waterproof solar panel for kayaking

I'm planning a 1200 mile, 3 month circumnavigation of Lake Superior and need a waterproof solar panel for the back deck of my sea kayak.

The idea is to run the cable into the back hatch to a battery contained in a waterproof box so I can charge all day while I paddle.  Getting into camp at 3pm each day may not give me enough time to charge my VHF radio directly from the panel.

Any ideas?

Cheers,

B