SR1 Silent Thunder thoughts
 

I am planning on cutting out the holes where the exhaust comes through the boat and leaving the platform intact but this will hopefully allow me to have through Hull Exhaust tips after I cut up the platform and fill in the part that is removed. Sounds complicated but if you look at the bottom you can remove the parts where the exhaust run through.

Like This ?

Thats what I was trying to say! Keep the platform but have through hull exhaust. I will fill in the ends where the exhaust exits now and fill in the the part that will be removed.

cut the holes but put in deck hole plates that screw in, gives you the abilith to use the silent thunder if you have to.

Problem is ..... the pipes exit the transom higher than the top of the platform ... Then path angles down below the platform ...

Thats why I am going to cut out the entire area fit it with through hull exhaust pipes and then fill in the cut edges, who will ever need silent thunder again? Have you ever been on a dock when someone else is driving your boat past you, it is so quiet you wont belive it and my boat has 502's with Gil exhaust.

There is and easier way to do this. Do you not want to take the plateform off?

OK i think i figured this out. If you do not want to take off the platform and want to do this with it on then just cut along the bottom of the platform parallel to the ground. If you look at the box right under the tips there is a indentation that follows the bottom all the way to the transom. If you cut the bottom off you can run your tubes to the tips and glass the bottom back on. Does this make sense with out pics? I wish i was more computer literate to photoshop what i am talking about. Here is my attempt at it from OFFTHEFRONT'S pic. Cut alond the red line parallel to the ground.

I'm confused on what your trying to do? Are the exhaust going to exit on Top of the Platform ?

I'm thinking Moe wants something similar to the post-SR1 platforms that have a removable box. When you take off the box, you've got the through-hull exhaust tips right there, under the platform. Then they can be left open, or mufflers added.
But like Mike says, the SR1 platform height is different, such that the exhaust is about the same height/level as the platform deck....I "think"...
I think the post-SR1 hulls have a taller transom with the swim platform molded in, so there's room underneath for the ST "box" and exhaust tips.
I'm telling you Moe, when you cut those baffles out and maybe add a hole or two (you really don't need much more than 1-2" diameter; one near the transom should already be there, one near each exhaust tip) to each section for the water to drain, there's very little "silent" left in the Silent Thunder...:D

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

If you are running a stock exhaust, it will never be really loud. I cut 4, 4" holes in my ST box, one in each chamber and it is not quiet at all... The difference is I'm running Gil dry to the tip pipes that extend thru the transom. If you want it loud, in my opinion your going to need to swap out your exhaust.