The Narak uses an integrated seat base and backrest with a fabric hinge between them. Both the base and the backrest have a hard plastic sheet and a sheet of thin closed cell foam as thier core. The seat base is located fore and aft by 4 straps that wrap around the bulkheads just in front of and behind the cockpit, and 2 extra straps run forward to locate the foot plate fore and aft (one of which came unstitched last week, leading me to rethink things)
Their are 3 problems with this set up:
1. The seat is really hard and not contoured so it gets uncomfortable after only a few hours
2. The seat back, like the Fujita one I've also junked, is straight/not contoured so provides no lower back support IMHO,
3. Because the footplate essentially attaches to the bulkheads fore and aft via the seat straps, when you push ("peddle") hard on it, the bulkheads rotate about their verticle centre axis
After trying a range of ideas, what seems to work best instead for the seat base is a thermarest type self inflating bum pad sitting on strips of polyeurethane closed cell foam running between the stringers directly against the hull. In calm seas I let it self inflate considerably for (slightly wobbly) maximum comfort. In confused seas I let it inflate just enough to keep my pelvis off the keel. This puts the seat a bit lower than the original configuration, and the Narak is very maneagable in rough seas like this. As it's self-inflating, I can do this on the move if it's not too rough
For a backrest I fitted a Snap Dragon back band, which slides over its rigid plastic 'belt' (same as on the Cape Falcon F1). This is mounted very low, located vertically by a tape loop and attached directly to the footplate straps to locate it fore and aft, so taking the stresses off the bulkhead. As you push on the footplate, it pulls the back band against your lower back on the same side and I find this also helps my hip/torso rotation, as well as providing more support.
Just did my first ever 20 nautical mile paddle, out and around the island of Procida and back, much of it in seas churned up by powerboats, and was definitely more comfortable and less fatigued than usual
It does mean you have to sit at the back of the cockpit to clear the keel tensioning lever, but that hasn't been an issue.