I made new covers for all my bunks out of the blue marine grade vinyl. Same stuff I use for all the other doodads about the place. I used the same stuff on my fishing vessels bunks and they look new still after 20 years of abuse. Used to sleep fully dressed in trawler garb and rubber boots of course. On my yacht it's fine as long as your not having bare skin on it on a hot day. The blue vinyl is thicker and easier to sew than the other colours for some reason.