Reply
 
Thread Tools Search this Thread
 
Old 25 April 2008, 11:57   #1
Member
 
martini's Avatar
 
Country: UK - Channel Islands
Town: jersey
Boat name: Martini II
Make: Arctic 28/FC470
Length: 8m +
Engine: twin 225Opti/50hp 2t
MMSI: 235067688
Join Date: Jun 2005
Posts: 3,021
counter rotating - port or stbd?

Does anyone know if it matters which way round the motors are on a twin c/r outboard set up? Is there an industry standard that everyone sticks to?

Thanks
__________________

__________________
martini is offline   Reply With Quote
Old 25 April 2008, 13:32   #2
Member
 
Country: UK - Channel Islands
Town: Jersey
Boat name: t/t
Make: Honda
Length: under 3m
Join Date: Oct 2002
Posts: 255
Top of blades moving towards each other. So clockwise rotation on port and anti clock on starboard. Think it has something to do with density of water and surface so any sideways movement of water is pushed together nearer surface?
__________________

__________________
karlT is offline   Reply With Quote
Old 25 April 2008, 15:03   #3
Member
 
Country: UK - England
Town: Hamble
Length: 9m +
Join Date: Dec 2002
Posts: 2,317
Quote:
Originally Posted by karlT View Post
Top of blades moving towards each other. So clockwise rotation on port and anti clock on starboard.
Are you sure about that, it's usually the other way round!
__________________
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 25 April 2008, 17:17   #4
Member
 
martini's Avatar
 
Country: UK - Channel Islands
Town: jersey
Boat name: Martini II
Make: Arctic 28/FC470
Length: 8m +
Engine: twin 225Opti/50hp 2t
MMSI: 235067688
Join Date: Jun 2005
Posts: 3,021
Google has it 9:0 in favour of counter rotate on the port side. How sure are you Karl?!

I'm still none the wiser about the theory behind it all
__________________
martini is offline   Reply With Quote
Old 25 April 2008, 19:22   #5
Member
 
Country: Other
Town: San Carlos, Mexico
Boat name: INDE
Make: LOMAC 730
Length: 7m +
Engine: 200 Merc.
MMSI: Please press 1
Join Date: May 2006
Posts: 1,688
Send a message via Skype™ to Limey Linda
Quote:
Originally Posted by martini View Post
Google has it 9:0 in favour of counter rotate on the port side. How sure are you Karl?!

I'm still none the wiser about the theory behind it all
Just called my Merc. mechanic who is factory trained and a 20 year offshore racing mechanic. Conventionally most riggers will mount counter rotate to port. Howver on racing boats they do it the other way round. as Karl suggested. Reasons: cleaner water turning towards each other, can mount them higher on the transom and run a higher rpm and the boat will be more stable.
Hope this helps.
__________________
Running around like a head with it's chicken cut off.
Limey Linda is offline   Reply With Quote
Old 26 April 2008, 03:35   #6
Member
 
martini's Avatar
 
Country: UK - Channel Islands
Town: jersey
Boat name: Martini II
Make: Arctic 28/FC470
Length: 8m +
Engine: twin 225Opti/50hp 2t
MMSI: 235067688
Join Date: Jun 2005
Posts: 3,021
Quote:
Originally Posted by Limey Linda View Post
Just called my Merc. mechanic
You didnt do that just for me did you?!

I dont think we can class my rib as a racing boat so port it is then!

Cheers Limey
__________________
martini is offline   Reply With Quote
Old 26 April 2008, 09:06   #7
Member
 
Country: UK - England
Town: Hamble
Length: 9m +
Join Date: Dec 2002
Posts: 2,317
Quote:
Originally Posted by Limey Linda View Post
. Howver on racing boats they do it the other way round. as Karl suggested.
That isn't strictly true.... Turning out is normal, but turning in does sometimes work better, although it nearly always gives trickier handling.
__________________
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 26 April 2008, 10:42   #8
Member
 
Country: Sweden
Town: Stockholm
Boat name: Osprey & Ring
Make: Osprey & Ring
Length: 9m +
Engine: Plenty
Join Date: Mar 2003
Posts: 860
Its ften a counter on starboard gives more bowlift (not in all cases, depends on engine porp etc etc)
__________________
www.grandrib.se
Petrov is offline   Reply With Quote
Old 26 April 2008, 12:56   #9
Member
 
Country: Other
Town: San Carlos, Mexico
Boat name: INDE
Make: LOMAC 730
Length: 7m +
Engine: 200 Merc.
MMSI: Please press 1
Join Date: May 2006
Posts: 1,688
Send a message via Skype™ to Limey Linda
Quote:
Originally Posted by martini View Post
You didnt do that just for me did you?!

I dont think we can class my rib as a racing boat so port it is then!

Cheers Limey
Right decision I think. I hope you have ordered a factory manual. They have excellent installation instructions. Well worth the money. About $70.00 I think and you can order on line using your engine serial number.
__________________
Running around like a head with it's chicken cut off.
Limey Linda is offline   Reply With Quote
Old 26 April 2008, 15:40   #10
Member
 
Country: UK - England
Town: Farnborough
Boat name: Eleven
Make: Arrow
Length: 8m +
Engine: 557cu, 700hp
Join Date: Jul 2003
Posts: 1,255
Listen to dirk!!!!!
__________________

__________________
Matt 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





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 06:47.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.