Reply
 
Thread Tools Search this Thread
 
Old 16 December 2009, 16:28   #1
Member
 
Razorbill RIBs's Avatar
 
Country: UK - Wales
Town: N. Pembrokeshire
Boat name: Various
Make: RIBs & Hovercraft
Length: 9m +
Engine: Outboards
MMSI: Various
Join Date: May 2009
Posts: 1,358
RIBase
Counter Rotation

A quick query, and possibly a stupid one....

Is there any reason not to buy a counter rotation OB (second hand) and run it as a single set up? Are the gearboxes any weaker /more expensive to repair than standard?

I assume the offset would need to be over the other side to a standard rotation?

Have done a search of the forum, but can't find the answer so any info appreciated....

Dan
__________________
Dan Worth
www.razorbillribs.co.uk

Follow us on Facebook https://www.facebook.com/#!/group.php...17306504953480
Razorbill RIBs is offline   Reply With Quote
Old 16 December 2009, 16:33   #2
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
No reason why not. Some people run counter rotating props on twin installations.
I think the boxes are the same apart from the gear selector, just from from memory on my Dads stern drives.
__________________
chewy is offline   Reply With Quote
Old 16 December 2009, 16:33   #3
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,622
I believe that is exactly what Hightower has done here.

I can't see any reason why in normal circumstances it shouldn't work OK. I guess if something goes wrong and you need to get spares for inside the gearbox it could be harder/more expensive but you might well need to replace the whole box then anyway. The only other headache might be the availability/range of props?
__________________
Poly is offline   Reply With Quote
Old 16 December 2009, 18:12   #4
Member
 
Razorbill RIBs's Avatar
 
Country: UK - Wales
Town: N. Pembrokeshire
Boat name: Various
Make: RIBs & Hovercraft
Length: 9m +
Engine: Outboards
MMSI: Various
Join Date: May 2009
Posts: 1,358
RIBase
Thanks Chewy.... Thanks Polwart......

It's a 175 Opti XL from overseas.....

I'm awaiting a print out on the OB to pass to the mech / guy who looks after the boat. I am really lucky in that respect, he's a great guy and a Mercury expert....he was the race mechanic for the four time F1 World Powerboat Champion....

Will let you know how we get on.

Dan
__________________
Dan Worth
www.razorbillribs.co.uk

Follow us on Facebook https://www.facebook.com/#!/group.php...17306504953480
Razorbill RIBs is offline   Reply With Quote
Old 16 December 2009, 18:25   #5
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
Turbo Diesel or Uncle Al on here should be able to help.
__________________
chewy is offline   Reply With Quote
Old 16 December 2009, 18:46   #6
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,866
As Polwart has mentioned, I run a Left hooker with no problems. Just remember to get the outboard offset correct when installing.

As for Props. If you're buying New there aren't any problems, but they might have to wait for stock or order something you want.

Second hand props are rare, but keep your eye open on ebay ( I was the only bidder) as I bought a New SST for £45 and a little used BRP Viper for £90 Those two props would be easy over £600 quids worth brand new. So be eagled eyed and pick up a bargain.

The other disadvantage is that you cannot borrow props to try out. Other than that the only prob you might have is if the RIB was set-up with a standard rotation outboard. The battery and fuel tanks etc might have been placed to one side to counter the force of the Prop Torq and with a CCW Outboard might cause you balance problems. Or landing off a wave on one side. This can be overcome with weight distrabution but due to the size of RIB I doubt that will be an issue.
__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Old 16 December 2009, 20:00   #7
Member
 
Nasher's Avatar
 
Country: Other
Town: Principalite d'Chaos
Boat name: The Nashers Revenge!
Make: Windsor Brothers
Length: 6m +
Engine: Optimax 225
MMSI: "Mmmmm SI" she said!
Join Date: Jan 2004
Posts: 4,821
On the other hand, without realising it, I've been running a counter rotating gearbox in reverse with a std prop for several years.

