60 MPH Club, finally made it!
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=23013
Printed Date: May-06-2024 at 8:50pm
Topic: 60 MPH Club, finally made it!
Posted By: PAPA
Subject: 60 MPH Club, finally made it!
Date Posted: August-08-2011 at 11:16am
Well, this turned out to be a good weekend for me. Saturday afternoon after some rains came thru and most peole were off the lake I took out the 77 Ski Nautique which has a stroker 351W, now 392 cubic inches spinning lefty.Previously I was running a Acme 431 and spinning 5700-5800 rpm's and getting 57-58mph. Since this engines peak horsepower is at 5500 I decided to get a Acme 1459 and try it out. Made a pass back and forth on the third basin of Lake James and looked at the GPS and it was 60.1 mph.Definately made my day as I was grinning ear to ear. The prop brought the rpm's down to 5000-5100 at WOT. Now if I want I can throw some more mod's at the motor to gain some more hp. Still smiling on Monday on my way to work. 
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Replies:
Posted By: panda
Date Posted: August-08-2011 at 12:51pm
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impressive ------------- 95 Ski Nautique GT40 |
Posted By: storm34
Date Posted: August-08-2011 at 1:33pm
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Wow....
The 84 Ski Tique made it up to 64 MPH this morning....on the trailer  ------------- |
Posted By: JoeinNY
Date Posted: August-08-2011 at 2:30pm
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So how does it handle at 57+... do you feel the LH prop contributes significantly to any leaning towards the driver side at lower speeds? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: skyway2k
Date Posted: August-08-2011 at 3:08pm
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Can I get a ride?? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5240&sort=&pagenum=1 - '91 Ski Nautique |
Posted By: TRBenj
Date Posted: August-08-2011 at 4:13pm
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Got any more info on the engine build?
The rpm vs. speed numbers look pretty close to correct with the 1459 (reversed 1458). You seem to be way off with the 431 (reversed 430) though, based on the limited data we have now. IIRC, Alan is spinning that prop ~5200 at 55-56mph on his '81, which has the same hull as you. Hotboat was pretty close with his Martinique as well. I would not expect to see those last 400-500 RPM only good for 1-2mph. Interesting nonetheless. Like Joe, Im curious how the boat behaves above 55mph... a few of us have started to note some "interesting" behavior at the limit. The LH powertrain has me intrigued as well. If that 60mph is a repeatable number, then congrats- a few of us have touched it, but not consistently enough for our liking! ------------- |
Posted By: JoeinNY
Date Posted: August-08-2011 at 4:17pm
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I dont know if he is that far off on the 431 numbers.. back when I was running that prop I also found it to fall off a cliff at the upper limits, the last 200 rpm werent worth a half mile an hour.. I attributed it to flex/slippage ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: TRBenj
Date Posted: August-08-2011 at 4:25pm
Good point Joe- anything is possible. For kicks, I looked up Hotboat's numbers again.
Those numbers look pretty darn consistent with what Alan has seen. Of course, we're relying on old (inaccurate?) tachs in most cases, so who knows what to believe. That 430 seems to be a good match on a 2nd gen SN hull with a hot 351w... maybe the torque that a few more cubes brings pushes it past the range where it works efficiently? ------------- |
hotboat wrote:Posted By: PAPA
Date Posted: August-08-2011 at 4:44pm
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Joe, In the past with the 431 prop at 55+ the boat had tended to porpoise at times, not always, but a lot of times. This back to back run actually did not porpoise at all and I did not realize I was going that fast due to the engine rpm's being only around 5000. I was really happily surprised by this. At slow speeds it does list to the starboard side but no problems with its handling.
