Quieting Boats down

[AWaddle322]

Like what Terry Kelley had been doing?

Allen

 

[Brian_Nelsen]

Yes Terry has been doing this as well as most of the outboard guys that like the nitro style pipes. I personally have never used one on an inboard boat but I hear they work.

I run cooper quiet pipes and all my inboards except my 90 rigger which has an old Muck muffled pipe on it.

Brian

 

[oldlugs]

Hopefully this pipe hanger/mount will help (haven't run this one yet).

PIPE HANGER

It's actually "hanging" the back of the pipe with a loop of .078" music wire covered with fuel tubing. It loops around one side of the pipe, clearing it by about 1/4", and only the top actually touches. Has a good bit of spring and movement to it, but it may be somewhat fragile when run over at speed... Can always use heavier wire. The idea was to try something flexible.

I was thinking about something similar, but two mounting locations on the transom, then suspending the pipe with O rings, similar to some automotive exhaust mounts. May seem wacky, but we'll give it a try (my son's .21 Seaducer, so he'll give it a good workout...). If not, back to the drawing board...

Duane

 

[Terry Keeley]

Now we're moving in a good direction..... Spent the morning reading Jennings section on internal stingers, anyone with testing results/measurements, theyd care to share? Terry? A DB meter is out of reach for me at this point, but, I can sure attempt and try stinger ideas... Thanks...

Guess we had two threads going on this, I'll C&P from my other post:

I've been using internal stingers since we adopted a noise rule in '03. Someone mentioned on the RCBoat listbot that he saw something in the Jennings book about it, picked up my copy and read it and couldn't believe it worked as well as he said, so, naturally I had to try it.

My noisiest boat at the time was my 60 hydro running a Picco 67, high comp. head, "Big Belly" CMB pipe, 60% nitro and a rubber mount. I could top 105 dB on a good day, it had what some of my buddies called the "Keeley Cackle".

The stinger alone brought it to 91-92 and if I put my Muck double cone muffler on it also it goes to 89-90. I ran this combination at this years Nats with a CMB (no after muffler) and was not given a warning, and they had plenty of time to check it as I ran open water a lot both Friday and Saturday.

A trick I found was that if you make a drain hole in the stinger keep it 1/16" or smaller, any openings bigger than that near the end of the pipe (high pressure area) increases the noise dramatically.

Workin' for me and I can use all my old pipes!

Terry,

What size tubing are you using on the pipe. and how far in does it go...

I am assuming you have to expand the pipe stinger??

Thanks,

Chris

I use 1/2" tubing with 0.035" wall so that's 0.430 I/D. I turn it down most of the length to about 0.460" and leave 3/4" on the end full diameter to act as a lip to keep it from falling back inside the pipe. You could also use 15/32" brass tubing (7/16" I/D) and solder a short piece of 1/2" to the end. Red Locktite holds it well.

Yes, the CMB needs the stinger stretched, I use gauge pins going bigger and bigger 'till I get to the right size, but you could use something else if you look around. Most pipes need the stingers choked anyway, so this works well. You need the tube to go to the start of the converging cone or the weld on most pipes.

 

[Mark Bullard]

I got the idea of internal stingers from helping Terry at the 2004 Internats and also a record trial at Huntsville that year. He showed me how he was doing it. So I took it one step further. I made my internal stingers out of aluminum tubing that I drilled out to the right stinger diameter of 0.440" and then welding them in place. Now these were 13cc Muck nitro pipes running on K 90's. I have been running this setup for two years. I have been below 90dB and below every where else. Why do you think that I was busted with numbers of 96dB and above and then DQ at the Internats?

Mark Bullard

 

[Brian_Nelsen]

Mark

I am not going to answer your question. This post was set up to try to discuss ideas on what can help and what cannot. Your question is better asked in the Noise and DB meter thread.

