I am trying to find some PVC trap runners. The smooth black one's that were about 2 x 2 1/2 and I think 12 ft long. Roger Smith used to carry them and I think Brooks did as well. They don't seem too popular anymore.
Try looking on ebay for UHMW lots of scrap cut off pieces on there. I think that stuff is kinda slick when the pot sits on the rail and when they are stacked on the boat. Get some of that composite lumber they use for home decks and rip your own on a tablesaw. I made a mold out of PVC pipe and cast my own concrete runners on my shrimp gear.