We just finished up graphics on 25 yeti coolers a couple months ago. The tops didn't have that really bumpy surface like some coolers, but they were by no means completely smooth. We used a really high tack adhesion vinyl from kapco and used a heat gun to set the adhesion quickly. Here is the
link. We tested the durability of the graphics over a couple weeks time, leaving a cooler outside, on a boat, sitting and sliding back and forth on it, spilling stuff and cleaning it up with different cleaners, etc. and the graphics held up really well, very well actually and to the point that I was confident enough they would make it through the year, without a problem. I also told them that I would replace the graphics for up to one year from the sell date, if any were to fail.
We got the job because nobody else wanted to touch it and the ones that did (last year) used the wrong vinyl and had problems. It was obvious because they said within two weeks of having the coolers, graphics fell off. I told the customer that the there is a vinyl specifically made for that surface but it was kind of pricey and not something we normally keep in stock. The graphics were small, approximately half a square foot each and were a nightmare to weed out, but with install costs, they paid roughly $25 a piece. It took us about 4 hours for the install including travel time. We got lucky because the sample roll that was sent to us for testing purposes worked out great and had enough room to print all of the decals. Still ended up ordering a roll.
Call Chuck at Kapco and tell him you want the high tack satin vinyl made for low energy surfaces. He will hook you up. It is has a white or gray adhesion. We used the white.
BTW, IMO, if the surface is really bumpy, I would do as visual800 said, and walk away. Nothing will permanently stick that surface and hold up over time. Well, never say never, but you got to look at whether the job is really worth it or not. In my instance, it was. Good luck.