Here's an item that I find useful in making the seat of my kayak more comfortable.  I also use this in my truck on long trips. It's the Big Game Lumbar support - Cabelas item # ik 463025. 

This has a lightweight frame and is mesh, so is not affected by water.  Weighs next to nothing and makes my time on the water so much more comfortable.  I started using this in my tree stand last deer hunting season, however, I find it is more valuable for me in making my fishing comfortable.

I don't know how to post a picture, so you will need to look at the item number listed above.  This is only $13 and is really a small thing that has made a big difference in comfort for me.

Hope I can help someone else with this post.

 

Here's what it looks like

Would this work on a canoe. I need something for my father he loves to come but has back pain. Any other ideas that people have fee free to post and thanks for this post I'm going to get it asap.

For a canoe, you will need to get a stadium style seat to strap to the canoe seat. Attach this stadium seat to the horizontal canoe seat.  You can then attach the lumbar support to the stadium seat to get added comfort if the stadium seat is not sufficient.

Search for a GCI bleacher back stadium seat.  This or something similar should work for you.

Best of luck, whatever you can do to get your father out on the water will be nice.

That's what I got for the canoe. He loves to row for exercise but this year his back is bad and he's looking for a solution. Thanks a lot!!!