Don’t do it! I did and now they are so slippery that it’s difficult to sit without sliding around! CARPIO
Waterproofing your boat seats
Here is a product made just for boat seats, It will nenew the color/vinyl coating of boat seats. It's not cheap but if you own a boat your probably use to spending more for things than they are worth. The Rustoleum is about 1/3 the price of the SEM but I have not tried the Rustoleum. The SEM product seems to work OK.
I forgot the name, I’ll post it later but it was a well known boating product. CARPIO
What did you put on them, just curious.