94 jones brothers needs more speed

Discussion in 'Outboards' started by Josh Hudgens, Nov 2, 2018.

  1. Josh Hudgens
    Joined: Nov 2018
    Posts: 3
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    Location: North Carolina

    Josh Hudgens New Member

    I currently am running a 2018 70 hp Suzuki on my 19.8 ft jones brothers flat bottom skiff but I’m just not getting enough speed at around 37 mph. I wanted to upgrade to a 115 but was told because of my boat being a flat bottom the 115 would actually create more drag and not make it faster at all.. something about it being a flat bottom doesn’t lift the boat out of the water properly to make it be able to go faster. The engine is only 60 pounds more and I planned on putting it on a jack plate to help the transom. Any insight on putting the 115 making it faster?
     
  2. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    The 70 Suzuki has a decent gear reduction from memory, and isn't intended for speed fireworks. 37 mph sounds pretty respectable, but running at full throttle isn't smart for engine life or fuel economy, the odds are 115 will go faster with the right prop, but if you are going to floor that, the fuel economy is going to be worse. But you'd probably get a faster cruise speed with similar fuel usage.
     
  3. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Adding 45 horsepower and propping it correctly will most definitely make your boat faster, but I’m not sure the flat bottomed hull will be stable at speeds much above what you’re already achieving.
     
  4. Josh Hudgens
    Joined: Nov 2018
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    Location: North Carolina

    Josh Hudgens New Member

    The only reason for reaching maximum speed is gettin over shallow areas around my area and of course getting to the hole first. But thanks for your reply I just wasn’t sure about the whole science of the thing
     
  5. Barry
    Joined: Mar 2002
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    Barry Senior Member

    This is incorrect. Most drag boats are flat bottom because the provide more lift at the same speed for the same chine width. (generally but practically)
    Google Flat bottom drag boats for info

    What creates more drag is the increase of speed at which the boat moves and hence the need for more horsepower to overcome the increased drag. But this drag is mainly hydrodynamic not because
    hang a bigger motor off it ( splitting hairs, certainly the skeg of a bigger outboard compared to a smaller horsepower will add Some extra drag)

    This ignores stability etc, but more hp means more speed for what you have in mind. Then the corollary of that is that you should then get rid of the 115 and buy a 90 because the 115 is slowing you down???
     
  6. Josh Hudgens
    Joined: Nov 2018
    Posts: 3
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    Location: North Carolina

    Josh Hudgens New Member

    So you are saying a 90 would make me go faster than a 115?
     

  7. Barry
    Joined: Mar 2002
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    Barry Senior Member

    of course not, I highlighted your comment that someone told you that if you added horsepower that you would not go any faster than with your 70

    So my comment " Then the corollary of that is that you should then get rid of the 115 and buy a 90 because the 115 would not increase the speed???"

    Corollary "proposition that follows from (and is often appended to) one already proved.
     
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