Props

[Mr-DIY]

Hey Ya'll,

Whats better 2 blade or 3 blade?

I have a 15t double motor, but my prop can only be bout 35mm(1.5inch) max in diameter.

Cheers all

[MikDee]

Normally a 2blade prop, unless it's a heavy boat.

[Floater]

Was looking around for a min on internet and found this info on props for real boats, maybe it'll help you some.

Number of Blades

Propeller blade count is a compromise. Increasing the number of blades will reduce vibration and improve the "holding" of the propeller, but the increased drag will reduce top-end performance. Although lowest horsepower outboards frequently have 2-blade propellers, for most marine engines a 3-blade propeller will deliver the best overall performance. The 4-blades are used when (1) additional "bow lift" is needed to reduce hull drag, (2) there's a problem with ventilating - see below - or (3) the engine is primarily used for towing.

From what i've heard and read on msg board 2 blade is way to go unless you need some extra lift to get the bow up.

[Hydro Junkie]

I think the biggest question is how much work do you want to do to balance your props? While the 3 blade has 1/3 more thrust and less vibration, they are considerably harder to balance than a 2 blade. In your case, having limited room, a 3 blade might be a viable option. You might also look at using different pitches on a 2 blade. If you are using a 400 or 1400 series Octura, you might want to look into a 500, 600, 1500 or 1600 series prop. The hub is longer on these than the 400/1400 series, but you may get more speed with the higher pitches. These also take more torque to turn, so it might cost you some run time. Just something else to consider :)