Pleae do not laugh:
I purchased a set of "suction cup" under gunwale rod racks for Trayder. I bought them cheap, from offshore angler, or bass pro shops. I never thought the would work. I made a 120 mile day offshore with them and although I cracked my T-top ( to give you an idea of the seas and pounding on that trip) those suction cup rod holders held 4 medieum duty spin setups, 2 on each side.
Here is a pic:
Best part is you do not have to drill any holes and the belt holds the rod in the rack very tightly