Touring on a fixed

decathlon has these good waterproof stuff sacks that (from the video) you start rolling down the top, then let air out, then roll them a bit more e.t.c then strap and seal them. The video show if being down with a sleeping bag but it looks like it would work well for other stuff.

Dry bags and stuff sacks from here - http://www.ewetsuits.com/acatalog/Dry-Boxes-dry-bags-uk.html
Truly fantastic value for money. I've been using them in my kayak for a fair few years and no problems at all.