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Single engine V - NXT drive?

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Old 03-14-2009, 10:54 PM
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Chris
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Default Single engine V - NXT drive?

Has anyone seen or heard of, a single engine V hull with an NXT drive, and how well did it work?

I saw the cover of Performance Boat magazine showing a Nordic ski boat with the 700sci and the NXT. 93mph seems kinda slow for a 21ft boat with 700hp. I am wondering how the NXT drive is working out. Thinking it might be slow when it is run fully submerged like that.

What was the prop-shaft depth in relationship to the keel measurement.

Chris
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Old 03-14-2009, 10:58 PM
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more than a couple....there is a 32 veloctiy for sale with one. A lavey craft race boat too. If im not mistaken, prop selection WAS the issue....not now.
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Old 03-15-2009, 01:30 AM
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Originally Posted by CB-BLR View Post
Has anyone seen or heard of, a single engine V hull with an NXT drive, and how well did it work?

I saw the cover of Performance Boat magazine showing a Nordic ski boat with the 700sci and the NXT. 93mph seems kinda slow for a 21ft boat with 700hp. I am wondering how the NXT drive is working out. Thinking it might be slow when it is run fully submerged like that.

What was the prop-shaft depth in relationship to the keel measurement.

Chris
I get the impression that its good for doubles but in single engine apps there are handling issues due to the shape of the lower.

Lavey pulled the NXT drive off their race boat.

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Old 03-15-2009, 10:17 AM
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I get the impression that its good for doubles but in single engine apps there are handling issues due to the shape of the lower.

Lavey pulled the NXT drive off their race boat.

Uncle Dave

Lavey pulled the NXT off the race boat because it has been banned from the 525 class. Really upset Kevin Cooper because he spent a great deal of time and money getting the setup right.

There was an issue originally with singles. The prop would blow out due to the case design and the amount of torque steer. It could easily be resolved with a welded on torque tab. They have permanently resolved the issue with the new lower unit design that has an aero shaped skeg that is much more efficient then a welded on torque tab.

Other then the "blow out" issue, at least on our boat, I am really impressed with the drive. One of my original concerns was low speed driveability especially in a single engine cat. It drives very well at both high speed and low speed. You really can't tell that you don't have a bravo on it once it is on plane.

Hope this helps.
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Old 03-15-2009, 11:34 AM
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Somewhere I read, and an engineer in the Merc booth in Miamuh confirmed, they have a new skeg design for single NXT boats..

Edit: what he said above
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Old 03-15-2009, 01:03 PM
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Lavey pulled the NXT off the race boat because it has been banned from the 525 class. Really upset Kevin Cooper because he spent a great deal of time and money getting the setup right.

There was an issue originally with singles. The prop would blow out due to the case design and the amount of torque steer. It could easily be resolved with a welded on torque tab. They have permanently resolved the issue with the new lower unit design that has an aero shaped skeg that is much more efficient then a welded on torque tab.

Other then the "blow out" issue, at least on our boat, I am really impressed with the drive. One of my original concerns was low speed driveability especially in a single engine cat. It drives very well at both high speed and low speed. You really can't tell that you don't have a bravo on it once it is on plane.

Hope this helps.


I didnt know about the "banned part" -Ill bet coopers pist. I know they got like 4MPH out of it after all their tweaking.

<If I were him Id move over to the new Ilmor Indy as soon as it gets certified by popra and OSS>

I got my information straight from Jeff Camire on the handling issues and in the tirio of on line forums it seems to be well known that the lower causes a problem.

Interesting that a company with the resources that mercury has get get such a major thing that wrong out of the gate.

How does that work? Do they replace the lower for N/C?
How about the guys that welded the piece on? Do they pay for that?

Or is this a case of the early buy in guys got hosed?

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Old 03-15-2009, 01:08 PM
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There was a blurb in Powerboat or one of the boating magazine about the NXT now being offered with a cambered skeg for single engine applications about 3 months if memory serves me correct. Page 23 of the PDF in this link:

http://www.mercurymarine.com/_media/...acing_2009.pdf
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Old 03-15-2009, 02:21 PM
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Quote:
Originally Posted by damdonzi View Post
There was a blurb in Powerboat or one of the boating magazine about the NXT now being offered with a cambered skeg for single engine applications about 3 months if memory serves me correct. Page 23 of the PDF in this link:

http://www.mercurymarine.com/_media/...acing_2009.pdf
You are right the blurb was in powerboat mag, I remember reading it recently.
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Old 03-17-2009, 04:54 PM
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I have the 32 Velocity with single 700 application. The biggest issue was prop selection. Merc had no props for test to meet a single application (17-18" Diameter, 29-31" Pitch). Everything out there was for twin application in the range of 36 to 40 Pitch. At the time we started testing, Merc had gone to full CNC, and they claimed to have scrapped all of the old cast props. Also, they did not have the offeset skeg, so we had a slight wedge welded on the skeg to counter the torque(which was not that bad). We started high with the X and brought the prop shaft down to 1" above the bottom with spacers. I am curently running a Merc 5 blade, 16 degree rake, 30 " pitch, 17" Diameter. At the time, Merc was not offering the 18 degree rake, which would have been better for that boat, so the prop has been modified by BBlades to give more bow lift. the boat runs mid 80's in fresh water. Have seen better than that with light load in salt. Have one more slight modification for the prop this spring which whould bring 1-2 MPH. The boat is a relatively large full cabin boat, so the numbers are not too bad. Handling is fantastic with the modifications to bring more bow lift.

Last edited by Oh Deere; 03-17-2009 at 06:39 PM.
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Old 03-17-2009, 10:03 PM
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I forgot to mention that there were also issues with the skegs not being long enough. Merc has taken care of that. We had a few times early on when testing props where you could feel the boat begin to walk sideways when it was trimmed out, due to the short skeg with a big blade. Not a problem now at all. I would go for it if you can. It is a nice package.
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