Tim, like I noted above 55+ would at time porpoise but I don't know if was attributed to Lake conditions or not. I will not take the boat out on speed runs unless the water is relatively calm. As for the build specs it is just an older 392 Ford Racing crate engine rated at 430 hp at 5500 rpm's. 9.7:1 compression, roller cam .563 lift intake and .584 lift exhaust,GT-40 heads with 1.94 intake and 1.54 exhaust.It has an Edelbrock dual plane with a Barry Grant marine demon 750 and some Hiteks. |
Posted By: peter1234
Date Posted: August-08-2011 at 9:49pm
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I wish mine would porpoise then recover.. hey has anyone tried hole shot racing to see what its like head to head first 100 ft? 1/8th mi? are there some monster launches that run out of steam at 55? ------------- former skylark owner now a formula but I cant let this place go |
Posted By: PAPA
Date Posted: August-08-2011 at 10:29pm
| Tim, I wondered about tach accuracy and also it being such a small sweep on my boat so I changed the tach to a Autometer pro-comp marine 0-7000 RPM with a hourmeter along with the rest of the gauges and senders this spring. I didn't want to be guessing about the RPM'S and then making changes. The new tach is much easier to get an accurate reading. |
Posted By: connorssons
Date Posted: August-09-2011 at 1:13am
| congrats Papa! cool numbers. Jeff |
Posted By: KRoundy
Date Posted: August-09-2011 at 2:35am
Holy cow, that is really fast. What is the wake like at that speed?  I can read the 80's WaterSki Magazine review now (back when their boat reviews were really awesome):
"The table was a little rough and hard, but the wakes are very minimal and easy to cross. You'll have to contend with some spray at short line lengths, which really stings at 60 MPH." ------------- Previous: 1993 Electric Blue/Charcoal Ski Nautique Current: 2016 Ski Nautique 200 Open Bow |
Posted By: GottaSki
Date Posted: August-09-2011 at 2:36am
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I suspect the porpiosing with the other prop was due to being on the wrong side of the torque curve, it was falling off above 5500, setting up an oscillation. Now that its pulling harder, it runs flat. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: JoeinNY
Date Posted: August-09-2011 at 11:21am
I don't doubt there is some of that going on, but I have also noticed that on several of the heavily powered boats you go past a speed where you will see any porpiosing. My boat will run relatively bow high until about 57 then it is nose planted until you run out of motor or cavitate the rudder, and I am running well past the hump of my torque curve in the 5900+ range. The boat also behaves pretty similarly but slightly slower with the big prop that only runs 5000 or so rpm. Similar behavior occurs with reids orange and white mustang even though there is less than factory hook left in the hull. Tims barefoot (when it is running) also seems pretty well planted at higher speeds. Just be careful to keep the rudder in the water, and particularily careful coming down the backside of waves traveling in the same direction.. they help the nose down and the rudder up.. slowing down mid wave is also not encouraged as you can drop the nose quick. A lanyard kill switch is not a bad idea either.. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: Luchog
Date Posted: August-09-2011 at 11:50am
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a cavitation plate could help the rudder to run wet and the hull to sit farther back in it's running surface. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: TRBenj
Date Posted: August-09-2011 at 11:59am
Ouch!
Very true though. I havent driven the boat enough to know exactly when it plants the nose, but its well north of 50mph, thats for sure. I suspect that at some point, the steep shaft angle simply overcomes the hull's propensity to porpoise. 
No one stated it above, but I dont consider porpoising to be a bad or scary tendency. If youre bouncing, it means youve got plenty of bow lift- and getting the hull out of the water will generally speed the boat up a bit. If you look at pictures of some of the boats doing speed runs, you'll notice that there will generally be some weight in the back seat (1-3 passengers) and only the driver up front. Things like chine locking, rudder stalling, etc- that cause unpredictable and uncontrolled maneuvers at speed are the types of things you want to prevent. Joe, a little off topic here- but I was looking at the boat on the lift the other day and couldnt help but notice how much further the prop extends into the water past the rudder. Its a safety requirement on v-drive flat/drag boats that the rudder extend a certain distance past the prop. Something to think about. ------------- |
Posted By: eric lavine
Date Posted: August-10-2011 at 9:45am
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i thought i was going to hit the 60 year old club before you guys hit the 60mph club
------------- "the things you own will start to own you" |
Posted By: peter1234
Date Posted: August-10-2011 at 11:15am
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got you by a yr ? ------------- former skylark owner now a formula but I cant let this place go |
Posted By: connorssons
Date Posted: August-12-2011 at 2:15am
I have experanced rudder stall in my mustang at high speeds the ride is extremly wild after that.  a kill switch is advisable.
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Posted By: Alex47
Date Posted: August-12-2011 at 2:44am
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What is rudder stall? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5444&sort=&pagenum=1" rel="nofollow - 1977 Ski Tique |
Posted By: 8122pbrainard
Date Posted: August-12-2011 at 8:40am
It's air and not water around the rudder so, you loose some or most control of the boat. ------------- /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 < |
Posted By: fiz140
Date Posted: August-12-2011 at 12:40pm
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Way to go Papa. It's great to see what you and Bryan have done with my old boat.
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Posted By: kapla
Date Posted: August-12-2011 at 1:40pm
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now some pictures of wild footing behind that 60mph beast!!! ------------- <a href="">1992 ski nautique |
Posted By: wakeboardin2k4
Date Posted: August-14-2011 at 8:36pm
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pictures/video or it didnt happen! ------------- "I'm planning to bring my girl that rides on a trailer with me and leave my girl that complains about camping at home" |
Posted By: Nautique2001
Date Posted: August-14-2011 at 9:34pm
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I hate to be the one who missed a previous post/discussion, Tim, your BFN isn't running? Could have fooled me from the photo above.
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: PAPA
Date Posted: August-15-2011 at 10:38am
Great idea from you and Joe both. I will definately put one in. |
Posted By: PAPA
Date Posted: August-15-2011 at 10:43am
Bill, I know Bryan has kept you updated in the past, glad to see you are still interested. I sure he will stay in touch as there is more to come. John. |