Yes, you will damage your freshwater rod and reel by fishing saltwater and to properly clean them means total disassembly and lubrication and wipe down of your rod. Here's your best options. 1. Use a junky rod and reel that you can do a quick washdown and spray some wd-40 etc on, then throw away when the bearings and gears get corroded. 2. Buy a used penn conventional reel and a fiberglass boat rod. They are cheap, easy to disassemble and clean, plus durable and easy to get parts for. I just cleaned up a 12/0 Penn (like the reel in Jaws) the other day that had never been cleaned since new, repacked the bearings, cleaned the old grease off and it is just like new. Penns are great for boat fishing for mackerel and flounder, durable and no nonsense.When I go flounder and mackerel fishing I just use my regular freshwater spinning rod with braided line, is it going to rust or break from salt water? If that is a bad choice what rod, reel, and line should a I use.