Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
12-07-2005, 02:07 PM
#42
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
Terry....I'm on a corner on the Palaco canal...white Christmas tree on the dock out back and older blue 30 Velocity on the lift on the side canal. Watching your boats go by is usually the high point in my day. Skip
12-07-2005, 02:11 PM
#43
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
I rode in Terry's boat in Key West and the new quiet exhaust was awesome! I NEVER thought I'd like a quiet performance boat but this was pretty sweet. You get to hear the engine whine and no longer need headsets to have a conversation. Definitely a great idea!
Thanks again Terry.
Thanks again Terry.
12-07-2005, 03:34 PM
#45
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
Originally Posted by Wild
Talked to a guy in key west with a 43 cat, I noticed that there were no exhaust tips coming out the back, he explained the new exhaust to me. Nice guy good info
12-07-2005, 04:28 PM
#46
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
Originally Posted by salesmanship
We changed OU to eliminate the molded exhaust ports. On the 36 we left them and replaced the pipes with grilles which gives a little more ventilation. On a new boat you can get it either way.
Not a great view but here's a pic
Not a great view but here's a pic
12-07-2005, 10:23 PM
#47
Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
Looks and sounds great!
A lot of the noise reduction is because of 2 other notable items; 2-into-1 exhaust and the tailpipes are wet for a fair length, but low enough to have less risk of reversion. Of course having it under water at idle helps around the dock and being aimed back low and into the prop wash helps even more at speed, but I think a reasonable job could be done without the exit in front of the prop, just off to the sides. You could put 2into1 on cats and stagger vees to the outsides down as low a possible (might have to be a little higher because of tabs), and 2into1 on the insides on side-by-side vees. This still has to be less restrictive than mufflers.
A lot of the noise reduction is because of 2 other notable items; 2-into-1 exhaust and the tailpipes are wet for a fair length, but low enough to have less risk of reversion. Of course having it under water at idle helps around the dock and being aimed back low and into the prop wash helps even more at speed, but I think a reasonable job could be done without the exit in front of the prop, just off to the sides. You could put 2into1 on cats and stagger vees to the outsides down as low a possible (might have to be a little higher because of tabs), and 2into1 on the insides on side-by-side vees. This still has to be less restrictive than mufflers.
12-15-2006, 08:47 AM
#48
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
Originally Posted by salesmanship
Tired of the noise, the complaints, the applause when you shut it down? Well most of us still love the roar of open exhaust but the times are changing.
In response, Nor-Tech in conjunction with CMI has developed a new system for our Supercats that routes the exhaust below the waterline and through the transom below the gimbal housing.
This system virtually eliminates most of the noise at idle. To relieve any back pressure there are 1" vent pipes that exit above water but the maximum at idle with Mercury 850's was 83db. Well below existing limits. In fact most of the noise present is coming from the fuel pumps and blower whine.
Once on plane the exhaust is introduced into the prop flow.
At high speed the only sound heard both inside the boat and outside is again, the whine from the blowers. It actually sounds like a muffled turbine.
Mercury was concerned initially about possible back pressure. According to their tests not only was back pressure absent but it created a vaccum, flowing better than tail pipes.
The end results, close to totally quiet and no loss of performance or horsepower.
This system is available for all new Nor-Techs and available for the retro fitting of existing boats.
Terry
In response, Nor-Tech in conjunction with CMI has developed a new system for our Supercats that routes the exhaust below the waterline and through the transom below the gimbal housing.
This system virtually eliminates most of the noise at idle. To relieve any back pressure there are 1" vent pipes that exit above water but the maximum at idle with Mercury 850's was 83db. Well below existing limits. In fact most of the noise present is coming from the fuel pumps and blower whine.
Once on plane the exhaust is introduced into the prop flow.
At high speed the only sound heard both inside the boat and outside is again, the whine from the blowers. It actually sounds like a muffled turbine.
Mercury was concerned initially about possible back pressure. According to their tests not only was back pressure absent but it created a vaccum, flowing better than tail pipes.
The end results, close to totally quiet and no loss of performance or horsepower.
This system is available for all new Nor-Techs and available for the retro fitting of existing boats.
Terry
I just watched the latest video released here on OSO/powerboat TV with the clip on this whole new set-up you have developed with your team.
My only question is:
How does putting all that airiated pressure into the prop not affect it and increase prop slip / decrease the performance?
Thanks
Cougarman
12-15-2006, 09:00 AM
#49
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
The underwater exhaust on Sunseekers 34 and 48 (actually 40 and 50 when fitted with surface drives) has nothing to do with Sunseeker. It is part of Fabio Buzzi's transom design for Trimax surface drives. It's very effective as far as noise reduction is concerned but it also virtually eliminates smoke and transom soot usually seen on diesel boats. It also actually helps performance, especially coming on plane.
12-15-2006, 09:02 AM
#50
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Re: Worlds QUIETEST 36 Nor-Tech!!!!!!!!!
We've delivered more than a dozen of these set-ups since this post. Haven't seen any negative side effects.
With the 6's the top half of the prop is out of the water at speed so the airiated pressure doesn't seem to change anything.
With the 6's the top half of the prop is out of the water at speed so the airiated pressure doesn't seem to change anything.
