When you say "pinched in" to reach the seat, what kind of kayak or make? Is this a recreational type of boat? Composite plastic or a fiberglass boat? Generally, the answere is that seats normally do not provide structural support for the kayak but who knows. But if you boat pops out wider upon taking the seat out, you can always put a bulkhead in or support bar behind the seat. There's so many variations on "kayaks" these days, its hard to be exact with some of hte questions that come in on tyhis site. The bottom line is, it you're uncomfortable, you have to change something.