3 blade vs. 4 blade prop for open water fishing

Post by **KarstRanger** » June 19th, 2005, 3:31 pm

Now this is probably a topic that has been chewed over before here, but...

My sterndrive has a 3 blade 14" prop with 19 pitch. If I wanted to go with a 4 blade, do I stay with the same pitch?

Post by **Chalk** » June 19th, 2005, 3:40 pm

All things being equal (diameter, rake, cup, etc.) a 4 blade will spin slower by approx 200 RPM than the 3-blade. That means you would need to drop one inch in pitch to run the same RPM as the 3-blade. The four blade (if it is a good one) will slip less, which will help make up for the reduced pitch with regard to speed at any given RPM. In general the 4-blade will probably be 1-3 MPH slower at WOT with a light load, but as fast with a heavy load. The 4-blade will have less steering torque, particularly if you run at high jackplate or trim settings. The 4-blade will also generally handle better, particularly in rough water, because it generates better stern lift.

Post by **KarstRanger** » June 22nd, 2005, 10:17 am

Thanks for the detailed info, Chalk. I think I will stick with the 3 blade for now until I know more about how this boat handles in various conditions.

Happypappy · Post by **Happypappy** » June 27th, 2005, 2:26 pm

Not necessarily true. Most 4-blade props are smaller in diameter and will run fairly close to the RPM of the 3-blade. This, of course depends on the Mfr. of the props. In general the 4-blade will carry the bow much better than the 3-blade, stay hooked up better in turns, and use a little less fuel as the efficiency or slippage rate is better. Top speed, depending on the hull, is sometimes better by 1.5-2mph also.

Post by **KarstRanger** » June 28th, 2005, 4:18 pm

Well, I already bought a 3 blade. But, it has a hub that allows you to put another prop (shell) on it, using that same hub. So, I can try a 4 blade later about 1/3 less cost.

I got the prop at Iboats.com

-- I scour the web and they have had the best prices out there for a couple of boat parts I ordered recently - this prop and a Ritchie compass -- very good service

and reasonable shipping cost

- youall should try them.

Post by **Chalk** » June 28th, 2005, 4:27 pm

Choosing the right prop is a task in it's self....You need to work with a good shop....Your loading and boating style will be the judge of what prop is the best...BTW...I said the same thing as HP except for the gas mileage...