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Fantasy
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Joined: November 30 2006
Posts: 324
Posted: January 24 2014 at 20:42 | IP Logged Quote Fantasy

Bob,
Just about everyone who has replaced their old refrigerators has seen substantial reductions in their energy use. That's a nice benefit when you are plugged in to dockside power but that's only money. When you are limited by the power you can make underway and at anchor, it's more than money. Glad it has worked out for you as it has for us.

On fuel use, my engines are also rated at 450hp. I have considered reducing the injector size, which could bring the engines down to 410hp at max rpm. However, I have not been able to find any documentation that the smaller injectors would reduce fuel use at lower speeds. Regardless of the injector size, I would think that the same amount of fuel would be used at lower speeds. It's only the top end speeds that are limited by smaller injector size and fuel volume. Let me know if you have found otherwise.

I've never had a soot problem and I note that most of the boats that have reported problems are 92's. Still, I have thought about transom elbows for no other reason than sound reduction. Thought about trying some cheap galvanized stove pipe elbows, as an experiment, to see if there was any improvement, but haven't tried it.

John

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"Fantasy"
460 Chris Craft Constellation
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eshover
"Deckhand"




Joined: July 02 2011
Posts: 205
Posted: January 24 2014 at 20:49 | IP Logged Quote eshover

If anyone has a source for a good/reliable turbo builder, could
you please give me the contact information. I may need one

Emory Shover
540-220-4346
eshover47@gmail.com

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"Southern Charm"
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Grey Goose
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Posted: January 24 2014 at 20:52 | IP Logged Quote Grey Goose

John and Kevin
I had 450hp 6-71s in my last Chris . I found hose for street cleaners fit
perfectly over the exhaust through hull flange. It was flexible and I
bent it around and over the swim platform bracket. This raised the
exhaust about an inch with more water in the muffler. Made a big
difference in lowering the exhaust noise.

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"Grey Goose"
1987 Chris Craft 501
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NautiKall
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Joined: January 22 2014
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Posted: January 24 2014 at 22:38 | IP Logged Quote NautiKall

Water in the exhaust system that reduces noise is an interesting point of view.  Does anyone know the anatomy of the big mufflers on our Connies?  Is it possible that the muffler is supposed to retain water and as the mufflers age some of the internals that retain water are now gone; corroded away?

Goose, my turn-outs were originally installed in hopes of quieting the exhaust.  It didn't have much effect on noise.  Interestingly, when my bimini top is down the noise level is reduced.  Like when the top is up it creates a sound chamber.  Would rather have more noise than hot sun, so we leave the top up.

A couple of years ago, I searched on the web site for muffler info and found a Dr. of something in the engineering dept. at Penn St.  We talked on the telephone for a while and he suggested that the boat may be acting like a violin case and the engine noises were amplified by the boat.  Solution would be to replace old hardened motor mounts with new sound dampering mounts.  ?????  Sound good? After paying closer attention to the source of the noise on our boat, I believe it is coming from the exhaust pipes behind the boat!

I'm for attacking the muffler issue.  Any ideas?

Bob K.


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"NautiKall"
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Pete37
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Joined: November 12 2006
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Posted: January 25 2014 at 00:25 | IP Logged Quote Pete37

Hi All,

I'm a little curious about why anyone would care about exhaust noise. In the days when we all ran around at full throttle (20 knots, burning 45 gph) our Connies produced a lot of noise. But now that most of us are running at 10 knots or therabouts to conserve fuel our engines are real pussycats and produce very little noise.

Are there still some of us who haven't heard about high fuel costs and still cruise at 20 knots? I guess if you still have plenty of cash you could ignore the $180 per hour fuel cost at 20 knots. But I see very few yachts in the 50' and up class running at those speeds.

Somewhere in my Connie records I have a descripition of the muffler construction. If it's important I'll look it up.

Pete37

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Fantasy
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Posted: January 25 2014 at 09:06 | IP Logged Quote Fantasy

Bob,
I think you are right about the exhaust noise reflecting off the bimini. I have experienced the same thing, which is why I thought the elbows might help.

It is possible that the cockpit and overhang on the 500 helps to reflect the noise before it reaches the flybridge but the 460 is a straight shot up.

I have had numerous boaters comment on the sound level when I pass them slowly on the ICW. Others have mentioned that they could hear me coming a mile away when approaching an anchorage.

I haven't been able to find the anatomy of the muffler either.

