max prop size for Carpenter 29

[Vivaldi 53]

Hi all,

Does anyone know what the maximum diameter propeller size a Carpenter 29 can take. We currently have a 12 x 9 but I want to go to a bigger size folding prop and want to go for more diameter to reduce slippage. Boat is powered by a 21 hp Nanni.

[ab1974 1]

Bit difficult to answer from the info as depends on optimal WOT rev range for the Nanni, boat weight, folding v fixed, 2 blade v 3 blade etc.

 

Best bet to contact Nanni.

 

Having said that the 12x9 sounds very small for a 21hp.

 

Remember 12 is the diameter (in inches) and 9 the pitch (theoretical movement forward per revolution).

 

For the same diameter - Lower the pitch (littler number) equals more thrust (think lower gearing) and higher pitch equals better top speed (think higher gearing).

 

So say on an outboard, Generally lower pitch for pulling / pushing power - waterskiing and higher pitch for speed on the same motor with same diameter. Obviously bigger diameter equals more push but the motor needs to be able to hit the designed max revs at wide open throttle. So gearing is therefore also a factor.

 

My 13hp volvo diesel runs a 16x11 and my 25hp high thrust outboards a 12x9. The volvo needs to hit 3000rpm and the yamaha needs 6000rpm.

 

So no simple answer but hopefully that helps assist with the differences.

[Vivaldi 53]

Hi AB,

Thanks for that. I understand the diameter / pitch / WOT stuff, what I was actually trying to find out is the actual physical space available without pulling the boat out. I'm looking at a folding 2 blade and some of the calcs say it should be a 14 x 91/2. I'm wondering if there is enough physical space to swing that size prop and thought that given its a production boat someone might already know.

 

cheers

 

Paul