I’m not familiar with your boat, but if it’s padded vinyl it would likely have been glued on and the foam and glue is degraded. Is that what you are facing?
If so, I’d remove the vinyl sheet and foam, then remove the remaining foam clumps and glue (a terrible job) then you will be left with a raw fiberglass surface. Due to surface imperfections I’d paint with a thick rubberized outdoor paint made for cinder blocks and brick, and use a roller that’s also made for the job to get a stippled surface. Google for images using the term “stipple texture roller”.
I did this about 15 years ago on a former boat and it came out well. I went to a Benjamin Moore store with a sample of the removed vinyl and was able to match the paint color exactly.
Removing old adhesive:
Use a full-face chemical vapor mask and protective clothing and chemical resistant gloves when working with solvents and spray. Most solvent based adhesive removers just push the old adhesive around in clumps and aren’t effective. What worked best for me is 3M Woodgrain and Stripe Adhesive Remover
https://www.3m.com/3M/en_US/company...Adhesive-Remover/?N=5002385+3293194059&rt=rud
That converts the adhesive to another compound that it loses its “grab“ and looks and feels similar to soap but it’s more easily removed with plastic scraper and rages. The converted residue is more easily dissolved with solvent and can be wiped off from the surface with a solvent soaked rag. 3M recommends it’s “general purpose adhesive remover” for the final step, but that stuff is brutal and dangerous to work with in an enclosed area (strong VOC) so I used WD40 as the solvent for the next step and then removed the WD40 with the 3M product. That allowed me to work with the (more dangerous) 3m general purpose adhesive remover for less time.
Good luck.
Edit: If you decide to do this, practice with the roller on some scrap sheet material before you start the boat. They sell stipple brushes and smaller size rollers also, for more contoured areas and edges. Practice will enable you to get the desired results more consistently.