Quick question

G

Gpayne

Petty Officer 3rd Class
Joined
May 28, 2012
Messages
75
Please forgive my ignorance, but I've seen a few newer I/O's with twin props on the same outdrive, pitched opposite of each other. Is this a counter-rotating drive or something like that? If so, does it help with torque-steer or help reduce cavitation? How does reverse work? Do both props reverse, or just one? Thanks.
 
Thalasso

Thalasso

Commander
Joined
Jan 18, 2011
Messages
2,876
Re: Quick question

Gpayne said:
Please forgive my ignorance, but I've seen a few newer I/O's with twin props on the same outdrive, pitched opposite of each other. Is this a counter-rotating drive or something like that? If so, does it help with torque-steer or help reduce cavitation? How does reverse work? Do both props reverse, or just one? Thanks.
Click to expand...

One prop turns one direction while the other turns the opposite direction.In reverse they turn the opposite direction to what they were while moving forward. You pretty much answered your question. Much easier to back up and have control then a single prop.
 
QC

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: Quick question

Yes, eliminates torque steer, helps reduce "ventilation", helps with hole shot, limited to around 60 MPH and then singles excel.
 
M

MarkSee

Lieutenant Junior Grade
Joined
Sep 10, 2010
Messages
1,172
Re: Quick question

For the majority of I/O boats you see with these props, if it's a:

Volvo it'll be called a Duoprop

Mercruiser it'll be called a Bravo 3

OMC it's be called a Dual Prop


Mark
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,158
Re: Quick question

Those were also used on WWII torpedoes. That era Torpedo needed to run straight, as they were unguided.
 
QC

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: Quick question

Well there you go. Learn something new every day. I did not recall that OMC had marketed the Volvo DP under their name during the JV period. I assumed (always bad) that was only the SX that was branded both ways. Cool :)
 
S

shrew

Lieutenant
Joined
Dec 29, 2006
Messages
1,309
Re: Quick question

QC, I thought the same as you and went to look it up before I cried 'foul'. I was as surprised as you are.
 
QC

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: Quick question

Heck, I cheated, I talked to Don ;) Looks like '96 - '98 they were marketed both ways . . .
 
M

MarkSee

Lieutenant Junior Grade
Joined
Sep 10, 2010
Messages
1,172
Re: Quick question

...think I just pulled that out from somewhere without looking it up also?????.....it was a distant memory of being at a boat show in the 90's that made me remember they had something with their name on it also.......

Mark
 
bekosh

bekosh

Lieutenant
Joined
Apr 27, 2004
Messages
1,382
Re: Quick question

Out of curiosity, are there any twin prop outboards? :confused:
It seems to me that the same benefits for twin prop I/O's would apply to OB's as well.
 
You must log in or register to reply here.
Top