Volvo Penta DP sizing

[Bert Bergen]

I have a VP 280 duoprop with A10 propellers. I run a diesel and am underpropped. What is the differences in pitch and diameter between the A10's and a set of B8's. The B8's are the largest that I can find and having a hard time getting information. Any help would be appreciated.

Bert Bergen

 

[Don S]

Re: Volvo Penta DP sizing

In the A series props, the 10 is the most pitch you can get. If you go down in size you will be even further under propped. The B series props are for gas engines, the aft prop only has 3 blades, not 4 like the diesel props do. It would make your problem worse.

Sounds like you may have the wrong gear ratio on your drive. Do you know what the ratio is? There should be a metal tag on the upper gear box just in front of the top cap.
What engine do you have?

 

[Bert Bergen]

Re: Volvo Penta DP sizing

Thanks Don. The boat is a custom 32 foot aluminum and the engine is a Perkins T6-354 putting out about 145 shaft hp

 

[Don S]

Re: Volvo Penta DP sizing

Are you sure you are under propped, and not actually over propped? What WOT are you supposed to get with that engine, and what are you getting? Again, what is the gear ratio of the drive?

 

[Bert Bergen]

Re: Volvo Penta DP sizing

Don:

The engine max rpm is 2400. I can spin it up to about 2700 rpm with the A10's. I have checked everywhere for the ratio however i cannot find any info. Let me back track a bit. Original outdrive was a 270 with a 280 duoprop leg. I also believe the ratio is wrong and the B set of props will not help. Recently purchased a used 280 complete outdrive with a single prop to take advantage of the hydraulic tilt/trim. Can I use the lower gear in the 280 and put it into the DP bottom end if the ratio is a better match. Thanks