1.67:1 Transmission w/ 16x12.5 Prop - Overkill?

[Vati' Gang]

Does anyone have experience with the 1.67 Transmission with "High Elevation" 16x12.5 prop?

This is our current selection but I am wondering if it is overkill as we are low elevation. We only surf and have no real need to go above 25mph at any time.

We will have 700lbs of lead and normally run a decent sized crew. Obviously looking to optimize performance for surfing but don't want to over do it

Would love everyone's thoughts.

[2in2out]

We boat at 6000’ with 1.76 transmission and a 16x15, 900# of lead and have no issues. That was crew of 2, but I’m sure 5-6 more would matter much. The 16x13.9 might be a better option. I intend to pick up one and decide which I prefer.

[Isaguel]

The 1.76 is a welcome upgrade. If you only want to go no more than 25 mph then you won't care if you prop down to a 12.5"pitch, you'll have torque to spare, but, I don't think it is necessary. You can sport a 15" pitch prop, at a lower elevation with 4-5k lbs ballast and be fine. It is essentially a balance between speed and torque, finding that happy medium. I would not go over 15", other than that, it's a matter of preference.

[larry_arizona]

The 16x13.9 is a prop Supra designed with acme specifically for the 1.76 trans.

It also replaces the 16x15 factory option.


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[DDNorCal]

I have the 3145- 16x13 prop. It is overkill at low elevation but at 6000+ with 10 people it is needed. 16x15 will be perfect at low elevation.

[larry_arizona]

My understanding is the 16x13.9 pulls like a 13 and top ends like a 15.


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[2in2out]

My understanding is the 16x13.9 pulls like a 13 and top ends like a 15.


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It would be wonderful if you could get one. Wakemakers doesn’t list them. ACME is back ordered since early December.

[SONIC]

Wakemakers is showing in stock on the 13.9 when I looked yesterday

[2in2out]

Wakemakers is showing in stock on the 13.9 when I looked yesterday

I had to clear my cache to get updated page information. It’s in the cart now just waiting for authorization from the CFO. Thanks for waking me up to my mistake.

I want to put the 3591 on and keep the 3337 as a spare. When we move to Austin, I’m going to test them both to see which is better.

[SONIC]

I'm going to do the same.
I don't need the extra torque really but it's always nice!

[2in2out]

Ordered a 3591 today from Wakemakers and just got this response:

“ We wanted to be sure you are aware that your order will be delayed because the items below are currently on back-order or are pre-order products. We currently expect your order to leave our warehouse within the next four weeks.”

Hopefully they can ship it and the foil I ordered two month ago in the same delivery and refund me some shipping costs.

[Moombas]

I was chatting with ACME about 16" props for the 1.76:1 transmission. I have a 23 moomba max and have been struggling to find the right 15.5" prop for all my ballast. I have talked to a few guys that went to a 16" prop on their moomba max and say its perfect. ACME even says with a raptor 400 and a 1.76 trans that 16" is the better decision but I just worry about prop burn.

[KnoxMojo]

I was chatting with ACME about 16" props for the 1.76:1 transmission. I have a 23 moomba max and have been struggling to find the right 15.5" prop for all my ballast. I have talked to a few guys that went to a 16" prop on their moomba max and say its perfect. ACME even says with a raptor 400 and a 1.76 trans that 16" is the better decision but I just worry about prop burn.

I have seen people online go to 16" on Moomba but get prop burn, others have gotten lucky and not had it happen. Skiers Choice does not recommend them with Moomba as they have different clearances. a 15.5x14 should be more than enough for any ballast you are running.

[Moombas]

I have seen people online go to 16" on Moomba but get prop burn, others have gotten lucky and not had it happen. Skiers Choice does not recommend them with Moomba as they have different clearances. a 15.5x14 should be more than enough for any ballast you are running.

15.5x14 is not enough prop if you are running at the target pitch of 9.5*-11*

I tried a 3407, (15.5x13) it would pull the weight but when pitch was 9* or more I was at 4400 RPM.

I currently have a 3829 on the boat (15.5x14.5) and on the regular side when pitch is at 9* it drops speed and will not hold anything above 11mph.

Sure I can bring the bow down to hold speed but 6-7* of pitch is not ideal for the most push.

I have been chatting with mainly Moomba Max owners and not a single one has gotten prop burn with a 16" prop, I did hear of 1 Makai that got prop burn but also another Makai did not get prop burn.

[larry_arizona]

15.5x14 is not enough prop if you are running at the target pitch of 9.5*-11*

I tried a 3407, (15.5x13) it would pull the weight but when pitch was 9* or more I was at 4400 RPM.

I currently have a 3829 on the boat (15.5x14.5) and on the regular side when pitch is at 9* it drops speed and will not hold anything above 11mph.

Sure I can bring the bow down to hold speed but 6-7* of pitch is not ideal for the most push.