I will say that the internal stinger does not do the job in all cases. I Have two 90 nitro pipes for my rigger that will not make 92 db with an internal stinger. I have a muck pipe and a cmb pipe with internal stingers. at my site with my testing methods they run 97 for the muck and 94 for the cmb. These are just my personal results in all cases we are discussing ways to reduce the overall noise in a boat. We always tend to focus on the pipe first. I think induction noise is also important as Don has stated. There are many areas which create noise in our boats.

Thanks for your post and the information it contained

Brian

 

[Ed.R]

Also what besides exhaust makes allot of noise on a twin rigger?

Induction noise! There is a distinct audible drop in sound when the cowl goes on my twin 90 SGX. While I have not measured the exact dB change the mere fact that's it's detectible to the ear tells me it's worth noting.

Don,

Heres a link to a photo of an air box used for karting , most sanctioned karting events these are mandatory . Not sure MAYBE someone could try something like this for boating plus a good sealed cowl I would think should help. from my experiance with them they help a ton. It was alomost hard to hear another kart along side you.

Ed.R

https://www.intlwaters.com/gallery/thumbnails.php?album=568

 

[Mike Rappold]

I am still not following what an internal stinger is. Could someone post a picture?

Thanks in advance.

Mike

 

[Roxyflash]

Imagine a pipe that will fit into the stinger end of your tune pipe that goes to the fat part of it. :wacko:

 

[Mike Larson]

Sorry Terry, I read your post, and went back to my copy of the book, and read some more..... Have you attempted to have the stinger "blocked" in the center, as jennings stated, or just straight through? Im gonna try some stinger buildin, any help is appreciated..... thanks mike

 

[Bob Finn]

I installed two of Steve Coopers add on mufflers on my twin 90 boat at the Internats. This boat was VERY loud even with the homemade cans I made for 2004 and 2005. The Cooper mufflers brought the DB readings down to 86 - 88. Although the boat wasn't running at peak performance, the mufflers worked great.

Bob

What are your thoughts on getting it up to speed? Can you do it with the mufflers? What you posted is a significant change in DB so if you can keep it there and get it back up to speed we all would like to know.

Also what besides exhaust makes allot of noise on a twin rigger?

Lohring thanks for the post, thats some very good data.

Thanks to all, so far we are actually posting ideas that work or could work with more testing. I like this.

Brian

I just need to get the needles balanced and cure a carb problem I've had with it for 2-3 years. Just haven't tested at all. Yes, I think it will stay under 90. Its really quiet now. Obviously carb noise makes a difference, and resonance in the hull for sure. Coopers new pipe is even quieter. Thats what I plan to run on it next year.

 

[Brian_Nelsen]

Ok here are my ideas for my new mono's

I am building two new mono hulls this fall one is a .21 and the other is a .45

I plan to use isolation engine mounts, isolate the stuffing tube with some form of rubber. I also plan to try to isolate as much as I can the radio box mountings and the pipe mountings. I will use cooper quiet pipes on both boats.

Once I get them built I will test them as they are, then I will add some type of cowl to see the difference. I know there will be a difference I just want to see how much.

This should be a pretty good test. I will also be exploring the air box idea that Ed posted. I have no idea how that will look but I will have to see.

Bob

Please let us all know how the boat progress goes and goo luck with the carb issue.

Thanks.

Brian

 

[bzubee]

Brian, don't forget to stuff the front under the deck with as much foam as you can, this was mentioned in one of the other threads by the europeans on the mono with no foam it acts like a drum so the foam eliminatesor at least minimizes the drum effect. I also install foam along the side rails and engine rails.

 

[Terry Keeley]

Sorry Terry, I read your post, and went back to my copy of the book, and read some more..... Have you attempted to have the stinger "blocked" in the center, as jennings stated, or just straight through? Im gonna try some stinger buildin, any help is appreciated..... thanks mike

No, I haven't tryed blocking the stinger, just run it through to the middle. If you have a copy of last year's Rule Book a good picture is on page K-3, it's not there anymore with the new rule.

