Prop questions??

my questions are how do i tell what prop i currently have and what prop i should get? i definitely need more low end as the boat seems a bit lagging with weight. i have been in MC,Tige,and SAN and they all take off like rockets and have similar HP. but definitely get you a bit better outta the hole.

we normally run 1500lbs plus atleast 3 people, what prop should i get? ACME or OJ? and what pitch?

thanks for your help

What kind of boat do yo have? Is it a Nautique? If not then it will be a left-turn prop. As for the type I would ask whether yo want to run brass or stainless. Brass if you are runnin in places like the delta with low depths and high chances of hittin things like a sandbar. A brass prop will save you in conditions like these as the prop will fold on impact which will limit torque to your drive line or other parts of your propulsion system. If runnin lake conditions with high depths I would run a stainless. The pro will stay true and balanced longer and will chop through any small debris with no problem and/or worry as to your prop getting bent.

With this being said I would definately recommend that your upgrade be a 4-blade prop. Whether OJ or Acmen. The newer style props, such as acme and oj i think, have ridges on the prop. They say this is supposed to be more efficient when cutting through the water. You may want to call the manufacturer of your boat and or the mostr reputable dealer that sells them and ask what the most common size upgrade for a 4 blade prop. I believe the most common size is around a 13 x 16 or 13 x 17. The first number reflects the diameter size of the prop. In this case it is 13 inches. The next number reflects the pitch of the blades. In this case the pitch would be 16. The bigger the diameter prop the more top speed you will notoce. The higher the pitch blade the more torque and hole shot. You want that perfect combo and a 13x 16 or 13 x17 is right in that range. Give or take a little as I have seen 14 in diameter props ran on boats. Anyway goodluck

look around the ring of the shaft hole on the prop. It will usually have the size there.

Look at it this way. A the pitch on the prop is like threads on a screw. A 17 pitch prop will theoretically move your boat 17 inches per revolution. But you need to account for drag, etc. Most ski boats have a right hand spin on the prop and use 13-14 pitches. Low end dig but they aren't speed boats. You have a huge motor, but the low end torque gets the rider out of the water, with ballast, with gas, but you won't go 70mph

I agree, call a service center about the recommended prop. If you know how to drive a boat in 2 1/2 feet of water, get the 4 blade, 14 pitch prop and you won't be disappointed. Should cost you around $400-$500.

Lower pitch = better hole shot. The screw is turning faster with the weight but not driving up the RPMs.

Send me an e-mail with your boat model, engine size, current prop, and total load (factory ballast, extra ballast, and number of people) and I'll let you know your options in both OJ and Acme.

rider@boarditup.com

ok..we have a 2004 sky supreme vdrive with a 350/315 merc engine

i looked and the prop says 13x11.5 L1 1/8

The L1 1/8 means Left hand turn. 1 1/8" diameter shaft.

Your prop diameter is the 13, pitch is 11.5.

I know the "ridges" in the prop arent supposed to make it more efficent due to the ridges, it is because they are now CNC cut with much higher tolerances than in previous manufacturing methods.

I also heard that the new Acme 3-blade is the way to go? Anyone else hear anything about this?

The Acme 3-blade has more surface area than most 4-blades and works quite well. However, on most v-drive boats, a 4-blade still is the better choice.

Just so people know, jonny's boat has a very low pitch prop right now. I don't recommend that he pitch down further. He is out of motor for the application. There is only so much a prop can do for any situation - it is a 5-10% tweak. His boat came with a 12 or 12.5 pitch stock, he is about 1" below stock. A 10" prop is not available and would have the engine screaming at him while running. Not good.

General note - when buying a boat, go big with the motor. It is almost always worth it. I had a boat with a very similar set up to jonny's and ended up with the 13X11.5 3-blade as the best prop for the appliation. My next boat I added 40 hp to the motor selection and it was much better.

www.boarditup.com

Hey Jonny,

I would stay with the same diameter prop. In your case is a 13 inches. That will maintain your top speed. Trust me....step it up to a 16 or 17 pitch and you will get that holeshot you are looking for. I dont know what school of thought some of these guys came from but I guarantee you drop your pitch any more than it is and your boat is going to run worse...not better. Buy a 13 x 16 or 17 and you will be all good. I have an OJ right hand turn(nautiques only) 4 blade 13 x 16 brass (delta) prop. This size was recommended to me by Wesr Coast Correct Craft. I know the size is right because alot of the newer wakeboarding boats if you look at the size props they are runnin...it is in that range. Trust me my boat will tear the arms off you and anyone that has been pulled up behind my boat will vouch for that. I run 1000 lbs ballast.

