Underpropped or underpowered?

Discussion in 'Prop Shop' started by rashouri87, Jul 28, 2009.

  1. rashouri87

    rashouri87 I Love microskiff.com!

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    I have a 15'4" classic with 6hp suzuki. The prop says 200x190 on it. I guess 7 7/8 x 7.5 ?? Anyways, I can only ever get 11 mph, one or two people, no difference. Ive tried trim changes with no luck? Using a prop calc it says im getting 33% slip? could my prop just be bad?
     
  2. Brett

    Brett > PRO STAFF <

    Underpowered gets my vote... ;)

    But that's because I'm only running a 5 hp 4 stroke on a 16 foot boat.
    Top speed 12.6 mph with a flat bottom hull. Thats with a 9 inch pitch on the prop.

    You want speed? Get a bigger motor!  :cool:
     

  3. rashouri87

    rashouri87 I Love microskiff.com!

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    so you're going faster, with a smaller motor and a bigger boat?? ok, whats the secret, a flat bottom hull makes THAT much difference??

    I think I need a 9 pitch, my hole shot is fine, and I could sacrifice a little there.
     
  4. Brett

    Brett > PRO STAFF <

    Flat bottom hulls are just easier to plane. and the speed difference
    has to do with air bubbles trapped under the hull by the forward motion,
    that cuts down on friction caused by the wetted surface area of the hull.
    Also the hull is as balanced as it can be.
    I stand and control the tiller at the hulls center of gravity.
    And I've spent 6 months tweaking everything I can
    to get the last bit out of her. I'm so easily entertained.
    Anyone else would of just hung a 15 hp 2 smoke on her and been happy.

    [​IMG]
     
  5. noeettica

    noeettica Well-Known Member

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    Under Powered ...

    But Enjoy what 'ya got :)

    Dave
     
  6. rashouri87

    rashouri87 I Love microskiff.com!

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    can having some minor damage to the prop (knicks ect) make you slower?? I noticed that there are a few spots of damage to the prop and I'm wondering if I can't squeeze more juice with a new prop??
     
  7. firecat1981

    firecat1981 BBA Counselor

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    if its a highsider then 11 mph sounds about right, I have a 4hp and get about 9mph if I'm lucky. if its a classic then be thankful you can even get 11 mph out of it since a classic is rated for 25hp.
     
  8. TomFL

    TomFL Well-Known Member

    Under powered. I ran an 8hp 4-stroke on an LT 25 hull and I think with 2 people it did just about that, maybe a touch faster.

    So your speed sounds about right for the combination.

    If you're bored out of your skull at 11mph I wouldn't waste a dime on the prop. I'd save up for a 15-25hp motor.

    -T

    -T
     
  9. rashouri87

    rashouri87 I Love microskiff.com!

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    Well the problem isnt that I'm bored, I dont mind going slow. The issue is that I needed a motor to do at least two of these three things. ... go shallow, go fast, and cut light grass/weeds. Any two of those would work. Unfortunately, the motor I have does none of those things (well one, kinda). I hunt and fish in areas that have a 10 hp or less restriction as well. The hull is a Hi-Sider, so the hull has a 10 hp limit too. I dont mind going slow so long as I can pull through some weeds. I need to be able to motor into spots that are 2 ft or less, which the current motor can do (I need to be able to hop out in safe, shallow water without being up to my chest!!). I figure if i go fast, I could also cut through weeds fairly easily too.

    In conclusion, it seems I just have the wrong motor!!

    Would anyone be intrested in a trade for a Suzuki DT6 (great condition) for an older, running, well kept 9 or 9.9 hp two stroke?? ;D ;D
     
  10. mark_gardner

    mark_gardner I Love microskiff.com!

    i would find a good merc 15 hp 2 stroke and put a 9.9 sticker on it to satisfy your lakes size restriction, they are the same motor only different jetting or bigger carb (not sure which) but basically they are the same exact motor , that way you'll have a  little extra power if your hauling a slightly heavier load than normal plus if your good you'll be able to run wot in the straights  :)