I had the same problem with my bench seat material coming apart and replaced it with bucket seats from Bassboatseats.com about 8 years ago, they are a fantastic company to work with. The seats still look like new and are very comfortable indeed. I originally had the center folding seat that became a step however I found that it wasn't all that sturdy. After almost going in the drink a few times, I removed it and just put a thick piece of wood on a piano hinge over the center hole. I like the center step and storage in the pic above though, I may have to look in to this, thanks!
Here's the pics from the original thread :
Before:
6156885657_dac33dd74e.jpg
After:
6157429460_201536a585.jpg
I liked the seats so much that I later ordered a couple of matching fishing seats for the front and rear decks.