John

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"Fantasy"
460 Chris Craft Constellation
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Pete37
"Commander"




Joined: November 12 2006
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Posted: January 25 2014 at 10:22 | IP Logged Quote Pete37

Hi All

Subject: Connie Noise Levels

Ambient Sound Levels
Normal ambient sound levels within my marina are 60 to 65 dB(a) The major contributor to the ambient sound level is traffic noise from the Rt. 50 bridge. On some of the slips closest to Rt. 50 on a busy weekend the ambient sound level sometimes rises to as much as 70 dB(a). Sound levels are normally measured in dB which is a logarithmic form of measurement. Therefore an increase of 3dB is a doubling of the sound level, 10dB is an increase of 10 times, 20 dB is an increase of 100 times and 30 dB is an increase of 1000 times.

A level of 90 dBa is therefore 100 to 1000 times louder than the ambient sound level in the marina, depending on the location.

Measured Noise Levels
Back before I even owned my present 50’ Chris Craft, I purchased a Radio Shack sound level meter. I planned to use it to test the effectiveness of some sound insulation I intended to install on my 42’ Ocean Yacht but I never got around to doing that. In 2005 it was still in fine shape except for needing a new battery.

On August 25, 2005, with the meter in hand I decided to do some testing of the noise levels on my Chris Craft. I started the engines and set them at a 600 rpm idle. I set the meter on the “a” weighting scale, went to the flying bridge helm station and measured the noise level there; It was 66 dB.

Remembering that the boat tests in Power & Motoryacht magazine usually list the noise levels, I found my latest issue and looked to see if there were any boats of similar size and horsepower to mine.

There were two, a 52’ Jefferson and a 53’ Post. The Jefferson with 920 horsepower had an at helm noise level of 62 dB while the Post with a whopping 2400 horsepower had a noise level of 75 dB. At 66 dB my Chris with 1100 horsepower fell between them.

But my readings were taken at 600 rpm while theirs were taken at 1000 rpm so I added 3 dB to my results making my noise level an estimated 69 dB at 1000 rpm.

Interestingly, the noise level from both boats in Power & Motoryacht rose by 13 dB (twenty times), at full throttle relative to the 1000 rpm level. This placed the Jefferson at 75 dB, the Post at 88 dB and my Connie at 82 dB.

The noise level from a Connie at 1000 rpm is 69 dB and at full throttle it is 82 dB. Both levels are reasonably consistent with the noise levels from other boats of similar size.

Bottom Line
Connies aren’t any noisier than other boats and at 69 dB are only about twice as high as normal conversation.

Pete37


Edited by Pete37 on January 25 2014 at 10:47


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eshover
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Posted: January 25 2014 at 11:10 | IP Logged Quote eshover

I survey around 55 to 60 boats a year. These boats can
range from 25' to 65'. I can tell you from experience,
there are plenty of boaters out there who may complain
about the high cost of fuel, but it doesn't stop them from
running their boats on plane. Simply put, there are plenty
of folks who own boats from all levels of economic levels.

Yes, the bimini will reflect the sound. I operate a 65'
Pacific Mariner for a company in DC (private) and the
hardtop was removed and a hydraulic tower was installed
to lower the navcom stuff when having to clear the bridges
on the Potomac River heading into Georgetown. With that
in mind, we had a bimini installed to offer protection from
the sun, light rain, etc. We must also lower the bimini as
well. The difference in the sound level, even running at 6
kts, is remarkable! With the bimini up we hear the sound
of the vessel moving the water, with the bimini down you
cannot hear the water at all. The Pacific Mariner 65 is
powered by twin 800 hp Cats. It is one of the quietest
vessels I have ever been on. She has to VERY large lift
mufflers in the engine room. The 500 does not have lift
mufflers. These are cannisters which have a "flapper" in
the mufflers which will open with an amount of water and
exhaust gas pressure and allow a release. I have had my
exhaust system apart to a point were I could use a high-
powered light and look down the entire system. (Some of
you will remember my famous muskrat incident) I could
run a hose down the exhaust line until I hit the "flapper". I
thought I had more blockage (I was flushing muskrat
condo stuff out of my exhaust sytem), until I pushed a little
harder and the hose moved the flapper and I could see
daylight from the transom outlet. Pete may find his
drawing and blow this out of the water but this is what I
found.
Dan, installation of new motor mounts would only be
desired if you are concerned about the INTERIOR noise
level. Yes, the engines transfer a lot of vibration and noise
to the hull, but from what I'm reading here, that's not what
you're talking about. If it is, there are several ways (none
cheap and all labor intensive) of attacking interior noise.
But that's another discussion.

