There's a product called Keelguard. Not familiar with it myself, but preparation is everything to get a decent bond when applying.
Removing the old one (depends what's been used already) as it could be 3M contact adhesive. Read a few forums suggesting everything from soaking glue residue in WD40 and using heat-gun while scraping with plastic ice scraper. Also came across a product recommended by someone in vehicle livery business who need to remove stubborn adhesives called Big Orange available here:
Zep United Kingdom - Catalogue:BIG ORANGE AEROSOL
Good luck, sounds like a sod of a job.