I have been chatting with mainly Moomba Max owners and not a single one has gotten prop burn with a 16" prop, I did hear of 1 Makai that got prop burn but also another Makai did not get prop burn.

Unless the Moomba are significantly different on pitch requirements compared to Supra, anything over 9.5 is severe overkill and drives RPM up by at least +750 rpm. You lose prop angle efficiency over 10 deg.

The main advantage of SC hull design is relatively low bowrise while surfing.


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[Moombas]

Unless the Moomba are significantly different on pitch requirements compared to Supra, anything over 9.5 is severe overkill and drives RPM up by at least +750 rpm. You lose prop angle efficiency over 10 deg.

The main advantage of SC hull design is relatively low bowrise while surfing.


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Yea I think we actually end up surfing at 8.5-9* pitch on goofy side and its an insane wave.

The problem was the regular wave I couldnt get over 7* pitch, wake9 says 9-9.5* pitch is the best wave for a Max.

With the 3591 I should have no problems holding 11.2-11.8 on regular side now at 9* pitch.

[larry_arizona]

Interesting that you can't achieve 9/9.5* pitch on one side, are you using auto wake?

I don't see a pitch difference goofy to regular, I am trying to envision how prop effects one side only.

Seems it would be more ballast or wake plate related.

Typically I hit 9-9.5 pitch, roll isn't super critical (Gen3 SA) and then add or remove wake plate to adjust length of wave or kill some push if the rider is constantly on their back calf hitting the brakes.

I quit using auto wake, got ballast dialed in water and lead, factory goofy and regular surf plate settings, might move a human as needed worse case, then adjust wake plate as needed between
0-25%

I don't mean to challenge your set up. But just struggling how prop will fix your pitch on just one side.


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[Moombas]

It's pretty common when you're at the edge of a prop that you struggle to hold speed on the regular side.

So basically at my current weight I have to deploy some wake plate to bring bow down to 7* pitch to hold 11.2mph on regular side. If I pitch back up to 9* speed starts dropping because it's not enough prop.

No auto wake for me either, just using the auto wake screen to aim for target pitch and roll.


Prop will fix my power issue, I'll be able to hold speed at the higher pitch numbers instead of bleeding off speed. No worries at all asking questions, been working on it with Jim at ACME and sounds like this new prop will fix the issues I've described.

[cucv]

@Moombas, please tell me about your ballast confirmation. I messed around with ballast and props a bunch on my Tige, and it was super satisfying getting to the right prop for my confirmation. I've got several new bags to plumb into my Mojo and expect a prop change in my future. I plan on using a scuff guard to avoid gelcoat burn if necessary.
Megaware - ScuffBuster Bow Guard for Boats - Protects from Scuffs and Scratches - Stainless Steel Shield with 3M Adhesive - Mirror Polished Finish (5.75 x 4.5 in) https://a.co/d/85oTBKd

I finally found a ballast combination on my Tige where I could run low pitch heavily weighted and get great push and super low RPM's. I'm hoping to find that on the Mojo.


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[Moombas]

@Moombas, please tell me about your ballast confirmation. I messed around with ballast and props a bunch on my Tige, and it was super satisfying getting to the right prop for my confirmation. I've got several new bags to plumb into my Mojo and expect a prop change in my future. I plan on using a scuff guard to avoid gelcoat burn if necessary.
Megaware - ScuffBuster Bow Guard for Boats - Protects from Scuffs and Scratches - Stainless Steel Shield with 3M Adhesive - Mirror Polished Finish (5.75 x 4.5 in) https://a.co/d/85oTBKd

I finally found a ballast combination on my Tige where I could run low pitch heavily weighted and get great push and super low RPM's. I'm hoping to find that on the Mojo.


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I have 1,345 lbs wakemakers rear bags, factory subfloor bags under each side bench seats (500lbs each side), factory center bag 1,000lbs and the wakemakers 860lbs bow bag = 5,500lbs of water ballast.

I have 600 lbs of lead right now, I have 200 each side locker as far back as they can go/butt up to the rear bags. 100 in passenger/amp/audio area, 100 under helm/controls.

Boat came with a OJ932- 15.5x16.5

First prop I tried was ACME 3407 (15.5x13) which worked and moved the weight but RPM were very high at 9* pitch, over 4,000 rpm 4200-4400.

I then tried my friends ACME 3829 (15.5x14.5) rpms at 4,000 when surfing but at times I cannot hold speed over 10.8 on regular side if I have pitch above 8*.

I have now ordered a 16x13.9 acme 3591.

I am not worried about prop burn, I am chatting with 3 people right now on facebook Moomba Max group who have no prop burn after a year of running 16" prop. My dealer also confirmed the strut is the same length from a supra to a moomba of my year, the prop will have enough room to be safe.

[cucv]

Great info, thanks for sharing

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