15x13 or 15x12 Prop

[snyderaaron]

I currently run the OJ 945 which is a 15x13. Would I gain much by getting a 15x12 prop. I run a lot of weight and noticed my RPMs running pretty high. Thought this might help. Plus I haven't spent much money on the boat this year.

[mcjimmy33]

15x12 you will run higher RPMs. I run a ACME 2313 which is a 15 x 12 but with .150 cup to keep the RPMs down some at higher speeds. Switching from a 15 x 13 to a 15 x 12 will get you more torque and low end power and sacrifice top end speed.

[Sickpainter18]

When weighted down and surfing what rpms is everyone else turning

[Shoebox]

15x12 you will run higher RPMs. I run a ACME 2313 which is a 15 x 12 but with .150 cup to keep the RPMs down some at higher speeds. Switching from a 15 x 13 to a 15 x 12 will get you more torque and low end power and sacrifice top end speed.You will likely run lower rpms surfing though, because the engine doesn't have to work as hard and the prop isn't "slipping" as much.

[Shoebox]

When weighted down and surfing what rpms is everyone else turningDepends on the size crew on board. At 11.2 I'm between 3300 and 3600 rpm.

[snyderaaron]

Depends on the size crew on board. At 11.2 I'm between 3300 and 3600 rpm.

That’s what I am running. Just didn’t know if the 13 to 12 pitch would make that much of a difference.


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[Shoebox]

That’s what I am running. Just didn’t know if the 13 to 12 pitch would make that much of a difference.


Sent from my iPhone using TapatalkI tried both, preferred the 15x12. Engine didn't seem to work as hard at a given rpm.

[Sickpainter18]

Depends on the size crew on board. At 11.2 I'm between 3300 and 3600 rpm.
We are running about 4,000 rpms is that too high?

[Shoebox]

We are running about 4,000 rpms is that too high?That's pretty high. What prop do you have?

[Sickpainter18]

That's pretty high. What prop do you have?

OJ 945 15x13

[snyderaaron]

OJ 945 15x13

That’s what I have and run about that too while surfing.


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[Shoebox]

What boat/ballast are you guys running?

[Sickpainter18]

I have a 2018 craz with stock 3000 lbs ballast usually 5-6 adults 1-4 kids

[snyderaaron]

Mojo. About 5000lbs of ballast [emoji2960]


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[schwan]

16 mojo here with a 15x12 and I'm really impressed by it. We run at least 5k ballast and run around 3300 to 3600 rpm. No experience with a 15x13 though.

[Shoebox]

If you're at 4k, especially with stock ballast, you should at least try out a 15x12.

[KnoxMojo]

I am running 4000 pounds plus people in the SA, but I am going the other way. Had the 15x13, but hated running high rpms cruising the river and only doing 27 mph unweighted. I am still looking for that happy medium. So far, the 15x14 is doing well. But the 15x13 didn't lack for hole shot pull.

[larry_arizona]

I am running 4000 pounds plus people in the SA, but I am going the other way. Had the 15x13, but hated running high rpms cruising the river and only doing 27 mph unweighted. I am still looking for that happy medium. So far, the 15x14 is doing well. But the 15x13 didn't lack for hole shot pull.

SA 400 stock ballast plus people and running a 15x12.5

Pulls great and cruises at 38 without ballast at 4800rpm, going above 5000rpm and it doesn’t go any faster and might cavitate.

Does everything I need it to do at wake and surf with ballast and cruise without ballast




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[KnoxMojo]

Guess I am used to the Mojo where I was using the 1235 (14.5x14.25) and could surf at 3500 rpms with over 4k ballast, wakeboard with 3500 pounds around 3700 rpms and cruise at 32 empty at around 3500 as well. That thing seemed to sip fuel for longer days on the water as compared to the SA. But I guess that why it has a bigger tank. Lol. I don't like my boat to be at a steady state over 4000 rpms.

[snyderaaron]

How will the RPMs be when wakeboarding at 23 mph with the 15x12.


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[KnoxMojo]

How will the RPMs be when wakeboarding at 23 mph with the 15x12.


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They'll be fairly high, teetering on 4000 or more. Cruising speed at 4000 rpms around mid 20s.

[Shoebox]

How will the RPMs be when wakeboarding at 23 mph with the 15x12.


Sent from my iPhone using TapatalkHow much ballast do you run when wakeboarding?

[Shoebox]

So with 700 lbs lead, ballast bags empty, I got 3200 rpm at 23 mph on my 15x12 Acme 2419.

[snyderaaron]

How much ballast do you run when wakeboarding?

I run about the same. Just move my lead wake.


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[Shoebox]

I run about the same. Just move my lead wake.


Sent from my iPhone using TapatalkOK, well my Mondo was 3200 rpm at 23 mph, 3400 at 26 mph, and 4000 at 32 mph.