It's a long story

Nasher.
__________________
Nasher is offline   Reply With Quote
Old 16 December 2009, 20:05   #8
Member
 
Razorbill RIBs's Avatar
 
Country: UK - Wales
Town: N. Pembrokeshire
Boat name: Various
Make: RIBs & Hovercraft
Length: 9m +
Engine: Outboards
MMSI: Various
Join Date: May 2009
Posts: 1,358
RIBase
Thanks Andy....

Agree that balance shouldn't be an issue...my fuel tank is below deck (like Nashers) and teh triple battery system is centrally located.

I've also got Hydraulic Trim tabs which help with balancing (esp. when laden with Dive Gear etc.)

Take your point re offset

Hope this ones a goer...it's a 2005 Opti with 340 hours XL shaft with 21 SS prop.

I understand it was from a marine police RIB (Dorset?) and was sold as pair at auction (engines upgraded to 225 Opti's I'm told, but who knows...)

Went to dealer in Holland...that is who's selling (not been used since). have asked some more questions and asked for a diagnostic report to show my mech....wait and see.

Thanks again guys!!

Dan
__________________
Dan Worth
www.razorbillribs.co.uk

Follow us on Facebook https://www.facebook.com/#!/group.php...17306504953480
Razorbill RIBs is offline   Reply With Quote
Old 16 December 2009, 20:11   #9
Member
 
Razorbill RIBs's Avatar
 
Country: UK - Wales
Town: N. Pembrokeshire
Boat name: Various
Make: RIBs & Hovercraft
Length: 9m +
Engine: Outboards
MMSI: Various
Join Date: May 2009
Posts: 1,358
RIBase
Quote:
Originally Posted by Nasher View Post
On the other hand, without realising it, I've been running a counter rotating gearbox in reverse with a std prop for several years.

It's a long story

Nasher.
__________________
Dan Worth
www.razorbillribs.co.uk

Follow us on Facebook https://www.facebook.com/#!/group.php...17306504953480
Razorbill RIBs is offline   Reply With Quote
Old 16 December 2009, 20:43   #10
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,622
Quote:
Originally Posted by Dan Worth View Post
I understand it was from a marine police RIB (Dorset?) and was sold as pair at auction (engines upgraded to 225 Opti's I'm told, but who knows...)
I don't want to put you off that engine, because it may well be in perfect condition, but I got the distinct feeling from the tender documentation that their boats (and so possibly their engines) were not as 'loved' as we might expect for ex government stuff.
__________________
Poly is offline   Reply With Quote
Old 16 December 2009, 20:56   #11
Member
 
Country: UK - England
Town: Dorset & Hants
Boat name: Streaker/Orange
Make: Avon/Ribcraft
Length: 4m +
Engine: 50Yam/25 Mariner
Join Date: Apr 2007
Posts: 5,551
Quote:
Originally Posted by Polwart View Post
I don't want to put you off that engine, because it may well be in perfect condition, but I got the distinct feeling from the tender documentation that their boats (and so possibly their engines) were not as 'loved' as we might expect for ex government stuff.
Tough call - a Dorset police RIB ( or one of them!) used to be kept very near me ( along with the Christchurch HArbour RIB) . The local Merc dealer I believe looked after both - defo the Harbour RIB & this was in top shape with alot of hours ( thousand + ) on it.

Always serviced etc, but depends if its the same boat !

Nasher - you all fixed up now? ( in the right direction ?)
__________________
PeterM is offline   Reply With Quote
Old 16 December 2009, 21:05   #12
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,622
Somewhere in the depths of my inbox I should have the tender paperwork if you want to see how it was originally advertised - pm me an email address.
__________________
Poly is offline   Reply With Quote
Old 16 December 2009, 21:13   #13
Member
 
Country: UK - England
Town: Dorset & Hants
Boat name: Streaker/Orange
Make: Avon/Ribcraft
Length: 4m +
Engine: 50Yam/25 Mariner
Join Date: Apr 2007
Posts: 5,551
Quote:
Originally Posted by Polwart View Post
Somewhere in the depths of my inbox I should have the tender paperwork if you want to see how it was originally advertised - pm me an email address.
Dont worry - I'm not buying it.

