Update:Prop for Yam F115 FS, on Key West 196BR

[mandopickr]

I looking to replace my current 3-blade prop with a 4 blade to improve stern lift, and mid range cruising. I am not concerned about top end. 5 mph cross wind, 1 person with 1/2 tank fuel.
Data: (rpm, gps speed)
3500 17.5
4000 21.5
4500 26.5
5000 31.5
5500 35.0
5800 37.5 wot

Currently using Yamaha 16-k (13.5x16). Considering two:
Amitas al 13x15 or Solas HR Titan 13.25x15. Would like to maintain 5800 rpm at a minimum. Max rpm is 6000.

Thoughts, recommendation.

 

[mandopickr]

Re: Prop for Yam F115 FS, on KW 196BR

Re: Prop for Yam F115 FS, on KW 196BR

As an update, I purchased a Solas 4 blade al prop, 13X15.
Compared to my Yamaha 16-K (13.5x16), these are the numbers:

prop---------16-k----------- solas
3500---------17.5-----------15.0 not on plane
3800--------------on plane
4000---------21.5------------20.00
4500---------26.5------------25.5
5000---------31.5------------29.0
5500---------35.0------------32.6
wot---5800---37.5---5900----34.4

I only saw improved stern lift above 5000 rpms. At 5500, the attitude of the boat was much improved. However, this was not what I was trying to improve.
Motor height appeared pretty near perfect, based on cavitation plate.
The boat did respond to trim better with the 4 blade, and low speed maneuverability was improved. It did everything, except what I was looking for (which was to improve mid-range cruising and stern height).

Now I'm not sure if I can do what I want with the prop. May have to go to trim tabs, though clearance of the swimming platform may be an issue.