Hydro sponson dancing and turn fin angles

[drumzzzzz]

does anyone know if the angled leading edge on turn fins is what causes the dance between sponsons on typical hydros? If the counter rotating prop torque is driving the right sponson into the water while the turn fin is acting like an inclined plane is trying to lift it out, causing the motion to oscillate back and forth?

 

[carlnoki]

what boat you talking about?

Carl

 

[drumzzzzz]

most any 3 point hydro with a turn fin - doesn't seem to happen as much with outriggers as full bodied hydros though - wondering if it's caused more by aerodynamics?

 

[Tom Foley]

does anyone know if the angled leading edge on turn fins is what causes the dance between sponsons on typical hydros? If the counter rotating prop torque is driving the right sponson into the water while the turn fin is acting like an inclined plane is trying to lift it out, causing the motion to oscillate back and forth?

Thats not causing it , drop your strut a 1/4 " and observe .

 

[drumzzzzz]

Ahhh so it's the angle of attack? that makes sense - the more agressive the more the bounce.