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  1. #1
    Member Largemouthlou's Avatar
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    Prop Slip Calculator

    I know some of you guys already use this one, but for those that don't plug in your #ers!!

    http://www.go-fast.com/Prop_Slip_Calculator.htm

    Louis

  2. Moderator LarryP's Avatar
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    #2

    Re: Prop Slip Calculator (Largemouthlou)

    Lou,
    When I put the information in this I do not get answers? should the gears be put in as 1:62 or 1/62 or something else?

    Rest in Peace Buddy Poche - Bayou Bullet.
    I will miss you my dear friend.

  3. Member Largemouthlou's Avatar
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    #3

    Re: Prop Slip Calculator (pijman)

    1.62 is what you should put.... If it still don't work post all the info and I will run it for ya.. Louis

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    #4

    Re: Prop Slip Calculator (Largemouthlou)

    So how do I fix 13% slip?
    2.07 gears 23p prop 4800rpm I get 48GPS.

  5. Member Largemouthlou's Avatar
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    #5

    Re: Prop Slip Calculator (j10b)

    John, what boat and motor ya runnin?? Also water Pressure at WOT?? Louis

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    #6

    Re: Prop Slip Calculator (Largemouthlou)

    700lx 120 12psi 90-100+ temps.

  7. Member Largemouthlou's Avatar
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    #7

    Re: Prop Slip Calculator (j10b)

    John, Need a little more help with boat brand and make of motor.. Is it a 2.5 or 3 liter?? Water pressure might be a touch low and depending on boat type and weight you might be close to where you should be with the 13% slip.. Might want to try and drop the motor 1/4 for a little better prop bite or get a little cupping added, just a touch for better prop bite = less slip... Louis

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    #8

    Re: Prop Slip Calculator (Largemouthlou)

    Louis, I,m running a 202 blazer with a 300hpdi, 29p/prop at 5800/ 85mph with approx 15% slipage! what do ya think? AL, told me to ask one of you bullet guy's about sanding the pad and approx how much would it help if any? oh the h2o pressure is 21psi!

  9. Member Largemouthlou's Avatar
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    #9

    Re: Prop Slip Calculator (Porkfrog)

    Try picking the motor up a 1/4" and watch water pressure, no less then 15# to be safe.. Move all weight to back and be sure boat is level(balanced) from side to side.. Trim up in small bumps till ya stop gaining speed or lose speed, tap it down a bump and this will be your best trim position for the load you are carring that day.. The higher you can raise the motor the less trim you should need.. Also might need a little more cup for the prop to bight a little better.... Let me know if any of this helps or if you have any ? on it!! Louis

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    #10

    Re: Prop Slip Calculator (j10b)

    unless I read something wrong your slip is 6%, not 13%. your theoretical speed would only be 51 mph. sounds like a Force 120 & if it is you're lugging that motor a bit.


    1997 Astro 1700 W/ Merc 125

  11. Moderator 21XDC's Avatar
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    #11

    Re: Prop Slip Calculator (Astro1700)

    Did you add 1 inch of pitch for cupping? Read how it works first.

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

  12. Member Largemouthlou's Avatar
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    #12

    Re: Prop Slip Calculator (j10b)

    <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by j10b &raquo;</TD></TR><TR><TD CLASS="quote">So how do I fix 13% slip?
    2.07 gears 23p prop 4800rpm I get 48GPS.</TD></TR></TABLE>

    Mike he is right, useing these #ers it is 6% slip, no cupping was mentioned, but adding one pitch for cupping would only pick it up to 9% slip Louis

  13. Moderator 21XDC's Avatar
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    #13

    Re: Prop Slip Calculator (Largemouthlou)

    2.07 gears?

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

  14. Member Largemouthlou's Avatar
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    #14

    Re: Prop Slip Calculator (21XDC)

    Can't say as I heard of them before, but it's his boat he should know!! Louis

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    #15

    Re: Prop Slip Calculator (Largemouthlou)

    Sorry to invade your space, but I have a question about prop slip. I have a 202 Champion with a 250XB, 27 trophy, I think it is a 1.87 gear, at 5800 rpm I run 82 mph and that comes up to a -4% slip. What does this mean and what kind of numbers am I looking for?
    matt m



    Matt Miller Central SC
    1996 202 CHAMPION
    2000 250 MERC XB

  16. Moderator 21XDC's Avatar
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    #16

    Re: Prop Slip Calculator (202champ)

    The 250 XB has 1.75 gears. 82 may be possible if you could turn that prop to 6000.

    Your not doing the calc right . Read &gt;&gt;&gt; http://go-fast.com/prop_slip.htm

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

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    #17

    Re: Prop Slip Calculator (21XDC)

    I did it again at 1.75 gear and, assuming that my tach is off 100 rpm, put it at 5900, prop is a b&b by Mark 27 trophy, speed at 82 on gps. It says my theoretical speed is 86 and I have 5% slip. Is this good or bad? What percentage am I looking for?



    Matt Miller Central SC
    1996 202 CHAMPION
    2000 250 MERC XB

  18. Moderator 21XDC's Avatar
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    #18

    Re: Prop Slip Calculator (202champ)

    You still did not read the link I posted. Did you add 1 inch of pitch for cupping? I'd try another gps...

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

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    #19

    Re: Prop Slip Calculator (21XDC)

    I did read the link, putting 28 instead of 27, the speed is from a handheld AND a LMS480, with about 27 gallons of gas and all of my gear, sooo, the speed is actually a little slow at 8%, since the link said the fastest speed possible, if I assume that I gain 2 mph by emptying my boat, it comes up 6%. You still have not said what kind of numbers that I am looking for.



    Matt Miller Central SC
    1996 202 CHAMPION
    2000 250 MERC XB

  20. Moderator 21XDC's Avatar
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    #20

    Re: Prop Slip Calculator (202champ)

    Lets just say... A Bullet will run close to 10% ... 6% is not acheivable in your rig. If your speed goes up, so does your rpms. Anything in the 11-13% would be more like your goal.

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

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