|What is the advantage of a four blade prop?|
|Matt, four blade props are going to be smoother, hold a better speed and give you a better holeshot. You might loose one or two miles per hour on the top end though.|
|Thanks Danny, so they would be better for a boat using ballast?|
|yes, much better. our's use to struggle coming out of the hole, once we got a 4 blade it was not a problem. |
|I suppose it also means much higher gas consumption? |
|Matt - new technology has produced 3-blade props that compete well with 4-blades. 4-blades are still the choice application for some loaded V-drives, but not all. E-mail me with your application and I can tell you of some of your options. firstname.lastname@example.org|
|It saves a lot of gas as well. The boat isn't having to work as hard to get out of the hole. |
|An older style prop is smoother in a 4 blade configuration. The extra blade, plus the blades being smaller decrease the imbalance of the prop. |
A modern (CNC) like Acme or the new OJs can built with much better tolerances. So, a CNC 3 blade can be used with better results in some applications. The idea behind them being a bit better is that the blades are a bit further apart and not churning through each others wash like a 4 blade (due to the blades being so close...)
Other things like the cupping and blade size help too. On my boat, the stock old OJ 4 blade 13x13 was a bit of a dog out of the hole and would get my boat unloaded to about 47mph. I changed to a Acme 13x11.5 3 blade, I get much better hole shot, better speed holding, a little less prop wash and 47mph top speed unloaded.
For what we do, ride between 20 and 29mph (wakeskating, wakeboarding and Skyskiing) the Acme is great. I don't really care to race bass boats up and down the lake, so topping out at 47mph is no big deal.
A lot of V-Drives work really well with the CNC 4 blades like Karl mentions.
|Hey, I've got a question about props. Do higer or lower pitches provide taller wakes?|
|Bryce, I don't think that the pitch will cause the wake to be taller or lower. |
A lower pitch prop will give you better hole shot. A higher pitched prop will give the potential for higher top end speed. Cupping plays a part too.
|hey...when you're talking about "hole shot" what are u talking about?|
|Okay, I'm totally confused. I have a 2002 Malibu LXi (direct drive) with the stock 3-blade. My friend keeps telling me to get a 4-blade since I run with 1800-2000 lbs. Is it worth the $340 to upgrade to a 4-blade?|
|Yes, I am getting confused too. I have a 3 blade and 4 blade prop. Both are OJ and both are 13x13. Which is better? What difference should I see in the two? |
|I don't know the specifics of the various applications for each of you, but to repeat what some have already said and put it in simpler terms: CNC is the new technology and it offers better performance than a traditional forged prop, as the tolerances are much tighter. This is a given. If you want a performance upgrade, this is the place to start. They're a bit more spendy but not that much more. Acme makes them and now also OJ. As far as the other variables, they would be more specific to the individualized applications, and you might have to work a bit harder to figure those out and get it tweaked optimally. |
|I hear you, but since Malibu COMES with CNC props, guess that means an upgrade wouldn't get me much.|
|I called up Acme looking for a better prop for my boat. They asked me a number of questions about my boat including how much ballast I was running and they recommended a 3 blade 542 for my 1986 SN 2001. This prop is wicked!!! Great people and very helpful. I would call them up.|
|Paul - call up Acme and describe your situation. They may recommed a different prop for your application. Also, Malibu was using props other than Acme for a while. You might want to check. Also, Acme has added some designs of late and their perfromance recommedations may have changed. I can get you whatever Acme prop they recommend. |
Flying Frenchmen - going from an older OJ to the new Acme will provide a noticible difference. The new OJ CNC is still not up to the Acme on most applicatons. Acme still has the better design and it show it in hole shot and top end numbers.
|better holeshot means getting into a plane much quicker, the pitch of a prop or the amount of blades doesnt increase wake size, your rpm's will be lower with a 4 blade prop. I would definetly go with a 4 blade, its the better prop to use for watersports, and its not very often your gonna be going top speed. |
|The former major benefit of the 4-blade was the balance and increased surface area. The Acme 3-blade has more surface area than most competing 4-blade props. |
The major benefit of the surface area is the hook-up under acelleration. The 4 blade does have increased drag, which is why it has a lower top end.
In general, using an Acme, the 3-blade will perform as well as the 4-blade. It is precisely balanced. The big exception is loaded V-drives. There, 4-blades still hold the performance edge. Acme does not know exactly why, but that is the data. My personal belief is it has to do with slippage and displacement drag (4-blades having smaller negative pressure areas).