Which do I want? 3 blade prop or 4 blade prop?

lumpy19 · Criminal Joined: 12 Jan 2003 Posts: 97 City: Rochester

Boat is a new 2004 Moomba Outback LS. It's been sold to me with a 3 blade prop on it but the listing says 4 blade prop so I can get the 4 blade if it's better for wakeboarding. This is my first inboard boat so I'm not sure which prop is better for boarding. Some skiing will be done, maybe 2% of the boats use and I don't care how fast the boat goes, I just want a nice wake.

Thoughts?

I searched the forum and surprisingly couldn't find too much info on 3 blade vs 4 blade for inboards.

Scooby · Posted: Dec 16, 2004 9:43 am Post subject:

It really depends on the prop that they are giving you. If they give you a 3 blade acme Prop, then I would say stay with the Acme Prop.

oshensurfer · Posted: Dec 16, 2004 10:16 am Post subject:

SupraBoarder · Posted: Dec 16, 2004 10:44 am Post subject:

It really doesn't matter as much if it's three or four blades... It's all about surface area and pitch. Call up the guys at acme and they can help u out.

Nauty · Addict Joined: 12 Feb 2004 Posts: 827 City: Lake Dallas

In the past 4 blade props were preferred because when manufaturing propellers it was easier to balance a 4 blade than it was to balance a 3 blade. The number of blades doesn't have as much to do with hole shot as most people think. Hole shot has more to do with the pitch.

Now days 3 blade props can be made with a CNC machine. This enables propeller manufacturers to precisely balance 3 blade props just as well as a 4 blade. Acme makes a CNC 3 blade that many people prefer over a 4 blade because with some CNC 3 blades there is actually more surface area than a 4 blade. More surface area means more water displacement which means improved propulsion or hole shot.

A balanced prop means that you will be able to maintain your speed much easier. With a balanced prop you won't have to constantly adjust the throttle to maintain your desired speed. Therefore, in years past a 4 blade was the preferred prop to use for wakeboarding so that speed could be maintained.

As mentioned above, call Acme and describe to them what you plan on using your boat for. They can reccomend the proper prop for you. If you plan on primarily wakeboarding you might want to go with a lower pitched prop. This will improve your hole shot when the boat is weighted with ballast. The downside will be your top end speed will be decreased.

I believe Moombas come with a stock prop that is somewhere in the middle. I think they are a 17 pitch? This will work fine for skiing and wakeboarding as long as you aren't throwing a ton of ballast in your boat. If you are riding with 1400 lbs or more you may want to drop down to a 16 pitch. If your're running with 2000 lbs + you may want a 15.5 pitch.

The only caution in going to such a low pitch is when you are cruising WOT with no weight the RPMs will be reving pretty high. Just keep an eye on it so you do not red line.

I am no expert on the subject, so you may want to call Acme to be sure.

- Richard

deepcove · Soul Rider Joined: 15 Mar 2004 Posts: 296 City: Vancouver

Lumpy,

I have a 04 Mobius LS with the stock 4 blade OJ which is 13 pitch. I am going to try a 3 blade Acme this year, I talked to Acme and they recomend the #541 or go to the 543 if you are running in access of 1200 lbs. the #543 is pitched down 1/2" to accomodate the extra weight.

There is lots of info in this Forum, you just gotta look.

Nauty · Addict Joined: 12 Feb 2004 Posts: 827 City: Lake Dallas

Deepcove,

I stand corrected! You are correct with your pitch. I was think LSV, not LS.

Sorry!

Wakebrad · Ladies Man Joined: 11 Dec 2003 Posts: 12257 City: Dallas

So am I correct in saying you should adjust the pitch of your prop based on what was initially on there. Because Nauty, you're talking about a 15.5 being low and then deepcove says some come with 13. I am not sure what came on mine initially but I think I have a 16 pitch prop on there now. It's a 4 blade. Would I be screwed if I went to a 13 or whats the story?

