Prop selection

cozza

Seaman Apprentice
Joined
Mar 25, 2015
Messages
45
Hi all
Need help working out what's the right prop to use. I recently bought this boat and with it it had 3 different size props
I'm running a Volvo Penta AD41B with a 290 sp leg it's a 26 foot boat that weighs around 3tn. At WOT I'm only getting 3400 RPM at 18nts.
The boat gets service regularly and I've just replaced the turbo for a new one, the motor seams to be running fine??
Any answers would be great thanks
 

cozza

Seaman Apprentice
Joined
Mar 25, 2015
Messages
45
Sorry the prop I have on at the moment is a 15.5x17
 
Last edited:

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
Hi all
Need help working out what's the right prop to use. I recently bought this boat and with it it had 3 different size props
I'm running a Volvo Penta AD41B with a 290 sp leg it's a 26 foot boat that weighs around 3tn. At WOT I'm only getting 3400 RPM at 18nts.
The boat gets service regularly and I've just replaced the turbo for a new one, the motor seams to be running fine??
Any answers would be great thanks

Sorry the prop I have on at the moment is a 15.5x17

WOT for your engine should be at 3900 to 3950RPM. Being 500 rom low and running a 17 will want to go down to 15. Keep in mind that the diameter also has an impact with rpm. Getting a 15 instead of a 15.5 will also increase rpm
 
Last edited:

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Ad seems to know the Volvo.Volvo is pretty much a mystery to me
I figured it was a Diesel But what is the hp. I can do a prop calculation.
I'm always suspicious of the tach and speedometer until I have some concrete numbers.
Do you know the gear ratio and is the speed by gps?
 

cozza

Seaman Apprentice
Joined
Mar 25, 2015
Messages
45
Thanks
Ok it's a 200hp but I don't know the gear ratio on the leg??
And the speed is from GPS
 
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