Sound Dampening Idea (maybe)

[Noko]

The egg carton is basically the same design on the new 242 that was in the video on this site. That geometric shape of the egg carton and the foam insulation in the new Yamaha is similar and is what helps with the sound deadening. If you've ever seen a music studio, they have the same type insulation to help deaden sound and create a better sound when recording. So maybe I should go to Costco and buy some eggs. Anyone for a group buy?

 

[motorboater]

@dan144k I completely agree with your observations. Bulb seal and Solas impellers were the biggest difference makers, followed by redoing the material on the engine hatch. I dont think my efforts with the gas tank cover were worth the time and expense.

I should really finish my project. The last steps I intended to take were the engine compartment sidewalls and the rear wall. I have some self-adhesive MLV for the rear wall and had planned to put some closed cell foam on the sides. I dont think there is much more that could be done. The swim platform is like a huge drum than amplifies the engine and pump resonance, as are the hull sides. I tried to solve this by putting some large shims inside the platform but didnt really get anywhere and I dont think MLV stuck to raw fiberglass will do any good. The boat design itself with the inboard pumps and poor engine dampening creates a lot of vibration that sound deadening wont cure in my opinion. This is where the more efficient Solas Concordes made an impact, by creating less vibration.

I bet the jetboatpilot kit will make a noticeable difference as it does hit the worst spots and you dont need to experiment with your own materials.

 

[Murf'n'surf]

For the Classic boats it is rumored that foam filling the hull voids will quiet the boat down extraordinarily well. Most noise in my boat resonates through the hull voids like a bass drum.

We need somebidy willing to drill some holes and fill her up!

 

[Chillypilot]

There's nothing special about the kit Jetboatpilot is selling it is just Soundown which can be purchased at many marine stores. The plug he has for the fire extingusher hole is a nice touch. I did my engine compartment with soundown and the ski locker and fuel tank hatch with Stinger Roadkill which is similar to Dynamat. The harmonics are much better and the noise level decreased but it's no where near as quiet as my buddies Nautique. I do feel that it was worth the effort and expense. Hmmmm Maybe I should buy some Solace impellers.

 

[dan144k]

?question? do most other boats exhaust exit underwater?
This was another idea I thought about.
The Yamaha AR240 exhaust exit's into the side of the tunnel next to pump. Their is not much room between the exhaust point exit and the side of the pump. I considered building 90 degree something to deflect the exhaust downward or maybe 45 degrees (down and rear) to try and see if it would reduce the sound some. But never implemented idea.

 

[Ronnie]

I need to do some rework on my sound absorbing/deadening project from last year.

Here is my plan:
1. Replace the pipe insulation I used around the engine hatch perimter. It stsrted cracking at various points, hopefully the bulb seal it is replaced with lasts longer.


2. I need to either reinstall the material on the bottom of the engine hatch and add another layer of 1" or 2" inch egg carton textured material to it or just replace it with 3" thick material from mcmaster carr. The material i had on there got wet and heavy which caused some of the adhesive on the back to fail, so i peeled it off in preparation for the next attempt. Why 3" because as far as i can tell thats what yamaha uses in the 2015 240 series boats.



3. I hope the kit at jet boat pilot works and sells well but the material didnt look thick enough to me. I'm speaking from the perspective of a person who has already lined the engine compartment and underside of the hatch with similar 1" thick material advertised to absorb 60% of the sound. It is quieter than stock just not quite enough for me. I will try plugging the fire port as well although that seems to eliminate most of the functionality of the fireport. I've already covered the back wall of the compartment but was careful to keep the stock ventilation as it came from the factory.

4. I may put some material on the compartment walls under the swim deck/clean out plugs, the water boxes are in there so i think something in there can only help.

5. I forgot that switching to aftermarket impellers may help with the noise. I hope it helps me as i just put two solas screws in but for the performance upgrade not sound reduction.



That should do it for me. Whether it makes a difference or not is hard to tell. Just like beauty is in the eyes of the beholder, noise is in the ears of the person(s) listening.

 

[PaulyB]

Anyone ever tried this stuff? http://www.soundproofcow.com/Silent-Running-5.html

From the Details of the Product:

Great for the Marine Industry:
SR-500 is lightweight, waterproof, resists chipping and corrosion and bonds permanently to your vehicle, making it the perfect solution for creating a quiet environment.

• Hatch Cover Liner
• Engine Compartment Liner
• Hull Liner

 

[Ronnie]

That product looks interesting but to do the side walls in the engine compartment you would have to remove the carpet lining them first. Not sure if this would be easy to do but doubt it would be. Still 1 gallon for $108 should cover quite a bit of area. By the way I bought 17' linear feet at 54" long of the 1" thick material and it covered the entire engine compartment including the hatch as well as the underside of the fuel tank cover with only a little material remaining.

Who wants to go first?

I forgot to mention that I still have the paper templates (front and side walls of the engine compartment, possibly the back wall as well) I made when I installed my sound absorbing material. They are free to whoever wants them but only useful to those with a 240 series boat.

