This is the rod holder I use on my DIY Fishing Trolley project.
It’s made for boats and comes with stainless steel screws. Holds three rods comfortably. Has notches to accommodate your reels when a rod is inserted. Is a solid but lightweight construction and comes with handy holders for knives and pliers.
It’s cheaper than going to a hardware store and making your own equivalent using PVC pipe, too. By the time you buy the pipe, screws and fashion the knife etc holders.
It just gets the job done. I love mine.