changing my props to duo props??

[laugh9876]

Hi all, i amconsidering changing my volvo twin 5l gxi 270hp from a single prop to duo props, hoping to get more control/speed and avoid some of the walkabout? any advise? is it worth doing, what sort of costs can i expect. mark

 

[duncan]

what walkabout on a twin engine installation?

on the one hand you will get an improvement in overall fuel economy because of the inherent efficiency enhancement (but not necessarily top end speed because of increased drag (ie probably more speed but not guaranteed)

on the other hand it will cost a fortune - and that assumes you can simply bolt on the replacement drives...

generally these things are only just financially viable when you have to replace the drives anyway for some reason.

 

[MapisM]

If the boat has twin engines, I would rather run than walk away from such idea.
Btw, if by walkabout you mean the prop-walk effect, with twin engines that's actually an advantage!
PS: when manuevering, of course.

 

[BartW]

I have been investigating this issue a lot recently, this statement I copied from another forumboatdiesel.com)

As to single prop Vs. duoprop; Figure a 10 - 12% efficiency gain. What you will notice most is acceleration, maneuverability, fuel consumption and comfort (less vibration, prop generated noise and straight tracking). Speed gains are typically very boat dependent; An underpowered boat that struggles to get to 25 knots will see a significant pickup, In a boat with a good hp to weight ratio that easily cruises at 35 knots the difference in top speed would be minimal.

I agree with previous reply, if you have a twin installation I wouldn't replace the single prop to duo just for performance, unless you need to change anyway,
but have a spare pair of props with higher/lower pitch, the lower pitch for the dynamic, heavy weight travels, and the higher pitch for the lower weight, long distance, lower fuel consomption applications

 

[DAKA]

The extra cost of twice as many props to repair/replace each season or two is not insignificant.

The inner 4 blade aliminium prop is only good for 2 seasons in my expirience.

I used to carry a spare set of props ie/ 4 props are twice the space and cost of singles.

 

[laugh9876]

thanks for all your help, and replies. can anyone give me a ballpark figure as to costs?

 

[BartW]

here even more info,

http://destinsharks.com/reviews/105

I am sorry, I don't know about prices

 

[scottie]

volvo do an exchange unit for the lower drive
so you do not need to change the whole leg

 

[oldgit]

Coastal rides will prob be flog you the kit,a set of duo props will set you back a lot of dough compared fairly easy to source single units.

 

[DoubleVision]

I bit the bullet and put stainless props on my duo drives. It hurt alot at the time but pays dividends. Just finishing the fourth season now and still scrub up like new. Mind you i`m spending the saving on anodes now /forums/images/graemlins/confused.gif

 

[davedpc]

The single props. on my 10 year old Bravo 2 legs are as solid as new.With one foward and one in reverse you can spin in your own length....almost as good as shafts which are usually further apart.