16' Playtime Bowrider Leaning to left under power

Discussion in 'Stability' started by PlayTime, Jul 6, 2009.

  1. PlayTime
    Joined: Jul 2009
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    Location: Virginia

    PlayTime New Member

    I got a Playtime 1600 Bowrider and fixed it up and put a newer 90 hp outboard on. I took it out this weekend for the first time, it ran great except two things.

    First was that after planing the boat would lean to the left side even when heading in a straight path. I have read a lot of articles already, the weight distribution was one piece that came up a lot, but I noticed this everytime I took it out over the weekend. I find this hard to be the issue because most of those times it was just me and my girlfriend, I weight about 185 and she is about 105, then there is the gas can which is on the right side of the boat, the battery is mounted centerline, the anchor is stored on the right side. All signs of weight tell me the boat should lean to the right, not the left.

    Second when in reverse there was a little smoke that came out of the exhaust hole. The only times I went in reverse was out of the dock which was near a busy part so the water was a little rougher there than in other places of the lake, not sure if that was causing water go get into the exhaust.

    Other than those issues, the boat ran GREAT, it planed quickly and cruised at good speeds. I have read some articles that may suggest that the motor is mounted too low. Are there any thoughts as to what could be causing this and how to fix it?
     
  2. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    Its only prop torque that is makeing it lean ..prop rotates to the right so the boat leans left ..put the battery on the rhs ...you can sit a bit to the right but if the layout does not suit then a trim tab on the transom left side will put it flat .....Cavitation plate on the motor should be level with the bottom of the hull unless its on a pod when it should be lifted 2 inches for every 6 inches of pod length ..forget the smoke go forwards !!
     
  3. messabout
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    messabout Senior Member

    I have a problem with any article, magazine or otherwise, that says the motor is mounted too low. From an exhaust outlet point of view, maybe. From a weight distribution/stability point of view you can not mount the motor too low.
     
  4. pistnbroke
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    pistnbroke I try

    Yes you do have a problem ..!! couple of points ..if the transom was sized for a short shaft and you put a long shaft on then the tipping forces when turning are greater and this affects some boats a lot others little ..If the motor is too low then extra leg is in the water and this increases drag ...from a "keep the weight low " perspective you are right....
     
  5. mwatts
    Joined: Jul 2009
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    mwatts Martin

    Hanging a long shaft engine on a boat that has been designed for a short shaft engine will be bad for performance. There's not just the tipping forces when turning, but also the long shaft will work as a lever so the deep prop will cause the bow to rise, greatly increasing the time it takes for the boat to get into plane.

    A long shaft may keep the weight low, but it's weight you don't even need and want in the first place. ;)

    All in all, you might loose 20% performance or more if you hang the wrong engine on the transom.

    But as you boat planes quickly (subjective, but I assume you mean just a couple of seconds after opening the throttle wide open), that's probably not your problem.

    Pistnbroke is probably right about the prop making it lean. You haven't said what engine you have, but it's possible it has a disc at the bottom of the cavitation plate, right behind the prop, with a small fin. This disc has a bolt which can be loosened, so the disc can be turned. You can use it to compensate for the prop effect.

    Here's a pic:

    [​IMG]

    Don't turn the disc too much. It's a fine adjustment, and you'll probably have to alter the ajustment a few times before you have it right.
     
  6. pistnbroke
    Joined: Jan 2009
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    pistnbroke I try

    That tab has nothing to do with it leaning ...it adjusted so it runs in a straight line if you take your hand off the steering ...like a mini rudder

    I dont thiink the long shaft argument is valid either ..on a small say 3m boat maybe but at your size it just increases the water you need under the boat ...the lean is prop torque ...I get the same on my outboard powered jetski and on a 16 ft with 90 hp and have to lean /sit to the right to keep the boat level ....
     

  7. mwatts
    Joined: Jul 2009
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    mwatts Martin

    Well, my personal experience, with a 50HP Johnson on a 4m speedboat, tells me otherwise. Adjusting that tab definately had impact. Maybe simply because the engine has to be at an angle to go straight, pushing the boat to one side of the V.

    I guess a long shaft engine on a boat designed for a short shaft has more effect if it is a small boat with a lot of power. But it will cost some top end performance anyhow.
     
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