Osprey Viper ---Twitching

[nugent]

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

[Kernow Buoy]

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.

[Daniel]

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.

[Kernow Buoy]

Originally Posted by Daniel

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.

[biffer]

Ain't boating fun

[Hightower]

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!

[nugent]

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

[Chris Caton]

just splash the cash on some go juice

[SPR]

Originally Posted by nugent

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 ?

[Dirk Diggler]

Originally Posted by nugent

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?

[jambo]

Apart from Scott's question re the tank I would agree with HT's point leave the OB alone and move wt around the deck

Sent from my iPhone using Rib.net

[nugent]

Originally Posted by Chris Caton

just splash the cash on some go juice

Cheeky

[nugent]

Originally Posted by SPR

did you remove a s/s tank from it - hence the weight issues ?

Kin ell. ,
Why did I not think of that yes I did,, and it's a hell of a lot lighter, than the one I replaced it with,,

Going to try couple bags sand up front if it works,,
will cut hole in floor make a bucket shaped well and fill with what ever I have left in the sand bags once I have meddled and am happy,, and re seal water tight leaving it there for ever,,,

ribnet. As allwaŷs great helpful forum

Cheers guys appreciated ,, 2nd eye allways spots some thing some one else misses ,,

[nugent]

Originally Posted by Dirk Diggler

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?

Yep brand new hydro and well bled and checked again yesterday

[Chris Caton]

Originally Posted by nugent

Cheeky

[Ribandmotorhome]

The cavitation plate on the engine should be roughly level with the bottom of the vee on the hull when fully down.
Is it?

[Dan Gurney]

This has shit me up a bit now. Was planning on raising mine up to combat splashing, but since our first proper run will be Angelsey I don't want to bugger it up for myself!

[SPR]

Glad to help ! Remember steel has a higher density - sash weights or some lead - smaller loads to carry - although sand is cheaper..

S.

[nugent]

Originally Posted by Clamchowder

This has shit me up a bit now. Was planning on raising mine up to combat splashing, but since our first proper run will be Angelsey I don't want to bugger it up for myself!

Must admit it has really pissed me off,,,

Lucky enough I can get it back out before Wales meet and iron out the bugs,,, does look more like a weight issue now though,,,all that spray up the back is not right and must slow the rig down as well as put un needed drag on engine mounts not to mention fuel consumption,


Again thanks guys,,

[Mollers]

Originally Posted by Kernow Buoy

will now do mid 40's before she misbehaves.

F'cough!