I think I finally quieted my Yamaha!

[2nazt]

Between this and adding thicker plywood as @Bruce has done this could be a great solution. Looking forward to your ear to ear comparison between the two boats. Maybe a meet up and unbiased ear could be found close by

 

[Bruce]

Between this and adding thicker plywood as @Bruce has done this could be a great solution. Looking forward to your ear to ear comparison between the two boats. Maybe a meet up and unbiased ear could be found close by

I removed the factory plywood on the sides and blocked off the under seat and behind the seat openings into the engine compartment with new plywood that was carpeted on the front and dynamatted on the back. I used the new found space in the engine compartment to install a 16 gallon tank and pump for a shower on the starboard side and dual 100 amp batteries in boxes on the port.

You can see the new plywood pieces in this thread https://jetboaters.net/threads/what-is-the-best-sound-deadening-product.2088/#post-32655

 

[ridinpropless]

I certainly felt like mine was quieter but that's kind of like asking me if I think my kids are smart. I know that the db meter on a phone isn't accurate, but I was hoping it would give me some concrete evidence. If mine showed 80 and his showed 85, at least that was something.

My daughter's friend is going out with us this afternoon. Her dad has a 2013 242. My daughter swears ours is quieter. I'll be interested to hear what her friend says. If I can get her to admit it is, I think I'll be onto something.

 

[Derek Fosbury]

I think the db levels are only part of the story. What is more significant than the overall db change (if any) is the removal of particular frequencies. mid-range or higher-range frequencies are way more intrusive than the low's, especially for conversations, etc.

What I notice the most, independent of my meter readings, is that I am way less audio-fatigued after sound deadening, and the fact that I can hear way more OTHER sounds at those frequencies, i.e., water noise, music, etc.. For example, after the improvements on both my current and my old boat, I can hear when the ladder is left down by mistake. I could never hear that before!

 

[swatski]

Well, I have good news and bad news.

First, the good. The adhesive has stuck great. Hasn't budged. It turned out to be a nice clean install and I can't even really show people what I did because you can't tell. I downloaded an app (Sound Meter) for my phone (Galaxy Grand Prime from Cricket) and copied the original boattest.com sound test spread sheet. I figured I would just test it at the same RPM reading they did. The results were fantastic! Here is an overview of it all

RPM Original db After mods
2500 72 70
3000 75 75
4000 83 79
5000 84 81
6000 80 80
7000 83 80
8000 87 78
9000 92 79
10000 93 N/A

So, as you can imagine, I was ecstatic! Convinced that I had cracked the code!

We went to the beach for the day and that's where the bad news came in. A guy pulled up in an SX 230 with no mods. Made some conversation and asked him to take me for a ride so I could verify. I didn't want to take too much of his time, so I just asked him to run it up to 8000 RPMs. My sound Meter app read...80db. Damn-it.

I've decided that my phone likely has a noise canceling Mic on it that I need to disable somehow, or try on a different phone. I'm heading back out this afternoon and will try with a different phone to see if there's a difference.

@ridinpropless I think these results are fantastic. The best I have seen, I think. Your before and after is impressive, at higher RPMs it is over 3-fold I believe in sound pressure. That is at face value the same or better than the quiet cruise equipped new 24fters.

The other SX230, even stock, could have been older and/or have various issues that may affect sound level. I would take a test done on the same boat over it. And I still feel the personal impression of the volume of noise is the most telling, I think that @Derek Fosbury really nailed it in his description.

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[ridinpropless]

@swatski , don't get too excited. I'm pretty confident the fact that the readings level out at 80db is a function of the phone mic more than the sound proofing.

That said, my daughter's friend said she definitely thinks our boat is quieter than their 242. In her words, "You can hear the music while you ride. You can't do that in our boat." Which brought up an interesting idea for the sound test. How high do you need to turn your stereo to hear it? I have the stock stereo in my boat and with it set at 23-24 on the volume meter, I can hear it just fine at 8-9,000 RPMs. Anyone else running the stock stereo? I'd be interested to know how well or if you can hear it at speed.

 

[swatski]

@swatski , don't get too excited. I'm pretty confident the fact that the readings level out at 80db is a function of the phone mic more than the sound proofing.

That said, my daughter's friend said she definitely thinks our boat is quieter than their 242. In her words, "You can hear the music while you ride. You can't do that in our boat." Which brought up an interesting idea for the sound test. How high do you need to turn your stereo to hear it? I have the stock stereo in my boat and with it set at 23-24 on the volume meter, I can hear it just fine at 8-9,000 RPMs. Anyone else running the stock stereo? I'd be interested to know how well or if you can hear it at speed.

That is an interesting idea for sure, a competitive binding/interference assay of sorts... It would have to be the exact same unit. A boombox for that matter that you can transfer.
That said, I think the "conversation test" is about as relevant as a measuring unit of your success as it gets.
Thank you for sharing, this is great!

