4 Blade vs 3 Blade

[robinr]

Would like to get a few opinions based on some others past experience before I spend money on a new prop. I'm currently running a 12 pitch 4 blade pt prop with a little cup on a 40 merc w/60 carbs, Weldbuilt 1648VF with a tunnel. At wot I'm only running about 35 mph at 5500 rpm with a typical fishing load. Was wandering how much speed increase I should expect to see with a 3 blade. Any suggestions on what 3 blade would work best in this application. I was thinking about the Powertech SCB3.

[Pole_benda]

Call power tech and talk with Marcus. Hes very knowledgeable and knows his stuff.

4 blade is to help you jump up and plane faster but you sacrifice top end speed, 3 blade is more for speed but lack the ability to jump up in skinny water. If you do switch props you'll probably gain a few mph, but nothing crazy

[southern151]

My 40, on a heavy boat, with two men, a gun dog and decoys does 34 on gps. Not sure about rpm though.

Oh yeah, 3 blade prop.

Montauk may be able to help more here...

[davidkyle323]

I Have a 16-42 south fork tunnel with same motor and carbs I run a SWC4 power tech 12 pitch and run about 35 but this prop is built for the marsh not speed it comes with cup from the factory. I also have a SCB3 powertech in 13 pitch with heavy cup it runs about 38 but it does not have near the hole shot the 4 blade has and weight in the boat affects it a lot more than the 4. If it had less cup u could prolly get close to 40 but would have blow out problems taking off and turning, not to mention what tunnels are designed for, taking off in the mud.