As a side note my bud Olly Douglas just put a Muck pipe on his Scale boat with an internal stinger. He runs the exhaust to the back of the boat with silicone tubing and it's very quiet. We didn't get a meter on it but it's below 90dB for sure.

It might not make it on a big twin but I think if the engines are rubber mounted, you don't have a big drain hole in the pipe and you use a small after muffler it might be close...

 

[Mark Bullard]

Sorry Terry, I read your post, and went back to my copy of the book, and read some more..... Have you attempted to have the stinger "blocked" in the center, as jennings stated, or just straight through? Im gonna try some stinger buildin, any help is appreciated..... thanks mike

No, I haven't tryed blocking the stinger, just run it through to the middle. If you have a copy of last year's Rule Book a good picture is on page K-3, it's not there anymore with the new rule.

As a side note my bud Olly Douglas just put a Muck pipe on his Scale boat with an internal stinger. He runs the exhaust to the back of the boat with silicone tubing and it's very quiet. We didn't get a meter on it but it's below 90dB for sure.

It might not make it on a big twin but I think if the engines are rubber mounted, you don't have a big drain hole in the pipe and you use a small after muffler it might be close...

Of course Brian does not want me to post in his post, but the facts must be known.

Terry the stingers that I made have 0.062dia. drain holes about a 0.250 from where the stinger welds into the pipe. The stinger diameter is 0.440 which is the stock diameter for those pipes. The motor mounts are delrin, the screws that bolt the motor mount to the tub are nylon, the grommets in the tub are rubber that carry the motor mounts, and of course the pipe mounts have rubber grommets that carry them. Now I do not know how much more sound deading that I can do on the boat.

My good friend Bob Londress and myself did some of the first work on rubber motor mounts to help reduce noise and vibration. The main reason was for the mono's. Everyone told us that it would not work 30 years ago but now it is commom practice. If the true be know we even brought you the stainless fastners. We were bring them to the races and selling them like hotcakes. But that enough gloking.

I think the real problem is the K 90 motor is a very loud motor. It has a lot of mechincal noise plus a great amout of intake noise. And with the timing numbers that I run and the low taper P/S creates a lot of noise. One K 90 motor being turned by a starter will produce about 86 to 87dB standing about 20' from the side of the motor. And this is before I light the plug. When I placed the long pieces of tubing on the end of the pipes and ran them down to the water right before the props I could not hear the exhaust to set the needles when the boat was running but I could sure hear the intakes and that was how I set the needles.

Now I feel that some people think that I was cheating or trying to skirt the rule. Not so, I spent about $300.00 trying to comply that week on that boat. And after the trick of turning the exhaust to the inside of the course it was to late because I had burned a piston badly. Was this the way to fix the problem to get the boat to pass the dB meter at that lake site, NO. But like I said before I do have some more ideas that I think will improve the internal stinger.

Mark Bullard

 

[Terry Keeley]

Sorry Terry, I read your post, and went back to my copy of the book, and read some more..... Have you attempted to have the stinger "blocked" in the center, as jennings stated, or just straight through? Im gonna try some stinger buildin, any help is appreciated..... thanks mike

No, I haven't tryed blocking the stinger, just run it through to the middle. If you have a copy of last year's Rule Book a good picture is on page K-3, it's not there anymore with the new rule.

As a side note my bud Olly Douglas just put a Muck pipe on his Scale boat with an internal stinger. He runs the exhaust to the back of the boat with silicone tubing and it's very quiet. We didn't get a meter on it but it's below 90dB for sure.

It might not make it on a big twin but I think if the engines are rubber mounted, you don't have a big drain hole in the pipe and you use a small after muffler it might be close...

Of course Brian does not want me to post in his post, but the facts must be known.

