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champ
05-04-2011, 08:09 PM
After reading and reading , can somebody make it easy without any math. I understand there are so many variables, but laymens terms will help me out before I try changing props.
Thanks.

Boat: 1966 Champion
Length: 17'
Motor: new 351 ford
Hp: 280+
RPM's @WOT: 5300 (need to be below 5000)
Outdrive: 280 volvo
Prop Now: 14x22 Lh 3 blade stainless
New prop: 16x17 Lh 3 blade stainless

So now for the question: Needing to bring down my rpm's, and in theory or experience what will the new prop do in comparison performance wise to the prop on it now.

Sweet little 16
05-04-2011, 08:38 PM
After reading and reading , can somebody make it easy without any math. I understand there are so many variables, but laymens terms will help me out before I try changing props.
Thanks.

Boat: 1966 Champion
Length: 17'
Motor: new 351 ford
Hp: 280+
RPM's @WOT: 5300 (need to be below 5000)
Outdrive: 280 volvo
Prop Now: 14x22 Lh 3 blade stainless
New prop: 16x17 Lh 3 blade stainless

So now for the question: Needing to bring down my rpm's, what will the new prop do in comparison performance wise to the prop on it now.
it is going to raise your rpm and probably decrease your speed

100 rpm for every inch of pitch or diameter
as a rule of thumb so,

14x22= 5300

16x17

-200 rpm for increase in diameter of 2 inches and +500 for the decrease of 5 inches of pitch( 500 -200=300 increase) so the new prop should bring you upto 5600 rpm
you should be looking for a 23-24 pitch 14-14 1/2 dia prop

MOP
05-04-2011, 09:40 PM
IMO 23X14 with a decent cup will do a better job.

champ
05-05-2011, 07:15 AM
Now that I know which diameter and pitch, What would be the difference between a 3 or 4 blade prop if they were to be the same in pitch and diameter?
.... And where to get one?

Sweet little 16
05-05-2011, 07:21 AM
never run a 4 blade on a aq volvo I think solas might make a 4 blade and the 3 blade titan which works well on the 280. the question is the 22 pitch you have now how does it handle? if you like the prop it might be worth having it worked on to have some rpms taken out of it.