At nearly 30 years old, there could any number of styles wiper arms on there. Replacements depend on the arm/connection you have. We would need that info or a pic.
I had success with NAPA finding the old style "school bus" stainless wipers and blades. I also switched to Ancor auto arms and blades for a while. The arms can be popped off and replaced. Two years ago I removed the wipers completely from the boat.
The best tip I can offer is to get blades that fit the windshield. Don't put excessively long ones on that protrude beyond the curve of the windshield so folk don't get caught on them - either injury or breakage can occur.