3 Blade vs 4 blade props

[mkuehnl]

I have a 350 Mag tournament ski, inboard, ( Sea Ray - Spitfire) and I am considering changing the prop from a 13 pitch 3 blade to a 4 blade. What do I need to consider, regarding pitch, when I go from 3 to 4 blades?

[Elk Chaser]

DETERMINING THE CORRECT PITCH:Adding 1 inch of propeller pitch will reduce wide open throttle rpm by 150 to 200. Subtracting 1 inch of propeller pitch will increase wide open throttle rpm by 150 to 200. If you are upgrading from a three blade to a four blade propeller, remember that a four blade propeller generally uses up to 50 to 100 rpm more than a three blade prop with the same pitch. 4-BLADE PROPELLER FACTS:Plane the boat faster than 3-blade propellers Keep the boat on plane at a lower speed Give improved mid-range speed at the same rpm as a 3-blade propeller Provide quicker acceleration than most 3-blade propellers Run smoother than 3-blade propellers Have better holding power in rough conditions are less likely to ventilate in sharp turns provide better low speed handling

[kopy kat]

Better yet-look at Mercury's Stainless Steel High Five 5-blade. My 21ft SeaRay comes out of the hole real nice and smooth.

[mkuehnl]

Graet advice - does that hold true for inboards(Ski boat) as well?

[tommays]

we have a correct craft and it is so compleaty different than and i/o boat because of the center mount engine and hull design thay really go through the water rather than rise up on plane to keep the correct ski wake i would talk to a prop shop that works on ski boats or people in the water ski comunitytommays