I have a 2 step solution.
Step 1: Toss Seatasaurus Rex to the tip, or donate to local croquet club. (Cause that is what it looks like it came from)
Step 2: Insert Surf to Summit Expedition Seat.http://www.surftosummit.com/gts-expedit ... 99_294_325
Besides the "Gatsby" look of the original seat, it weighs a ton, and is a dangerous item. Possibly the most dangerously, over engineered, under thought (besides our friend Rodney Rudder) item on the thing. Why? because as you lean to counter the roll, ones butt simple falls away and increases the moment of rolling.
Take a look at the GTS seat Hobie geeks. THIS is design.