPM. I didn't push it to see how far but it popped up to 6200 on me, this also occurs more easily when I'm pushing my load limits up. But I may have been over trimmed. I can set the trim and hold the WOT at 5800. I would like more hole shot and acceleration with the large loads I'm carrying if that's possible. I know Mr. Bob suggested the Mercury High Five I hope this info is enough for some recommendations. Thanks in advance boating gurus.

 

[Tom Pulaski]

If you put your info into the prop calculator you should be going 56 mph at 5800. So your 21P Laser is too much prop. You are over trimming to get your WOT. Also in my experience the Laser is more of a top end prop, when loaded doesn't have a hole shot even with it's large vents. The high five is a good choice along with an Enertia or even a small hub Trophy. I'd be trying a 19P or even a 17P when you are loaded with gear and people>

 

[Tom Pulaski]

You can find that calculator online. Look for it at "prop slip calculator"

 

[Kenny Benoit]

Awesome info, thank you.

 

[Kenny Benoit]

Would this also be why I feel like i fall back into the hole too quickly at lower RPMs? And also is the too much pitch a possible culprit in my high RPMS if I am not trimming too high?

 

[Tom Pulaski]

Exactly. Prop loses bite and creates more slip. I'd also check the engine height, it could be mounted too high on the transom. One bolt hole makes a difference http://www.jaymartinpropellers.com/id26.html . Check this site for a how too measure prop height to the pad.

 

[Bob Bourget2]

+1. Go with the 19" Hi-Five.....

 

[Kenny Benoit]

As always you guys give great info, thanks again.

 

[Kenny Benoit]

Any advice on where to purchase one? My local Propeller dealer should be wearing a helmet just to leave his house, I will not deal with him again.