Reply
 
Thread Tools Search this Thread
 
Old 16 January 2014, 02:07   #1
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,547
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
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 16 January 2014, 02:48   #2
Member
 
Kernow Buoy's Avatar
 
Country: UK - England
Town: Cornwall
Length: no boat
Join Date: Oct 2004
Posts: 1,518
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.
__________________

__________________
Kernow Buoy is offline   Reply With Quote
Old 16 January 2014, 03:08   #3
Member
 
Country: UK - England
Town: Margate / Ramsgate
Boat name: Bumbl
Make: Scorpion
Length: 8m +
Engine: Yanmar diesel
Join Date: Feb 2002
Posts: 2,837
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.
__________________
Daniel is offline   Reply With Quote
Old 16 January 2014, 03:35   #4
Member
 
Kernow Buoy's Avatar
 
Country: UK - England
Town: Cornwall
Length: no boat
Join Date: Oct 2004
Posts: 1,518
Quote:
Originally Posted by Daniel View Post
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.
__________________
Kernow Buoy is offline   Reply With Quote
Old 16 January 2014, 03:49   #5
Member
 
biffer's Avatar
 
Country: UK - England
Town: swanwick/hamble
Boat name: stormchaser
Make: custom rib
Length: 8m +
Engine: inboard/diesel
Join Date: Aug 2007
Posts: 3,848
Ain't boating fun
__________________
biffer is offline   Reply With Quote
Old 16 January 2014, 04:56   #6
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,855
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!
__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Old 16 January 2014, 05:16   #7
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,547
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
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 16 January 2014, 06:34   #8
RIBnet supporter
 
Chris Caton's Avatar
 
Country: UK - England
Town: Wirral & Caernarfon
Boat name: That's Enuff
Make: Revenger & Avon SR4
Length: 7m +
Engine: Honda 150HP & 50HP
Join Date: Jul 2011
Posts: 4,294
just splash the cash on some go juice
__________________
Chris Caton is offline   Reply With Quote
Old 16 January 2014, 06:48   #9
SPR
Trade member
 
SPR's Avatar
 
Country: UK - Scotland
Town: Central Belt of Scotland
Boat name: Puddleduck III
Make: Bombard
Length: 5m +
Engine: 50 HP
Join Date: Mar 2009
Posts: 2,066
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 ?
__________________
SPRmarine / SPRtraining
RYA Training Courses & Safety Equipment Sales
SPR is offline   Reply With Quote
Old 16 January 2014, 06:53   #10
Member
 
Country: UK - England
Town: Hamble
Length: 9m +
Join Date: Dec 2002
Posts: 2,317
Quote:
Originally Posted by nugent View Post
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?
__________________
It is better to remain silent and be thought a fool, than to speak and remove all doubt!
Dirk Diggler is offline   Reply With Quote
Old 16 January 2014, 06:56   #11
Member
 
jambo's Avatar
 
Country: UK - Scotland
Town: Girvan & Tayvallich
Boat name: Breawatch
Make: Ribcraft
Length: 5m +
Engine: Mercury 150 F/stroke
MMSI: ex directory!!
Join Date: Sep 2008
Posts: 6,154
RIBase
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
__________________
jambo
'Carpe Diem'
Member of the ebay Blue RIB cover club
Member of SABS ( Scottish West Division)
jambo is offline   Reply With Quote
Old 16 January 2014, 07:36   #12
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,547
Quote:
Originally Posted by Chris Caton View Post
just splash the cash on some go juice
Cheeky
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 16 January 2014, 07:40   #13
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,547
Quote:
Originally Posted by SPR View Post

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 ,,
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 16 January 2014, 07:41   #14
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,547
Quote:
Originally Posted by Dirk Diggler View Post

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
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 16 January 2014, 08:20   #15
RIBnet supporter
 
Chris Caton's Avatar
 
Country: UK - England
Town: Wirral & Caernarfon
Boat name: That's Enuff
Make: Revenger & Avon SR4
Length: 7m +
Engine: Honda 150HP & 50HP
Join Date: Jul 2011
Posts: 4,294
Quote:
Originally Posted by nugent View Post
Cheeky
__________________
Chris Caton is offline   Reply With Quote
Old 16 January 2014, 14:51   #16
Member
 
Country: UK - England
Length: no boat
Join Date: Jan 2014
Posts: 314
The cavitation plate on the engine should be roughly level with the bottom of the vee on the hull when fully down.
Is it?
__________________
Ribandmotorhome is offline   Reply With Quote
Old 16 January 2014, 15:49   #17
Member
 
Dan Gurney's Avatar
 
Country: UK - England
Town: Bingley, West Yorks
Boat name: Iolar
Make: Redbay
Length: 6m +
Engine: Suzuki DF140
Join Date: Sep 2012
Posts: 1,030
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!
__________________
Dan Gurney is offline   Reply With Quote
Old 16 January 2014, 19:01   #18
SPR
Trade member
 
SPR's Avatar
 
Country: UK - Scotland
Town: Central Belt of Scotland
Boat name: Puddleduck III
Make: Bombard
Length: 5m +
Engine: 50 HP
Join Date: Mar 2009
Posts: 2,066
Glad to help ! Remember steel has a higher density - sash weights or some lead - smaller loads to carry - although sand is cheaper..

S.
__________________
SPRmarine / SPRtraining
RYA Training Courses & Safety Equipment Sales
SPR is offline   Reply With Quote
Old 17 January 2014, 01:50   #19
Member
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,547
Quote:
Originally Posted by Clamchowder View Post
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,,
__________________
˜™
MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Old 17 January 2014, 03:14   #20
Member
 
Country: UK - England
Town: Mighty Penryn
Boat name: Little Joe.
Make: Avon Searider
Length: 4m +
Engine: Honda BF50
Join Date: Aug 2005
Posts: 8,869
Quote:
Originally Posted by Kernow Buoy View Post
will now do mid 40's before she misbehaves.
F'cough!
__________________

__________________
Mollers is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT -5. The time now is 05:20.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.