After the first time out in less than ideal conditions I’ve been out a few times more and having added a couple of strips of wood along the bottom for better longitudinal support it’s behaving quite well. If I was making a version which didn’t need to dismantle at all I’d just use two lengths of pipe joined at each end with an adjustable seat in the middle straddling the two pipes. This would be simpler, lighter, stronger and easy to wrap in a skin. It would just need a seat brace and a brace to rest your feet on which would be very easy to do with a couple of planks with spacer blocks.
Definitely not ruling out another build in future, but this time round due to good swimming conditions being almost identical to good conditions for the kayak I didn’t use it as much as I’d hoped. A better trolley system for moving it would also help with that as moving this version was a pain at times. Was quite fun when out though, but never did add that motor.