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-   -   MB F21 max ballast for factory prop (http://www.wakeworld.com/forum/showthread.php?t=781131)

mdaijogo 06-29-2010 2:28 PM

MB F21 max ballast for factory prop
I found a situation where my F21 would not get to plane this weekend.

I had both tanks full, 7 guys in the boat, one in tow. Being conservative, the average weight of each passenger was 180lbs.

Total weight (ballast) = 3240

All 7 passengers were in the cabin of the boat. I take off and the boat is just staying at about 14mph (GPS reading). I stopped the boat and moved 2 guys into the bow. The boat finally planed after a long time.

Has anyone else had this issue? I may have that many guys in the boat in the future and would hate be under propped. I don't know what pitch the 4 blade I have is, but it is from the factory.


boardnxtx 06-29-2010 3:23 PM

I can tell you that the immediate response will be that you had too many guys in the boat, and that boobs are much better for ballast. Other than that, I have nothing constructive to add.

Thank you and good bye

buffalow 06-29-2010 4:52 PM

Hey Mario, Which motor do you have? My boat has the bigger motor and it rips out of the water even with a fair number. That does seem to be a fair amount of guys + ballast. I would have got some weight in the nose for sure- ideally a few of those dudes. Maybe drop some of the ballast if you are running that many guys? How is it with like 3-4 guys?

mdaijogo 06-29-2010 6:46 PM

The boat runs fine with 3 adults and 2 children. The boat gets up and goes. I could always just go 3/4 full if I have that much of a passenger load.


buffalow 06-30-2010 5:31 AM

Of course the obvious is switch 7 dudes for 7 women and you get the best of all worlds :)

cwb4me 06-30-2010 5:43 AM

i've been in a mb witth 12 dudes and full ballast with a factory prop. we have to get at least 6 guys up front in bow annd walk way . but once you get it to shift it will plane out and makes a huge but steep wake that boots you straight up!

alans 06-30-2010 6:31 AM

What prop do you have on there, I know you said factory, but that can mean a lot of things.

I was out last night with 7 Adults, average weight at about 170 and one toddler 30 lbs. Very little fuel. <200 ft. altitude. We were riding full ballast and it was still planing very quickly, with very little hesitation.

This is a TWB, 343 Cataium, and 14x14.25 Acme. Top speed is 44 unweighted.

wake26 06-30-2010 6:32 AM

My cousin has a F21 he went back and forth with MB about the same problem but his would struggle to get on plane with full ballast and two adults. After a lot of prop testing and testing the motor to make sure it was running right Mb decided to install a wake plate at there cost that made all the differece in the world he is now back to the stock prop but with a wake plate. this past weekend we had 6 adults and 3 kids full ballast and the boat had no problems getting on plane. If I were you I would check into getting a wakeplate installed like I said it was a night and day defference.

wakecumberland 06-30-2010 6:37 AM

Hey Alan, when you coming to KY? Im anxious to see the MB!

slipknot 06-30-2010 8:19 AM

Who said factory is enough anyway? What aftermarket prop is the best for this boat? And don't say the factory one is the biggest please. Should we run an ACME 1235? Anyone else care to chime in?

alans 06-30-2010 9:24 AM

My boat came stock with the 1433, which is 14x14.25 .105 Cup. The 1235 would have a little worse hole shot than the 1433 14.25x14.25. If you were riding with ton's of weight all the time, I would probably go with something like the 1417 14x13.75. This is all assuming that you are running the 343 and not the Zr 409.

adam4x4 06-30-2010 9:25 AM

Its funny this came up. i had the same problem this weekend to. I moved some people to the front of the boat and then it was fine. Yes no madder it going to take longer to get to plane. The ride that was ridding also told that the wake was killer. I had i had 10 people in the boat and fill to max. i may look in to a wake plate, but i do not know if the boat was built for one.

slipknot 06-30-2010 10:10 AM

Thanks Alan, I will also ask Acme before I pull that trigger. 1217 sounds good. It came with a 1161, 1125, or 1433 from what ACME said. And there is more aggressive than that, that will be put on soon, and the stock one will be my back up. Once I confirm and purchase/install I will post results.