 

[Murf'n'surf]

Anyone ever tried this stuff? http://www.soundproofcow.com/Silent-Running-5.html

From the Details of the Product:

Great for the Marine Industry:
SR-500 is lightweight, waterproof, resists chipping and corrosion and bonds permanently to your vehicle, making it the perfect solution for creating a quiet environment.

• Hatch Cover Liner
• Engine Compartment Liner
• Hull Liner

Great find! I don't think this product would do much for the engine hatch but it would work wonders if the hull, deck and voids were sprayed with this product during construction.

 

[Britboater]

Egg boxes aside, all/any sound insulation thats being used in the engine compartment needs to be flame resistant, anything thats not is just asking for trouble.

 

[CrankyGypsy]

in my opinion, upgrading existing sound proof is going to give minimal results.

I'm redoing my deteriorating hatch foam in new 1.5" egg crate foam; replacing the engine wall carpet with 1" triangle cut; KnoKnoise under the fuel pump and locker door.

BUT I doubt any of that is going to help like lining the back of the resonator (yes, the RESONATOR) and seat storage dividers with 4" triangle foam. the sides of the boat are like sound cannons. gonna be at least a few weeks until I get everything back together.

 

[buckbuck]

dan144k,
If you do something with your exhaust please keep us informed. It seems to me that dumping the exhaust underwater would quiet things better.

 

[MikeyL]

@Geoff Cooper wrote a great thread in October of 2014, here, , about his experience replacing his hatch cover with egg-shell insulation. Lotsa photos. Worth your time to peruse .....
https://jetboaters.net/threads/replacing-engine-bay-soundproofing-ar-230-06.3903/

Enjoy and Happy Easter, Mikey Lulejian - Lake Oconee, GA

 

[CrankyGypsy]

i'll start a new thread when it's all done, but here is the 4" wedge (i called it triangle earlier) foam on the back of the "dividers"


foam from The Foam Factory. glued with 3M 77 spray adhesive on both surfaces.
i cut the large/medium holes and silhouette with a Black & Decker EK700 carving knife. small holes cut with hole saw (with the drill bit removed to prevent snagging). these were the first panels - on the others, i used a hole saw for medium holes as well.

EDIT: 3M 90 is a better choice here.

 

[Ronnie]

Looks good.

 

[KXCam22]

There are lots of holes between the engine compartment and the rest of the boat. Sealing those up with some acoustical sealant (or anything) would help quite a bit. When I was installing ballast the idea that got to me was that general soundproofing would achieve minimal results without plugging all of the sound passages that lead under the floor and seating areas. In my 230 the bulkheads around the engine don't fit all that tight and there are direct passages to the under floor area. All of these will transmit and radiate sound. The external hatch sealing is a great start. I think plugging the underfloor holes should be next. Cam.

 

[sysinu]

I'm in the process of adding 2.5" thick egg crate foam/sound absorbing materials in my aft storage compartments. There is a ton of room around the walls of the engine compartment and holes for ballast and power, etc going through. I need to look at airflow/ventilation again, but I'm pretty sure I just need to put a wall on both sides back there (one in front of the fresh water tank on stbd and another lining the port side of the outer engine compartment. THEN I'm going to go crazy with all the open area around the gas tank. Going to put the same egg foam aft of the tank (cut some slots in it to help it slip around the cables, lines, etc) and then I'm going to put a 1" thick adhesive insulation on the fuel tank access panel. I think that's a majority of where sound is coming from actually (is the fuel tank area). Finally I'm going to put a little inside the engine compartment (on the bottom) of the compartment to avoid hull transfer of the sound.

 

[Jim Robeson]

i'll start a new thread when it's all done, but here is the 4" wedge (i called it triangle earlier) foam on the back of the "dividers"
View attachment 19701

foam from The Foam Factory. glued with 3M 77 spray adhesive on both surfaces.
i cut the large/medium holes and silhouette with a Black & Decker EK700 carving knife. small holes cut with hole saw (with the drill bit removed to prevent snagging). these were the first panels - on the others, i used a hole saw for medium holes as well.

Unless you have already done this, you might want to use 3M Spray 90. I think you'll have better results.

 

[dan144k]

Water-Box's, does anybody know proper material to sound proof the water-box's in the rear of boat.

Maybe best and easiest way would be to build a 2.5" foam (eggcrate) box or enclosure and surround the area to contain the noise from the exhaust box's.

Got the idea working on boat in driveway. Held down the rear hatch buttons, these turn off engine engine for clean out plug access. Started the engines, and listened to the of rear boat. Then open the center oval pop out hatch and listened. Sounded like a good amount of noise inside that section.

Boat still in storage, 6 hours away, and won't be able to build or test idea personally for a month. In May or June when I install ballast I will need to remove waterbox so that will be the time to insulate them.

 

[CrankyGypsy]

(EDITED)

as per @Jim Robeson , 3M 90 is a better option for this project due to the heat resistance, thicker delivery of adhesive, and increased hold with these materials.