Nauty · Addict Joined: 12 Feb 2004 Posts: 827 City: Lake Dallas

Brad,

I initially thought we were talking about an LSV (V-drive). Lumpy has an LS (direct drive). For his boat (according to Acme via wakeside) the correct prop size is:

Stock

541 - Acme 3 Blade Propeller
Diameter: 13
Pitch: 12
Cup Size: .080
Bore: 1"
Rotation: LH
Price: $332.95

For additional ballast they suggest:

1000 lbs Ballast

543 - Acme 3 Blade Propeller
Diameter: 13
Pitch: 11.5
Cup Size: .080
Bore: 1"
Rotation: LH
Price: $332.95

For 2000 lbs and over they suggest:

2000 lbs Ballast +

649 - Acme 3 Blade Propeller
Diameter: 13
Pitch: 11.5
Cup Size: .040
Bore: 1"
Rotation: LH
Price: $332.95

As far as your boat goes Brad you should give either Acme or Correct Craft a call. A 16 sounds right, but your boat does seem a little sluggish out of the hole. I run a 16 pitch on mine, but my Nautique is quite a bit shorter than yours. It may be possible that you need to drop yours down a little to account for a bigger boat with ballast.

Calling Acme is your best bet. The diameter and pitch vary from boat to boat based on transmission, shaft angle, boat size, and application. The props listed above that I took from wakeside are for Moomba direct drives. The prop you need for your boat will most likely be different.

- Richard

deepcove · Soul Rider Joined: 15 Mar 2004 Posts: 296 City: Vancouver

I believe boats with gear reduction use the higher pitched props, your best bet is to call Acme. These guys are really knowledgable (sp) and will point you in the right direction.

Nauty · Addict Joined: 12 Feb 2004 Posts: 827 City: Lake Dallas

Also, I left out one very important factor.........

As with breasts, the cup size of your prop is very important as well. Laughing

Notice the difference in cup size between the last two props listed for the Moomba LS.

acurtis_ttu · Soul Rider Joined: 16 Aug 2004 Posts: 499 City: Houston

just curious, but when it comes to props, can you just take you standard stock three blade to a propeller repir shop and have them repitch and recup to the specs of lets say an acme?

lumpy19 · Criminal Joined: 12 Jan 2003 Posts: 97 City: Rochester

Thanks for all the info guys. I did search the forum but most of the stuff I found was based on I/O props and I wasn't sure if there was a difference or not.

I plan on talking to my dealer about it but I fear he'll just tell me the 3-blade is best since that's what's on the boat but we'll see.

oshensurfer · Posted: Dec 17, 2004 8:18 am Post subject:

lumpy19,
Call ACME. They will give you impartial info on which prop is best. Do tell them what you have, just ask what's best. They are very helpful. I think you can find a matrix of props/boats on the web too.

boarditup · Addict Joined: 01 Dec 2003 Posts: 731 City: Allendale, MI

I am an Acme dealer. If you want the 3-blade, which is what they will recommend, let me know and I will ship it to you for $310 in the CONUS. I am less than an hour from the factory and am one of their dealers.

rider@boarditup.com

absolutofft · Outlaw Joined: 12 Oct 2003 Posts: 162 City: Langley

I just called ACME to ask them if that 11.5 pitch prop would be the best choice for my boat which is a 1998 mastercraft sportstar.

649 - Acme 3 Blade Propeller
Diameter: 13
Pitch: 11.5
Cup Size: .040
Bore: 1"
Rotation: LH
Price: $332.95

and he told me that I should actually go for the 10.5 pitch over the 11.5 pitch. The 10.5 pitch prop is called the 913. What do you guys think?

scooter · Addict Joined: 15 Jul 2003 Posts: 633

HEY lumpy19 i saw you the other night out on Conesus. It was yesterday at about 9pm and I went past you slowly then you followed behind my boat into the cove. Sweet Boat, I hope to see you out there.
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