Pain in the arse on the long hauls

Have recently been putting in longer paddles (20+ miles)and have found my previously comfortable bucket to be causing a good deal of low back and sit bone discomfort. To the point where it becomes too uncomfortable to continue without a break.

Has anyone encountered this and if so, any advice?

Have a look through my album here,

www.facebook.com/media/set/?set=a.574551...&type=1&l=1be4e01fa1

a little bit of application and you can paddle your ski in comfort all day if you want to. I've done 5-6 hours no problems at all.

Nice! Any issue with tearing?