Gear Reduction from 1:1 to 1:1.46
 

Anyone done this on their boat before?

I'm finding my engine to be a bit lacking for the really big surf days, and have already gone to the most aggressive 13" 3 blade prop (2083).

Trying to determine if doing the gear reduction so I can fit a 14" 4 blade (2571) prop will give me a noticeable performance boost or not. All I do is surf, so hole shot and getting up to 12mph is everything.

Acme seem unsure.

Duffy made the change on his old avy.

http://www.wakeworld.com/forum/showthread.php?t=777091

Thanks, but Duffy didn't really say much after he completed the installation. Hoping someone else out there has done the same thing and can say more. I imagine it'll be about a $2000 job, and need help deciding if the benefit is big enough to be worth it.

Get your prop hammered out to a custom spec?? What is the pitch right now?

It was worth it, but I would try custom props first. Cheaper and easier. I did the whole project for pretty cheap and it only took a few hours.

What prop size can you clear? What boat is it?

I'm using a 2009 Sanger v237. Great boat, but a little under powered for its size when you really start weighing it down. Running a 2083 prop right now, which is a 13" x 9. Most aggressive thing Acme has for a 3 blade. I can just barely fit a 14" prop, with 5/8" clearance leftover, if I move to 4 blades. Acme was recommending the 2571, which is a 14" x 12 4 blade for the most possible low end torque.

How much weight are you running and how slow is it to "plane". Mind boggling that something beyond a 13x9 is needed. I want to see pics of this boat slammed out and the wave when it's running!

What about a 13.5" prop. Thats a lot more surface area.

I don't know if that's an option for 3 blade props? At least not with ACME.

But i don't have an issue with doing the gear reduction... If the performance gains are there. I just don't want to do it and find that it's marginally better than what I have now... or worse.

In your old thread you said you were using a more extreme version of the 911 before the reduction ... I imagine that must have been similar to what I'm using now, the 2083.

So if you went from a 13" prop to a 13.5", I'm guessing I should expect even better performance with a 14"?

How big a difference was it for you when you did it? Was it much easier to plane, or allow you to plane with even more weight?


I think there's a bit of a curse with making big waves... Once you start chasing it, you can't stop trying to go bigger.

Andrew, do you have a hydraulic tab on your 237? That will make a huge difference in getting up out of the hole with a load.

Going to a higher gear ratio makes a little more noise and is a significant cost. Of course, I bet Sanger could install one of their new Indmar 6.2 engines with a new tranny for you. (might cost a tad more again)

I run a Acme 911 3 blade and it comes out of the whole easier then any other prop I have had on my 2004 Avy with the 1:1 All we do is surf, and I run 2300lbs of ballast plus people

I've got the surf tabs on the outsides, but the middle tab is stationary. I do use the surf tabs to try to help out, but they can only do so much to help planing before they hurt the wave.

I think a new engine is out of the question. I've had the boat for 7 seasons, and played around with her a lot. Ultimately a bigger engine when I bought it would've helped, but on cost, age of the boat now, and current prop clearance, seems like a bit overkill.

I'll probably be stepping in to a new boat in a year or two, so a smaller job like a gear reduction seems more doable.

Reduce the gears or talk about a 5 blade. I struggled with my 24v until I went 5 blade. Now I can go 25 with 3k in ballast if I wanted.

Good idea. I just read your old thread about the 14" 5 blade you were/are running.

A gear reduction and a 13.5"-14" 5 blade might just do it.

Sounds pricey, but we'll see.

However I do remember seeing a piece by Acme, how their 4 blades got to speed faster than a 5 blade OJ. I wonder if the science/marketing has changed since they started putting out 5 blades.

Compare the cost of dropping in a trans and a new prop and possibly shaft to the cost of building your engine for more power. What engine are you running? Maybe time for a stroker or a big block?