As for the noise level at the fly bridge, you are discussing
the sound coming out of the exhaust. I can totally
understand what you are talking about. At a certain cruise
rpm on plane, my boat exhaust level is a constant cyclic
rumble, or roar if you will. I can put you to sleep on a long
haul if you're not careful! It certainly puts my wife to
sleep. :
I really don't have a suggestion other than to vary rpms. I
am also not becoming a 500 Connie Trawler operator to
save on fuel. I find that there is less stress on me and less
exhaust level at 10-11 kts. But it takes getting used to if
you are still in the planning mind set. It took me some
time to get used to it, but I'm getting there. The advantage
is, I CAN get up and go on plane if I need to.

This weather is driving me nuts!! Can't do anything on the
boat. Space heaters are no good in this temp at all.

Once the restoration of the dinghy is completed, I hope to
post pictures. At this point, my little Whaler is looking
sweet!

Have a great weekend!

Emory

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NautiKall
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Posts: 73
Posted: January 25 2014 at 12:22 | IP Logged Quote NautiKall

Pete,

Were you on the O. J. Simpson defense team?  I think what you are saying is that my boat with 2 cycle Detroit Diesell engines is not noisy.  You can try to convince me but there a lot of others out there that can hear the noise but are not on this forum.

 In the world I live in, with other 45' plus size yachts, the detroits have the reputation of being "bullet proof" but loud. This is not a new understanding. The newer boats with Cummins, Caterpillar and Volvo engines can barely be heard when idling through the marina.  Why do you think all of the boat adds list low db's at all of the speed levels as a plus?  Noise is an issue that is important to some people, like my wife and I.  Our Chris' are cushier than most of the other yachts, but noisey.

I can accept that Detroits are noisier due to their being 2 cycle engines.  The combustion chambers are open to exhaust in the latter stage of combustion allowing a sweep of new air into the cylinder, but I was wondering that maybe, with age, and exhausting unburned fuel because of higher fuel flow injectors the mufflers are "burned out" or "corroded out" and aren't working as they did when they were new and are now straight pipes.  Not important to you / Important to me.  If the design of the muffler internals is available, I would be interested in seeing

The cost of fuel doesn't have anything to do with my noisy engines.  We travel a lot and have almost never exceed 10.5 knots (12 mph for inland waters and lakes boaters) unless we are out-running a storm or racing for a lock-thru. When you do the Great Loop you are often restricted to 6 knots. We usually average about 10 gallons per hour.  Regardless, if your passion is boating, speed is not important because you are already where you want to be and the cost is what it costs to do what you want to do as long as you not foolish and wasteful.  Our comfortable engine speed is 1500 rpm.

When we spend a day on other big boats with our dock friends it is much more relaxing to be on their quiet fly bridge.  Federal law restricts workers from having to work in an atmosphere of 92 db's for extended periods.  Our fly bridge noise approaches that level.  Also, your analysis of db's on your Connie at different speeds is based on estimates of added noise from your 600 rpm level - not actual measurement. I have not measured with a meter.  I do know noise when I hear it!

I am still wishing I could do something to quiet my engines.  It may not be possible. 

Bob K.


Edited by NautiKall on January 25 2014 at 12:24


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Pete37
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Posted: January 25 2014 at 12:34 | IP Logged Quote Pete37

Hi All,

As Emory states, I too find that 10-11 knots is much less stressful. And I too don't run at that speed to save fuel. It's to cut down on the stress. I find that $180 per hour for fuel is very stressful. Glad to hear Emory is getting used to 10-11 knots.

And I too, as Emory states can't work on my boat in 10F to 20F weather. You just can't get the boat warm enough even with several 1500 watt heaters going. My solution is to go to Florida in February. Works great!

No I don't have a photo of the muffler but I have seen it (when I was working on the exhaust pipes) and it seemed to be two 45 degree baffles. Not super efficient but super efficient mufflers block exhaust flow and increase fuel consumption. So the muffler design is a trade-off between fuel efficiency and noise. On my Connie I don't find the noise objectionable (particularly at the 69 dB I get at 11 knots) so I'm not going to do anything about it.