Terry the stingers that I made have 0.062dia. drain holes about a 0.250 from where the stinger welds into the pipe. The stinger diameter is 0.440 which is the stock diameter for those pipes. The motor mounts are delrin, the screws that bolt the motor mount to the tub are nylon, the grommets in the tub are rubber that carry the motor mounts, and of course the pipe mounts have rubber grommets that carry them. Now I do not know how much more sound deading that I can do on the boat.

My good friend Bob Londress and myself did some of the first work on rubber motor mounts to help reduce noise and vibration. The main reason was for the mono's. Everyone told us that it would not work 30 years ago but now it is commom practice. If the true be know we even brought you the stainless fastners. We were bring them to the races and selling them like hotcakes. But that enough gloking.

I think the real problem is the K 90 motor is a very loud motor. It has a lot of mechincal noise plus a great amout of intake noise. And with the timing numbers that I run and the low taper P/S creates a lot of noise. One K 90 motor being turned by a starter will produce about 86 to 87dB standing about 20' from the side of the motor. And this is before I light the plug. When I placed the long pieces of tubing on the end of the pipes and ran them down to the water right before the props I could not hear the exhaust to set the needles when the boat was running but I could sure hear the intakes and that was how I set the needles.

Now I feel that some people think that I was cheating or trying to skirt the rule. Not so, I spent about $300.00 trying to comply that week on that boat. And after the trick of turning the exhaust to the inside of the course it was to late because I had burned a piston badly. Was this the way to fix the problem to get the boat to pass the dB meter at that lake site, NO. But like I said before I do have some more ideas that I think will improve the internal stinger.

Mark Bullard

How many drain holes do you have?

 

[Mark Bullard]

Sorry Terry, I read your post, and went back to my copy of the book, and read some more..... Have you attempted to have the stinger "blocked" in the center, as jennings stated, or just straight through? Im gonna try some stinger buildin, any help is appreciated..... thanks mike

No, I haven't tryed blocking the stinger, just run it through to the middle. If you have a copy of last year's Rule Book a good picture is on page K-3, it's not there anymore with the new rule.

As a side note my bud Olly Douglas just put a Muck pipe on his Scale boat with an internal stinger. He runs the exhaust to the back of the boat with silicone tubing and it's very quiet. We didn't get a meter on it but it's below 90dB for sure.

It might not make it on a big twin but I think if the engines are rubber mounted, you don't have a big drain hole in the pipe and you use a small after muffler it might be close...

Of course Brian does not want me to post in his post, but the facts must be known.

Terry the stingers that I made have 0.062dia. drain holes about a 0.250 from where the stinger welds into the pipe. The stinger diameter is 0.440 which is the stock diameter for those pipes. The motor mounts are delrin, the screws that bolt the motor mount to the tub are nylon, the grommets in the tub are rubber that carry the motor mounts, and of course the pipe mounts have rubber grommets that carry them. Now I do not know how much more sound deading that I can do on the boat.

My good friend Bob Londress and myself did some of the first work on rubber motor mounts to help reduce noise and vibration. The main reason was for the mono's. Everyone told us that it would not work 30 years ago but now it is commom practice. If the true be know we even brought you the stainless fastners. We were bring them to the races and selling them like hotcakes. But that enough gloking.

I think the real problem is the K 90 motor is a very loud motor. It has a lot of mechincal noise plus a great amout of intake noise. And with the timing numbers that I run and the low taper P/S creates a lot of noise. One K 90 motor being turned by a starter will produce about 86 to 87dB standing about 20' from the side of the motor. And this is before I light the plug. When I placed the long pieces of tubing on the end of the pipes and ran them down to the water right before the props I could not hear the exhaust to set the needles when the boat was running but I could sure hear the intakes and that was how I set the needles.

Now I feel that some people think that I was cheating or trying to skirt the rule. Not so, I spent about $300.00 trying to comply that week on that boat. And after the trick of turning the exhaust to the inside of the course it was to late because I had burned a piston badly. Was this the way to fix the problem to get the boat to pass the dB meter at that lake site, NO. But like I said before I do have some more ideas that I think will improve the internal stinger.

