Surface piercing prop help!

[tyst67]

How does that semicleaver do on it?

It is about the same!!! They are both good working props but my motor was too high! I cut my transom down 2 inches and gained 1 mph! I think I have to drop it farther!!! I am still 50mm above where I run last year an still 2 mph slower!

[omcstratos]

I've kept up with a boat on screamandfly thats a 13ft tunnel with a yamaha v4. He runs et props because his motor height is too high for a cleaver to grip.

Can you squeeze a bigger diameter prop on?

[ice_spy]

On a tunnel, a surface drive prop should be level with the bottom of the tunnel plank. Remember the more set back the more you have to raise the engine as the water rises the further back your motor is from the transome. Ideally, an adjustable motor jack plate that also gives you set back is the best way to adjust engine height with different props. Choppers are surface drive props. 18 p would be far too much pitch to drive submerged for a 30hp. Also these props are designed to run out of the water not under. Tip cup will reduce some prop slip. You are probably running the prop too low, is venting the prop under the water and you are just getting a lot of slip. You need to 'free' the prop and gearbox to unleash the surface drive props potential.