Reply
 
Thread Tools Search this Thread
 
Old 28 October 2004, 02:24   #1
Member
 
Country: Canada
Town: Bella Coola
Boat name: Water Rocket
Make: Polaris
Length: 9m +
Engine: twin Yamaha 150 hp
Join Date: Nov 2003
Posts: 149
twin engine ??

Howdy Gang,
I was wondering about the prop rotation on outboards in a twin engine set up.
Are they set up to spin in opposite directions?

Which side would have the right hand wheel and which would have the left?

Can one engine be run in reverse ?

BTW the motors are Honda 45's


thanks
hank
__________________
hank is offline   Reply With Quote
Old 28 October 2004, 07:07   #2
Member
 
Nick Hearne's Avatar
 
Country: UK - England
Town: Bucks
Boat name: Blue & Ding Dong
Make: Ribeye,SR4 & Bombard
Length: 6m +
Engine: 115,50 & 15Hp Yams
Join Date: Feb 2004
Posts: 3,252
"Which side would have the right hand wheel and which would have the left?"

HI port engine runs anticlockwise & starboard runs clockwise, as you look from behind!


"Can one engine be run in reverse ?" yes great for maneuvering!

Nick
__________________
Nick Hearne is offline   Reply With Quote
Old 28 October 2004, 07:56   #3
Member
 
Jono's Avatar
 
Country: UK - England
Town: Over here
Boat name: S.S. Nobstick
Make: Three Wise Monkeys
Length: 3m +
Engine: 44lbs of thrust....
Join Date: Nov 2003
Posts: 2,127
Are you talking about putting a left handed prop on and running the gearbox backwards? As opposed to a proper contra rotating unit?
__________________
Jono is offline   Reply With Quote
Old 28 October 2004, 10:34   #4
Member
 
Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 100hp Yam/150hp opt
Join Date: Sep 2003
Posts: 2,069
RIBase
Props

Quote:
Originally Posted by hank
Howdy Gang,
I was wondering about the prop rotation on outboards in a twin engine set up.
Are they set up to spin in opposite directions?

Which side would have the right hand wheel and which would have the left?

Can one engine be run in reverse ?

BTW the motors are Honda 45's


thanks
hank
Hi Hank,

Ideally, if the machinery allows it, you would want to have a right hand rotation propeller (clockwise when going forwards) on the starboard engine and a left hand rotation (anti-clockwise when going ahead) on the port engine. This allows for the best maneouverability and dynamic stability.
You could put them on the other way round and this "may" give more speed but may also be less stable.

Unfortunately very few outboard gearboxes can be run anticlockwise for extended periods without damage unless they are specifically "counter rotation".

Therefore I think that with the Hondas you will probably have to run right hand propellers on both engines.

Regards
__________________
Searider is offline   Reply With Quote
Old 28 October 2004, 12:28   #5
TIM
Member
 
Country: Ireland
Town: Dublin
Boat name: WIZARD
Make: REDBAY 7.4
Length: 7m +
Engine: OPTI 225
Join Date: Aug 2002
Posts: 417
Honda 45 are too small for counter rotation... it only when you get over a 100 Hp or so, it becomes an issue ...

We run twin 75's , same rotation.. no problems... on a flat day you have to trim one of the engines slight to allow for a slight lean caused by rotation...
__________________
NOT THE SHARPEST KNIFE IN THE DRAWER
TIM is offline   Reply With Quote
Old 28 October 2004, 16:35   #6
Member
 
Country: Canada
Town: Bella Coola
Boat name: Water Rocket
Make: Polaris
Length: 9m +
Engine: twin Yamaha 150 hp
Join Date: Nov 2003
Posts: 149
Hi Again,
Your replies made my job a lot easier.

We will just use the Honda's as is and see how it goes.

Thanks
hank
__________________
hank is offline   Reply With Quote
Reply


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. The time now is 07:45.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.