The seat is fine. The paddler needs adjustment, which you will get in the classes you have coming up shortly.
Unfortunately for your current comfort range, the folks you will be working with are likely to disabuse you of any notion about actually using a seat back for support. For a good forward stroke, you are supposed to erect and rotating from the hips up, thru the torso. Rotation is point blank not possible if you are leaning back against the kind of seat you had in the other boat. Core muscles etc.
What you should have in that boat is a back band, set lower to support you at the top of your pelvis.
There are things that you may eventually find you want to do about thigh and leg angle - everyone has slightly different places where you need to tweak the seat and thigh braces - but for a proper stroke you need to replace the reliance on a high seat back with reliance on core muscles.
Touring Kayak Paddles
EZ Launch™ Kayak & Canoe
Kayak Motor Kit
|Table of Contents|