Changing from 3 blade to 4 blade prop

The diameter of the four-blade propeller will be determined by the propeller manufacturer and you likely will not have any choice in diameter. Most outboards 90 percent by some estimates are equipped.

For example on a three bladed propeller you would drop the diameter and keep the pitchOn a four bladed you would drop the diameter and the pitch.

Changing from 3 blade to 4 blade prop. Thanks in advance. I went from a 3 blade 21p stainless to a 19p 4 blade stainless for the same revs on my DF140. 4 blade will use slightly more fuel but will grip better in the rough.

I get zero cavitation with the 4 blade where the 3 blade used to blow out. Never argue with an idiot. 3 blade prop changing to 4 blade change pitch.

The ventilation is primarily during accelerration and in a following sea. There is a lot of turbulence between the hulls of a single engine cat The 4 blade will have more grip agreed thankyouSo if I understand a 4 bladed prop of the same brand solas and same diapitch will turn the same revs as a 3 blade. I was running a 3 blade aluminium prop and the mechanic who was taking care of my boat at the time had a 4 blade ss prop off his 23 running a 200 Johnson.

He assured me the prop would be an improvement. So I bought it and been running it for 3 seasons now. I noticed I picked up about 3-4 knots faster plane better bite in chop.

Remember many manufacturers claim that an operator can run either a 3 or 4 bladed prop on a motor with no rpm change. If they make this statement it is because the manufacturer does one of both of the following. Decrease the length of the prop blade.

Decrease the overall blade area. Changing to a 4 blade and dropping pitch from 21P to 20P I expected similar wide open throttle WOT RPM between the 2 props. What we actually found was surprising.

The smaller by 75 inch diameter resulted in WOT being too high now which set off my engine overspeed alarm every time I tried to. The conversion for a 3 and 4 bladed propeller is a simple tasked if you know what 2 bladed propeller you use on a given Engine or Motor. For example on a three bladed propeller you would drop the diameter and keep the pitchOn a four bladed you would drop the diameter and the pitch.

For instance if you had a two bladed 24-10 propeller and you wanted a three bladed you would use a 22-10 and. When it comes to acceleration 4 blade propellers seem to have the upper hand on 3 blade propellers. Three Blade vs Four Blade Propellers and Handling.

One of the main reasons people seem to choose 4 blade propellers over 3 blade propellers is the benefits afforded by the increased blade area given by the extra blade. ENTER TO WIN A SOLAS PROP. Lots of Prop info.

I went from the aluminium 10X12 3 blade to the aluminium 10X12 4 blade. The 4 blade gives transom lift and having an extra blade more paddles in the water more push so should get up better. My WOT RPM dropped about 250 rpm going from 3 to 4 blade.

A four blade gives better holeshot much better in cornering and the top end loss is negligible. At least on my 115 4 stroke. Also I can run my motor higher in the water column with a 4 or 5 blade prop which actually gives me more top end as I dont get slippage and cavitation like I do with my 3 blade props.

It depends on your current 3 blade as well as potential 4 blade prop. Sometimes you dont have to change the pitch at all on the prop when going form a 3 blade to a 4 blade if the diameter of the 4 blade prop is smaller than the diameter of the 3 blade prop. Turning a prop is about blade design total prop area and pitch.

To convert from 2-blades to 3-blades as a general rule youll want to DECREASE the propeller diameter by 1 inch and then KEEP the same pitch. To convert from a 3-blades to a 4-blades youll want to KEEP the same diameter and DESCREASE the pitch by 1 to 2 inch. Typically when you add blades you get rid of some of the pitch.

An example would be going from a 21 pitch 3 blade prop to a 19 pitch 4 blade prop. Yes the 4 and 5 blade props will get you a lower planing speed and is great for water sports like pulling a skier or wake boarder up out of the water. Many other factors including how you will be using your boat can affect your choice of prop.

The propeller experts at Ace can help you find the right 3 or 4-blade Piranha Propeller. Call us at 1-866-621-7767 or use our custom sizing request form. Or browse our extensive selection of 3 and 4-blade props here with our Piranha Prop Finder.

4 blade props typically give less torque steer to the operator 4 blade props tend to run more smoothly with less vibration over the entire rpm range. 4 blade props tend to load the engine more - if you compare a 3 blade prop of identical blade size and pitch. 4 blade props tend to have a lower top speed.

If you were generally satisfied with your 3 blade prop then you could continue with a 3 blade replacement. I happened to go from a 3 blade Black Max Mercruiser OEM prop on my boat to a 4 blade Mercury Marine Spitfire and the results were subtle but noticeable. I used the same pitch on both Technically a 4 blade uses more fuel than a 3.

A general rule for propeller pitch when changing to a four-blade propeller from a three-blade would be to reduce the pitch one-inch. The diameter of the four-blade propeller will be determined by the propeller manufacturer and you likely will not have any choice in diameter. The most widely used propellers are three-blade propellers.

So Im looking at changing props from a 3 blade SS Yamaha 17-M 1425 x 17 to a 4 bladed Aluminum unit. My sticking point right now is keeping the same diameter and pitch or changing one or the other. Three-blade props offer a nice compromise when it comes acceleration efficiency lift and speed.

A four-blade propeller on the other hand can boost acceleration efficiency or lift but at the cost of a lower top speed. Jim Hendricks Sport Fishing. Most outboards 90 percent by some estimates are equipped.

Changing a 3 blade to a 2 blade prop. Feb 13 2012 0648 AM. How do I determine 3-blade prop replacement for 2-blade.

Sep 06 2011 0149 AM. Why is 2 blade prop more efficient then 3 blade prop. Sep 05 2008 1136 PM.

The equal power rule for 2 to 3 blades is take 10 off the diameter and leave pitch the same. So the old take 1 inch off works ok. If youre starting with 10 or 11 2-blade props.

Its not so good if you start with 20 or 5 props.