3 Or 4 Blade Prop?

[spongy]

Hey all,

Im looking at getting a new prop for my Yamaha 70HP 2-Stroke.

Originally it had a 13 1/4" 17Pitch Alloy 3 Blade, which I replaced about 2 years ago with a 15Pitch Solas 3 blade Alloy Prop.

The Difference that I noticed was slightly lower top end speed (dont really care) but better acceleration and easier to get on the plane.

Now Im looking at improving fuel economy without loosing the easier planing ability.

Do you think a 4 blade 15Pitch stainless steel solution would work? Im hoping to get lower RPM at planing speeds, but still have the power to accelerate out of the hole quickly. How much of an difference will it make?

Thanks,

Jeff

[spongy]

BUMP

Anyone????

Hey all,

Im looking at getting a new prop for my Yamaha 70HP 2-Stroke.

Originally it had a 13 1/4" 17Pitch Alloy 3 Blade, which I replaced about 2 years ago with a 15Pitch Solas 3 blade Alloy Prop.

The Difference that I noticed was slightly lower top end speed (dont really care) but better acceleration and easier to get on the plane.

Now Im looking at improving fuel economy without loosing the easier planing ability.

Do you think a 4 blade 15Pitch stainless steel solution would work? Im hoping to get lower RPM at planing speeds, but still have the power to accelerate out of the hole quickly. How much of an difference will it make?

Thanks,

Jeff

[a boat]

Hi Jeff, all hull and engine combinations are different and react differently so impossible to say what will happen without trying a prop. I have never seen a 4 blade SST prop to suit your HP engine and even if one is available I doubt you would have the torque to turn it from a relativily small cc engine.

That said let us know what your WOT RPM is with the current alloy prop and we can go from there. SST props can turn a few more RPM and can run higher on the transom so if you revs are good with the 15 inch alloy prop then a non swept design 17 inch SST prop would be worth a try. Important part with any brand or technology of outboard is that the WOT RPM are good with your average load-your engine wants to be seeing about 5500 at WOT trimmed correctly and before you go playing with props it is easier to make sure the engine height is right because if the outboard is too low in the water that will rob RPM and speed.

Cheers,

Huey.