Got my own thrashed opti already - and thats just me driving it.
__________________
PeterM is offline   Reply With Quote
Old 17 December 2009, 09:25   #14
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
Quote:
Originally Posted by chewy View Post
I think the boxes are the same apart from the gear selector, just from from memory on my Dads stern drives.
Not quite true.

Must not run a counter rotation / left hand Mercury gearbox in reverse as a right hand gearbox - the internals are different and won't like it.

Volvo sterndrives on the other hand can be run either way with no problems.

Will need to stick with LH props.
__________________
Searider is offline   Reply With Quote
Old 17 December 2009, 09:33   #15
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
Quote:
Originally Posted by Searider View Post
Not quite true.

Must not run a counter rotation / left hand Mercury gearbox in reverse as a right hand gearbox - the internals are different and won't like it.

Volvo sterndrives on the other hand can be run either way with no problems.

Will need to stick with LH props.
Thats what we have Volvo Stern drives. Didn't know if the same was true for over gear boxes.
__________________
chewy is offline   Reply With Quote
Old 17 December 2009, 21:26   #16
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,866
Quote:
Originally Posted by Dan Worth View Post

Hope this ones a goer...it's a 2005 Opti with 340 hours XL shaft with 21 SS prop.
I was supplied with a 21"er but now run with a 19" Prop now and would guess you might well have to drop the pitch size down as well. Good luck with the purchase.
__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Old 17 December 2009, 21:29   #17
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,866
Quote:
Originally Posted by Nasher View Post
On the other hand, without realising it, I've been running a counter rotating gearbox in reverse with a std prop for several years.

It's a long story

Nasher.
Oh, that's why you had plenty of wear then. It did quite well for a jerry rigged gearbox.
__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Old 18 December 2009, 09:41   #18
Member
 
Nasher's Avatar
 
Country: Other
Town: Principalite d'Chaos
Boat name: The Nashers Revenge!
Make: Windsor Brothers
Length: 6m +
Engine: Optimax 225
MMSI: "Mmmmm SI" she said!
Join Date: Jan 2004
Posts: 4,821
Andy

Strangely the only wear in the box was on the edges of the dog clutch for what I was using as reverse.

My only issue was not being able to select reverse with the engine running, and I now realise it was due to my crashing in and out of forward and reverse gear holding the bow nudged up against a beach whilst some small waves broke.

Nasher
__________________
Nasher is offline   Reply With Quote
Old 18 December 2009, 13:37   #19
Member
 
Country: UK - England
Town: Hamble
Length: 9m +
Join Date: Dec 2002
Posts: 2,317
Quote:
Originally Posted by Dan Worth View Post
Thanks Chewy.... Thanks Polwart......

It's a 175 Opti XL from overseas.....
Ah ha, Those motors were supplied by TNT Custom Marine in Miami, and shipped in for the Police Rib (actually belonged to Customs and Excise) about 5 years ago. Barrus couldn't supply them as the 175 opti wasn't available in Europe at the time!

They've had a hard life!!!!!
__________________
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 18 December 2009, 14:44   #20
Member
 
Razorbill RIBs's Avatar
 
Country: UK - Wales
Town: N. Pembrokeshire
Boat name: Various
Make: RIBs & Hovercraft
Length: 9m +
Engine: Outboards
MMSI: Various
Join Date: May 2009
Posts: 1,358
RIBase
The search goes on...

Cheers Dirk....

was in regular contact with the dealer, had asked for diagnostic print out /pics etc (he told me the engine had done 382 hours) and all gone quiet since....not sure if i should read anything into it, but your mail has helped me make my mind up to keep looking........any and all leads gratefully received (150 /175).

Thanks to all who have responded /sent through info.... this forum really is useful when it comes to stuff like this....always seems to be someone who knows the history!...cheers

Dan.
__________________
Dan Worth
www.razorbillribs.co.uk

Follow us on Facebook https://www.facebook.com/#!/group.php...17306504953480
Razorbill RIBs 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. The time now is 07:10.


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