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Prop Advice for '99 Air Nautique

Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=42299
Printed Date: April-19-2024 at 8:55pm


Topic: Prop Advice for '99 Air Nautique
Posted By: curiouslibra
Subject: Prop Advice for '99 Air Nautique
Date Posted: January-10-2018 at 8:59pm
Long time lurker first time poster. I just filled out my profile so it's waiting for review.
I have a 1999 Air Nautique with a ford GT-40 310hp engine fitted with an OJ 14x16 prop.
I really liked the thread "Factory 4 blade prop VS. new ACME" and it fit my situation perfectly except the OP boat was only 260hp and mine is 310hp. So would an ACME 422 be the prop for my boat or would I need a bigger dia/pitch prop? if I do need a bigger prop which one does anyone have experience with that has a nice wake i.e. low roster tail and the prop doesn't growl like some have commented about with other props.
              RPM / MPH (phone gps)
WOT     4900 / 40.1
              4500 / 37.0
              4000 / 34.0
              3500 / 30.0
              3000 / 24.0
              2500 / 17.4
             2000 / 12.0
             1500 / 8.0
These speeds were with just me in the boat with ski gear and 3/4 tank of gas at 600ft above sea level, temp was high 90's that day.
I've read where ideally you should get RPM / 100 = MPH is this for only top end or through out the speed range? I'm wondering if the ACME 422 would allow me more top end speed than the OJ? I'm not sure the tach is accurate but if it is then would the ACME 422 give me a couple of more RPM at WOT? I think I remember someone saying theirs topped out at 5200? I mainly do skiing and kneeboarding and just starting wakeboarding and looking to try a skyski this spring. The boat pulls me up without needing full throttle so I could lose some holeshot to get a better ski speed that is not reving the engine so high as I think 4000RPM to keep 34MPH is a little high or is that what is normal?
Thanks in advance for any thoughts and suggestions as to what prop would best help get a better performing boat.


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"Don't argue with idiots, onlookers will not be able to tell the difference between the two of you, as the idiot drags you down to their level and beats you with experience."



Replies:
Posted By: gt40KS
Date Posted: January-10-2018 at 10:00pm
I have a 95 SN also with the GT40 and have recently replaced the factory 3 blade OJ with the ACME 422 and noticed a huge difference in low and mid-range acceleration as well as increased top speed. However, your AIR and my SKI are two different boats on the bottom side - TSC vs TWC. As a boat more designed for wake sports, the bottom focus was more on creating a larger wake at lower speeds than a smooth wake for slalom.   Wake hulls typically create more drag than ski hulls and thus will not react the same given the same prop. While the 422 would probably increase your RPMs and top end somewhat, there may be a trade-off with the wake performance you may be used to and expect.   Having said that, there are several, more qualified folks on the forum to direct you with your final choice given your criteria.   

Welcome to the Forum!!

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JCCI
1995 Ski Nautique GT40


Posted By: SNobsessed
Date Posted: January-10-2018 at 10:28pm
You could call Delta prop & ask them for advice. They know their stuff.

I think they have a return policy (for a different prop) as long as it is undamaged - lowers your risk of buyer remorse.

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“Beer is proof that God loves us and wants us to be happy.”

Ben Franklin


Posted By: curiouslibra
Date Posted: January-10-2018 at 11:30pm
Originally posted by gt40KS gt40KS wrote:

I have a 95 SN also with the GT40 and have recently replaced the factory 3 blade OJ with the ACME 422 and noticed a huge difference in low and mid-range acceleration as well as increased top speed. However, your AIR and my SKI are two different boats on the bottom side - TSC vs TWC. As a boat more designed for wake sports, the bottom focus was more on creating a larger wake at lower speeds than a smooth wake for slalom.   Wake hulls typically create more drag than ski hulls and thus will not react the same given the same prop. While the 422 would probably increase your RPMs and top end somewhat, there may be a trade-off with the wake performance you may be used to and expect.   Having said that, there are several, more qualified folks on the forum to direct you with your final choice given your criteria.   

