Major source of engine noise 2015 242+

[Mainah]

I am finally getting around to removing my shower kit to make room for ballast. In the process with cup holders, speakers and bilge access panel removed this caught my eye. That light on the left of the frame next to the fiberglass is coming from the swim deck speaker hole which is right above the resonator. So the bilge has free flowing air and noise right into the rear benches. Sealing this up should cut down a good bit of noise.

Edit - Shower kit sold

 

[swatski]

I am finally getting around to removing my shower kit to make room for ballast. In the process with cup holders, speakers and bilge access panel removed this caught my eye. That light on the left of the frame next to the fiberglass is coming from the swim deck speaker hole which is right above the resonator. So the bilge has free flowing air and noise right into the rear benches. Sealing this up should cut down a good bit of noise.

P. S. Shower kit will be listed for sale very soon with uninstall photos, items labeled, and all hardware except through hull air vent and swim deck cover.

View attachment 68935

Good point! I have noticed the same thing.
For example, try opening the seat while driving WOT - a lot of noise coming from that compartment.

I have stuffed the rear of that compartment with old ballast bags inflated with air -and guess what? - it helps tremendously!

I have previously sound-deadened the bulkhead separating the rear compartment from the engine bay, but you are right - that gap you show must be a huge noise leaker!!!!

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[Mainah]

Boat covered for the night now but I had hung on to some of this furniture or appliance packing material. This stuff filled it perfectly snug with the straight wnge going in and the jagged edge crating a lip seal againt the fiberglass.

Sharpie for size reference because it happened to be right at hand.

 

[Mainah]

Already back to this because planning to mount my inflator on bilge side of the bulkhead with 3/4 wakemakers hose off of that and coming through the shower head door. Power controlled through Connext by turning on the shower which will go to a 30 amp relay to handle the extra load.

Thinking about mounting the inflator made me realize that there is not any sound deadening on either side of that single panel fiberglass bulkhead. That thing will resonate sound fowards in the boat even with the gap filled. So will need to add egg foam or something to that bulkhead. Good thing I am not claustrophobic.

@swatski what material would you recommend for that and the storage side of the engine compartment panels since I am at it?

 

[swatski]

@swatski what material would you recommend for that and the storage side of the engine compartment panels since I am at it?

I really like RAMMAT/Ensolite combo. I like that better that any other "high end" sound deadening product I used such as Dynamat (Extreme?), or Hushmat, or FatMat.
Still think that @gmtech16450yz approach with memory foam is best - most cost effective by far. However, those compartments will always get wet one way or another and consequently there will be need to replace any conventional mattress foam, but not RAMMat, due to molding.

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[gmtech16450yz]

Yep those are the panels I took out and covered both sides with closed cell foam. About 1" thick on each side, and I made them bigger than the panel so they filled in the gaps on the sides. That is a major source of engine noise, it does transmit right up the sides of the boat to the front. The sides of the boat not having any carpet on them act like giant speaker boxes. I carpeted the bare sections on the sides of the hull and added more foam insulation in those areas too. Made a huge difference in engine noise.

Did you actually crawl into those compartments? lol. I had to a couple times to get those panels out and back in. I was a little afraid I'd get stuck in there and not be able to get back out! I was literally laying with my head all the way at the back of those compartments. It was definitely my exercise and yoga workout for the day!

 

[Mainah]

Yep crawled up the starboard side far enough to get a wrench on the through fitting that was on the bulkhead. I thought that was tight then I crawled up port side and was not pretty getting back out. As I said in another thread one of my lean teenage sons will being doing that when I install the ballast and add sound insulation.

 

[LukePrinsloo]

Any update now that you are on the water? Did it help with noise?

 

[Mainah]

I would say everything I did helped some. Sealing gaps did the most and was noticeable but I did seal a lot of gaps and now have sub boxes built in between the inner and outer hull mid cabin which helps as well. Mlv adds a lot of weight for very little gain on wood/fiberglass. Accoustic foam does more than mlv but takes much more space. My top speed at 60 degrees, 360 ft elevation, smooth water, half tank of fuel, clean hull, and two people use to be 51 mph with nearly nothing else on board. After all of the mods I have done since .. kegerator, trim tabs, ballast system, sound deading, enclosing sub locations, wake/surf racks, boards kept on the boat, cover kept in storage, etc 48.4 mph is my top speed. Normal useage with my family of 5 and loaded down for a day on the water full tank of fuel and a temp of 78 makes 46.5 my top speed. I find this to be an acceptable trade off given all of the weight of all of my mods and gear in total. If I were to do it again I would limit my useage of the MLV.

 

[swatski]

This is what I started doing these days, when cruising.
A fast, 30sec setup w/ two (old style) 550lbs ballast bags (filled w/air to capacity/fit) and a 12V air pump.
Works exceptionally well, very noticeable difference in engine sound/noise suppression.

STRBD side:


And PORT side:


EDIT: My crew seems to like it, lol

 

[Mike & Lilly]

Lol and the family taking a nap is enough proof awesome pic