View Full Version : Prop to pad height!
Tennesseejugger
03-30-2012, 02:39 PM
What is it for a 18' Hydra Sports with a rude 150, no jack plate?
Buccaneer
03-30-2012, 04:05 PM
Generally speaking, the sweet spot is going to be in the 3.5" propshaft below pad ballpark. Although I have 6" jackplate, on my Stratos 285 (18.5') with 150 it is at 3-3/8" below pad. Hopefully your bolt pattern will let you get near 3.5". Long term however you are better off with a 6" plate if you can find one used somewhere.
Lots of setup info here - http://www.bbcboards.net/zeroforum?id=11
Tennesseejugger
03-31-2012, 08:24 PM
Generally speaking, the sweet spot is going to be in the 3.5" propshaft below pad ballpark. Although I have 6" jackplate, on my Stratos 285 (18.5') with 150 it is at 3-3/8" below pad. Hopefully your bolt pattern will let you get near 3.5". Long term however you are better off with a 6" plate if you can find one used somewhere.
Lots of setup info here - http://www.bbcboards.net/zeroforum?id=11
Thnks Brother!
tkwalker
03-31-2012, 11:54 PM
TNJUG ......... I have never worked with Jack plates ...(but once and that was a customer of mine was sweet talked by a salesman at Bass Pro into one on a flat bottom Duck boat !! like he was going to run 50 MPH in 2 feet, stump infested water to get to his Duck blind in the dark !!) Forget about propshafts as a ref .. ... Prop Diameter changes the whole dynamics from measuring from the propshaft when you change props ... Think about it !! (but when dealing with a jack plate my method will reference the motor as well at the lowest position ... ).......By the way ... I hate whale tails (never found where they are beneficial, you have other problems. IE ... Prop, HP overload ...etc ) ... Anybody wants used whale tails at a cheap price $4 let me know i have a bucket full of them !!!
I have ran High performance bass boats power from 115 to 250 HP ... ... all my life .......... Here is the rule of thumb .......... Take a straight edge and tape it to the bottom of your pad ... (use a yard stick and Duct tape) ... If your motor uses a positioning rod ... Stick it in the second position from the bottom nearsest the transom ... ( this matches the 16 to 20 degree angle the boat transom was designed from the factory in the tucked position )
I checked out he above website ... Now measuring from a concret floor ??? http://www.bbcboards.net/zerothread?id=700838 Use the method below it works 100% of the time ..the reference is the boat pad and the Anti cavitation plate which was designed to control the action of the prop and boat at the water level on plane ...
Position the motor with the ANTI Cavitation plate (No it is not a cavitation plate !!) no more than 1/2 inch below the pad ( use ruler for reference) Go to the top of the yard stick for your measurement. YOUR ANTI CAVITATION PLATE IS THE REFERENCE .. NOT THE PROP SHAFT ... You can't run a prop any larger than what will fit between the propshaft and the anti cavitation plate ... Your trim will compensate from hole shot to blowout ... Blowout degrees depends on pitch and angle of trim ... Large pitched props will blow out easily with one of two things ... Not enough HP for the weight ratio or to much hull displacement causing a void in water entry during a hole shot ...
I have set tens of dozens of race and tourney boats up this way and it works ... I learned this from APBA pros in the 60's ... and it has never failed ... Hope this helps .. <'TK>< :)
Tennesseejugger
04-02-2012, 08:09 AM
TNJUG ......... I have never worked with Jack plates ...(but once and that was a customer of mine was sweet talked by a salesman at Bass Pro into one on a flat bottom Duck boat !! like he was going to run 50 MPH in 2 feet, stump infested water to get to his Duck blind in the dark !!) Forget about propshafts as a ref .. ... Prop Diameter changes the whole dynamics from measuring from the propshaft when you change props ... Think about it !! (but when dealing with a jack plate my method will reference the motor as well at the lowest position ... ).......By the way ... I hate whale tails (never found where they are beneficial, you have other problems. IE ... Prop, HP overload ...etc ) ... Anybody wants used whale tails at a cheap price $4 let me know i have a bucket full of them !!!
I have ran High performance bass boats power from 115 to 250 HP ... ... all my life .......... Here is the rule of thumb .......... Take a straight edge and tape it to the bottom of your pad ... (use a yard stick and Duct tape) ... If your motor uses a positioning rod ... Stick it in the second position from the bottom nearsest the transom ... ( this matches the 16 to 20 degree angle the boat transom was designed from the factory in the tucked position )
I checked out he above website ... Now measuring from a concret floor ??? http://www.bbcboards.net/zerothread?id=700838 Use the method below it works 100% of the time ..the reference is the boat pad and the Anti cavitation plate which was designed to control the action of the prop and boat at the water level on plane ...
Position the motor with the ANTI Cavitation plate (No it is not a cavitation plate !!) no more than 1/2 inch below the pad ( use ruler for reference) Go to the top of the yard stick for your measurement. YOUR ANTI CAVITATION PLATE IS THE REFERENCE .. NOT THE PROP SHAFT ... You can't run a prop any larger than what will fit between the propshaft and the anti cavitation plate ... Your trim will compensate from hole shot to blowout ... Blowout degrees depends on pitch and angle of trim ... Large pitched props will blow out easily with one of two things ... Not enough HP for the weight ratio or to much hull displacement causing a void in water entry during a hole shot ...
I have set tens of dozens of race and tourney boats up this way and it works ... I learned this from APBA pros in the 60's ... and it has never failed ... Hope this helps .. <'TK>< :)
This is really foreign to me LOL
tkwalker
04-02-2012, 10:45 AM
Drop by and I will show you how to do it ... Easy !! <'TK>< :)
Tennesseejugger
04-02-2012, 12:35 PM
Drop by and I will show you how to do it ... Easy !! <'TK>< :)Thanks!
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