Loud Outboards - How to Reduce Sound?

[Chotu]

I have a catamaran. It’s Fiberglass and foam.

It has Outboard Wells at the Stern. These wells are ahead of the rudders. Where a sail drive would normally go. So the prop sticking down in the water is essentially in the exact same position that a sail drive is on all the other catamarans.

These work pretty well. No complaints except that they are currently under propped. I need to get higher pitch.

The problem is the noise. They are excruciatingly loud to me once they rev up.

They currently hang off of mounts made from very thick plywood. Like you would do for a transom. These mounts are about the width of the outboard itself. These mounts slide up and down in an aluminum track.

The aluminum track is bolted to a bulkhead in the hull.

These are 30 hp fuel injected, modern two-stroke engines.

The sound is pretty much deafening in each of the hulls. It seems to act like a drum and amplify the sound and vibration of the outboard. And it’s a buzzing sound almost like a chainsaw at full throttle mid cut. And it’s about as loud as if you were holding that chainsaw cutting through a big log. Very very loud. You can’t even yell over it and hear someone in parts of the hulls.

it’s pretty darn loud up on the bridge deck as well. But most of that sound seems to come from outdoors through the open aft door and into the main salon room.

Any tips for stopping all of this noise? How would you attach the Outboard differently in order to stop the noise?