Pete37

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Grey Goose
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Posted: January 25 2014 at 12:46 | IP Logged Quote Grey Goose

Mufflers make a huge difference even on these old two strokes. My
501 has giant lift mufflers and makes very little exhaust noise.    She
has the same engine as the 500 which makes the that beautiful rumble
sound of the Detroit 2 stroke. As far I I know the only thing that is
different is the type of muffler.

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"Grey Goose"
1987 Chris Craft 501
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Pete37
"Commander"




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Posted: January 25 2014 at 14:16 | IP Logged Quote Pete37

Hi All,

Subject: The Great Muffler Hunt

OK, some of you guys want to modify your mufflers. So the first question is "Where are the mufflers?" I can only address the anatomy of a 500.

I've removed the exhaust system on the port side back to the aft bulkhead of the guest head. A'int no mufflers there. So the muffler must be aft of that. My best guess is under the shelf in the master stateroom closet. If not there it must be under the shelf on the port side of the master stateroom.

On the starboard side I can see the exhaust pipe all the way from the engine room back to the aft bulkhead of the den/office and there isn't any muffler there either. So it must be under the shelf in the master stateroom head or under the shelf on the starboard side of the master stateroom.

So that's where the mufflers are. But I'm not going to go clamboring around in 10F weather looking for mufflers. It can wait until spring or until someone in the warmer climes finds them.

Pete37

Edited by Pete37 on January 25 2014 at 14:22


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NautiKall
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Joined: January 22 2014
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Posted: January 25 2014 at 14:30 | IP Logged Quote NautiKall

I was surfing the internet for muffler design info and found a generic explanation under: "muffler design",   then scrolled down to: "3.0 Exhaust Muffler Design Principles".  A basic description of different muffler applications.

Two types of mufflers are discussed -  dissapative and reactive.  I think the 500's and the 460's musty be equipped with the dissapative variety.  They are the straight thru design.

Emory, I also tried: "boat muffler design exhaust system"    then scrolled down to:       "Designing a Marine Exhaust System".  An intertesting article with lots of photos by "Seaboard Marine - Custom Diesel Repower Specialists".  They might be a lead on rebuidling a turbo.

Bob K.


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"NautiKall"
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NautiKall
"Seaman"




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Posted: January 25 2014 at 14:40 | IP Logged Quote NautiKall

On my 460 the port side muffler is under the sink in the aft head.  I've seen it.  I'm not sure, but since things on the Connie are pretty much symmetrical, I'm guessing the starboard muffler is under the shelf in the mid cabin.

Bob K.


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NautiKall
"Seaman"




Joined: January 22 2014
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Posted: January 25 2014 at 14:49 | IP Logged Quote NautiKall

If there are Murry Chris Craft Constellation Yacht owners out there just watching because you can't figure out how to get on the forum, I suggest you call Susan at BoatUS for help.  After three days of solving problems, she was able to get me on-line. Super helpful gal.   Number:  1.800.395.2628  ext 8131.

Bob K.


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"NautiKall"
1985 Connie 460
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NautiKall
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Posted: January 25 2014 at 15:14 | IP Logged Quote NautiKall

Goose,

I wonder why Murry Chris Craft went to the lift style of muffler?  Was it to reduce the noise?

What is the physical size of your mufflers and their configuration?  Does the inlet and the discharge line up?  In other words could a straight thru muffler be replaced with a lift style?  My 460 has a space limitation where the muffler is located.

Bob K.


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Fantasy
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Posted: January 25 2014 at 15:34 | IP Logged Quote Fantasy

In the master stateroom there are three drawers that run horizontally on both the port and starboard side. Under those drawers is a panel that is easily removed with about a dozen wood screws. 460 owners should find the end of both mufflers behind those panels. On the port side the muffler extends forward into the area under the sink. They are about 4ft long from flange to flange. Most of the muffler is in the area of the two hanging lockers.

The starboard side, looking forward, looks like this. The vertical trim on the left is for the starboard hanging locker. Both mufflers are covered in insulation and foil.
John



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"Fantasy"
460 Chris Craft Constellation
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NautiKall
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Posted: January 25 2014 at 16:08 | IP Logged Quote NautiKall

Great shot.  Thanks.

Bob K.


