Just bought a 1988 LS 24' . was told silent thunder was leaking badly. pulled the platform off and found the wood was
pretty much completely gone, looks like previous owner tried to repair it once before but did a real botch job. I'm a good mechanic and a handy all around guy do I thought this would be a fairly simple repair. Wrong. After cleanig out all the old rotted wood and examing things closely I'm a liitle confused as to how to get it back together. Do I need to split the platform in 2 pieces? looks like the original wood sat in a channel acroos the top that went staight acroos the top on side to the other , but the platform curves at the corners so how do you seal the open space. use Marine plywood and fiberglass over? never having seen an intact one leaves me at
a big disadvantage, I want to do this right so it lasts, I cant run without it due to noise restrictions on the lake. also should there have been flappers (external and internal) at the transom. this had neither. any help , pictures would be greatly appreciated.
Thanks
Dennis

I have done this on my 242, I think we used two pieces of marine ply, glassed and epoxy and it was solid as a rock. It is pretty straight forward I think I used to much glass and had to sand it down a bit. I didn`t take as many pics as I wanted to. The last one is the stainless tubing for exhaust we added

good luck

if you do a search on oso i think you will find some pics that should help you

do a search under my logon. i rebuilt mine on my 272 ( twin engines)
but same thing, front plywood rotted out
had it professionally fixed and have some picsin the post
you can order the factory gaskets. ribbed seal for the outside perimeter, hollow o rings seals for around the thru hulls.


Ramb

Use 5/16 vacuum hose put a slit in it and glue it on with clear silicone glue. The original gaskets slip and the exaust hits the thunder box and viberates so bad you get about 8 decibels extra. Trust me been working on my 336 exactly what you are doing.

Your 336 is totally different than the older style full-bolt on platforms.

right, the 336 has the silent thunder box underneath the swim platform, which is integrated into the boat, unlike the older Formulas with bolt-on platforms.