I've done a ton of research on this and tried numerous chemicals personally... Some things seem like they 'help' but nothing I have found is truly effective at removing silicone residue that will be nearly 'forever' trapped.
When I installed a new shower glass shower door in my house I tried an off the shelf H-D silicone remover (It claimed to break the bond between the silicone and the substrate). I 'think' it kinda worked as claimed, but it just smelled like a standard citrus stripper gel and basically I used a flat razor blade in the standard glass crapping knife to manually remove the residue. Coming off of glossy flat tile it was relatively easy. Still, the gel 'silicone remover' didn't do much.
Primarily removing silicone caulking is a mechanical process. Use a stiff plastic scraper to get the majority of it, metal is fine if you are not worried about scratching non sensitive areas. Then progress to a razor blade to get the rest, which only works really well on flat, glossy surfaces. You need to get as much as you can off but getting all the residue off depends on the application. If you have to do a fiberglass or gelcoat repair you MUST grind away the gelcoat or glass to ensure there is no trace of silicone residue. If you are re-bedding hardware, manually scrape an razor the old stuff out and bet meticulous about it. If the area isn't sensitive and will be covered you can sand it, but you'll notice the sand paper get mucked up by the silicone residue. Generally speaking, wherever there is silicone residue and I have to re-bed I do so with butyl tape. It will still give an excellent seal and the silicone residue does not seem to hinder it. If you have to re-bed with a polysulfide or polyurethane, that's when you need to grind/sand the surface to ensure you get all silicone reside. There is NO commerically available chemical I know of that you can 'wipe' on the surface of fiberglass/gelcoat that will dissolve silicone residue trapped in gelcoat or laminate pores. DOW apparently does make a product that is supposed to do this but it is only for sale to industrial customers and I'll be it is really nasty stuff. You can find the SDS on DOW's website.
If you are resealing windows/port-lights that had silicone.... typically, new silicone will seal to cured but clean silicone just fine. The only silicone that should be used for this is DOW 795 and it is NOT expensive, about $8 a tube I think. As long as you manually scrape away the old sealant and razor blade the majority of the film off, new DOW 795 will still stick like crazy, residue in the pores is no concern.
I am a Practical Sailor subscriber... the article linked above recommends a product called RE-MOV for silicone. Actually, the write is pretty convincing and I want to try it, it may make me re-think my statement that there is 'NO commercially available chemical' that is effective at removing silicone residue. They recommend two applications, 20 minute dwell time, 15 minute interval, then scrape off and use a stiff bristle brush to get after the residue. This might be your ticket!
My general rule of thumb; NO SILICONE ON A BOAT (for the average DIY sailor); for the above average DIY sailor or professional; there are only a few places on a boat for silicone: DOW 795 for windows/port-lights, appropriate silicone gaskets and sealants for engine/machinery components, and appropriate plumbing fixtures & that's it, otherwise keep silicone off the boat and out of the hands of the un-informed or illiterate!