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  1. #1
    Join Date
    Nov 2005
    Location
    Des Moines, Iowa
    Posts
    77

    Default Prop for barefooting

    I have the original 13x13 3 blade OJ prop on a 2007 Outback. RPM's are 200 higher than mph for barefooting speeds of 38 mph (4000 rpms to 38 mph and broader range at 43 mph for 1 foots). On my 05 Malibu it's rpms are same as mph with the 13x13 prop. So 38 mph is 3800 rpms. The Moomba sounds like it's screaming at 38 to 43 mph. Any recommendations on different prop for barefooting? There is no nicks in the prop and it has been like this since the boat was purchased new.

    Thanks.

  2. #2
    Join Date
    Jan 2008
    Location
    Pensacola, FL
    Posts
    1,585

    Default

    It's pretty common for the OB to be 2 mph off of RPM, that is the way my boat is also. You should call Acme or OJ for a recommendation for a prop.
    1997 MasterCraft 205

    2008 Moomba Outback
    1999 MasterCraft Sportstar OB
    1992 MasterCraft 205
    1999 Malibu Response LX
    1987 Marlin Magnum Skier

  3. #3
    Join Date
    Feb 2009
    Posts
    442

    Default

    I would recommend calling the prop people for the best answer.

    I do know that as far as prop solection that at wide open throttle you want to be at the very top of the rpm range. This way you are using the most of you engine. The steeper the pitch the more load you create on the engine. If the engine can turn the steeper pitch the faster you will go. If the engine can't turn it to the top rpm you will be going slower you go (as compared to the prop with less pitch). I hope you follow what i'm trying to say.

    I have an 03 OB with the 320 hp engine. I run 4600 rpm with the OJ legend 13x13 3 blade prop. I don't know what speed it is. I never figured it out as i know the speedos are off.
    2003 Outback, Assault EFI, (6) Polk Audio DB651s, JL Audio M6600 amp, JL Audio M1700 amp, JL Audio 10w6v2 subwoofer

  4. #4
    Join Date
    Nov 2005
    Location
    Des Moines, Iowa
    Posts
    77

    Default

    I use a GPS twice a year to adjust the mph on the speedos. It's different in cold water than warm water. About a mile and a half to 2 miles off from 30's degree water to 70 degree. And if you didn't catch it, we barefoot ski until the lakes freezes over. Last year we skied when only a 1/2 mile stretch was not iced over (out of 7 miles of lake).

  5. #5
    Join Date
    Apr 2009
    Location
    Coventry, CT
    Posts
    95

    Default

    Quote Originally Posted by barefooterh2o View Post
    I use a GPS twice a year to adjust the mph on the speedos. It's different in cold water than warm water. About a mile and a half to 2 miles off from 30's degree water to 70 degree. And if you didn't catch it, we barefoot ski until the lakes freezes over. Last year we skied when only a 1/2 mile stretch was not iced over (out of 7 miles of lake).
    THATS JUST CRAZY!!! Good for you. I don't think you'll see me out there.

  6. #6
    Join Date
    Oct 2008
    Location
    N.E. Minneapolis
    Posts
    210

    Default

    Not sure but I think the Bu has a little less wetted surface area which is likely why you are seeing the difference in rpm/speed. Give the boys at Acme a call, I know most of the three event clubs around here running MC's with a 310 or 350 hp engine and 1:1 are running the 13x12 Acme with 0.08 cup, not sure if thats what the footers are running or not.

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