Engine room sound reduction

SoundDown in Ft Lauderdale can provide you with their dense rubber matting. Remove the wood flooring, cover the floor with the rubber matting, and then reinstall the wood floor atop a thin underlayment to which the wood can be adhered so that your reinstallation floats without fastener penetrations. Those penetrating fasteners transmit noise. The rubber mat will kill a significant amount of the engine volume. Removing flooring fasteners helps quite a bit as well.

The rubber matting is 2# PSF, and it will remain in place where you put it, so don't fasten it.

How do you keep the rubber mats and laminate in place for engine room hatches etc? Can you use some 3M sticky glue?

The sound down and dynamat products work very well. Can be installed in multiple layers also. I like foil backed ones cause they help with heat. Look for any penetrations in salon floor sound can pour thru. Wire chases and such will transmit sound and heat very well. For any hatches or semi permanent openings we carefully mark the sound down with a sharpie out lining it. Use a razor to cut when needed, duct tape cut when completed. Don't forget sound down in bottom of cabinets. Sound is good at finding holes in your armor. Padded headliner helps also.

Our 43 has about 3" thick acoustic matting on the undeside of the hatches (look above the engines), and thick acoustic batting on boards mounted to stand-off the hull sides. (can see around the board holding bettery cutoffs). No idea when/who put it in, I had presumed it was factory?

-greg

And perforated aluminum is the better choice for this, as opposed to stainless. Aluminum will absorb more heat more quickly and cool faster.

Keep in mind the time in the future where you'll need the major overhaul. That floor will need to come out. I did a similar salon in full length T&G mahogany with oversized T&G for a quality lap. The boards were numbered on the bottom side and refinished prior to install. Once in place I drove rubber wedges between the wall and outer edge of the floating floor to lock them in place and keep the laps tight. I secured the rubber wedges with baseboard trim made of the same flooring material, mechanically fastened to the walls. I created a stainless trim overlap for the door openings to secure and protect the end grains and eliminate trips. The floor was purely floating atop the heavy rubber mat. The full structure was removable for major ER work, and it killed noise with terrific success.

Good stuff. I focused my sub-floor insulation with thermal insulation and perforated aluminum sheets to resist heat transmission and relied on a hollow core (nidacore) floor system as well as the Sounddown rubber to kill the noise. Yes, attack chases and any surfaces in touch with the ER shell like steps and cabinets, etc...

Cockpit and salon floor is 2" foam core with carbon skins. Good thermal properties but not sound. So dynamat made a big difference.

Yes, as it did for me, too. And the installation concept still allowed pretty easy access for major maintenance in the ER or on the engines themselves...

cant believe how much room is in Greg Page's 43 engine room with those cats!

The CATs are at least a foot shorter then the DD's. The old engine mount holes are filled with resin. I like being able to sit on the stringers ahead of the engines to access the engines and the systems on the outboard side. I think the top clearance to the hatches is larger as well. The transmissions are in essentially the same place.

really nice job, C9's?