I agree with Michael. Mine has 3 " holes in the 3 sections you marked-2 in the center. The box no longer holds water so it is only slightly muffled and sounds like a thru hull boat with only a slight reduction at rest. Just to let you know it measures 105 dB at idle with stock 502 mpis and Stainless Exhaust.

So your going to cut the platform ...then run pipe back to the original rectangle outlet ? Then Glass it back on ...
why not just pull the box ...do the pipe work then reattach the box ...cept the problem with that is attaching the pipe work to the thru Hulls and then trying to reattach the box ...

your idea might be a better one ... We have gutted my box so when it goes back on it will be open (sorta) to the original Tips ... But I am afraid that it will make the Box Resonate back into the boat ...m

Ted is there any Vibration or resonance from the box in the boat ?

No resonance at all and fairly manageable soundwise except when the rear is facing something like a seawall. I do get "ladder rattle" but I have learned to live with that since it happens with the system stock too.

OFFTHEFRONT- That is what i am trying to convey to moeron. I took my box off and gutted it and put "thru thunder" pipes just like rambuntious did. It is a WHOLE lot easier to just pull the box off and run the pipes. I was giving him another solution if he did not want to take the box off.http://www.offshoreonly.com/forums/s...st+box+upgrade

When i just cut the baffles out and left it that way it resonated so bad i could not stand it. That is why i put pipes thru mine and it got rid of almost all of it.

I have already drilled the holes and cut out the baffel it is as quiet as before (when standing on a dock and someone else running your boat, I slip at Big Thunder Marina I hear loud all day and ours is quiet). I am going to remove enough of the platform for through hull to come through like a regular boat and see whats left. I might be ordering a aluminum platform but thought I would try this first.

Try to imagine the box with the black areas cut out like this.

This is what I came up with S.S. piping with new tips then drilled small holes under the platform to drain water, so for the most part it comes out as a dry exhaust and sounds nice.

formula actually made an sr1 swim platform that did not have the silend thunder chambers. the bottom half had sides and center sections to give it strength but if looked at from the rear you looked at through hull pipes.

someone said once that they found the molds out back somewhere at formula????...........

sure wish someone could find them again. prolly would have 20 clients at least.

my solution and carbiz's was to make extensions to run from the transom flanges to the platform's square tips. mine had rubber exhaust hose that allowed me to tighten up hose clamps on the transom flanges, and then finish sliding the platform on the last 6" and bolting it tight. carbiz did it with semi truck stianless flex exhaust pipe.

ramb

http://www.offshoreonly.com/forums/f...t-upgrade.html