OPA P class boats???
01-17-2006, 09:05 AM
#21
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Re: OPA P class boats???
Originally Posted by TYPHOON
Prop slip is SO hard to get right. Like some of you have said with 3-6 blades its all over the lot. The other problem is X dimension of the drive height. With those 2 variables and all the combinations they have you would have to be a rocket scientists and you would still be guessing. Back to the original problem, its a good starting point until we can build a better mouse trap!
Here is an example.
Say I have a 28' Pantera (heavy conventional vee), the horsepower and speed get me into the 70-80 MPH range. I want run P4. OPA dictates that ALL single engine deep vee hulls will use a 18% slip number in determining the max speed. I have some choices, I can run a 26" at 5900 with a slip% of 18, puts me at 79.4 mph.
Or I can run a 28" prop with a 5500 rev limiting chip to achieve the same speed. Just that the prop calc must not exceed the max speed of your bracket. You can run whatever style prop you want, it will be stamped with a pitch #, that is what will be used. raised x, lighter layup, more streamlined topsides all contribute to having a more efficient boat. Your ACTUAL prop slip numbers may be lower than what OPA says that hull style should be, but that is why we tweak our boats and try to get them to go faster. The teams that spend the time dialing in the boat and props should prevail over the guy who just trows the cooler and water ski's out and goes racing. And it will still be close!!
Last edited by JohnS; 01-17-2006 at 09:09 AM.
01-17-2006, 09:21 AM
#23
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Re: OPA P class boats???
Bruce,
I don't, but the Manta is a close cousin to it. I'm only using the Pantera because I know the slip calcs for it, and it is a conventional deep vee. These hulls make up the majority of the P classes.
Are you bringin' the ol' girl out next season to run some P class?
I don't, but the Manta is a close cousin to it. I'm only using the Pantera because I know the slip calcs for it, and it is a conventional deep vee. These hulls make up the majority of the P classes.
Are you bringin' the ol' girl out next season to run some P class?
01-17-2006, 09:23 AM
#24
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Re: OPA P class boats???
I would take the 5900 RPM ALL DAY LONG. Woulnt you?
01-17-2006, 09:24 AM
#25
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Re: OPA P class boats???
Is there a P5 class rep?
01-17-2006, 09:25 AM
#26
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Re: OPA P class boats???
Originally Posted by JohnS
Bruce,
I don't, but the Manta is a close cousin to it. I'm only using the Pantera because I know the slip calcs for it, and it is a conventional deep vee. These hulls make up the majority of the P classes.
Are you bringin' the ol' girl out next season to run some P class?
I don't, but the Manta is a close cousin to it. I'm only using the Pantera because I know the slip calcs for it, and it is a conventional deep vee. These hulls make up the majority of the P classes.
Are you bringin' the ol' girl out next season to run some P class?
yes...looks like I will be runnin the Pantera again. just to keep it fair, we will be in P-2 this year
01-17-2006, 09:32 AM
#28
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Re: OPA P class boats???
Originally Posted by harry turner
Well Talke About Beating A Dead Dog I Looks To Me P5 P4 Are Where The Problem Lies I'm Building A New Boat I'm Building It For A Certain Class And It Will Pass Any Test You Want To Give It Again I Don't Think Avg Speed Is The Way To Go If You Look At Last Years Races P1 P2 P3 Nobody Brock Out I Only Hope We Can Get Things Fixed Now No At The Race Site
Harry
Harry
It's great to see you coming back out. Another "Obsession" boat? Outerlimits or something else?
See ya soon,
Ron
01-17-2006, 09:53 AM
#30
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Re: OPA P class boats???
Who is planning in running P4 in OPA this year, my boat can do an honest 80 mph....with my na motor not the blower motor. I couldnt run with my blower motor that would put me in P1 at 100 +.
