[August Rush]

Hello,

Since I am on the hard for the winter time to tune the props. The boat is a 1999 Tiara 40 Express with Cat 3208 TA 435 engines.

The current prop set up is 24” 3 Blade (I can not recall the pitch at the moment)., The boat is slightly over propped as I can barley hit the rated RPM. I was planning to take an inch of pinch out of the props.

I have a set of 22x24 4 blade props with medium cup. These were in the boat as spares and have not been used.

Aside from the rpm issue, the boat rides very bow high. This is a common complaint for the 40 Express. in part the engines are far aft, as they are v drives,. 

My question is about the benefits of a 4 blade set up vs 3. Assuming they are pitched correctly what changes in performance (positive or negative) could I expect going from the 3 blade to the 4? I was reading that more blades can create stern lift which might address some of the running attitude concerns. 

I am not concerned with WOT speeds. I am a coastal cruiser...