Edited by NautiKall on January 25 2014 at 16:10


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Pats2nd Connie
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Joined: June 28 2013
Posts: 157
Posted: January 25 2014 at 16:34 | IP Logged Quote Pats2nd Connie

Hello all, you fellas have been quite busy lately. We just returned from
scouting marinas in Fort Myers. Salty Sams had the winning bid with
great concrete floating docks and miles of mangrove to paddleboard
through. Albeit half commercial, including a Pirate Ship and a few
fishing boats.
The mufflers deffinetly could use some improvement. I'm sure the
insulation around most of them is inadequate. The sound on my boat
is less without the Bimini top.

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Pete37
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Posted: January 25 2014 at 18:10 | IP Logged Quote Pete37

Hi Bob,

Subject: Engine Noise Levels

The noise levels I gave in my previous post were not subjective opinions based on an observer's ears. They were measured with a sound level meter and they are what they are regardless of subjective opinions.

A noise level of 69 dB is only about twice the level of normal converation and subjectively my wife and I can have normal conversations on the FB without raising our voices.

Perhaps your Connie (a 460) is noisier but I would think a 671 would be quieter. Or perhaps the sound insulation or muffler is defective. And apparently, from what you say, your Bimini top is trapping the exhaust noise and directing it toward the the FB helm station.

But the objective sound meter readings and subjective impressions from our ears both confirm that the sound levels at 1000 rpm and at the FB helm station of a 500 are about 69 dB on the A scale. The A scale is the scale normally used for this type of measurement. This is pretty typical of what you would expect from a 50' motoryacht.

I'm not saying your boat isn't noisey. I'm saying it isn't significantly noisier than other similar boats.

One of the first things a scientist learns is not to depend upon subjective opinions.

Pete37

PS: Interestiingly it seems to be mostly 460 owners who are complaining about the noise. Is it possible that 460s are noisier than 500s? John of Fantasy posted that he believed the extra 4' on the FB made the 500s quieter.

His picture and post on the mufflers also confirmed they were about where I expected. But there are some differences between the locations on a 460 versus a 500.

Edited by Pete37 on January 25 2014 at 18:37


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Pete37
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Posted: January 25 2014 at 18:45 | IP Logged Quote Pete37

Hi John,

Subject: Mufflers

Do you think you could identify the manufacturer's name on that muffler so that we can estimate a price? It looks a bit like a 6" Vernatone at a cost of about $500.

But of course we want something bigger and better. $1000 per muffler might not be unreasonable. Plus, some structural modifications might be required to fit it in.

Pete37

Edited by Pete37 on January 25 2014 at 18:54


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Fantasy
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Posted: January 25 2014 at 19:08 | IP Logged Quote Fantasy

Pete,
No, I don't want to rip off the insulation and foil to see if there are any markings. That old insulations turns to powder if you disturb it.

I think it is an 8" flange and is about 4' long. I hope I never need to replace them because the plywood supports are tabbed into the hull. It would be a bear of a job.
John

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NautiKall
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Posted: January 25 2014 at 19:17 | IP Logged Quote NautiKall

Pete,

I agree.  One of the first things a scientist learns is not to depend upon subjective opinions or to draw conclusions based on a case study of one.  I'm an engineer not a scientist.



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David Ross
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Posted: January 25 2014 at 21:57 | IP Logged Quote David Ross

A little belated welcome aboard to you Bob. Glad to have your input. I'm sure John, and the other 46 owners, are happy to have another one here. Pete, I'm with you in getting away from all that cold. We were also going to spend February (and most of March) in Florida, but my wife wanted to stay in Palm Springs, California this winter. She also wanted to leave earier (January). I'm glad I did the marital compromise (did what she wanted). Got out just in time. It has been warmer here than Florida (75 to 82). Goose, you mentioned your 501 has giant lift mufflers. Do all the 501's have that set up? I know there has been a picture sending problem here... it would be interesting to see a picture of your muffler lifts. Where are they located?  



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Pete37
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Joined: November 12 2006
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Posted: January 25 2014 at 22:27 | IP Logged Quote Pete37

Hi All,

Subject: Engine Noise Levels

The discussion of engine noise levels has been kind of pointless siince the only objective measurements were the ones I took. I'm sorry I didn't take more measurents but I'm not going to do them now. It's too cold and the boat is winterized. But in the spring I'll do some more measurements.

We did find out where the mufflers are located and their approximate size. From Fantasy's picture we get a rough idea what they look like and I can probably figure out who made them.

Once we know who made them and what model they are we can get their performance specs and how much they cost. Based on what I have seen to this point I think the cost of a pair of them would be $2K to $4K plus whatever the modification costs to install them are.   Ultimately I think cost wiil preclude replacing the mufflers.

