Prop

[bgunterman]

Hey I just bought a 99 Pro Air and I wanted to buy a new prop. Any recommendations on brand and does anyone know the shaft size? I can't find it in the manual. I did find out that it is right hand rotation, and what size is it? I am new to boat owner and had great luck on this forum for my ballast pumps. Thanks!!

[JoeCos]

RE: Prop

Welcome to the site !

You might want to add info such as what motor your Pro Air has, what type of boating will you be doing ? boarding ? skiing ? What type of prop do you have now and how its performing to your needs ?

I have learned from this site that there is No such thing as a "Perfect - All purpose" prop. There will always be a compromise.

As for brand - you will find most users here prefer Acme 4 blade Nibral props. They seem to match very well with CC boats and engines.

Once you give more information about your engine, I'm sure you will get specific response here.

JoeC

[TRBenj]

Re: RE: Prop

As for brand - you will find most users here prefer Acme 4 blade Nibral props. They seem to match very well with CC boats and engines.

The 3-blade Acmes outperform their 4-blades, at least on a direct drive that isnt weighted down. I would think the 470 would be a great prop for you.

[M3Fan]

Re: RE: Prop

As for brand - you will find most users here prefer Acme 4 blade Nibral props. They seem to match very well with CC boats and engines.

The 3-blade Acmes outperform their 4-blades, at least on a direct drive that isnt weighted down. I would think the 470 would be a great prop for you.

I can't wait to see how the 612 3 blade stacks up against the 422 in testing this spring. I don't know that the 470 is a valid comparison since you're taking out pitch and adding RPMS. I'd imagine a prop with less pitch would naturally have more out of the hole and allow you to turn higher RPM's WOT by nature. I think the 612 Vs. the 422 is the real apples-to-apples comparo.

[bgunterman]

prop

Sorry I forgot some tech details. The engine is a GT 40 5.8 L. It will primarily a wakebard boat. I have an OJ 4 blade and when I tested the boat it seemed to do very well although I was only in the boat for 1/2 hour or so.

[TRBenj]

Re: RE: Prop

As for brand - you will find most users here prefer Acme 4 blade Nibral props. They seem to match very well with CC boats and engines.

The 3-blade Acmes outperform their 4-blades, at least on a direct drive that isnt weighted down. I would think the 470 would be a great prop for you.

I can't wait to see how the 612 3 blade stacks up against the 422 in testing this spring. I don't know that the 470 is a valid comparison since you're taking out pitch and adding RPMS. I'd imagine a prop with less pitch would naturally have more out of the hole and allow you to turn higher RPM's WOT by nature. I think the 612 Vs. the 422 is the real apples-to-apples comparo.

Very true- the 612 (12.5x15.25 3-blade) vs. 422 (12.5x15.5 4-blade) would be the most accurate comparison on 3-blade vs. 4-blade since their dimensions are very close. However, the 470 (12.5x15 3-blade) will turn 180 more RPM at WOT than the 422, and will give better performance all around- especially on a larger boat like the Pro Air which will presumably be weighted down and used for wakeboarding.

Even on a non-weighted 196, the 470 outperforms the 422. (Either prop blows the OJ Legend 4-blade away though.)

The other problem with the 612 is that its no longer available- the 470 was found to outperform it, and due to their similar sizes the 612 was discontinued.

Next spring I will have to get some numbers comparing the 422, 470, 612 and OJ Legend. Maybe OJ would send me an XMP as well?

[NCH2oSki]

RE: Re: RE: Prop

I actually prefer my old OJ 4 Blade to my new 422. It has a softer pull for skiing. After some discussions with some engineers that work for another boat company they agreed that a larger prop will have a softer pull, even 1\2" will make some difference.

[SquamInboards]

RE: Re: RE: Prop

Sorry to interrupt, but while we're on the topic. My 2001 has a 330hp EFI with a 13 x 14 4-blade. Engine is rated to a max RPM of 5000 which gets the boat to around 49 mph, but there is still plenty more there which is blocked by the rev limiter. What would be a good solution to increase speed while maintaning below red line RPM, regardless of out of hole power loss?

[M3Fan]

RE: Re: RE: Prop

Completely out of curiosity, I wonder why CC never embraced the 3 blade Acme for their factory prop- perhaps they don't want to wipe out Acme's "upgrade" market by giving the boat the best prop out of the box. Who knows. AFAIK, they still come from the factory with the 4-twenty-twizzle.

[TRBenj]

RE: Re: RE: Prop

Joel, Ive spoken to Bill at Acme and even he's not sure why CC hasnt switched to their 3-blade. Perhaps CC doesnt want to turn the motor an extra 180 RPM (470 vs 422) to get the slight performance advantage?

Squam, are you running the 1.23 tranny with that motor? If so, you definitely dont have the right prop. Either way it sounds like you need more pitch- a prop like the 470 (12.5x15) would probably be a good choice for you.

[steelerguy]

I have a 470 Take a look

http://planetnautique.com/index.php?...amp;highlight=

[TRBenj]

You can get the 470 for $308.75 (free shipping) with our PlanetNautique discount. They were great to deal with and extended my trial period until I could use my boat last spring.