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Old 16 January 2014, 02:07   #1
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Osprey Viper ---Twitching

in need of some advise,,

after raising my engine up 1 hole I am getting some unnerving chine walk,,,

tried it on a lake yesterday with hardly any fuel in her,, wanted to see how fast it would go,, around 40 knots it was not feeling safe,,

same set up on sea few weeks back seen 48 knots on gps and it felt fine, in fact exceptionaly so,

I raised the engine due to getting a large amount of spray up the transom due to the cavitation plate sitting to low,

the boat in my eyes is balanced out fine and in any stage of trim I felt uncomfortable,,
A} could it just be the fact I was running with 20ltrs of fuel or less?
B} drop engine back down where it was and ignore the spray?
C} don't want to do this, Or re drill transom so I can go 1/2 hole up?

or would simple set of trim taps sort it out?
to be fair she is over powered by 50hp but it is not the first time I have done it.. it was originally built as a twin engine boat and re modified by mike Witham of Osprey, so I know the transom is the correct angle etc,,,

interested in opinions from the more experienced bods,,,

eventually it will be having a 150hp on it as its meant to be,, but for my own use I want to keep the larger donkey on there
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Old 16 January 2014, 02:48   #2
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I had something a bit similar, ran my 5.85 with a 150 Opti very lightly loaded and little fuel, 30 knots and upward she felt very flightly and started to chine walk. I added a 2nd anchor & chain to the bow locker, filled with fuel and she was transformed, will now do mid 40's before she misbehaves.
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Old 16 January 2014, 03:08   #3
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Interesting, had the exact opposite on our 6m viper / 150 opti. With anchor & chain in the bow locker she was too bow heavy and tended to try and hook regardless of trim. Moving this aft under seats cured that and and she behaved upto a top speed of over 40knts. Top was 45/46 I think light of fuel.

I might have a photo of engine height.

I do vaguely really the strange rooster tail type spray under way but it's 10 years ago unfortunatly.
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Old 16 January 2014, 03:35   #4
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Quote:
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Interesting, had the exact opposite on our 6m viper / 150 opti.
should clarify my 5.85 is a Ribtec not an osprey, different hull different result perhaps.
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Old 16 January 2014, 03:49   #5
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Old 16 January 2014, 04:56   #6
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I'd leave the outboard as it is and move some ballast around the deck. Buy a bag of sand or two, experiment and enjoy!
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Old 16 January 2014, 05:16   #7
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Thinking set of trim tabs can not do any harm ,
then move my second tank further to the rear rather dig up the floor than put more holes in my transom
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Old 16 January 2014, 06:34   #8
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Old 16 January 2014, 06:48   #9
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Quote:
Originally Posted by nugent View Post
Thinking set of trim tabs can not do any harm , then move my second tank further to the rear rather dig up the floor than put more holes in my transom
did you remove a s/s tank from it - hence the weight issues ?
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Old 16 January 2014, 06:53   #10
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Quote:
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Thinking set of trim tabs can not do any harm ,
That isn't really what tabs are for.

Is raising the motor the only thing that you've changed? And I assume your steering is nice and tight?
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