Prop Torque Rolling Ship

Discussion in 'Propulsion' started by Beaver, Sep 4, 2015.

  1. Beaver

    Beaver 2020 Rookie of the Year Admiral (Supporter)

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    I'm looking for a solution to the way my cruiser heels while running. When she is trim and level while still, but when I give her full throttle, she heels about 10 to 15 degrees. I'm guessing this is from the amounts of torque it takes to drive a 1 3\4 in prop. It isn't all that bad when running straight, but when you turn it's decks awash. Any ideas as to what I can do to reduce this?

    Thanks,
    Caleb
     
  2. SteveT44

    SteveT44 Well-Known Member

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    Tighter deck seal! ;)

    As you surmise, the torque from that single large prop is twisting the hull in the opposite direction. A smaller prop would reduce the roll.
     
  3. Beaver

    Beaver 2020 Rookie of the Year Admiral (Supporter)

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    Deck seals is the next thing on the list then.
    I'm thinking of making a 1 1\2in prop to see what the difference is between them. The 1 3\4 prop is a bit excessive. I think a smaller propeller might actually be more efficient. I will have to see.
     
  4. Iunnrais

    Iunnrais Active Member

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    1.5 will work fine on a Suffern (did on my FS Dupleix back in the day). You'll still get some torque roll. Bilge keeps will help some but mostly you just learn to deal with it (can be helpful at times to use the torque to roll the ship as someone fires sterns at you...). Worst was when I was trying a big motor direct drive. The entire drive system torqued the ship. Going back to gears helped some as the motor torque somewhat offset the prop torque.
     
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  5. Beaver

    Beaver 2020 Rookie of the Year Admiral (Supporter)

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    Thanks for the insight, Iunnais. I went out to the shop and built a 1.5 in prop to see what kind of difference it makes.
     
  6. froggyfrenchman

    froggyfrenchman Well-Known Member

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    I didn't see this thread earlier. I posted something in your Suffren build thread about it though.
    Mikey