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  1. #1
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    hub diameter question

    Would there be a difference in performance between a 14 3/4" hub and a 15 1/8" hub?

  2. Moderator 21XDC's Avatar
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    #2
    Quote Originally Posted by Rustyjigz View Post
    Would there be a difference in performance between a 14 3/4" hub and a 15 1/8" hub?
    Looks like you are talking about prop diameter, Not hub/barrel diameter.

    No positive answer can be told about your question.

    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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    #3
    If you are still running a Bullet you might ask the question using prop instead of hub diameter on the Bullet Forum.

    Better chance of getting help there.

    If you are running 87 you are doing well.

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    #4
    Yes I'm pretty sure Mike couldn't help him with a Bullet problem.

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    #5
    Here is what I want to know, if I have a 14 3/4 X 22 turbo fxp prop and an getting 6000 rpms and 56mph, will I gain more speed with a 15 1/18 X 22 prop?

    Does the extra 3/8 inch give me that extra surface to gain speed?

  6. Moderator 21XDC's Avatar
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    #6
    Diameter can actually slow you down on top end... More rotating mass and drag. You want a prop that transfers HP to the water efficiently with the correct lift for your hull and load. There is no answer to this question. 14 3/4 diameter is generally plenty of diameter if there is enough blade area, cup, pitch, rake for most bassboats from 150-300 HP.

    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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    #7
    How did skeeter get 59.7 mph at 6000rpms with 2 people in a zx 190 w 150 vmax sho with 15 1/8 X 22 pitch sho prop loaded with fuel and full tanks.

    I am in the same exact rig and engine with a 14 3/4 X 22 pitch FXP prop alone and only getting 5900 rpms (can get 6000 trimmed out) and getting 54-55 mph

    The cavitation plate was set at 5 1/8" above bottom just like the performance bulletin.

    This is why I ask if 3/8" makes the difference, because that's the only thing I can think of.

  8. Moderator 21XDC's Avatar
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    #8
    I have said this a million times and I'll say it again.....

    10 exact model boats can run 3 mph different in speed
    10 exact model outboards can run 3 mph different in speed
    10 exact model propellers can run 3 mph different in speed

    So..... There can be up to 9 mph difference between the same exact looking rigs.... I have seen this time and time again. Just because someone else's rig does something, Has no bearing if your boat has the same potential.

    Check to make sure you are getting full pull on the throttle linkage, lighten up the load in the bow of the boat, raise the motor on the jackplate to the sweet spot with safe water pressure, have the prop checked for flaws B&BP possibly,

    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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    #9
    Ok thank you will do all these things

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    #10
    Quote Originally Posted by Rustyjigz View Post
    How did skeeter get 59.7 mph at 6000rpms with 2 people in a zx 190 w 150 vmax sho with 15 1/8 X 22 pitch sho prop loaded with fuel and full tanks.

    I am in the same exact rig and engine with a 14 3/4 X 22 pitch FXP prop alone and only getting 5900 rpms (can get 6000 trimmed out) and getting 54-55 mph

    The cavitation plate was set at 5 1/8" above bottom just like the performance bulletin.

    This is why I ask if 3/8" makes the difference, because that's the only thing I can think of.
    Most manufactures run those boats on good air days with lightweight riders, the fuel indicated and the minimum required safety equipment.
    No trolling motor, batteries, fishing gear, electronics, bone dry livewell, etc. Not even an emergency roll of toilet paper.
    If it isn’t listed, then it’s not on the boat.
    Its how the game is played.
    You Don't Know what you Don't Know until you Know.

    1984 Champion 201/Yamaha 175
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  11. Member lpugh's Avatar
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    #11
    Quote Originally Posted by Rustyjigz View Post
    How did skeeter get 59.7 mph at 6000rpms with 2 people in a zx 190 w 150 vmax sho with 15 1/8 X 22 pitch sho prop loaded with fuel and full tanks.

    I am in the same exact rig and engine with a 14 3/4 X 22 pitch FXP prop alone and only getting 5900 rpms (can get 6000 trimmed out) and getting 54-55 mph

    The cavitation plate was set at 5 1/8" above bottom just like the performance bulletin.

    This is why I ask if 3/8" makes the difference, because that's the only thing I can think of.
    Very unlikely they didn't as that would be 4% prop slip with a 2.0 gear case, does not compute, maybe with a taller gear set under perfect conditions and a very light load going down stream with a tail wind
    Your numbers are far more realistic at about 12% slip, If you can tweak the setup and get the prop perfect you may be able to reduce slip down to 9 or 10% yielding a couple more mph. I am not at all confident that can be achieved with a average load
    Last edited by lpugh; 07-15-2019 at 09:37 PM.
    Thank You Leon Pugh

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    #12
    Thank you guys for all this info! I hope I can help one day...

  13. Member lpugh's Avatar
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    #13
    21XDC
    Provided the best answer you could get do to the many variables
    Thank You Leon Pugh