It didn't take me long to find the muffler. It's the Centek 10000235 Vernatone Round Marine Muffler Silencer 10" x 52" shown in the picture below:





It costs $1,600 ($3,200 for a pair) plus whatever it costs to install it and has a sound absorbing capacity of 16-18 dB depending on the engine it is used with. This is a preliminary identification. You would need a more definite identification before buying one.

And of course you wouldn't want to replace the old muffler with another of the same sound absorbance. You want something with better absorbance. That I haven't identified yet but it will most certainly cost more.

You guys can decide whether you want to install them. Until then there isn't much to say.

Pete37

PS: John, I wouldn't want to remove them either

Edited by Pete37 on January 26 2014 at 00:41


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Grey Goose
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Joined: October 25 2009
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Posted: January 25 2014 at 23:12 | IP Logged Quote Grey Goose

I don't have any photos of the lift muffler on goose. I found a photo of
a 501 on yachtworld that shows the muffler. In the photo, the copper
drum in the upper right corner is the muffler. I am working from an
iPad and can not post a photo. Below is the link to that photo.

http://www.yachtworld.com/boats/1988/Chris-craft-501-MOTOR-
YACHT-2612008/Marblehead/OH/United-States#.UuSHVH88KSM

Also in my Murray Chris Craft 422, I raised the water level in those
mufflers and in made a big difference. Not nearly as quiet as the lift
muffler, but much quieter. The 422 had vernitone oval mufflers. This
was a tip suggested to me by an exhaust specialist in a boat yard that I
was doing
some work. He worked for centek vernitone. It looks like from Johns
picture, those maybe the vernitone round.

Edited by Grey Goose on January 25 2014 at 23:14


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"Grey Goose"
1987 Chris Craft 501
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NautiKall
"Seaman"




Joined: January 22 2014
Posts: 73
Posted: January 26 2014 at 12:14 | IP Logged Quote NautiKall

Way to go Pete!  We are making progress on a an item that you don't even think is a problem.  Some of us are really interested.  Cost is a lot better than repowering with quieter engines.  Engineers solve problems, scientists just theorize.

Bob k.


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"NautiKall"
1985 Connie 460
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NautiKall
"Seaman"




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Posted: January 26 2014 at 12:23 | IP Logged Quote NautiKall

I think I have figured out how to edit photos for this forum.  Old dogs can learn new tricks!

Below is a pix of the other side of our boat. This is a test.


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"NautiKall"
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NautiKall
"Seaman"




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Posted: January 26 2014 at 12:26 | IP Logged Quote NautiKall

Decorative panel on starboard side before removal.

Edited by NautiKall on January 26 2014 at 12:46


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"NautiKall"
1985 Connie 460
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NautiKall
"Seaman"




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Posted: January 26 2014 at 12:30 | IP Logged Quote NautiKall

View after panel removed on port side showing vertical wood strip and clean-up problem.  Glue and caulk removal and patch of three screw holes was necessary.

Edited by NautiKall on January 26 2014 at 12:47


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"NautiKall"
1985 Connie 460
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NautiKall
"Seaman"




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Posted: January 26 2014 at 12:32 | IP Logged Quote NautiKall

Finished look on starboard side.  Note the Chris Craft name and the crest in new location.



Edited by NautiKall on January 26 2014 at 12:35


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"NautiKall"
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NautiKall
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Posted: January 26 2014 at 12:37 | IP Logged Quote NautiKall

View of transom with exhaust pipe turn-outs.

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NautiKall
"Seaman"




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Posted: January 26 2014 at 12:39 | IP Logged Quote NautiKall

Close-up view of exhaust pipe turn-out.  I cashed in on some owed pipe fitter favors.

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NautiKall
"Seaman"




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Posted: January 26 2014 at 12:41 | IP Logged Quote NautiKall

Anybody,

Is it possible to put more than one picture on a post?


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"NautiKall"
1985 Connie 460
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eshover
"Deckhand"




Joined: July 02 2011
Posts: 205
Posted: January 26 2014 at 13:23 | IP Logged Quote eshover

Awesome turn-outs Dan! Wish a pipe fitter owned me a
favor or two!

Without a lot of diatribe here; the larger the muffler, the
quieter the exhaust. But there has to be room for them.
The 500's didn't have the room with the Lectra Sans sitting
there. The logical choice was the canisters with the logical
location being the outboard shelves under the
port/starboard cabinets in the aft stateroom.