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[Topper232]

I'm no engineer, so I'll ask the stupid questions. Is there any risk of this holding heat in the engine compartment and any issues with flammability? I would also love to reduce the engine noise.

Thanks,

 

[2nazt]

@Topper232 I do not think this keeps excess heat in as it is already insulated (poorly) from Yamaha. Also I do not believe that it adds any additional flammability concerns as long as you keep space from anything hot or directly touching the engines. To reduce heat you can run with blowers on, but I do not wish to start that discussion once again lol as that is a personal preference and thought. As long as properly attached and no chance of falling. I see no concerns. I am not an engineer just stating what I see.

 

[swatski]

I'm no engineer, so I'll ask the stupid questions. Is there any risk of this holding heat in the engine compartment and any issues with flammability? I would also love to reduce the engine noise.

Thanks,

This has been discussed extensively in the past. I think the consensus is that it is not an issue. Same engines do very well in skis where the space is a lot more confined. Cooling is open loop water so the blowers are just for safety - to get rid of fumes and prevent potential ignition of fuel vapors.

Of course the air intakes access to fresh/cool air may be an issue if you obstruct the passages/openings in the back of the engine bay, that needs to be considered.

--

 

[Topper232]

Cool....thanks @swatski & @2nazt

 

[Majorsmackdown]

Have y'all noticed that running without the bimini top deployed is way way quieter too...

 

[blacksapphirez]

i simply put an insulation sheet over the engine bay and it was a huge improvement.

http://www.ebay.com/itm/68-x39-Acoustic-Foam-Insulation-Heat-Proofing-Mat-Studio-Sound-Proof-Isolation-/172269112368?hash=item281c0a0c30:g:pl0AAOSwzJ5XcJUz

 

[JetBoatPilot]

Well, I have good news and bad news.

First, the good. The adhesive has stuck great. Hasn't budged. It turned out to be a nice clean install and I can't even really show people what I did because you can't tell. I downloaded an app (Sound Meter) for my phone (Galaxy Grand Prime from Cricket) and copied the original boattest.com sound test spread sheet. I figured I would just test it at the same RPM reading they did. The results were fantastic! Here is an overview of it all

RPM Original db After mods
2500 72 70
3000 75 75
4000 83 79
5000 84 81
6000 80 80
7000 83 80
8000 87 78
9000 92 79
10000 93 N/A

So, as you can imagine, I was ecstatic! Convinced that I had cracked the code!

We went to the beach for the day and that's where the bad news came in. A guy pulled up in an SX 230 with no mods. Made some conversation and asked him to take me for a ride so I could verify. I didn't want to take too much of his time, so I just asked him to run it up to 8000 RPMs. My sound Meter app read...80db. Damn-it.

I've decided that my phone likely has a noise canceling Mic on it that I need to disable somehow, or try on a different phone. I'm heading back out this afternoon and will try with a different phone to see if there's a difference.

We've tried to get a metric for how much sound reduction our sound down kits actually provide and we had the same trouble with the phone app decibel meter. We can hear the noise level with our ears but can't give you a number to tell you how much quieter it is.

 

[Amar Nanduri]

i simply put an insulation sheet over the engine bay and it was a huge improvement.

http://www.ebay.com/itm/68-x39-Acoustic-Foam-Insulation-Heat-Proofing-Mat-Studio-Sound-Proof-Isolation-/172269112368?hash=item281c0a0c30:g:pl0AAOSwzJ5XcJUz

I Can't find it on eBay. My 2010 engines cause quite a racket compared to a 2013 of my friends. Name of the insulin sheet and pics ? Thanks

 

[blacksapphirez]

I Can't find it on eBay. My 2010 engines cause quite a racket compared to a 2013 of my friends. Name of the insulin sheet and pics ? Thanks

Sorry ive been trying to look for it but cant find it either. Once we get back on the water i will take some pictures and hopefully a comparison video.

 

[JetBoatPilot]

We sell a product called Soundown specifically created for engine rooms.

 

[njmr2fan]

Winter project. Any suggestions or things you would do differently? I'd like to quiet down our AR190 so we can take a civilized cruise on the water and be able to talk. do you think that wrapping the inside of the the swim platform and adding some noise absorbing eggcrate would reduce sound from that big hollow area?

 

[Bruce]

@njmr2fan, @swatski tried that. He ended up buying a new boat.....,

 

[Jgorm]

I'm going to try some west maybe engine insulation on top of the air filter. On my fx140 mr1 it's quiet with the seat on. It's loud with the seat off, and ear piercing with the air filter off. It's so quiet with the seat on that I revved the piss out of it because I thought it wasn't revving! (First and last time) it's much easier to hear the difference on the ski when your head is over the engine when you rev it.