r27ob - Turning Point 4 blade prop

[Jcat2010]

Does anyone have any experience with the Mach 4 Express prop for the R27s ? Claim to be able to outperform other 4 blade props due to mixed blade geometry. I know the Powertech works, but it has a few drawbacks that the Turning Point might overcome. Unfortunately, the Turning Point brand is carried by dealers who carry Powertech, so no direct dealer info.

 

[Submariner]

Cliff has one on his R27-OB. Here's a quote from him about it.

We currently have Turning Point 15x15 Mach-4 installed, love the midrange cruising but unable to hit +5500 at WOT on the Yamaha F300 (with our typical boat loading) Others have gotten 5400 using the same prop.

There's 4 options from PowerTech but the 16" x14 (0.5" bigger than the RT installed Yamaha Salt-2 15.75x15) but being 1P less, has me intrigued? slightly bigger diameter, plus 4 blades for more bite-lift, 1 pitch less would raise RPM by 200 (in theory) and possible balance the "more bite"?

The other PT options are all smaller diameter, similar to the TP I have currently installed.
Another user had tried the Turning Point 15x13 Mach-4, but reported 6100rpm at WOT, and not enough bite to get stern lift for easy planning.

Our numbers with the new prop running up to Oak Harbor.
Turning Point Mach-4 Express SS 4-blade 15"x15P
***update*** only able to hit 5300rpm, so the alternate 15.3" x13P would rev an additional 300-400rpm.

 

[Jcat2010]

Very interesting. TP initial recommendation is for :a 15.6 x 15, which, from Cliff's experience would not be able to hit the upper rpm band. I'd be interested to know if TP resolved the issue Cliff had.

 

[Rebel112r]

I tried the TP, 15 x 13. It was a struggle getting boat to plane. Would exceed 6200 RPM, almost like it was out of the water. Shipped it back for an exchange. Now am using the same as Cliff. WOT is 5300. I am not unhappy with it and also not in love with it. If they have something else to offer try it and let us know, they have a good exchange policy. Dan