Welcome to the Forum!!


Thanks for the info. Your comment brings up another question I have. TWC VS. TSC
it seems that in the 1998 to 2000 Nautique made an Air Nautique and a Super Air or Pro Air Nautique with the former having the TSC-1 hull and the later having the TWC hull? I have graphics on the side of the boat saying TSC but that could have been just added. How do I look at the hull and tell the difference between the to hull designs to know which boat type I have?

Also I think I have the gen 2 flight tower but how do I tell the difference between gen 1 and gen 2? Also the blue protective paint is chipping away in spots on the tower, where do you go to buy more paint to keep the exposed metal from starting to rust and corrode?

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"Don't argue with idiots, onlookers will not be able to tell the difference between the two of you, as the idiot drags you down to their level and beats you with experience."


Posted By: scottb
Date Posted: January-11-2018 at 3:48pm
Hi Will,

You can look in the reference section to see the differences between the TSC (total surface control) and the TWC (total wake control).
http://www.correctcraftfan.com/reference/bview.asp?id=31" rel="nofollow - Reference

It looks like the 1999 brochure also shows the Gen 1 tower.

Your numbers look pretty similar to what I had on my 2000 Sport w/the GT-40.


Posted By: lewy2001
Date Posted: January-11-2018 at 7:01pm
Have a read through these two threads and you will get most of your answers:-

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=21800&PN=2&title=prop-removal-questions" rel="nofollow - Sport / Air Props

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=20031&KW=98+Sport&title=98-sport" rel="nofollow - Sport / Air Hull

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If you're going through hell, keep going

http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski

<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta


Posted By: curiouslibra
Date Posted: January-12-2018 at 2:32am
Thanks for the links. The sport / air props was especially helpfull as I think I have the slower hull as the spray breaks right at the top part of the windshield which is ahead of where I sit. In fact I think my boat sits too nose heavy as it will take on water from my own wake as I turn around to get a down skier if I’m not above idle speed. I’ve noticed the backend looks higher up when the boat is resting on the lake with less than half a tank of gas. I’ll usually fill up my fat sacs with about a third full to get the aft to sit even waterline wise to the front. Next time I’m out on the lake this spring I’ll take a picture to show. Almost looks like the boat is nose heavy.
I think from all the comments the ACME 422 will be the prop I Order this spring for the boat. Thanks for all your advise.

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"Don't argue with idiots, onlookers will not be able to tell the difference between the two of you, as the idiot drags you down to their level and beats you with experience."


Posted By: 84SNautique
Date Posted: January-12-2018 at 8:57pm
Does anyone know what the rudder is specifically made of???


Posted By: 8122pbrainard
Date Posted: January-12-2018 at 9:14pm
Originally posted by 84SNautique 84SNautique wrote:

Does anyone know what the rudder is specifically made of???

Manganese bronze Why do you ask?

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/diaries/details.asp?ID=1622" rel="nofollow -

54 Atom

/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique

64 X55 Dunphy

Keep it original, Pete
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Posted By: 63 Skier
Date Posted: January-16-2018 at 9:49pm
Hello Will, those links have much if not all the info you need. I was very happy with the 422 for a season or two on my '98 Sport (same hull as yours) but then went to the 3 blade 1442 because I wanted more holeshot. If you are ok with the holeshot with the OJ then you'll probably like the 422, it is the best prop for keeping a Sport in the correct rpm band. Your WOT speed seems a bit low to me compared to what I got with my OJ, and your 34 mph rpm seem a bit high, but you never know if that prop was reconditioned at some point.

Super Air and Pro Air are more of a v-hull, Sport and Air are the flatter hull shape. There's a lot of discussion here and there on the site about Sports and Airs having the TSC sticker but not really being the same TSC hull as the Ski Nautiques.

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'63 American Skier - '98 Sport Nautique



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