I don't know if you *can* put an extension in, but I know you don't want to put one in. Touring kayaks are designed with low seat backs for a specific set of reasons. 1. While going into a "power" position to paddle, you lean more forward/upright. 2. While doing a self-rescue, the seatback is either mashed down/forward as you slide back into the cockpit or scuffs along your legs/PFD... a higher back would make it more difficult to attempt a re-entry.
You can find several recreation kayaks that have much higher backs, or contact a touring kayak manufacturer to see if they might do a special fitting for you.
Date published: 2018-01-24