Someone stated they have lift type mufflers on their 460. I
would like to see the engine room layout.

Emory

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1986 Connie 500
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NautiKall
"Seaman"




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Posted: January 26 2014 at 16:04 | IP Logged Quote NautiKall

I don't have Lectra Sans any more.  A previous owner removed them and installed a 40 gal holding tank under the generator room floor.  After looking at John's photo of the 460 muffler and looking at what is available from Centek Industries, I think a Veratone 16.25" dia x 66" long muffler would fit nicely.  The model 1420800 has 8" inlet and outlet with a 3 1/2" offset front to rear.  I guess the offset will allow it to hold water.

After looking at John's photo, it seems to me that the challange will be to disassemble the piping, since it is contained from end to end.  There might be a slip type fitting that would be water proof and vapor proof or, if the new unit is longer than the old, it would allow you to cut the rubber exhaust hose for removal. Structurally, a segment could be cut out of the perimeter plywood containment support converting it to a saddle.  The new muffler could then sit on the saddle and be secured with a strap type hold-down.

Of course, I will have to convince myself that the new muffler will be quieter than the old one before I pop for $1748.64 each.  That is about how much it costs to fill the tanks. With their 800 number this will require some discussion with people who know.  Ann is excited.

Bob K..


Edited by NautiKall on January 26 2014 at 16:09


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NautiKall
"Seaman"




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Posted: January 26 2014 at 16:30 | IP Logged Quote NautiKall

Pete,

I know you keep records on location of our boats.  Two years ago while on Lake Michigan, we met four of Dave Martin's boats as follows:

1984 Uniflyte 46   "Rules R Rules"  UNF08475M84K-46M641G  Ludington, Mi
1985 Connie 460  "Mist"                  CCMY 102 H 4 85              Racine,      Wis
1986 Connie 500  "Marcy Kaye"     CCMY E 151 L 5 86            Charlevoix, Mi
1989 Connie 501  "Miss T"             ?           ;           ;                     Holland,      Mi

Sorry I don't have names and addresses.  The '84 Uniflyte looked just like our 460.

Bob K.


Edited by NautiKall on January 26 2014 at 16:35


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Fantasy
"Navigator"




Joined: November 30 2006
Posts: 324
Posted: January 26 2014 at 16:38 | IP Logged Quote Fantasy

Emory,
Some people think the canisters hanging off of the 6-71's are mufflers. They do look like lift mufflers but are actually very weird exhaust risers (mixers).

This photo is the port side engine looking aft. The dry exhaust enters from lower left directly from the turbo. The smaller diagonal hose carries raw water to a shower head inside the top of the canister and the wet exhaust exits on the right and makes its way to the muffler.



The originals were cupronickel and these are stainless. The manufacturer also beefed up the structure in places where he had seen them fail before.

You can also see the electro scan (blue) below and aft of the mixer.
John

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460 Chris Craft Constellation
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Pete37
"Commander"




Joined: November 12 2006
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Posted: January 26 2014 at 16:42 | IP Logged Quote Pete37

Hi Bob & All,

Subject: That's a Damn Good Muffler!



The Vernatone muffler shown above is used on our Connie 500s and has a sound absorbtance of 16dB to 18dB depending of the engine used. I've shown the picture before but I'm not sure that you all understand the significance of 16 dB to 18dB.

Since we don't know the exact relationship between the dB and the engine I'll just pick the average absorbtance of 17dB. 17dB is an an absorbtance of 50:1 meaning that only 1/50th of the sound entering the muffler gets out of the back end. Or to put it another way 98% of the sound is absorbed in the muffler and only 2% goes out of the exhaust pipe.

That's a pretty good muffler and shows that it's not just the loudness of the engine noise but also the effectiveness of the muffler that determines how noisey a boat is. Connies seem to have unusually efficient mufflers.

Pete37

Edited by Pete37 on January 26 2014 at 17:26


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NautiKall
"Seaman"




Joined: January 22 2014
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Posted: January 26 2014 at 16:49 | IP Logged Quote NautiKall

Emory,

Thanks.  A very direct and ordinary approach to cooling the exhaust gas. You can do wonders with welding talent.

Have you looked at the "Seaboard Marine" website regarding tecky's who might know something about fixing turbo's

Bob K.


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