I'm a retired professional kayak fisherman and I own this piece of gear that I bought a few years ago. It is called "Leg luggage"
http://www.legluggage.com/ it is a neoprene wrap for your leg and you keep important gear handy attatched to this sleeve wrap using velcro pockets. I took it one step further and took three of my gear bags-one with a hammock, one with a bug screen, and one with my tarp. I put the three bags together and wrapped them into my neoprene leg wrap which has velcro closures that attatches to itself. Then I use velcro strips to wrap around my handle bars and attached it to neoprene wrap, holds like a charm. See Photos. Also you could probably use one of those stretchy neoprene back supporter
http://bit.ly/2pxJlJn as well. Then attach it to your handle bars with some 1" Sleeping bag straps
http://amzn.to/2qcCvFy