mdaijogo 06-30-2010 10:10 AM

I have the 343 cat engine. I forgot to mention that the boat had over 1/2 tank of fuel.


slipknot 06-30-2010 10:21 AM

Oh yeah forgot to mention, I ran a full tank of gas, 9 people, full ballast plus, and the wake is a perfect shape and absolutely redonkulous!

alans 06-30-2010 10:23 AM

Slipknot, you mean 1417 correct? Not 1217. I am pretty sure it would be a beast with that pitch. Definitely check with ACME regarding that purchase though. I love my 1433, I think it is the perfect prop for the boat. I would only go lower pitch if I was consistently riding full fuel, full ballast, 4-8 peeps, and 1k+ ballast on top. Which I am sure some of you are. I used to run over 4k in my Super Air.

alans 06-30-2010 10:35 AM

Slipknot, wow good info on the props. I knew MB was running lots of different props on the boats, but am a little surprised on the spectrum. The ZR409 might be able to turn the 1125 pretty well, but it would not be a good "full ballast" prop on a 343. I had an '09 TWB with the ZR409 and a 1125 on it, the thing would run 50+mph with a few people in the boat.

1161 = 13.5x16 .135 cup
1125 = 13.5x16 .150 cup
1433 = 14x14.25 .105 cup

As a manufacturer that makes boats with such huge ballast systems, it is tough to guess how each owner is going to use their boats.

ej_ojprop 06-30-2010 10:53 AM

More diameter, like an OJ 14.25 X 14.5 might help too.

alans 06-30-2010 11:01 AM

Eric, do you work for OJ? I always wonder if it is more of a pitch issue or a diameter issue. Props are super complicated to figure out in wake boats.

ej_ojprop 06-30-2010 12:11 PM

Alan - I do work for OJ. I built the larger diameter propellers a few years ago specifically for the wakeboats. The larger diameter helps the propeller bite with the lower pitch.

alans 06-30-2010 12:20 PM

So when a boat is attempting to climb onto plane and the tach is at 4600 RPM, what is happening? is the prop slipping? or is it gripping and moving water but not enough? thus a larger diameter.

ej_ojprop 06-30-2010 12:39 PM

Slipping due to the lack of diameter, usually.

hunter660 06-30-2010 4:51 PM

If you pull the 14.5 x 14.25 I would be interested in taking it off your hands.

adam4x4 07-01-2010 5:56 AM

I looked at my prop last night and it is a 1433 = 14.00x14.25 with a 105 cup. how much do u gain by putting on a 1235=14.5x 14.25 What cup it the best? i do not want to loose much top end because i do go to the delta and run a round some times.

alans 07-01-2010 6:21 AM

Eric probably knows a lot more than me, but I think something like a 1615 14.5x13.75 would give you the extra push you need. You will definitely loose a few mph though on the top end.

ej_ojprop 07-01-2010 7:06 AM

We have a 14.75 X 13 that is a real stump puller. I would go with the OJ 14.25 X 14.5 or our 14.75 X 15.5 if you are concerned about top end.

slipknot 07-01-2010 7:21 AM

Thanks Eric for posting and providing information this is what WakeWorld is for and about. Thanks WW! What prop would you say we should use? If it were your boat?

ej_ojprop 07-01-2010 7:27 AM

I would start with the 14.25 X 14.5

alans 07-01-2010 7:33 AM

Eric, it sounds like slipknot wants something to get out of the hole faster with heavy heavy ballast. How could a prop with more pitch than what he has help?

ej_ojprop 07-01-2010 7:58 AM

The larger diameter will help. We also have a 14.25 X 14 that I have run on the MB's.

adam4x4 07-01-2010 8:04 AM

how much room should we have between the haul and the prop?Right now with the 14.00x14.25 i have about 1".

alans 07-01-2010 8:13 AM

I always heard, 2 Fingers. I just put a 26x22 on my father-in-laws work boat last weekend with a little less than 2 fingers and it did fine.

ej_ojprop 07-01-2010 8:24 AM

The 14.25" diameter will be fine.

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