Deep V off plane wander. What are the forces causing it?

Discussion in 'Boat Design' started by cyclops2, Jan 21, 2012.

  1. cyclops2
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    cyclops2 Senior Member

    I have not heard ANYBODY I know have a total answer.

    What does cause that self correcting wandering ?

    Many thanks
    Rich
     
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  2. Mr Efficiency
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    Mr Efficiency Senior Member

    It isn't self correcting, you try to correct the wander and by so doing send it off line in a different direction. Deep V wander is the result of there being not much topside of the boat in the water aft. The chines are just kissing the water in a lot of cases. The near vertical slab sides resist sideways movement better than the inclined slope of the vee underwater. The centre of lateral resistance is well forward as a result, and not much urge is required to steer the boat, the action of the propellor will tend to push the stern sideways, you have difficulty then in applying just the precise amount of steering that would counteract that, overcorrect repeatedly and wander in a zig-zag fashion. It is no mystery, a moderate vee will have a fair amount of the topside underwater aft, and that makes the stern harder to push sideways. Maybe a deep-vee with counter-rotating props beats the problem 2 ways, props cancel and two legs offering more lateral resistance, but that is just a speculator on my part.
     
  3. cyclops2
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    cyclops2 Senior Member

    No. I do NOT touch the wheel. Hands off in glass smooth water. The bow swings P & S exactly 22 degrees back and forth no wheel movement. Forever.
     
  4. cyclops2
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    cyclops2 Senior Member

    It gets better if 2 adults sit at the very bow.
     
  5. cyclops2
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    cyclops2 Senior Member

    Old wooden inboard speed boats do not do this. I ride in lots of them.
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    It's one for old Ripley then ! What is commonly referred to as deep-vee wander is a phenomenon that occurs off plane at zero wake type of speed.
     
  7. philSweet
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    philSweet Senior Member

    Bizarre. What boat? what speed? and what is the period of swing? Do you have a bow thruster?
     
  8. Milehog
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    Milehog Clever Quip

    If the boat has twin engines the rudder or outdrive toe-in could be a factor.
     
  9. cyclops2
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    cyclops2 Senior Member

    2002 Chaparrral 186 SSI 8' wide 3200# 5.0L Mercruiser V8 210 hp . The V8 does cause some stern down boat angle. 2 adults sitting on the bow causes some bow down. The boat has a very deep / high sided hull. Actually too high. The 2012 186 SSI are chubby & high still.

    It is very fast out of the hole & up to 50 mph with 2 ..200 pounders.
    1 to 4 people, random seating, it still swings almost the same. the cycling time is 15 to 20 seconds.


    Edit ...No tgruster in a 19' LOA WL is about 16'.
     
  10. cyclops2
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    cyclops2 Senior Member

    Forgot the speed.

    It is in foward gear idling to adock wind or current does very little to stop the oscillation.

    Can a power steering valve cause hunting ? Marina people drove the boat & said... normal.
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    Hardly normal what you describe !
     
  12. cyclops2
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    cyclops2 Senior Member

    Mr. Efficiency

    I just realized that your statement about putting more vertical sides into the water should help !!

    I ran a 6 big seniors back from a picknick. NO WANDERING. 6 x average of 200# each = 1200# of ballast. 3 big ones on the full rear bench. 2 more 200s in mid seats. 1 in the bow.
     
  13. Mr Efficiency
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    Mr Efficiency Senior Member

    But you said it gets better if you put more weight at the bow?
     
  14. cyclops2
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    cyclops2 Senior Member

    Yes when there are just 4 of us. 2 in the mid seats 2 in the bow seats of a bow rider. It does reduce the swing ideling up to the dock.
     

  15. cyclops2
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    cyclops2 Senior Member

    I do Russian Roulette when I come in alone. The bow swings very quick if I idle into reverse to stop.
     
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