Mark Bullard

How many drain holes do you have?

Four

 

[Tim_Duggan]

I think the real problem is the K 90 motor is a very loud motor. It has a lot of mechincal noise plus a great amout of intake noise. And with the timing numbers that I run and the low taper P/S creates a lot of noise.

Hi Mark,

I have raced a single K90 with the sleeve raised 0.020" at the last two Australian Nationals in hydro's and have not been penalised or even warned about noise and we run to a 90dB limit.

The K90 has won several NAVIGA World Championships in FSR-H and they run an even tighter DB rule.

They may be a noisy engine as you state, but it is definately possible to make them legal.

 

[Brian_Nelsen]

Mark

I do not care if you posts its not my forum I just started the topic. I really just want this thread to stay informative and not go into the issues the other thread has. Facts as to the set ups we are using are what is needed.

Your current post has some very good information in it. The nylon bolts and delrin mounts and such. This is what we all need to hear. I have nylon fasteners for my new mono's but I do not have delrin mounts. Question for you are the delrin mounts of a solid type or are they rubber mounted as well.

Now I think we need to start looking at induction noise. If your is that loud just from intake noise that is a huge issue.

Thanks

Brian

 

[Terry Keeley]

Sorry Terry, I read your post, and went back to my copy of the book, and read some more..... Have you attempted to have the stinger "blocked" in the center, as jennings stated, or just straight through? Im gonna try some stinger buildin, any help is appreciated..... thanks mike

No, I haven't tryed blocking the stinger, just run it through to the middle. If you have a copy of last year's Rule Book a good picture is on page K-3, it's not there anymore with the new rule.

As a side note my bud Olly Douglas just put a Muck pipe on his Scale boat with an internal stinger. He runs the exhaust to the back of the boat with silicone tubing and it's very quiet. We didn't get a meter on it but it's below 90dB for sure.

It might not make it on a big twin but I think if the engines are rubber mounted, you don't have a big drain hole in the pipe and you use a small after muffler it might be close...

Believe it or not that will make it a lot louder, I just put one on the bottom...

Of course Brian does not want me to post in his post, but the facts must be known.

Terry the stingers that I made have 0.062dia. drain holes about a 0.250 from where the stinger welds into the pipe. The stinger diameter is 0.440 which is the stock diameter for those pipes. The motor mounts are delrin, the screws that bolt the motor mount to the tub are nylon, the grommets in the tub are rubber that carry the motor mounts, and of course the pipe mounts have rubber grommets that carry them. Now I do not know how much more sound deading that I can do on the boat.

My good friend Bob Londress and myself did some of the first work on rubber motor mounts to help reduce noise and vibration. The main reason was for the mono's. Everyone told us that it would not work 30 years ago but now it is commom practice. If the true be know we even brought you the stainless fastners. We were bring them to the races and selling them like hotcakes. But that enough gloking.

I think the real problem is the K 90 motor is a very loud motor. It has a lot of mechincal noise plus a great amout of intake noise. And with the timing numbers that I run and the low taper P/S creates a lot of noise. One K 90 motor being turned by a starter will produce about 86 to 87dB standing about 20' from the side of the motor. And this is before I light the plug. When I placed the long pieces of tubing on the end of the pipes and ran them down to the water right before the props I could not hear the exhaust to set the needles when the boat was running but I could sure hear the intakes and that was how I set the needles.

Now I feel that some people think that I was cheating or trying to skirt the rule. Not so, I spent about $300.00 trying to comply that week on that boat. And after the trick of turning the exhaust to the inside of the course it was to late because I had burned a piston badly. Was this the way to fix the problem to get the boat to pass the dB meter at that lake site, NO. But like I said before I do have some more ideas that I think will improve the internal stinger.

Mark Bullard

How many drain holes do you have?

Four

Believe it or not that'll make it louder, I just put one on the bottom...