Stop Hyper Ventilating

[Dheimbuch]

Boat: 89 Sanger TX , 21 foot closed bow ski boat ??
OMC 350 King Cobra
Recomended Max RPM is 4600 to 4800

Current Props
Michigan Match 14.5X19 Alluminum Cupped:
Max RPM about 4800 (In perfect conditions)
About 58 MPH
Hole shot is decent with 2 people (Pulling Skier)
Hole shot is Less than desirable with 4 to 6 people (Pulling Skier)
Prop Ventilates on mid to sharp turns (Trim does not make this better or worse)
Trim, Boat will porpoise when up and hold the bow low when down (Good Trim Levels)

Michigan Match 15X17 Alluminum Cupped: ??
Max RPM about 5000 to 5200 (In perfect conditions, this is a little high for the motor)
About 52 MPH
Gear Ratio ??
Hole shot is Great with 2 people (Pulling Skier)
Hole shot is descent with 4 to 5 people (Pulling Skier)
Prop Ventilates on mid to sharp turns (Trim does not make this better or worse)
Trim, Boat will porpoise when up and hold the bow low when down (Good Trim Levels)

What I need - More Hole shot Power then the 14.5X19 and Less Ventilation!
OR
What I need - Less RPM then the 15X17 and Less Ventilation!

I am not afraid of a Stainless Steel Prop, 4 blade, 3 Blade
Which props are best to stop Ventilation in Turns? - What other effects will this do to the Trim, RPM?
What will a small diameter prop accomplish of the same pitch?
Any Suggestions are appreciated

 

[Dheimbuch]

Re: Stop Hyper Ventilating


I am Thinking about trying the Solas HR Titan, 4-Blade. It has a High rake and extra cupping, Both these are suppose to help with Ventilating, but I am a little concerned the bow lift may make the boat porpoise! Does anyone have any comments about this selection of this prop!

 

[walleyehed]

Re: Stop Hyper Ventilating

If the 15X17 Aluminum makes it porpoise, you may get your best results with a TXP...an over-all lifter, and very fast...problem is...I don't think it comes as small as 19 pitch. A Turbo 1 may provide everything you're looking for....I've recommended it on several occasions with simular performance as yours, and has proven a good choice.
Dhadley may have some Ideas to add....he knows the entire line of Turbo (and several other brands) better than me...maybe we can get an Idea from him as well...

 

[Dhadley]

Re: Stop Hyper Ventilating

I'd be willing to bet that Sanger mounted the drive pretty high and that's not a bad thing. Good boat by the way!

There is a 19 Lightning that might work.

Is this a V bottom Sanger or the tunnel (Alley Cat bottom)?

 

[Dheimbuch]

Re: Stop Hyper Ventilating

I'd be willing to bet that Sanger mounted the drive pretty high and that's not a bad thing. Good boat by the way!

There is a 19 Lightning that might work.

Is this a V bottom Sanger or the tunnel (Alley Cat bottom)?

This is a V-Bottom Sanger! thankyou, I have never been in a boat with such a solid hull(And it is 17 years old!) - More more thing I noticed, it has 2 speedometer pickups, one on each side, When the back end starts to come around, would that possible be enough air to start the ventilating(they are original equipment)?

 

[walleyehed]

Re: Stop Hyper Ventilating

They should be no less than 14" from center, either side.