Exhaust under water line

[mud duck]

Hello, Has anyone moved their exhaust tips down below the water line? I currently have a covered engine with through transom exhaust and clamp on mufflers. I am thinking about moving the exhaust ports down below the water line and adding a one piece full width swim platform, similar to what a competition ski boat or wakeboard boat would be like. Then at idle the exhaust would be under water and less noisy. Has anyone done this recently? Am I wasting my time/money?

[9er]

My boat is pretty shallow so my tips are certainly under the water line when at an idle.
When I first put them on it sounded like a sewing machine in the marina.
But, up on a plane, it's the same old racket.....