BTW- in terms of how many blades...that is not even a question. Go with a 4 blade!

(Message edited by zride on April 24, 2006)

Isaac -

He has a 1:1 tranny. Going from a 11.5 pitch to a 16 or 17 pitch would overload the motor and his hole shot would be much worse than it is today. His case is very different than a boat with reduction gearing.

The number of blades is typically less important than surface area. However, for boats that operate at higher speeds, the lower the number of blades the better the top end. More blades equal better "traction" when coming up on plane. Wakeboarding V-drives typically are better with 4 blades. The reason used to be better balance and reduced vibration. The CNC machining eliminated this problem allowing 3 blade applications typically reserved for 4 blade props.

I sell about 200 props a year to wakeboarders and only ever had one returned due to inappropriate pitch. There are a few v-drive boats out there that are special cases, the 220V is one and the Elite is another. I don't know everything about props, but I have been at it for a while and have talked to a lot of customers to know what works well for them.

"He has a 1:1 tranny. Going from a 11.5 pitch to a 16 or 17 pitch would overload the motor and his hole shot would be much worse than it is today. His case is very different than a boat with reduction gearing. "

You are correct sir! 16 or 17 on that boat and it would have trouble getting on plane and would be the worst thing he could do. Call Acme tell them what boat you have how much ballast you want to runt and they will hook you up.
I would also recomend the 3 blade Acem over the 4 blade in any boat with a 1:1 trany


(Message edited by krbaugh on April 24, 2006)

Karl,

What would work good for my application:

01 X-Star/X-2/X-1 with the base 310hp, and currently running the stock OJ 4-blade. I plan on running about 13-1500lbs in the back and about 800lbs in the front. Any suggestions?

Most guys in your situation use the 537 or the 857 if they are really needing hole shot. You would lose more top end with the 857 and drop about another 50 rpms at wakeboarding speeds.

Is the 857 the "rev-limiter special"? What's the pitch/diameter on that one? Is it 3 or 4 blade?

I see Karl.....well you learn something new everyday. I didnt consider your transmision application. Well it sounds like Karl may be of better assistance than I but I still stick to the 4 blade choice. After all what wakeboard boat actually performs better with a three blade rather than a four? Thats just my opinion though. Thanks for new knowledge!

My Mobius LS fully loaded performs way better with my 3 blade ACME #543 than the original OJ 4 blade.....which i happened to get from Karl....thanks dude!!!

Karl,
Got your email. Thanks for the response.

I would like to put the following out here to see what others think.

The situation:
1) 2004 MC 205V.
2) Predator (310hp)
3) 13.75 x 19.5 OJ (current). A little slow out of the hole.
4) Wakeboard almost exclusively.
5) ~2,200lbs max ballast capacity + ~700lbs max people.

The local prop place said the ACME #1285 (for spline shaft) 14.5 x. 14.5 was flying off the shelf for wakeboarding applications. I told him there would be sporadic occasions of slalom and asked him estimated top speed drop. His response was that users said about -3mph off top end. Apparently this prop is being very well received for the wakeboarding application.

Questions:
1) Anyone here have experience with this prop?
2) Any other recommendations?
3) Does my '04 have a splined or tapered shaft? (#1285 for splined, #1235 for tapered).
4) Any advice you want to offer?

Thanks

Paul,

We developed the larger diameter lower pitch propeller specifically for the wakeboard boats last year. We offer a 14.25 X 14 LC and a 14.25 X 14.5 LC in both splined and taper bores. We have had very good success with these propellers. Testing of these propellers was done by many of the top pro riders. The XMP EDGE is outperforming any other propeller on the market. Your boat has a splined shaft. I would suggest our part #510, 14.25 X 14.5 LC .110 cup Splined XMP EDGE 4-blade for your application. Feel free to give me a call if you have any other questions.

Eric @ OJ PROPS 800-359-9730

Eric,
I'll call you to talk about some of the characteristic with the XMP EDGE.
Thanks for the response.
Paul