docricky

I'm trying to find comparitive tests for props, I have a 30ft Campion chase twin 496 HO's running 23p Rev 4 WOT 5000 rpm. want to switch to 25 p, The Rev 4 is a stern lift prop could use some more stern lift . How does hydromotive quad and Maximus compare.


Any Ideas?

Rick

Pat McPherson

Both will give more stern lift but you will likely loose speed on top.
Ask over on Prop Talk...

throttleup

Your rpm is right where you want it. Why do you want to go to a higher pitch?

What is your top speed at wide open throttle? Do you have some complaints about the performance of the boat? Does it feel as if the bow is too heavy, or light?

Matt

docricky

Hi Matt

Speed WOT is 80mph gps, concern is bow feels to light handles rough water much better with 2 heavy adults in V berth Anything up to 60mph I need to keep trim right down and sometimes use K planes with passengers in the back. Not worried about top end want to improve midrange performance and economy, and get more pressure on bow.

Regards

Rick

Revelocity

Your hull is very similar to the Velocity 320 and the handling characterisitics sound similar indeed. The 320 runs a 26" or 27" Hydro 4 blade with the same power. The Hydro works great on the hull. Good luck.

jpclear

Um, just what gear ratio drive are you running? Cause if it is a Bravo with standard 1.5 to 1, there is something funny going on here. It is mathematically impossible to achieve 80 MPH with a 23" prop driven by an engine turning 5000 RPM through a 1.5 to 1 reduction drive. Zero slip (or 100% efficiency) would yield 73 MPH and that too is impossible. --- Jer

Payton

I believe the 80 mph. I have a friend with the same boat with 24" Bravos and 330hp 454s. He tops out at 70. His boat doen not handle rough water like a true deep V though. I think it's a 23* hull.

Outdrive1

Even with a 1.36 drive you would need 0% slip to get those speeds. If you could run that effecient (and you can't) that would be a set-up that I wouldn't mess with. Change your gps from KPH to MPH or buy one that works.
As far as prop the Hydro has ton of stern lift.

jpclear

Thanks BADK--. At least someone here knows what I'm talking about. And Payton's friend's #'s could just possibly be believable, cause 24" of pitch is not 23", and 70 MPH is not 80 MPH. But that would still only be about 8% slip which is usually only found with very light, hi-perf cats. Any recreational "V" hull that can achieve 11% slip or less is running VERY efficiently. I think the REAL experts at Throttle-Up will back me up on this. --- Jer

Payton

My point was that with a 23*V and and a very light hull. 200 more HP could equal 10mph. I think he has more pitch on his prop now. The bow feels light because it is light. He's running like a bass boat.