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3-blade vs 4-blade props

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wnjsmith

New member
I need a little help and advice from those who have swapped props. This is my first boat and I’ve been doing a lot of searching and reading as I know my current prop is too shallow. I also know that prop size is dependent upon motor and boat combination.

Current equipment: 95 OMC Lowe 2200 (“22’ deck boat) with 95 Evinrude 130HP motor. The current prop is a 3-blade 15x13

Now, at 5500 RPM I’m traveling at about 25-27 kmph and still have more throttle. It has an incredible hole shot but my top end is not right. In all the reading I’ve found the 4-blade props have more drag but better bite. It seems like I’ll still come out of the hole fine with a longer blade pitch. To me, in my minute amount of knowledge, it appears my best option is a 14.5” 4-blade 17” pitch to give a good top end without over-reving and still a good hole shot and planing RPM for pulling a tube.

My question: has anyone went from a 3-blade to a 4-blade prop and what were your experiences?
 
Typically staying within same type prop (basic 3 blade aluminum to 4 blade aluminum) I'd expect to loose RPM going to 4 blade of the same pitch.

13P to 17P 3 blade will drop you perhaps 600 RPM. Going to 17P 4 blade maybe 750 to 800 RPM.

Now to throw another curve to consider: 1995 OMC props has pointer blades with less total blade area than later designs. This alone sometimes requires a pitch change lower when installing a new series prop.

Also rebuilt props frequently DO NOT perform exactly the same as new even when using the same part number. So how many times if any has that 13P been rebuilt? I will agree, you are underpropped. But 15P or 17P IDK.
 
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Droid said:
Typically staying within same type prop (basic 3 blade aluminum to 4 blade aluminum) I'd expect to loose RPM going to 4 blade of the same pitch.

13P to 17P 3 blade will drop you perhaps 600 RPM. Going to 17P 4 blade maybe 750 to 800 RPM.

Now to throw another curve to consider: 1995 OMC props has pointer blades with less total blade area than later designs. This alone sometimes requires a pitch change lower when installing a new series prop.

Also rebuilt props frequently DO NOT perform exactly the same as new even when using the same part number. So how many times if any has that 13P been rebuilt? I will agree, you are underpropped. But 15P or 17P IDK.
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Thank you for your input.

I’ve got an extreme over rev situation going. I have to watch the tach to avoid going into the limiter. That’s why I’m thinking the jump. I was thinking 4 blade because I read it will let me plane quicker and right now I’m not planing until close to 4k and 20MPH. From what you’re saying, I may have to shorted the jump If I use a four-blade.

From what I understand, the person I bought the boat from had to purchase this prop on the fly at a Marina. I don’t know if it’s rebuit but it shows no singns of slippage.

I’m not sure what a pointer blade looks like but it looks like a standard prop I seen on any regular boat headed to the lake. I’m understanding pointer blades are installed on boats for speed which this boat will not get
 
AllDodge said:
Also note; 4 blade props increase stern lift which can help or hurt depending on the boat
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Please remember I’m new to this so some questions may seem obvious to many. I say that because this is likely an obvious question I’m getting ready to ask.

When you say “increase stern lift” is this for the whole time the boat is in motion? A friend says it has a supper strong hole shot, more than a 22’ deck boat should have, and does not seem to drop the stern hard. What I am finding is being able to achieve 15 kph at about 3100 rpm but the bow is lifted the whole time with the stern still digging. If I barely bump the throttle, the boat planes out and the RPM jumps to 4000 at 18-20 kph. When I read that a four blade lifted the stern and planed out quicker I was thinking it would lower the RPM for planing and I’d be able to cruise at 20 kph at a lower RPM.
 
The stern will lift anywhere from slightly to up to 50mm. The amount of lift depends on weight of the boat, hull and weight distribution.

If there is an issue in most cases the boat may start propose because of how the boat is loaded. It may do nothing but increase speed and handling, but there is always a chance
 
AllDodge said:
The stern will lift anywhere from slightly to up to 50mm. The amount of lift depends on weight of the boat, hull and weight distribution.

If there is an issue in most cases the boat may start propose because of how the boat is loaded. It may do nothing but increase speed and handling, but there is always a chance
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Got it. It's amazing how this system is set up. You need to have the proper prop for max RPM range at WOT but there's no way to determine without spending $150 a pop until you find the right balance.

The only specs I can find for the boat is that it's 1800 lbs. It's an aluminum shallow V hull with an 8 foot beam. It sits high on the water so a four blade may not be good if it pushes the bow down.
 
Most shops have props to loan / try if you agree to buy one.-----Amazon may not do this for you.----I say 17" is the one you need.----Also need to use power trim to control bow up / down!
 
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