Like many who have responded I have had back problems for many years, and in later life a blown L2/L3 coupled with arthritis. Everyone’s back problems are aggravated by different postures, and take some experimentation to resolve. For me kneeling is worse than sitting.
Things that helped alleviate any paddling back pain, and add some boat control, to a seated position:
1)A seat canted slightly forward seems to take a lot of strain off my lower back, but only when coupled with 2 and 3.
2) A foot brace (or pedals), for oppositional force, paddle pulling forward, feet pushing back. But only when coupled with #3.
3) A back band. For me, #’s 1 and 2 without a back band are still near instant agony. The Surf to Summit Performance Pro is far and away my favorite back band.
https://www.surftosummit.com/perfor...ath=283_271&osCsid=2ankmsma9eaqean3a7es7quaq0
Easy to install. Easy to adjust to a comfort sweet spot. Easy to transfer from boat to boat. Low enough and flexible enough to not interfere with torso rotation. YMMV, but high or rigid “seat backs” were worse than nothing at all.
Minor #’s 4 and 5, visible in those photos:
4) Some padding on the seat. Mostly for arse comfort, but it also helps soften the front edge of the seat under my thighs. That is an old Grade VI pad on the bucket seat, but I usually just glue some RidgeRest foam on bucket seat pans, so it is always there and I can’t forget to bring it.
On bench seats, even contoured benches, I really like a ThermaRest “Trail seat”, aka stadium seat pad. This thing in a 20 year old iteration (they have proven very durable as canoe seat pads):
https://www.thermarest.com/catalog/product/view/id/16715/s/trail-seat/category/17/
Held secure under a couple lateral strips of webbing I can tuck the front edge under the seat frame and the pad doesn’t shift or move* (or blow away in the wind). I start with that pad mostly deflated, so my derriere has good contact with the seat. In that mostly deflated guise it cups my butt cheeks like a bucket seat and I can still reach back, open the nozzle and let a little air out once or twice to change the pressure points during a long day on the seat. I’ll let a little air back in when it’s time for a leg stretcher and start the deflation cycle again.
*Note from wet experiences: Any seat pad or seat back that can suddenly slide out of position, especially sideways, can be an invitation to swim.
5) “Knee bumpers” on the gunwale edge. I can use my knees to help lock my body in place when needed without leaving painful gunwale indentations in my LCL.
OK, 6 and 7. I use padding on the foot brace and under my heels. I’m a comfort wuss, and not just for my back. Padding those areas helps when I am paddling barefoot or in thin soled shoes.
That arrangement is the Barcalounger of canoe seating. If I am going to spend long portions of the day in the canoe it might as well be the most comfortable seat in the house.
I doubt the seat pad, glued in minicel knee bumpers and foot brace/heel pads weight more than a few ounces; a very small price to pay for day long comfort and better boat control while seated.