how to remove old nonskid flooring from an Eastport Pram

Hi all, I inherited an older Eastport Pram and it needs some TLC.  I am scuff sanding it and making minor repairs here and there, but I can't figure out how to pull out the old non-skid flooring.  I tried Goof-off and lacquer thinner but these don't seem to work.  I don't know if they had a "peel off" type of adhesive back then or if the previous owner might have epoxied it down?   Has anyone tried a heat gun?  Many thanks!  Gavin